WO2020153985A1

WO2020153985A1 - Infrastructure, methods, and systems for high accuracy global positioning and self-driving vehicles

Info

Publication number: WO2020153985A1
Application number: PCT/US2019/036198
Authority: WO
Inventors: Ming Li; Changqing Chen; Xiongbin Wu
Original assignee: Navioptronix, Llc
Priority date: 2019-01-27
Filing date: 2019-06-08
Publication date: 2020-07-30

Abstract

A global positioning system, method, and system for self-driving vehicle (SDV) navigation. The global positioning system includies: at least one SDV route; a number of radio-frequency (RF) emitters; and a dynamic digital map. The navigation method includes: determining an initial absolute global position of the SDV; storing a local portion of the dynamic digital map; receiving ID signals from a number of the RF emitters; determining an emitter angle between the forward direction of the SDV and each received emitter signal; determining the local map position and forward map direction of the SDV based on the emitter angles; determining an error distance between the local map position of the SDV and the current route, and an error angle from the forward map direction of the SDV to the tangent line of the current route; and determining navigation instructions for the SDV based on the error distance and the error angle.

Description

INFRASTRUCTURE, METHODS, AND SYSTEMS FOR HIGH ACCURACY GLOBAL POSITIONING AND SELFDRIVING VEHICLES

[0001] This application claims the benefit under Title 35 U.S.C. §1 19(e) and PCT Article 8(1 ) of U.S. Provisional Application No. 62/797,360 filed on Jan. 27, 2019, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

[0002] The present invention is directed generally to self-driving vehicle (SDV) navigation systems and methods, and, more particularly, to improved global positioning infrastructure, systems, and methods for use in SDVs.

BACKGROUND OF THE INVENTION

[0003] Self-driving vehicles (SDVs) are poised to become an important component of future transportation technology. Passengers of SDVs can relax more and escape their busy life while riding a car. It is also believed that SDVs may become safer than cars driven by humans.

[0004] Largely due to recent advances in this field, it is estimated that at least 10 million cars with self-driving features are likely to be on the road by 2020. (http://www.businessinsider.com/report-10-million-self-drivinq-cars-will- be-on-the-road-bv-2020-2015-5-61

[0005] Desirably, a passenger would be able enter the destination to the navigation system of an SDV. Then the SDV would take the passenger to his/her desired destination without any further bother on the part of the passenger. This stress-free trip would require the navigation system to have a sub-meter accuracy to guarantee that the vehicle could navigate safely through narrow streets and driveways in a typical city. Limits of the roads, such as curbs and road dividers, must be accurately detected. And very frequently, construction zones and detours may need to be recognized as well.

[0006] One current existing solution to this desire is a satellite-based GPS absolute positioning system, such as the system illustrated in FIG 23. In this prior art system, GPS receiver 2302 is designed to receive signals, which contain time stamps, from multiple GPS satellites 2300. If GPS receiver 2302 is able to receive good signals from 4 of satellites 2300, its 3D location can be obtained by triangulation, as Illustrates in FIG 23.

[0007] The United States government currently claims 4 meter RMS (7.8 meter 95% Confidence Interval) horizontal accuracy for civilian GPS. Vertical accuracy is often even worse. Obviously, this accuracy is not enough for navigation in a city such as the city 2400 with overpasses illustrated in FIG 24.

[0008] Another prior art solution that has been suggested to overcome this deficiency in GPS is to use on-board cameras and sensors to recognize the limits of roads, and/or obstacles. These cameras and sensors may be used alone or in concert with GPS. Currently, companies designing SDVs, such as Google^® and Tesla^®, equip cars with cameras, lasers, and optical sensors to recognize road signs, traffic signals, lane markings and moving objects. FIG 25A illustrates a number of example street signs that may be recognized by these cameras, lasers, and/or optical sensors, including: signs 2502 and 2508 which may be recognized and their meaning interpreted by their shape alone; and signs 2500, 2504, and 2506 that have painted symbols to encode the meaning of the sign in addition to their shapes. FIG 25B illustrates a multi-lane roadway with lane markings 2510, 2512, 2514, and 2516 that may be recognized by the cameras, lasers, and/or optical sensors.

[0009] These optical sensors and cameras may be fairly effective at recognizing street signs and lane markings, such as those illustrated in FIGs 25A and 25B on a sunny day. However, when street signs 2600 or lane markings 2602 are covered by snow, as illustrated in FIGs 26A and 26B, respectively, these cameras, lasers, and/or optical sensors may often become disabled. Additionally, street signs and lane markings may become damaged and/or worn, potentially rendering on-board cameras, lasers, and/or optical sensors less useful for the precise navigation necessary for SDVs.

[0010] Another known issue with optical sensors and cameras is illustrated in FIG 27. As shown in image 2700, high contrast objects, such as head lights or street lamps, may lead to the sensors becoming saturated when are exposed to these strong lights. Such saturation may not only cause a loss of detail as the sensor attempts to deal with the saturation, but may cause glare artifacts 2702 and 2704 in the sensor image 2700. These artifacts will adversely affect the sensors ability to provide sub-meter location information to an SDV navigation system

[0011] Therefore, it is desirable to provide an improved approach to SDV navigation. Example embodiments of the present invention includes such an improved approach. These example embodiments include an infrastructure to support the SDVs of the future as well as methods and systems that may significantly increase the accuracy and reliability of SDV navigation, as well as improving the speed, comfort, and safety of SDV travel. These and other advantages of the present invention may be understood by those skilled in the art from the following detailed description.

SUMMARY OF THE INVENTION

[0012] An exemplary embodiment of the present invention is a global positioning system for self-driving vehicle (SDV) navigation including: at least one SDV route; a number of radio-frequency (RF) emitters; and a dynamic digital map. Each RF emitter is located near at least one of the SDV routes and emits a predetermined periodic identification (ID) signal that has an ID signal intensity. The dynamic digital map includes: position data for each RF emitter and ID information indicative of the predetermined periodic ID signal associated with each RF emitter (emitter data); and position data for the SDV (s) route (route data). The route data has a predetermined route accuracy and the position data of the emitter data has a predetermined emitter accuracy.

[0013] Another exemplary embodiment of the present invention is navigation method for an SDV. An initial absolute global position of the SDV is determined using at least one of a GPS absolute positioning system or a cellular tower triangulation system. The absolute global position of the SDV having a predetermined global accuracy. At least a local portion of a dynamic digital map is stored. The dynamic digital map includes: position data for a multiple RF emitters flagged with ID information indicative of an ID signal associated with each RF emitter (emitter data); and position data for at least one SDV route (route data). The local portion of the dynamic digital map includes the initial absolute global position, at least a local portion of the route data, and at least a local portion of the emitter data. The route data has a predetermined route accuracy and the position data of the emitter data has a predetermined emitter accuracy. ID signals are received from an emitter number (at least three) of RF emitters for which the emitter data has been stored. The emitter angle between the forward direction of the SDV and the RF emitter associated with the received ID signal is determined for each received ID signal using that received emitter signal. The local map position and the forward map direction of the SDV in the local portion of the dynamic digital map is determined using these determined emitter angles and the stored emitter data. The local map position of the SDV being determined with a predetermined local accuracy. The local map position of the SDV is compared to the stored route data to determine the current position of the SDV along the closest one of the SDV route (the current route) and the error distance between the local map position of the SDV and the current route. The forward map direction of the SDV is compared to the tangent line of the current route at the current position to determine the error angle from the forward map direction of the SDV to the tangent line of the current route. Determine navigation instructions for the SDV based on the error distance and the error angle.

[0014] A further exemplary embodiment of the present invention is a navigation system for an SDV including: a local map memory coupled to the SDV; an antenna array coupled to the SDV; an ID module coupled to the local map memory and the antenna array; an emitter angle module coupled to the local map memory and the ID module; a map position module coupled to the local map memory and the emitter angle module; and a navigation module coupled to the local map memory, the map position module, and the SDV. The local map memory is adapted to store a local portion of a dynamic digital map. The dynamic digital map includes emitter data and route data. The local portion of the dynamic digital map includes at least a local portion of the route data and at least a local portion of the emitter data. The route data has a predetermined route accuracy and the position data of the emitter data has a predetermined emitter accuracy. The antenna array is adapted to: receive the ID signals from a current subset of the RF emitters; separate these ID signals; and generate a raw data stream for each separated ID signal. The ID module is adapted to: receive the raw data stream from the antenna array; access the ID information stored in the local map memory; identify the ID information of the RF emitter associated with each received ID signal using the raw data stream of that ID signal and the ID information; and link the identified ID information to that raw data stream. The emitter angle module is adapted to: receive the raw data stream and the linked ID information for each identified ID signal; access the store ID information; determine the emitter angle of the RF emitter associated with each identified ID signal relative to the forward direction of the SDV using the raw data stream and the linked ID information; and generate an emitter angle signal for each RF emitter including the determined emitter angle and the emitter data of the RF emitter associated with that ID signal. The map position module is adapted to: receive every emitter angle signal for the current subset of RF emitters; access the stored emitter data; determine the map position of the SVD and the forward map angle of the forward direction of the SDV using the received emitter angles and their associated emitter data; and generate a map position signal for the SVD including the determined map position and the determined forward map angle of the SVD. The navigation module is adapted to: receive map position signal; access the stored route data stored; determine navigation instructions for the SVD based on the received map position and forward map angle of the SVD, and the stored route data; and transmit the navigation instructions to control navigation of the SVD.

[0015] It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] According to common practice, the various features of the drawings are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawing are the following figures:

[0017] FIG 1 is an overhead drawing illustrating an example self-driving vehicle (SDV) and several example radio frequency (RF) emitters arranged along an example SDV route according to one or more embodiments of the present invention. [0018] FIG 2 is a schematic drawing illustrating a portion of an example dynamic digital map including RF emitter data and SDV route data according to one or more embodiments of the present invention.

[0019] FIG 3 is an overhead drawing illustrating example RF emitter data and SDV route data that may be stored in the example dynamic digital map of Figure 2.

[0020] FIGs 4A and 4B are perspective drawings illustrating example RF emitter data and SDV route data for an example overpass that may be stored in the example dynamic digital map of Figure 2.

[0021] FIG 5 is an overhead drawing of the example SDV, SDV route, and RF emitters of FIG 1 illustrating example regions around each RF emitter with a signal intensity greater than a predetermined detection intensity according to one or more embodiments of the present invention.

[0022] FIGs 6A and 6B are a series of graphical drawings illustrating an example autocorrelation method for determining time delay of an example digital RF emitter ID signal received at two separated antennae according to one or more embodiments of the present invention.

[0023] FIG 7 is a series of graphical drawings illustrating an example three wavelength interference method for determining time delay of an example analog RF emitter ID signal received at two separated antennae according to one or more embodiments of the present invention.

[0024] FIG 8 is a top plan drawing illustrating example geometry to determine an emitter angle between an example SDV and an example RF emitter according to one or more embodiments of the present invention.

[0025] FIGs 9A, 9B, and 9C are top plan drawings illustrating three example antennae placements on an example SDV that may be used in example embodiments of the present invention.

[0026] FIG 9D is a top plan drawing illustrating a further example antennae placement on an example SDV that may be used in example embodiments of the present invention.

[0027] FIG 10 is a schematic drawing illustrating an example wireless communications network coupling an example SDV to an example dynamic digital map according to one or more embodiments of the present invention.

[0028] FIG 11 is a schematic block diagram illustrating functional details an example dynamic digital map according to one or more embodiments of the present invention.

[0029] FIGs 12, 13, 14, 15, 16, 17, and 18 are flowcharts illustrating several example navigation methods for SDVs according to various embodiments of the present invention.

[0030] FIGs 19, 20, 21 , and 22 are schematic block illustrating several example navigation systems for SDVs according to various embodiments of the present invention.

[0031] FIG 23 is a perspective drawing illustrating a prior art GPS global positioning system.

[0032] FIG 24 is a perspective drawing illustrating a city with overpasses.

[0033] FIG 25A is a series of side view drawings illustrating prior art street signs.

[0034] FIG 25B is a photograph illustrating prior art lane markings of a street.

[0035] FIG 26A is a photograph illustrating prior art street signs obscured by snow.

[0036] FIG 26B is a photograph illustrating prior art lane markings obscured by snow.

[0037] FIG 27 is a prior art night image illustrating glare due to camera saturation.

[0038] It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the invention. DESCRIPTION OF THE INVENTION

[0039] The present disclosure includes a number of example embodiments related to the field of self-driving vehicles (SDVs) and the navigation of these SDVs along various SDV routes. As described herein, SDV routes may include any of the numerous types of roadways, parking lots, transportation structures, etc. on which an SDV may travel, e.g. an indoor route, such as a parking structure; an underground route, such as a tunnel; a covered route; a route passing between a plurality of high rise buildings, such as a city street; a multi-lane route; a one-way street; a two-way street; a divided highway; a freeway; a multilayer route, such as a multilayer highway, an underpass, an overpass, a cloverleaf intersection, a roundabout; and/or a parking lot. Please note, this list is merely intended to be exemplary, and is not intended to be exhaustive.

[0040] Example embodiments of the present invention include example global positioning system infrastructures for self-driving vehicle (SDV) navigation, as well as example SDV navigation methods and systems that may utilize these global positioning system infrastructures. The methods and systems of these embodiments use multiple radio frequency (RF) emitters located near SDV routes to precisely locate the SDV relative to the SDV routes. This approach allows embodiments of the present invention to take advantage of high-precision surveying techniques to measure the position of the RF emitters relative to the SDV route and the relatively short wavelength (compared to the desired positional accuracy for locating the SDV relative to the SDV route) of the RF signals used. Although this approach may result in some minor reduction of absolute positional accuracy, but any resulting error in absolute position may be corrected as the SDV travels along its route. By focusing on the relative positioning of the SDV to the route being followed by the SDV, the various embodiments of the present invention allow for simplified navigation of the SDV, while maintaining high precision for the most important positional information, i.e. the position of the SDV relative to the route it is following.

[0041] Example SDV Navigation Infrastructure Embodiments

[0042] One example embodiment of the present invention is illustrated in FIG 1. This example infrastructure system is a global positioning system for SDV navigation that includes: at least one SDV route 100; a number of RF emitters 104a-c located near the SDV route(s); and dynamic digital map 1 12. As illustrated in FIG 1 , dynamic digital map 1 12 is desirably coupled to SDV 102 through wireless communication link 1 14 and communications network 1 10, which may include, but is not limited to cellular communications networks, satellite communications networks, and/or the internet. Each RF emitter emits a predetermined periodic identification (ID) signal with a known ID signal intensity.

The dynamic digital map 112 includes both route data, such as position data of the SDV route(s), and emitter data, such as position data for the RF emitter and ID information indicative of the ID signal associated with that RF emitter. The position data stored by the dynamic digital map for both the SDV route(s) and the RF emitters have predetermined accuracies.

[0043] As noted above, the SDV route(s) may include many one or more types of routes. For example, route 100 in FIG 1 is a single lane route. FIG 2 is a schematic drawing illustrating a portion of an example area 200 that may be represented by the position data of the dynamic digital map 1 10. This example area 200, includes a number of features for which data may desirably be stored in the dynamic digital map, including RF emitters 104, one-way streets 100, two-way streets 204, intersections 206, and cloverleaf intersection 208. Example area 200 also includes example temporarily closed portion 212 of a one-way SDV route. In this example area, temporarily closed portion 212 has been bracketed by temporary RF emitters (TRFEs) 210. As described in detail below, example temporary ID signals from TRFEs 210 may be utilized in example embodiments of the present invention to alert SDVs of temporarily closed portion 212, so that the SDV may be navigated around this hazard.

[0044] FIG 2 also illustrates how area 200 that represented by the information in the dynamic digital map may be separated into multiple regions 202a-d. Information representing each of these regions 202a-d may be stored in a separate dynamic digital regional map, as described in detail below with reference to FIG 10. Each of these separate dynamic digital regional maps may be cloud-based or may be based in a specific server facility, the aggregate of these individual dynamic digital regional maps forming the complete dynamic digital map. Separating the dynamic digital map into multiple dynamic digital regional maps may improve the efficiency of the example embodiments of the present invention, both for updating the dynamic digital map as new information becomes available and for providing the most accurate and up-to-date information to the large number of SDVs anticipated to be accessing the example global positioning system at any given time. It is noted that regions 202a-d are shown in FIG 2 as tiling area 200 without overlap for simplicity and clarity of illustration; however, one skilled in the art may understand that this arrangement is not necessary and that the regions corresponding to the information stored by individual dynamic digital regional maps may overlap.

[0045] FIG 3 illustrates several types of example position data that may be stored in the dynamic digital map in example embodiments of the present invention. This example position data includes position data for example SDV route 100 and for example RF emitters 104a, 104b, and 104c. Centerline 300 represents the desired line that the center of gravity of an SDV would follow while driving along SDV route 100. The various embodiments of the present will be described herein in terms of this representation of SDV routes; however, one skilled in the art will understand that other indicia may be chosen to represent SDV routes, such an edge of the SDV route or a middle line between two adjacent lanes of a multi-lane SDV route, within the scope of present invention.

[0046] Position data for SDV route 100 may include absolute position data for centerline points 302 located along centerline 300 of SDV route 100. This absolute position data stored in the dynamic digital map for each centerline point 302 includes two dimensional position data for that point, such as, e.g., latitude and longitude, or an X and Y position in the region represented by a dynamic digital regional map measured from a predetermined point in the region. The absolute position data of each centerline point 302 may also include a height value. The separation between centerline points 302 may be a predetermined distance, such as e.g. 1 m, or the separation may be desirably determined based on one or more characteristics of that section of the SDV route. Example characteristics of the nearby section of the SDV route that may be used to determine the separation between centerline points may include, but are not limited to: the curvature; the average traffic congestion; the speed limit; the width; the measurement accuracy of the position data of the centerline points; and/or whether the SDV route is a single-lane or multi-lane route.

[0047] The example route data of the dynamic digital map for each of centerline points 302 also desirably includes width data for of SDV route 100 at each centerline point. This width data may desirably include the width of normal line 304 for each corresponding centerline point, or distance 306 from centerline point 302 to an edge of SDV route 100 along the corresponding normal line, as illustrated in FIG 3. Additionally, the direction of normal line 304, or the tangent direction of centerline 300 of SDV route 100, may be desirably included in the example width data. This direction may be desirably defined as illustrated in FIG 3, using horizontal angle 314 between normal line 304 and a predetermined horizontal direction, such as north 312. It may be desirable to additionally include a vertical angle between normal line 304 and the horizontal plane to more completely define its direction (or between the tangent line to centerline 300 and the horizontal plane). Although such a vertical angle is not shown in FIG 3 for clarity of illustration, one skilled in the art may understand how such an angle may be measured.

[0048] The example position data for RF emitters stored in the dynamic digital map may be two, or three, dimensional absolute position data, similar to the position data for centerline points 304 described above. Example methods for using this example infrastructure embodiment of the present invention to navigate an SDV along SDV route 100 may desirably involve determining the position of the SDV relative to several of RF emitters 104a-c, then using these relative positions to determine an absolute position of the SDV and comparing this absolute position of the SDV to the absolute position of centerline 300. In such an embodiment, the accuracy of the relative position of RF emitters 104a-c to centerline 300 may be more significant than the absolute position of the centerline. The accuracy of this example navigation method is, therefore dependent on the accuracy of both the RF emitter and SDV route position data. Thus, both the position data for centerline points 304 and the absolute position data for RF emitters in this example embodiment are desirably measured with a predetermined accuracy. This predetermined accuracy is desirably less than about 10cm and may possibly be less than about 1 cm.

[0049] Alternatively, the emitter data stored in the dynamic digital map may include two, or three, dimensional relative position data for the RF emitters, rather than absolute position data. This relative position data includes information identifying a nearest centerline point of the SDV route for each RF emitter (its associated center point). The RF emitter may be located at a fixed position relative to its associated center point, in which case no additional position data is included in the emitter data for the RF emitter; or the position data of the RF emitter may include relative position data for the RF emitter measured from its associated center point. It is noted that, in example infrastructure embodiments of the present with relative position data for the RF emitters, example methods for navigating an SDV along SDV route 100 may desirably involve determining the position of the SDV relative to centerline 300 directly from the relation position of the SDV to several of the RF emitters, rather than from the absolute position of the SDV. In such an embodiment, the accuracy of the relative position of RF emitters 104a-c to centerline 300 may be more significant for accurate SDV navigation than the absolute position of the centerline. It is also noted that the high accuracy measurement of the relative position between an RF emitter and its associated center point may be less difficult to perform than the high accuracy absolute position measurements of the multitude of centerline points. Thus, the predetermined route accuracy of the route data, in these example embodiments may desirably be larger than the predetermined emitter accuracy of the emitter data. Therefore, while the predetermined emitter accuracy may still be desirably less than about 10cm, possibly even less than about 1cm, the predetermined route accuracy may be larger, e.g. 50cm, without adversely affecting SDV navigation. Further, it is anticipated that example infrastructures based on these embodiments may include fewer RF emitters than centerline points, meaning that, by relaxing the accuracy of the route data, potentially many fewer high accuracy measurements may be necessary. Thus, this relaxation in the desired accuracy for measuring the absolute position of centerline points of SDV routes in these example embodiments may simplify large-scale implementation of the example infrastructure due to the potential difficulty of achieving highly accurate absolute position measurements for the large number of centerline points that such implementation of this example infrastructure may entail.

[0050] FIG 3 illustrates three example schemes for locating RF emitters relative to its associated center point 304of SDV route 100. Example RF emitter 104b is co-located at its associated center point of SDV route 100. The infrastructure system of this example embodiment may reduce both: the amount of emitter data stored in the dynamic digital map, as the relative position of every RF emitter is zero; and the method steps of example SDV navigation methods utilizing this infrastructure system, as the relative position of the SDV to RF emitter 104b is the same as the relative position of the SDV to its associated center point.

[0051] Example RF emitters 104a are located along the normal line of their respective associated center point of SDV route 104. In this example embodiment, the emitter data includes information identifying the associated center point and offset distance 310 between the RF emitter and its associated center point. Offset distance 310 between each RF emitter and its associated center point is desirably measured with a predetermined offset accuracy, which may less than about 10cm, or possibly less than about 1 cm. Alternatively, RF emitters 104a may located such that this offset distance 310 is a set distance along the normal line. The set distance may be equal to the half-width 306 of SDV route 100 at its associated centerline point 304 plus predetermined setback distance 308 (possibly zero), or offset distance 310 may be a predetermined distance. In this example embodiment, RF emitters 104a are desirably located relative to their respective center points with the predetermined offset accuracy.

[0052] Example RF emitter 104c illustrates another approach to locating a RF emitter relative to an associated center point 304 of SDV route 100. In this example embodiment, the emitter data includes information identifying the associated center point and two substantially orthogonal offset distances 316 and 318 between the RF emitter and its associated center point 304 of SDV route 100. This approach may simplify placement of RF emitters 104c as the only restriction on their placement is that they are near SDV route 100. Note that, herein,“near SDV route 100” typically means,“located within about 10m of centerline 300;” however, some RF emitters may be located farther from centerline 300, particularly along substantially straight highways in rural areas, or for middle lanes of multi-lane SDV routes if it is not practical to locate an RF emitter within 10m of the centerline of the lane. Alternatively, the relative position of RF emitter 104c may be stored in the emitter data as: a separation between the RF emitter and its associated center point and an angle of this separation relative to the predetermined horizontal direction 312. In this example embodiment, RF emitters 104a are desirably located relative to their respective center points with the predetermined offset accuracy.

[0053] Although FIG 3 illustrates example RF emitters 104a and 104c as located on a horizontal plane with SDV route 100, it is noted that these RF emitters may be located above, or below, this horizontal plane. In such an example embodiment, it may be desirable to include a vertical height of the RF emitter about or below the horizontal plane in the emitter data, or measured relative to its associated center point. This vertical dimension may also desirably be measured with the predetermined offset accuracy.

[0054] One skilled in the art may understand that RF emitters of the various example infrastructure embodiments of the present invention may be situated in place in various ways. For example, example RF emitters may be: mounted in dedicated structures precisely located near at least one SDV route; affixed to convenient pre-existing structures such as buildings, guard rails, or walls near at least one SDV route; set within the structure of SDV routes themselves; or a combination thereof. Alternatively, example RF emitters may be mounted within electrically powered SDV-route-side structures, such as, but not limited to: streetlights; lighted and/or electronic billboards; or traffic signals. These the electrically powered SDV-route-side structures may be coupled to the electrical grid, or may include an integral power source such as: a solar power source; a wind powered generator and/or another source of electrical power. Such self-powered structures may include a rechargeable battery and associated electronics, or the structure may be powered be a replaceable battery. Including RF emitters within such powered structures may simplify implementation of this portion of an example infrastructure system of the present invention.

[0055] FIGs 4A and 4B illustrate example embodiments in which the inclusion of a vertical dimension for the position data of both the SDV route(s) and for the RF emitters. These figures illustrates two example approaches for the placement of RF emitters near a skew crossing between two SDV routes, overpass 400, in which single-lane SDV route 100 crosses over double-lane SDV route 204. One skilled in the art may understand that similar approaches may be used for any multilevel structure of SDV routes, such as, e.g., underpasses, cloverleaf intersections, and/or multilevel thoroughfares.

[0056] FIG 4A illustrates an example embodiment that includes separate lower and upper RF emitters 104L and 104U, respectively. Each lane of double-lane SDV route 204 has a lane centerline 404, and each of the two lower RF emitters 104L is located near the outer edge of one of these two lanes at offset distance 310L from its associated center point 302L on the lane centerline 404 of its lane. It is noted that route data for multi-lane SDV routes, such as double-lane SDV route 204, may include absolute position data for a lane centerline of each lane and illustrated in FIGs 4A and 4B, which is substantially similar to treating the multi-lane SDV route as multiple, approximately parallel, single-lane SDV routes. Alternatively, the route data for a multi-lane SDV may include absolute position data for a single central route line of the multi-lane SDV route and relative position data identifying the relative position of each lane from this central route line. Depending on the specific construction of a multi-lane SDV route, one of these example approaches may be more desirable for measuring and storing route data of that route in the dynamic digital map. Therefore, it is anticipated that use of both of these example approaches may be desirable in example embodiments of the present invention.

[0057] Upper RF emitter 104U, in the example embodiment of FIG 4A, is located near an edge of single-lane SDV route 100 at offset distance 310U from its associated center point 302U on centerline 300 of the SDV route.

[0058] FIG 4B illustrates an example embodiment that includes RF emitter 104M, mounted on (inside of) support 402 of overpass 400. As illustrated in this example embodiment, if an RF emitter is located near more than one SDV route, or lane of a multi-lane SDV route, the route data for that RF emitter may include an associated center point and relative position for each SDV route, and/or lane. Thus, RF emitter 104M is shown with three offset distances 310M.

In this example embodiment, all three associated center points and their associated relative position vectors may be stored in the dynamic digital map as part of the emitter data of RF emitter 104M; however, depending on which SDV route is being navigated, an example SDV may be adapted to download only the portion of the emitter data corresponding to its route for RF emitter 104M.

[0059] In some example embodiments, pairs of RF emitters may be associated with a single center point of an SDV route and located with one RF emitter on each side of the SDV route, as illustrated by RF emitter pair 214 in FIG 2. [0060] In example embodiments including intersections between two SDV routes, the point located at the intersection of the centerlines of the intersecting SDV routes may be chosen to be a centerline point for both SDV routes. It may be desirable for an RF emitter to be associated with this double centerline point. Pairs (or even quads) of RF emitters may be associated with this double centerline point, or even located at the double centerline point. The pairs RF emitters in these example embodiments may be desirably located diagonally across the intersection, as illustrated by RF emitter pair 216 which is located diagonally across intersection 206 in FIG 2. In the case of a skew intersection, one or more sets of two RF emitters located may be located near the skew crossing wherein the RF emitters in each set of two RF emitters have substantially similar two dimensional horizontal position data, but different one dimensional vertical position data, such as for example with one the RF emitter mounted on a common pole with one RF emitter at a predetermined vertical height relative to the plane of the lower of the two skew SDV routes and the second RF emitter at the same predetermined vertical height relative to the plane of the upper of the two skew SDV routes. Similarly, in example embodiments including an SDV route with a multilevel section in which each level of the SDV route has substantially similar two dimensional horizontal position data and different one dimensional vertical position data, it may be desirable to include multilevel set of RF emitters located near the multilevel section of the SDV routes, in which each RF emitter in the multilevel set of RF emitters corresponds to one level of the multilevel section.

[0061] In further example embodiments of the present invention, at least one SDV route may be a divided highway having: a first lane; a second lane substantially parallel to the first lane; and a median separating the first lane from the second lane, similar to how two-lane SDV route 200 is illustrated in FIGs 4A and 4B, and the RF emitters located near this divided highway may be located within the median of the divided highway. The route data stored in the dynamic digital map for the divided highway may desirably include: centerline position data for first lane centerline points along the first lane and second lane centerline points along the second lane; and width data for the first lane at each of first lane centerline points and the second lane at each of second lane centerline points.

[0062] In example embodiments of the present invention, the RF emitters may desirably be arranged along an SDV route such that each pair of neighboring RF emitters is separated by a known separation distance, with each separation distance being within a predetermined separation range. Similarly to the separation between centerline points of SDV routes, this predetermined separation range between neighboring pairs RF emitters may be based on characteristics of the nearby section of the SDV route, well as characteristics of the RF emitters and the surrounding terrain. For example, the desired separation range between each pair of neighboring RF emitters along a city street may be 50m to 200m, while the desired separation range between each pair of neighboring RF emitters along a highway may be 50m to 1000m. Some example characteristics that may affect the predetermined separation range may include, but are not limited to: the curvature of the nearby section of the SDV route; the average traffic congestion in the nearby area; the speed limit of the nearby section of the SDV route; the width of the nearby section of the SDV route; the measurement accuracy of the position data of the RF emitters; the power of the RF emitters; the number of RF emitter that are desirably used by an SDV for navigation calculations; the presence of nearby SDV route intersections; the presence of terrain features such as hills, mountains, and cliffs; the presence of nearby buildings or other structures; and/or whether the nearby section of the SDV route is a single-lane or multi-lane route. [0063] Desirably, the ID signal power of the predetermined periodic ID signal of each RF emitter is set to a predetermined power level for that RF emitter. This predetermined power level for each RF emitters is desirably selected such that, at every point along the SDV route(s), at least a minimum number of periodic ID signals from the RF emitters have a minimum detection intensity or greater (the minimum number of detectable RF emitters). The minimum detection intensity is set at a level such that SDVs traveling along the SDV route are able to receive the periodic ID signals with a sufficient signal to noise ratio (SNR) to distinguish periodic ID signals from different RF emitters and to perform desired processing steps on these signals that may be used by the SDV to navigate, such as various example signal processing step described in detail below. It is contemplated that this minimum detection intensity may be between about -100 dBm and about -70 dBm, depending on the complexity of the periodic ID signals and the quality of the antennae and other electronic components of the SDV navigation system.

[0064] The minimum number of detectable RF emitters is at least three. Example SDV navigation methods of the present invention use relative position data between the SDV and three, or more, RF emitters to unambiguously determine the position of the SDV. FIG 5 illustrates SDV 102 traveling on an example section of SDV route 100 along which three RF emitters 104a, 104b, and 104c are located. In this example illustration, the approximately circular shaded regions around each of the RF emitters illustrate the loci within which the intensity of the periodic ID signal of that RF emitter is equal to or greater than the minimum detection intensity (the detection locus of the RF emitter). Darker shaded regions indication areas in which two or more of these detection loci overlap. Subsections 500xxx of the illustrated section of SDV route 100 have been labeled to identify the RF emitters with detection loci that overlap that subsection. Thus, subsection 500c is only within the detection locus of RF emitter 104c; subsection 500ac is within the detection loci of both RF emitters 104a and 104c, but not the detection locus of RF emitter 104; subsection 500abc is within the detection loci of all three RF emitters 104a, 104b, and 104c; and subsection 500ab is within only the detection loci of RF emitters 104a and 104b. Thus, SDV 102, which is located in subsection 500abc may detect signals from all three example RF emitters to aid in navigation in this example illustration. It is noted that FIG 5 includes only three RF emitters located near a short section of SDV route 100 for simplicity and clarity of illustration and is not intended as limiting. Desirably, additional RF emitters are desirably located further along SDV route 100 so that at least the minimum number of detectable RF emitters is met all along SDV 100.

[0065] It may be desirable for the minimum number of detectable RF emitters to be greater than three: e.g. four (i.e. a couple in front and a couple behind the SDV at most points) or five (i.e. the nearest RF emitter, plus a couple in front and a couple behind the SDV at most points). In example embodiments that include pairs of RF emitters associated with the same center point, such as emitter pair 214 in FIG 2, the desired minimum number of detectable RF emitters may be double these numbers, i.e. six, eight, ten.

[0066] It may also be desirable for the power level of the predetermined periodic ID signal of each RF emitter to further be selected such that there are no more than a predetermined maximum number of detectable RF emitters at every point along the SDV route(s). One reason for limited the number of detectable RF emitters may be to limit their power consumption. Additionally, limiting the number of detectable RF emitters at every point along the SDV route(s) may simplify the signal processing steps of example SDV navigation methods using these example infrastructures. Also, each ID signal desirably uniquely identifies the RF emitter that produced it; however, the approximate location of the SDV may be determined by other systems, such as GPS, or merely noting the last determined location. Therefore, if only a limited number of detectable RF emitters overlap, it may not be necessary for every ID signal to be unique. It may only be necessary that each detectable ID signal at any given location be unique and, thus, each ID signal may be selected from a limited set of periodic ID signals, as long as this limited set includes at least the maximum number of detectable RF emitters of unique periodic ID signals.

[0067] Reducing the number of unique ID signals used in the example infrastructure may reduce the complexity of: the ID signals themselves; the RF emitters; and the SDV navigation systems that detect and process the ID signals. Desirably, the maximum number of detectable RF emitters at every point along the at least one SDV route may be only a little greater than the predetermined minimum number of detectable RF emitters, e.g. less than four.

[0068] The GPS positioning system uses the time delay differences between signals from multiple satellites to determine the absolute position of a GPS receiver. Each of these GPS signals is encoded with information identifying the satellite and a timestamp indicating when the signal left the satellite. The timestamps of the GPS signals must be very accurately correlated for the GPS positioning system to work. To this end, each GPS satellite includes an atomic clock to maintain the precision of its timestamp. These atomic clocks must be accurately correlated.

[0069] In example embodiments of the present invention, the signals of different RF emitters do not need to be correlated. Instead of determining an absolute position of the SDV based on time delay differences between the signals received from different RF emitters, these example embodiments determine a position of the SDV relative to a set of detectable RF emitters by determining the direction from which the signal is received for each RF emitter in this set relative to the SDV. Each of these reception directions may be determined independently. Thus, it is not necessary for there to be any correlation between the signals of different RF emitters. This may simplify the construction of the RF emitters, as well as the implementation and maintenance of the overall infrastructure system.

[0070] One example approach to determining the direction from which each signal is received is to use the time delay between reception of the signal of a single RF emitter at one, or more, pairs of antennae located at different points on the SDV to calculate the angle between the reception direction and the forward direction of SDV, as described in detail below with reference to FIG 8. Thus, the predetermined periodic ID signal of each RF emitter is desirably selected to allow accurate measurement of the inter-antennae time delay(s). Either periodic digital ID signals or periodic analog signals may be employed.

[0071] The precision with which the reception direction may be determined from an inter-antennae time delay is related to the angle between the reception direction and the line connecting the antennae pair. The closer this angle is to 45°, the more precise the measurement can be. This geometric fact may be used to optimize both the design of example SDV antennae arrays and the placement of RF emitters in example embodiments of the present invention.

[0072] The precision with which the reception direction may be determined is also related to the structure of the predetermined periodic ID signal, i.e. how fine of a time delay may be distinguished. Thus, faster the predetermined periodic ID signal varies (bit rate for a digital signal, carrier frequency for an analog signal), the more precisely the reception direction may be determined; however, a very short repetition period may lead to degeneracy in determining the time delay if the time delay may be longer than one period of the predetermined periodic ID signal. Therefore, it may be desirable for the repetition wavelength of each predetermined periodic ID signal (i.e. its repetition period times the speed of light) to be longer than the maximum separation of SDV antennae pairs, thereby reducing the potential for degeneracy in time delay measurements. In many example embodiments of the present invention, repetition periods in the range of about 10ns to about 20ns may achieve this desirable result.

[0073] One method for determining the time delay between the receptions of a digital signal at two antennae is to analyze the autocorrelation between the two received digital signals. One skilled in the art may understand that, for any bit length (greater than one) and digit base size, a number period digital signals may be formed that have a unique autocorrelation signature for each bit delay step across their repetition period. Thus, the autocorrelation signal of such a periodic digital signal may uniquely determine the time delay, in bit steps, between the receptions of that periodic digital signal at each antenna. FIGs 6A and 6B illustrate such an example autocorrelation technique 600 utilizing two digital signals 602a and 602b representing the signal generated by the reception of a single periodic digital ID signal at the two antennae of an example antenna pair with time delays 604 in digits. For simplicity and clarity, example digital signals 602a and 602b have been chosen to be only six bits long, with each digit able to take on one of four values: 0; 1 ; 2; or 3 (i.e. base 4). These example digital signals are for illustrative purposes only; one skilled in the art may understand that digital signals hundreds of bits long may be desirable. Additionally, each bit may have a different range of potential values, e.g., two values (binary), eight values (octal), or other. In the example of autocorrelation technique 600 illustrated in FIGs 6A and 6B, digital signal 602a is shown started at the same bit of the sequence of the example periodic digital ID signal (120213) in each column; time delay 604 is number of digits that digital signal 602b is delayed relative to digital signal 602a in that column; and autocorrelation signal 606 is the sum of digital signals 602a and 602b in that column. FIGs 6A and 6B include six columns (numbered from 0 to 5), which represent all possible non-degenerate bit delays for a periodic digital signal with a repetition period of 6 bits, such as the example digital signal in these FIGs As may be seen in FIGs 6A and 6B the autocorrelation signal in each column is unique for this periodic digital signal.

[0074] In example embodiments of the present invention it is contemplated that the periodic digital ID signal of each RF emitter may be adapted to have a unique autocorrelation signal and that the example autocorrelation technique of FIGs 6A and 6B may be used by example SDV navigation systems to determine the time delay between when different antennae mounted on the SDV receive the periodic digital ID signal from a given RF emitter. The resulting time delay measurement may be determined with a precision of the inverse of the bit rate for the periodic digital ID signal. Thus, is may be desirable for the periodic digital ID signals of the RF emitters in this example embodiment to have a bit rate greater than about 500 Mbps, possibly between about 2 Gbps and about 10 Gbps.

[0075] Using example autocorrelation technique 600, the specific repeating digital pattern of the periodic digital ID signal for each RF emitter may both: identify the corresponding RF emitter; and be used to determine the reception angle of the signal. As described above, it may not be necessary for each RF emitter to have a unique repeating digital pattern; however, in such an example embodiment, the repeating digital pattern of an RF emitter is desirably distinct from that of every other detectable RF emitter within the detection locus of that RF emitter.

[0076] Alternatively, the functions of identifying the RF emitter corresponding to the periodic digital ID signal and determining its reception angle may be based on separate parameters of the periodic digital ID signal. For example, the repeating digital pattern of each periodic digital ID signal may be substantially the same, and the carrier wave frequency, and/or the bit rate, of the periodic digital ID signal corresponding to each RF emitter may different. In such an example embodiment, the repeating digital pattern may be used to determine the reception direction and the carrier wave frequency, and/or the bit rate, may be used to identify the corresponding RF emitter.

[0077] Or, the periodic digital ID signal of each RF emitter may include alternating (or superimposed) portions: one portion including the digital pattern for use in example autocorrelation technique 600; and one portion identifying the corresponding RF emitter. It is noted that, in this example embodiment, the portion of the periodic digital ID signal identifying the corresponding RF emitter may be digital, or it may be analog, forming a periodic hybrid ID signal.

[0078] In example embodiments in which the periodic ID signal is a periodic analog ID signal, a similar autocorrelation technique may be used to determine the reception angle of the periodic analog ID signal from each detectable RF emitter. In these example embodiments it may be desirable for the periodic analog ID signal of each RF emitter that is detectable at a given location along an SDV route to have a unique carrier wave frequency to simplify the separation of signals from different RF emitter before the autocorrelation step.

[0079] FIG 7 illustrates another example technique for determining the time delay between reception of a periodic analog ID signal at two antennae of an SDV, and thus, the reception angle of the signal. In this example technique, each periodic analog ID signal includes three, or more, carrier waves having different wavelengths. The wavelengths of the carrier waves are desirably selected such that the ratio of any two of these wavelengths is a non-integral rational number. For example, if a periodic analog ID signal includes three carrier waves with wavelengths li, l , and K , these wavelength may be desirably selected such that all three wavelengths may be expressed as rational numbers, l >l >li, hd is non-integral rational number, AVAi is non-integral rational number and K3IK2 is non-integral rational number. In such an example periodic analog ID signal, the superimposed analog signal does not repeat until all of the carrier waves return to their initial phase at the same time. In general, this repetition wavelength of such a superimposed analog signal is equal to the least common multiple of the wavelengths of the carrier waves; however, in the case of a superimposed analog signal such as of this example periodic analog ID signal is equal to the product of the wavelengths of the carrier waves. This relationship may be easily seen in an example such as periodic analog signal 706 FIG 7 in which all three carrier waves start at a phase of 0°. Note, the repetition period of the superimposed analog signal is equal to the repetition wavelength divided by the speed of light.

[0080] For simplicity and clarity of illustration, only three equal intensity carrier waves are included in example periodic analog ID signal 706 of FIG 7; i.e. example periodic analog ID signal 706 is the superimposition of three carrier waves: carrier wave 700; carrier wave 702; and carrier wave 704. It is noted that, although all carrier waves may be desirable emitted by an example RF emitter with substantially the same power level, the received intensity of the different carrier waves may not be the same due to atmospheric conditions affecting their transmission. Example carrier wave 700 has wavelength 700a (Ai); example carrier wave 702 has wavelength 702a (A ); and example carrier wave 704 has wavelength 704a ^ ). Also, for simplicity and clarity, these three wavelengths have the following ratios - Ai: K2. h.3 º 2AU:3AU:5AU. Repetition wavelength 706a (Ao) of the example periodic analog ID signal 706 is equal to 30AU, or the least common multiple of the wavelengths of the carrier waves. As illustrated, example periodic analog ID signal 706 includes nodes 706b at which the phase of all three carrier waves is 0° and node 706c at which the phases of carrier waves 702 and 704 are 0°, but the phase of carrier wave 700 is 180°.

[0081] As described above, it may be desirable for the repetition wavelength of the periodic analog ID signal of each RF emitter to be at least as long that the greatest anticipated antennae separation of an example SDV. It is contemplated that this desired minimum repetition length may be 2m or greater. However, it is also noted that the precision with which the inter-antennae time delay may be measured is related to the wavelength of the carrier waves. The wavelengths of the carrier waves may be selected to be whole numbers of a particular unit; e.g. a periodic analog ID signal formed by three carrier waves with wavelengths of 4cm, 7cm, and 13cm has a repetition wavelength of 384cm. Alternatively, the wavelengths of the carrier waves may be selected to have a predetermined ratio and result in a particular repetition wavelength. As noted above, a periodic analog ID signal formed by three carrier waves with wavelengths of 2AU, 3AU, and 5AU has a repetition wavelength of 30AU. If this is the desired ratio and the desired repetition wavelength is 2m, then setting 3AU equal to 20cm results in carrier wavelengths of 13 1/3cm, 20cm, and 33 1/3cm and a repetition wavelength of 2m.

[0082] Also, as noted above it may be desirable for the emission power, and location, of each RF emitter to be selected such that, at every location along the SDV route(s), the number of detectable RF emitters falls in a predetermined range. In example embodiments including superimposed analog ID signals, such as example analog ID signal 706 in FIG7, it may desirable for the emission power of all of the carriers wave that form the superimposed analog ID signals to be selected so that each carrier wave has at least the minimum detection intensity at every point within the detection locus of its corresponding RF emitter.

[0083] Using the example multiple carrier wave technique of FIG 7, the specific set of carrier wave wavelengths of the periodic analog ID signal for each RF emitter may both: identify the corresponding RF emitter; and be used to determine the reception angle of the signal. As described above, it may not be necessary for each RF emitter to have a unique set of carrier wave wavelengths; however, in such an example embodiment, the set of carrier wave wavelengths of an RF emitter is desirably distinct from that of every other detectable RF emitter within the detection locus of that RF emitter. For example in example embodiments including superimposed analog ID signals with three carrier waves, each set of carrier wave wavelengths may be select from a predetermined set of unique wavelength triples ([li, l , l ] ), where the number of members of this set (x) is equal to or greater than the predetermined maximum number of the detectable RF emitters.

[0084] Alternatively, the functions of identifying the RF emitter corresponding to the periodic analog ID signal and determining its reception angle may be based on separate parameters of the periodic analog ID signal. For example, the set of carrier wave wavelengths of each periodic analog ID signal may be substantially the same, and the emission power of one or more of the carrier waves of the periodic analog ID signal corresponding to each RF emitter may be modulated (i.e. an AM ID signal), or the frequency of one or more of the carrier waves of the periodic analog ID signal corresponding to each RF emitter may be modulated (i.e. an FM ID signal). In such an example embodiment, the phases of carrier wave wavelengths may be used to determine the reception direction and the AM, and/or FM ID signal, may be used to identify the corresponding RF emitter.

[0085] It is noted that one skilled in the art may understand that combinations of these various example approaches to determining both the reception angle and the corresponding RF emitter identity from periodic digital ID signals may be used as well.

[0086] FIG 8 illustrates example SDV 102. Example SDV 102 includes a transverse pair of antennae 800a and 800b mounted near its sides, approximately equidistantly from SDV center 103, along transverse line 802, which is substantially orthogonal to forward direction 106 of the SDV and may desirably be substantially horizontal when the SDV is at rest on a horizontal surface. The position of each of these antennae relative to the SDV center is desirably known to a high degree of accuracy, for example within 1 mm or less. Likewise, the length of transverse line 802 may be accurately known. As illustrated in FIG 8, the length of transverse line 802 is substantially equal to the width of the SDV; however it is contemplated that this length may be less in some example embodiments, or that antennae 800a and 800b may be mounted outside of the standard width of the SDV, e.g. on side view mirrors.

[0087] FIG 8 also includes example geometry that may be used to determine angle 108 between forward direction 106 and RF emitter 104 (i.e. the reception angle for the periodic ID signal of RF emitter 104) based on the time delay between the reception of the periodic ID signal of RF emitter 104 at the two antennae 800a and 800b. It is noted that reception angle 108 is shown as being measured around SDV center 103. This use of SDV 103 as the origin for the reception angle is based on the expectation that line segments 804a, 804b, and 806 (between RF emitter 104 and antenna 804a, antenna 804b, and SDV center 103, respectively) may be substantially parallel for example embodiments in which each of these line segment is large compared to dimensions of the SDV. It is noted, however, that in some example infrastructure embodiments, particularly those in which the RF emitters are co-located with their associated center points, this expectation may not be valid. Therefore, especially in such example embodiments, it may be desirable for antenna pair midpoint 808 to be used as the origin about which the reception angle is measured. It is also noted that reception angle 108 is illustrated as a two dimensional, horizontal, reception angle in FIG 8. One skilled in the art may understand that it may be desirable in example embodiments of the present invention for the reception angle to be measured as a three dimensional angle. The example methods described for two dimensions with reference to FIG 8 may be generalized to three dimensions using antenna arrays that include antennae arranged such that at least one antenna pair has a vertical component, such as the example antenna array of FIG 9D.

[0088] In the example geometry of FIG 8, distance 810 along line segment 804b is the path length difference between line segment 804b and line segment 804a. Distance 810 is, thus, equal to the time delay between reception of the periodic ID signal from RF emitter 104 by antenna 800a and antenna 800b times the speed of light. In the case that line segments 804a and 804b can be considered approximately parallel, distance 810 forms one leg and transverse line 802 forms the hypotenuse of a right triangle. Angle 812, which is the complement of reception angle 108, may be calculated as the arccosine of distance 810 divided by the length of transverse line 802. In cases in which RF emitter 104 is close (relative to the separation of an antenna pair) to SDV 102, it may be desirable to include an antenna array with three or more antennae and for reception angle estimates calculated by each pair of antenna to be compared to determine the reception angle more accurately.

[0089] FIGs 9A-D illustrate several example antenna array configurations that may be used in example embodiments of the present invention. One skilled in the art may understand that these example antenna arrays are not intended to be limiting, but rather that they mere illustrate several possible configurations and that other configurations, including combination and minor variations of these example antenna array may also be used in example embodiments of the present invention. FIG 9A illustrates example SDV 102 with a quartet of antennae 800 arranged in a rectangular layout. As illustrated in FIG 9A, this rectangular layout antenna array may have approximately the same length and width as SDV 102, which may be desirable as longer separations between antenna pairs may allow for more accurate determination of the reception angle of detected RF emitter periodic ID signal. Additionally, this rectangular antenna array may be arranged so that the layout is substantially horizontal when SDV 102 is at rest on a horizontal surface. Such an example antenna array may be operated as: two transverse antenna pairs; two longitudinal antenna pairs; two diagonal antenna pairs; or any combination thereof, allowing up to six substantially simultaneous determinations of each reception angle, thereby potentially improving accuracy and confidence in these determinations..

[0090] Both FIGs 9B and 9C illustrate example antenna arrays in which a quartet of antennae 800 are arranged in a cruciform pattern. In both of these example antenna arrays, the cruciform layout may be substantially horizontal when the SDV is at rest on a horizontal surface; however, particularly in the example antenna array of FIG 9C this horizontal arrangement may not be practical. In FIG 9B, a longitudinal antenna pair is arranged along the longitudinal centerline of SDV 102, and a transverse antenna pair is arranged along the transverse centerline of SDV 102. In FIG 9C, while the longitudinal antenna pair is arranged along the longitudinal centerline of SDV 102, and the transverse antenna pair is arranged along a transverse line forward of the cabin of SDV 102. (It is noted that the transverse antenna pair may alternatively be arranged along a transverse line behind of the cabin of SDV 102, or there may be two transverse antenna pairs, one forward and one behind the cabin.) A symmetrical layout of the antenna array, as shown in FIG 9B, may provide computational advantages; however, an asymmetrical layout of the antenna array, as shown in FIG 9C, may provide advantages for mounting the antennae of the array. As with the example antenna array of FIG 9A, the example antenna arrays of FIGs 9A and 9B may be operated as up to six antenna pairs.

[0091] FIG 9D illustrates a further example antenna array layout including a quartet of antennae 800. This example antenna array includes a vertical pair of antennae arranged along a vertical line, i.e. a line that is substantially vertical when the SDV is at rest on a horizontal surface. As shown in FIG 9D, this longitudinal pair of antennae may desirably be separated by approximately the cabin height of the SDV, however it is contemplated that the upper antenna may be mounted above the cabin, and/or the lower antenna may be mounted higher in the SDV to protect it from potential damage. The example antenna array of FIG 9D also includes a longitudinal antenna pair. One skilled in the art may understand that a vertical antenna pair may be desirable to assist in determining a vertical component of the reception angle, but at least one non-vertical antenna pair is also desirable for determining the horizontal component of the reception angle.

[0092] FIG 10 illustrates an example embodiment of the coupling between SDV 102 and dynamic digital map 1 12. SDV 102 is desirably wirelessly coupled to wireless communications network 110, which may include one or more of: a cellular communications network; a satellite communications network, a WIFI communications network; the internet; or a dedicated SDV communications network, via a wireless communications link 1 14. The wireless communications network 1 10 may be coupled to example dynamic digital map 112 via one or more wireless communications links 1 14 and/or wired communication links 1000. As illustrated in FIG 10, each wireless communications link 1 14 and each wired communication link 1000 is desirably a two-way communications link. In the example embodiment of FIG 10, example dynamic digital map 1 12 includes four dynamic digital regional maps 1002a-d. Each dynamic digital regional map may desirably correspond a distinct region of the area covered by dynamic digital map 122; e.g. dynamic digital regional maps 1002a, 1002b, 1002c, and 1002d may respectively correspond to regions of 202a, 202b, 202c, and 202d of area 200 in FIG 2. It is noted that the inclusion of four dynamic digital regional maps in FIG 10 (and four regions in FIG2) is merely for convenience and clarity of illustration, and is not intended to be limiting. It is also noted that each dynamic digital regional map 1002a-d may be located in a server facility, or the dynamic digital memory of one or more of the dynamic digital regional maps may be cloud based, with their corresponding data input module(s) and corresponding data output module(s) coupled to the dynamic digital memory via the internet.

[0093] A dynamic digital map 1 12 (or in example embodiments, such as the example illustrated in FIG 10, that include dynamic digital regional maps, each of the dynamic digital regional maps 1002a-d) according to example embodiments of the present invention includes several components, such as: a (regional) dynamic digital memory; a data input module; and a data output module. The (regional) dynamic digital memory is desirably adapted to store the portion of the emitter data and the portion of route data of the dynamic digital map that correspond to the area (or region) covered for SDV navigation by the (regional) dynamic digital map. The data input module is desirably adapted to receive map update data, which may include updated emitter data and route data, from various sources. The data input module is also desirably adapted to modify the portion of the dynamic digital map stored in the dynamic digital memory, based on the received map update data. In some example embodiments, the data input module may receive additional types of data and may process this data to determine the desirability of making additional modifications to the information stored in the dynamic digital memory. The data output module is desirably adapted to transmit the emitter data and the route data for the corresponding area (region) to SDVs.

[0094] FIG 11 illustrates an example layout of the components (and sub-components) of example dynamic digital regional map 1002. This example layout includes regional dynamic digital memory 1 110; a data input module formed of input/output (I/O) ports 110Oa-d, discriminator module 1108, emitter comparison module 11 12, route processing module 1 1 14, route comparison module 1 1 16, and map modification module 1 118; and a data output module formed of I/O ports 1 100a-d, request processing module 1120. In this example dynamic digital regional map I/O ports 1 100a- d function as both the input port of the data input module and the output port of the data output module. The I/O ports may be externally coupled to wireless communications network 1 10 via either wireless communications link 1000 or wired communications link 1 106, and may also be coupled to central operator terminal 1 104 via wired

communications link 1106 and/or remote operator terminal 1 102 via wireless communications link 1000. These external communication links are desirably two-way communication links over which example dynamic digital regional map 1002 may receive map update data from multiple sources and data requests from SDVs, or from other dynamic digital regional maps, over wireless communications network 110 and manually input map update data from central operator terminal 1104 and/or remote operator terminal 1102, as well as sending out map data, including data responses and map data updates for other dynamic digital regional maps, to wireless communications network 1 10, central operator terminal 1104, and/or remote operator terminal 1102.

[0095] Internally, example I/O ports 1 10Oa-d may be coupled, as illustrated in the example embodiment of FIG 11 : 1 ) to transmit received data, such as map update data and data requests received from wireless communications network 1 10 and manually input map update data received from central operator terminal 1 104 and/or remote operator terminal 1102, to discriminator module 1 108; 2) to receive data from request processing module 1120 to be transmitted externally. In the first of these functions, each I/O port 1 100a-d form a portion of the data input module of example dynamic digital regional map 1002 (i.e. a series of input ports); and in second of these functions, each I/O port 1 10Oa-d form a portion of the data output module of example dynamic digital regional map 1002 (i.e. a series of output ports). [0096] Example discriminator module 1 108 is adapted to separate the incoming map update data and incoming data requests from SDVs. Discriminator module 1108 is further adapted to separate the incoming map update data into: 1 ) emitter data sets, which are each associated with emitter data for a single RF emitter; and 2) route data sets, which are each associated with route data for a single SDV route. Discriminator module 1108 then separately transmits the emitter data sets to emitter comparison module 1 112, the route data sets to route processing module 1 114, and the data requests to request processing module 1 120. Each internal processing module (i.e. discriminator module 1 108, emitter comparison module 11 12, route processing module 11 14, route comparison module 11 16, map modification module 11 18, and request processing module 1120) of example dynamic digital regional map 1002 (or an example dynamic digital map) may include one or more of: a general-purpose computer system instructed by special-purpose software; a dedicated special-purpose computing system; special-purpose circuitry; an application specific integrated circuit (ASIC); or a distributed computing network instructed by special-purpose software. It is noted that example dynamic digital regional map 1002 is illustrated in FIG 11 as including one set of internal processing modules; however, it is contemplated that example dynamic digital regional maps (or an example dynamic digital map) may include multiple parallel sets of internal processing modules to distribute the processing of the large anticipated volumes of data. In such example embodiments, discriminator module 1 108 may include multiple modules, and/or stages, to separate incoming data before transmission to various sets of internal processing modules, or the example dynamic digital regional map (or example dynamic digital map) may use a bus architecture in which each set of data is received and processed by the first available appropriate internal processing module. For clarity, the remaining description of the internal processing modules below is based on a single set of these modules, with the understanding that example embodiments of the present invention may include parallel processing sets of internal processing modules.

[0097] Example request processing module 1 120 is adapted to receive the data requests, which vehicle information identifying the SDV requesting the data, from discriminator module 1 108, and process each data request generate one or more processed data requests, where each processed data request is associated with data stored in a specific one of the dynamic digital regional maps and consisting of: a regional emitter list; a regional route list; and the associated vehicle information for the received data request. (Note, in example embodiments that include only one dynamic digital map, this step is omitted.) The regional emitter list and the regional route list include the portion of the requested emitter data and route data stored in the associated dynamic digital regional map. For each processed data request associated with data stored in a different dynamic digital regional map, the processed data request is transmitted to I/O port 1 100a and/or I/O port 1 100d. In response to each processed data request associated with data stored in dynamic digital regional map 1002, request processing module 1 120, which is coupled to dynamic digital memory 1 110 to access data stored therein, transmits a data response including the requested emitter data and route data and the associated vehicle information to I/O port 1100a and/or I/O port 1 100d,. I/O port 1100a and/or I/O port 1 100d transmits, via wireless communications network 110, each processed data request received from request processing module 1 120 to the associated dynamic digital regional map; and the requested emitter data and route data of each data response to the SDV identified in the associated vehicle information.

[0098] Example emitter comparison module 1 1 12, which is electrically coupled to the discriminator module 1 108 and the dynamic digital memory 1 1 10, is adapted to receive separated emitter data sets from the discriminator module 1 108 and compare each of these emitter data sets with emitter data stored in dynamic digital memory 11 10 to determine whether that emitter data set: is associated with an RF emitter that is located outside of the corresponding region (an outside emitter); is associated with a new RF emitter inside of the corresponding region (a new emitter); or is updated emitter data associated with a stored RF emitter (an emitter update). A flag is assigned to each received emitter data set based on this determination and the emitter data sets that are flagged as either new emitters or emitter updates are transmitted to map modification module 11 18. Example emitter comparison module 1 1 12 may be further adapted to evaluated emitter data sets flagged as associated with an outside emitter to determine a dynamic digital regional map that corresponds to the region that includes that emitter data set; then, these emitter data sets are transmitted, as map update data, to the input module of their corresponding dynamic digital regional maps via I/O port 1 100a and/or 1 10Od and wireless communications network 1 10. (Note, in example embodiments that include only one dynamic digital map, this step may be omitted as there are no outside emitters.)

[0099] Example route processing module 1 114, which is electrically coupled to discriminator module 1 108 and dynamic digital memory 1 1 10, is adapted to receive separated route data sets from discriminator module 1108 and determine whether a received route data set is for: an SDV route located fully outside of the corresponding region of dynamic digital memory 1 1 10 (an extra-region route); an SDV route located fully within the corresponding region (an intra-region route); or an SDV route that is located partially inside and partially outside of the corresponding region (a cross-region route). Each received route data set determined to be for a cross-region route is processed to form a truncated route set including only route data within the corresponding region. These truncated route data sets and the route data sets determined to be for intra-region routes are both transmitted to route comparison module 11 16 as processed route data sets. Route processing module 11 14 may be further adapted to process each separated route data set determined to be associated with a cross-region route to form an additional route data set, a remainder route data set associated with the extra-region route portion of the cross-region route. Route processing module 1 1 14 may also evaluate each remainder route data set and each separated route data set determined to be associated with an extra-region route to determine whether the associated extra-region route is partially located within the regions of multiple dynamic digital regional maps (a multi-region route) or is located fully within the region of one other dynamic digital regional map (a single-region route). The associated route data set of each multi-region route may be separated into multiple regional route data sets, such that each regional route data set is associated with a portion of the multi-region route located fully within the region of one dynamic digital regional map. Each regional route data set and each route data set associated with a single-region route may then be transmitted, as map update data, to the input module of their corresponding dynamic digital regional maps via I/O port 1 100a and/or 1 100d and wireless communications network 1 10. (Note, in example embodiments that include only one dynamic digital map, route processing module 1 114 may be omitted as all routes are intra-region routes.)

[00100] Example route comparison module 1 116, which is electrically coupled to route processing module 1 114 and dynamic digital memory 11 10, is adapted to receive processed route data sets from route processing module 1 114 and compare each processed route data set with route data stored in dynamic digital memory 1 1 10 to determine whether that processed route data set is associated with a new single SDV route or is updated route data associated with a stored SDV route. Route comparison module 1 1 16 then assigns a flag to each received route data set based on this determination and transmit the flagged route data sets to example map modification module 11 18. [00101] Example map modification module 11 18 is electrically coupled to emitter comparison module 1 112, route comparison module 1 116, and dynamic digital memory 11 10. It is desirably adapted to: receive the flagged emitter data sets and the flagged route data sets; add emitter data from emitter data sets flagged as being associated with a new emitter to the emitter data stored in the dynamic digital memory; and add route data from route data sets flagged as being associated with a new SDV route to the route data stored in the dynamic digital memory. Additionally, Example map modification module 11 18 may desirably be adapted to update: the emitter data of each stored RF emitter associated with an emitter data set flagged as being associated with a stored RF emitter based on emitter data from that emitter data set and the stored emitter data; and the route data of each stored SDV route associated with a route data set flagged as being associated with a stored SDV route based on route data from that route data set and the stored route data. The details of how emitter data and route data are updated may be based on a number of factors including, but not limited to: the source of the map data update; the certainty of the stored data; and degree and nature of the changes in the update.

[00102] As noted above, I/O port 1 100c, which may function as central manual input port, is coupled (in the example embodiment of FIG 1 1 ) via a wired communications link 1 106 to central operator terminal 1 104, which may be desirably co-located with dynamic digital regional map 1002 at a central location. Central operator terminal 1104 may be used by authorized users to manually enter map update data to dynamic digital regional map 1002 through the central manual input port of I/O port 1 100c. Similarly, I/O port 1 100b, which may function as remote manual input port, is coupled (in the example embodiment of FIG 1 1) via a wireless communications link 1000 to remote operator terminal 1 102, which located at a remote location. Remote operator terminal 1 102 may be used by authorized users to manually enter map update data to dynamic digital regional map 1002 through the remote manual input port of I/O port 1 100c. It is noted that the primary distinction between central operator terminal 1 104 and remote operator terminal 1 102 is their location and that, in alternative example embodiments, central operator terminal 1 104 may be coupled to I/O port 1 100c via a local wireless communications link, such as Wi-Fi, and remote operator terminal 1 102 may be coupled to I/O port 1 100c via a direct wired communications link or through a packet switched network.

[00103] As also noted above, I/O ports 1 100a and 110Od are coupled to wireless communications network 1 10. This network may be coupled to one or more RF emitters that are adapted to generate and transmit emitter data sets based on predetermined emitter update criteria. These predetermined emitter update criteria may include:

initialization of the RF emitter; a manually input update request to the RF emitter, receipt of an externally generated update request signal by the RF emitter; scheduled periodic update; and/or detection of potential damage to the RF emitter. The I/O ports 1 100a and 1 10Od may receive the emitter data sets transmitted by these RF emitters through wireless communications network 110, thus functioning as automated emitter input ports. It is contemplated that, in alternative example embodiments, some or all of these self-reporting RF emitters may be coupled to an automated emitter input port of dynamic digital regional map 1002 via a direct wired communications link or through a packet switched network.

[00104] It is also contemplated that mobile emitter locating units adapted to generate and transmit emitter data sets may also be coupled to an automated emitter input port of dynamic digital regional map 1002 via wireless communications network 1 10. These mobile emitter locating units may be deployed to generate and transmit emitter data sets for multiple RF emitter based on the predetermined emitter update criteria. The mobile emitter locating units may employ one or more different types of measurement equipment, such as, for example: laser surveying systems; compasses; altimeters; gyroscopic sensor systems; GPS based sensors; cellular tower triangulation systems; optical systems; digital camera based systems; IR system, laser range-finding systems, and sonar based systems. Some or all of these mobile emitter locating units may include a data storage module and may be coupled to an automated emitter input port of dynamic digital regional map 1002 via a direct wired communications link or through a packet switched network to transmit their emitter data sets periodically, rather than transmitting their emitter data sets in real time (or near real time).

[00105] Additionally, wireless communications network 1 10 may be coupled to one or more mobile route tracing units that are adapted to generate and transmit route data sets, which are desirably determined within the predetermined route accuracy. The I/O ports 1 100a and 1 100d may receive the route data sets transmitted by these mobile route tracing units, thus functioning as automated route input ports. The mobile route tracing units may include several different types of units, such as, for example: land vehicles equipped with various positioning sensors; satellite based imaging systems; and/or laser surveying systems. Example land vehicles may be adapted to automatically measure route data, using its included positioning sensor, while driving along SDV routes and, then, transmit measured route data to dynamic digital regional map 1002 via an automated route input port. The included positioning sensors may desirably include one or more sensors selected from the set of: an accelerometer based sensor; a compass; an altimeter; a gyroscopic sensor system; a GPS based sensor; a cellular tower triangulation system; an optical system; a digital camera based system; an IR system, a laser range-finding system, and a sonar based system. Example satellite based imaging systems may be adapted to determine route data from high- resolution satellite images and, then, transmit the determined route data to dynamic digital regional map 1002 via an automated route input port. Example laser surveying systems may be adapted to measure route data and include a wireless communication system to transmit the measured route data to dynamic digital regional map 1002 via an automated route input port. One skilled in the art may understand that this list of mobile route tracing units merely provides a few specific examples to aid in understanding and is not intended to be limiting. It is contemplated that, in alternative example embodiments, some or all of these mobile route tracing units may include a data storage module and may be coupled to an automated route input port of dynamic digital regional map 1002 via a direct wired communications link or through a packet switched network to transmit their route data sets periodically, rather than transmitting their route data sets in real time (or near real time).

[00106] Further, wireless communications network 110 may be coupled to one or more SDVs that are adapted to generate and transmit vehicle. Each of these feedback-equipped SDV stores a portion of the emitter data and a portion of the route data of the dynamic digital map received by that SDV from the dynamic digital map (vehicle- stored emitter data and vehicle-stored route data) that may be used to determine whether to generate and transmit vehicle based map update data based map update data based on predetermined feedback criteria. These predetermined feedback criteria may include example criteria such as, but not limited to: 1 ) a scheduled periodic feedback; 2) an inconsistent location of the SDV based on its vehicle-stored emitter data; 3) a conflict between the location of the SDV based on its vehicle-stored emitter data and its location based on another positioning system, such as a GPS based system or a cellular tower triangulation system; 4) a conflict between the relative position of the SDV to an SDV route determined using the vehicle-stored emitter data and the vehicle-stored route data, and this relative position based on one or more vehicle-mounted sensor systems, such as: an optical system; a digital camera based system; an IR system, a laser range-finding system, or a sonar based system; 5) a manually input feedback request by an operator of the SDV; and/or 6) receipt of an externally generated feedback request signal by the SDV. The I/O ports 1100a and 110Od may receive the vehicle based map update data transmitted by these feedback- equipped SDVs, thus functioning as feedback input ports.

[00107] It is contemplated that in some example embodiments of the present invention the route data of the dynamic digital map may include a traffic congestion parameter. In such an example embodiment the predetermined feedback criteria of feedback-equipped SDVs may include a predetermined variance between the traffic congestion parameter of the vehicle-stored route data and the traffic congestion parameter measured by one or more vehicle- mounted sensor system of the SDV.

[00108] Still further, one or more I/O ports may adapted receive priority map update data via at least one of: manual input; a wired communications link; a packet switched network; or a wireless communications network, thus functioning as priority route input port. Example priority map update data includes, but in not limited to, priority self driving route closures due to at least one of: construction; public safety; natural disaster; or governmental order.

[00109] In some example embodiments of the present invention, input ports of the data input module of each dynamic digital regional map (or of the dynamic digital map) may require security protocols to verify the authenticity of received map update data. Example security protocols may include, but are not limited to: password protection; biometric verification of authorized users; encrypted data transmission over packet switched networks; encrypted data transmission over wireless communications networks; secure handshakes; automated comparison of map update data with stored emitter data and route data; selective manual review of map update data at the central location.

[00110] In alternative example embodiments of present invention the data output module of one or more of the dynamic digital regional maps (or the dynamic digital map) is coupled to a packet switched network and is adapted to: generate a number of static electronic files, each of which includes a portion of the emitter data and the route data from the corresponding dynamic digital regional map; and publish each of these static electronic file at a unique address on the packet switched network. These static electronic files may be periodically updated by the data output module using the corresponding dynamic digital regional map and republished at its unique address on the packet switched network. Requests for emitter data and route data from SDVs received via the packet switched network may then be processed by: selecting a set of the static electronic files, for each request, to include the requested emitter data and route data from the corresponding dynamic digital regional map; providing the address(es) on the packet switched network of the selected set of static electronic files to the requesting SDV.

[00111] In addition to the RF emitters with emitter data stored in the dynamic digital map (including TRFEs), example embodiments of the present invention may include one or more temporary priority RF beacons, for which emitter data is not stored in the dynamic digital map. Each temporary priority RF beacon is desirably located near at least one of the SDV routes and emits a priority ID signal having a priority intensity. Desirably, the priority ID signal of each temporary priority RF beacon is substantially the same, but is different from every predetermined periodic ID signal of stored RF emitters. This is because, in these example embodiments, the priority ID signal identifies that the portions of all SDV routes within a predetermined distance of the temporary priority RF beacon is temporarily off-limits to SDVs due to at least one of: construction; public safety; natural disaster; or governmental order. Desirably, temporary priority RF beacons may be used by public safety personnel, and other officials, to quickly close SDV routes for brief period while they are on site. If a longer closure is desired the temporary priority RF beacon(s) may be replaced by TRFE(s).

[00112] Example SDV Navigation Method Embodiments

[00113] Other example embodiments of the present invention include example navigation methods for SDVs. FIG 12 is a flowchart illustrating one such example navigation method. Example navigation method 1200 begins with the step of determining the initial absolute global position of the SDV, step 1202. The initial absolute global position of the SDV is desirably determined, with a relatively coarse global accuracy (e.g. less than about 10m), using absolute positioning system such as: a GPS absolute positioning system; a cellular tower triangulation system; or other similar absolute positioning system. The initial absolute global position determined in step 1202 is not sufficiently accurate to safely navigate the SDV, but localizing the SDVs absolute position with this relatively coarse measurement may greatly reduce the amount of data used and simplify the calculations performed in remaining steps of example method 1200.

[00114] A local portion of the dynamic digital map is then stored by SDV, step 1204. This local portion of the dynamic digital map desirably includes route data and emitter data for SDV routes and RF emitters located within at least a portion of the total area included in the dynamic digital may that includes the previously initial absolute global position. The stored route data desirably includes position data for the SDV routes (as discussed in detail above with reference to FIG 3). The stored emitter data desirably includes position data for each RF emitter that is flagged with ID information indicative of the ID signal associated with that RF emitter (as discussed in detail above with reference to FIGs 3, 4A, and 4B).

[00115] As discussed in detail above with reference to FIG 3, in some example embodiments of the present invention, the route data of the dynamic digital map for each SDV route may desirably include centerline position data for a multitude of centerline points along the SDV route. Additionally, each of the RF emitters may associated with one centerline point of the at least one SDV routes (an associated center point). In such example embodiments, the emitter data for each RF emitter desirably includes information identifying the associated center point and may the position data of the RF emitter may be measured relative to that associated center point. Thus, while the position data of the SDV route(s) are desirably absolute position data, the position data for the RF emitters may be relative position data measured relative to the nearest SDV route; therefore, the store position data of the emitter data and the route data may have different predetermined accuracies, less than about .10m for the emitter accuracy, and less than about .50 m, for the route accuracy. It is noted that the route data stored in step 1204 may further include the route width of the SDV route at each centerline point in some example embodiments. Additionally, in some example embodiments of the present invention, the route data stored in step 1204 may also include route data such as: the route speed limit of the SDV route at each centerline point; reported local safety information, including an obstacle map position of fixed obstacles and caution sections having unsafe surface conditions in reported the stored SDV route(s); and/or a local traffic congestion parameter. Example unsafe surface conditions may include, but are not limited to, one or more of: potholes; icy conditions; snow on the surface; water on the surface; downed power lines; or uneven surfaces. [00116] ID signals from a predetermined emitter number (at least three) of nearby RF emitters is received by the SDV, step 1206. Emitter data for these RF emitters was desirably stored in step 1204, and, by comparing the received ID signal to the stored emitter data, each received ID signal may be associated with the position data of its RF emitter.

[00117] For each ID signal received in step 1206, the emitter angle is determined using the received ID signal, step 1208. The emitter angle is the angle between the forward direction of the SDV and the RF emitter associated with the ID signal of that received emitter signal. As discussed in detail above with reference to FIGs 5, 6A, 6B, and 7, multiple RF emitters may be associated with the same ID; however, such RF emitters are located such that the detectable RF emitters at any point along one of the SDV routes have unique ID signals. Both the coarse localization of step 1202 and the possibly reduced portion of the dynamic digital map stored by the SDV in step 1204 may serve to prevent any misidentification of the specific RF emitter identified by a received ID signal.

[00118] Using the multiple emitter angles determined in step 1208 and the emitter data of the corresponding RF emitters stored in step 1204, the local map position and the forward map direction of the SDV in the local portion of the dynamic digital map is determined, step 1210. The local map position of the SDV is determined with a predetermined local accuracy, which is desirably less than about 1 0m, or possibly even about .50 m. The local map position and the forward map direction of the SDV are desirably determined as relative measurements based on the emitter data of the RF emitters used in the determination. In example embodiments in which the emitter position data stored in by the SDV in step 1204 is absolute position data, these relative measurement may be desirably converted to an absolute local map position and an absolute forward map direction for the SDV. In example embodiments in which the emitter position data stored in by the SDV in step 1204 is relative position data, such conversion is unnecessary.

[00119] The local map position of the SDV is compared to the route data stored in step 1204 to determine the current position of the SDV along the closest SDV route (i.e. the current route) and an error distance between the local map position of the SDV and the current route, step 1212.

[00120] In example embodiments in which the stored route data includes position data for a multitude of centerline points, step 1212 may include comparing the local map position of the SDV to the route data stored in step 1204 to determine the closest centerline point to the local map position (the current position of the SDV along the current route). The error distance may then be calculated using the local map position and the centerline position data of the current position.

[00121] In parallel with step 1212, the forward map direction of the SDV is compared to the tangent line of the current route at the current position to determine an error angle from the forward map direction of the SDV to the tangent line of the current route, step 1214.

[00122] In example embodiments in which the stored route data includes position data for a multitude of centerline points, step 1214 may include calculating the tangent line of the current route at the current position using the centerline position data of the current position along the current route and the centerline position data of at least one centerline point (in many cases, the two centerline points adjacent to the current position) of the current route adjacent to the current position. The forward map direction of the SDV may then be compared to this calculated tangent line to determine the error angle from the forward map direction of the SDV to the tangent line of the current route. In some example embodiments, step 1214 may further include calculating the curvature of the current route at the current position using the centerline position data of the current position along the current route and the centerline position data of at least two centerline points of the current route nearest to the current position (in many cases, the four centerline points nearest to the current position).

[00123] Then navigation instructions for the SDV are determined based on the error distance and the error angle, step 1216. These navigation instructions for the SDV may desirably include steering instructions to turn the SDV an amount equal to the error angle, plus a distance correction factor based on the error distance.

[00124] In example embodiments in which step 1214 includes calculating the curvature of the current route at the current position, step 1216 may include this calculated curvature in the determination of the navigation instructions for the SDV. For example, the navigation instructions for the SDV may include steering instructions to turn the SDV an amount equal to the error angle, plus a distance correction factor based on the error distance and a curvature correction factor based on the curvature of the current route at the current position.

[00125] In example embodiments in which the stored route data includes a route width of the SDV route at each centerline point, step 1212 may further include calculating an outer edge offset of the SDV by summing half of the vehicle width of the SDV, the magnitude of the error distance, and the predetermined local accuracy. In such example embodiments, the distance correction factor of the steering instruction may be set to zero if half of the route width of the current route at the current position minus the outer edge offset of the SDV is greater than a minimum clearance parameter. Setting the distance correction factor to zero in such case may reduce oversteering in situations when the SDV is slightly off course, but has adequate clearance, and may lead to a more comfortable riding experience for users. The minimum clearance parameter may be set to a constant, for example about 5m, determined to provide adequate clearance between the edge of the SDV and edge of the SDV route. Or the minimum clearance parameter may be dependent on the vehicle width of the SDV. Alternatively, the minimum clearance parameter be based on local conditions, for example being equal to twice the predetermined local accuracy, or may be dependent on the route width of the current route at the current position. As noted above, the route data stored in step 1204 may include a route speed limit of the SDV route at each centerline point. In such example embodiments, the minimum clearance parameter of the current route at the current position may desirably be dependent on the route speed limit of the current route at the current position.

[00126] Further, in example embodiments in which the stored route data includes the route speed limit of the SDV route at each centerline point, the navigation instructions for the SDV determined in step 1216 may desirably include acceleration instructions determined maintain the speed of the SDV within a predetermined range of the route speed limit of the current route, e.g. +/- 10% of the route speed limit. The speed of the SDV may be determined using the speedometer of the SDV. Alternatively, in another example embodiment of the present invention, an additional step (not shown) of repeating steps 1206, 1208, 1210, 1212, 1214, and 1216 at a predetermined route correction rate is included. Step 1216 further includes storing the local map position of the SDV as a previous vehicle position; and the speed of the SDV may be determined in step 1210 by multiplying the predetermined route correction rate by the distance between the newly determined local map position and the most recently stored previous vehicle position. In addition to providing a means of calculating the speed of the SDV, by repeating these steps, these example embodiments may repeatedly update the navigation instructions for the SDV as it traverses the SDV route. Thus, the desired navigation of the SDV along the SDV route may be maintained. Faster route correction rates may improve the accuracy of the tracking of the SDV to the centerline of the SDV route; however, slower route correction rates may improve the signal to noise ratio S/N of the received ID signals in step 1206 by allowing averaging of these signals (and their inter-antenna time delays) over multiple repetition periods, and/or allow more time for some of the signal processing in steps 1208, 1210, 1212, 1214, and/or 1216, thereby simplifying the circuitry. Based on these considerations, it is contemplated that the predetermined route correction rate may desirably by greater than about 100Hz, and possibly greater than about 10 kHz.

[00127] In example embodiments of the present invention in which the navigation instructions include acceleration instructions, the acceleration instructions may be further determined to maintain an estimated safe speed based on the magnitude of the steering instructions. Additionally, the estimated safe speed may be based on the magnitude of the curvature of the current route at the current position. For example, the acceleration instructions may be determined such that the transverse acceleration magnitude of the SDV remains less than a predetermined transverse acceleration level. In many cases this predetermined transverse acceleration level may be about 5m/s².

Or, the navigation instructions may be determined such that the total acceleration magnitude of the SDV remains less than a predetermined total acceleration level, such as about 9.8 m/s². Or, the navigation instructions may be determined such that the forward acceleration magnitude of the SDV remains less than about 9.8 m/s², and the transverse acceleration magnitude of the SDV remains less than about 5m/s². Maintaining such example maximum acceleration levels may improve both the safety and the passenger comfort of example SDVs according to the example embodiments of the present invention. It is noted that such maximum acceleration levels may be exceeded in emergency situations in which sudden braking and/or dodging to avoid obstacles may lead to higher forward and/or transverse accelerations, respectively.

[00128] In some example embodiments in which each of the RF emitters is associated with a centerline point of the SDV routes (its associated center point), step 1206 may include three substeps: (1 ) determining a current route section based on the absolute global position determined in step 1202; (2) selecting an emitter set of RF emitters from the emitter data stored in step 1204; and (3) receiving ID signals from the RF emitters of the emitter set. The current route section desirably includes the predetermined emitter number of associated center points estimated to be nearest to the SDV based on the previously determined absolute global position. The emitter set of RF emitters includes the RF emitters associated with those center points include in the current route section. Such example embodiments may also include three additional steps (not shown) following step 1216.

[00129] The first of these additional steps is a section loop, i.e. repeating substep 1206 (3), and steps 1208, 1210, 1212, 1214, and 1216 at the predetermined route correction rate (discussed above) until the local map position determined in step 1210 is outside of a route section locus of the absolute global position determined in step 1202. This route section locus may a sphere with locus radius centered on the absolute global position. The locus radius may be a set length, e.g. 10m, or may vary in different portions of the dynamic digital, in which case the desired locus radius for the local portion of the dynamic digital map may be stored in step 1204. Alternatively, substep 1206(1 ) may include determining the route section locus based on the route data stored in step 1204. For example, the route section locus may be determined to be the section of the local portion of the dynamic digital map in which each of the associated center points in the current route section is nearer to each point of the route section locus than every other associated center point in the route data stored in step 1204. The second of these additional steps is a portion loop, i.e. repeating step 1202, substeps 1206(1 ) and 1206(2), and the section loop for each new route section locus until the local map position determined in step 1210 is outside of the local portion of the dynamic digital map stored in step 1204. It is noted that in some example embodiments, instead than repeating step 1202, the most recently determined local map position may be used to determine the new absolute global position of the SDV. The third of these additional steps is to repeat step 1204 and the portion loop. This example embodiment provides a method for an SDV to follow any SDV route, for an unspecified length.

[00130] Example navigation method 1300, illustrated in FIG 13, is another example method for an SDV to follow any SDV route, for an unspecified length. This example navigation method includes many of the steps of example navigation method 1200, as illustrated by the use of a number of identical step numbers, and one skilled in the art may understand that many of the alternative example embodiments of navigation method 1200 may be similarly applied to example navigation method 1300.

[00131] Example navigation method 1300 begins with the step of determining the initial absolute global position of the SDV, step 1202. Then a local portion of the dynamic digital map is then stored by SDV, step 1204.

[00132] An emitter set of RF emitters is selected from the emitter data stored in step 1204, step 1302. This emitter set desirably includes the predetermined emitter number of RF emitters that are estimated to be nearest to the SDV based on the absolute global position determined in step 1202. As discussed in detail above with reference to FIGs 5, 6A, 6B, 7, and 12, multiple RF emitters may be associated with the same ID; however, limited the number of RF emitters in the emitter set to the predetermined emitter number may ensure that each RF emitter in the emitter set has a unique ID signal. This selection may desirably serve to prevent any misidentification of the specific RF emitter identified by a received ID signal in later steps of this example embodiment.

[00133] Once the emitter set is selected, ID signals from the RF emitters of the emitter set are selectively received, step 1304. For each ID signal received in step 1304, the emitter angle is determined using the received ID signal, step 1208. Using the multiple emitter angles determined in step 1208 and the emitter data of the corresponding RF emitters stored in step 1204, the local map position and the forward map direction of the SDV in the local portion of the dynamic digital map is determined, step 1210. This local map position is compared to the route data stored in step 1204 to determine the current position of the SDV along the current route and the error distance between the local map position of the SDV and the current route, step 1212. In parallel with step 1212, the forward map direction of the SDV is compared to the tangent line of the current route at the current position to determine the error angle from the forward map direction of the SDV to the tangent line of the current route, step 1214. Then navigation instructions for the SDV are determined based on the error distance and the error angle, step 1216.

[00134] In two alternative embodiments of example navigation method 1300, a loop is used to continuously update these navigation instructions as the SDV progresses along the SDV route. In the two example embodiments the absolute global position of the SDV may desirably be redetermined in step 1210 based on the local map position.

[00135] In one of these example embodiments, illustrated by the dotted arrow from step 1216 to step 1302, steps 1302, 1304, 1208, 1210, 1212, 1214, and 1216 are repeated at a predetermined route correction rate (discussed in detail above with reference to FIG 12), with the emitter set being redetermined each loop based on the current absolute global position, i.e. the most recently determined local map position. [00136] In the second of these example embodiments, illustrated by the dashed arrows and steps, an emitter set locus is determined, step 1306, following the selection of the emitter set in step 1302. This emitter set locus may be determined using any of the methods discussed for determining the route section locus above with reference to FIG 12. After the navigation instructions for the SDV are determined in step 1216, the current local map position is compared to the emitter set locus to determine whether the current local map position is within the emitter set locus, step 1308. If the current local map position is within the emitter set locus, steps 1304, 1208, 1210, 1212, 1214, and 1216 are repeated at the predetermined route correction rate (the navigation loop), updating the local map position, error distance, error angle, and navigation instructions based on new ID signals received from the same emitter set.

If, however, the current local map position is outside of the emitter set locus, then step 1302 is repeated to determine a new emitter set based on the current absolute global position of the SDV, a new emitter set locus is determined, 1306, and then the navigation loop is repeated (the locus loop). The locus loop may be desirably repeated until the local map position determined in step 1210 is determined to be outside of the local portion of the dynamic digital map stored in step 1204. At this point, if desired, a new local portion of the dynamic digital map stored in step 1204, and the locus loop resumed.

[00137] Alternatively, the local portion of the dynamic digital stored in step 1204 may include a map locus set that includes map loci sufficient to tile the local portion. Each of the map loci in the map locus set is associated with an emitter set of RF emitters that includes the predetermined emitter number of RF emitters. Desirably, each map locus may be the section of the local portion of the dynamic digital map in which each of the associated emitter set of RF emitters is nearer to each point in that map locus than every other RF emitter in the emitter data stored in step 1204. In such an example embodiment, the selection of the emitter set in step 1302 involves selecting the one map locus from the map locus set stored in step 1204 that includes the absolute global position. The emitter set associated with selected map locus becomes the selected emitter set. Step 1306, in these example embodiments, merely involves selecting the map locus as the emitter set locus.

[00138] In example embodiments in which the route data of the dynamic digital map for each SDV route include centerline position data for the SDV route and the emitter data for each RF emitter includes information identifying its associated center point, the set of map loci may be determined using on the associated center points of the RF emitters stored in step 1204. Each map locus in the set of map loci is associated with an emitter set including the predetermined emitter number of emitters. Each of these emitter sets includes a median RF emitter, defined as the RF emitter that is located nearer to a centroid of its emitter set than the other RF emitters in that emitter set. Thus, each map loci in the map locus set stored in step 1204 may desirably include information identifying the associated set of RF emitters and the associated center point of the median RF emitter of that emitter set of RF emitters (a midpoint of the map locus). The section of the local portion of the dynamic digital map corresponding to each map locus may then be defined that section in which all of the points are nearer to the midpoint of that map locus that to the midpoint of any other map locus in the map locus set stored in step 1204. Selection of the map locus in step 1302 (and thus, the emitter set) is simplified to merely determining the map locus midpoint nearest to the absolute global position of the SDV.

[00139] The example embodiments described with reference to FIGs 12 and 13 describe a number of example navigation methods whereby SDVs may follow any SDV route for an unspecified length. Example navigation method 1400 in FIG 14 illustrates a method for SDVs to determine and navigate a specific route based on a user-entered destination. This example navigation method includes many of the steps of the example navigation methods 1200 and 1300, as illustrated by the use of some of the same step numbers in FIG 1400; and it may be understood by one skilled in the art that many of the alternative example embodiments of navigation method 1200 and 1300 may be similarly applied to example navigation method 1400.

[00140] In example navigation method 1400, before the beginning of each trip, the initial absolute global position of the SDV is determined, step 1202, and a destination for the trip is received from the operator of the SDV, step 1402. This destination may be entered via various input apparatus including, but not limited to: a keyboard; a mouse; a touchpad; a touchscreen; a voice-activated control unit; and/or a remote control device. Once the initial absolute global position of the SDV is determined and the destination is received, a trip route (extending from the initial absolute global position to the destination) is determined along the SDV route(s) of the dynamic digital map, step 1404. Desirably, as in example navigation methods 1200 and 1300, the complete dynamic digital map is stored and maintained at one or more central map facilities, and/or in one or more cloud-based computing infrastructures. In an example embodiment, the SDV may transmit its determined initial absolute global position and the received destination to the dynamic digital map over a wireless communications network and the trip route may be determined by processors within the dynamic digital map. Then, the local portion of the dynamic digital map to be transmitted to the SDV (the subset of the route data corresponding to the trip route and emitter data for a set of RF emitters within an emitter distance of the trip route, AKA the trip portion of the dynamic digital map) may also be determined by these processors.

[00141] In another example embodiment of navigation method 1400, a route map including a summary portion of the position data for the SDV routes may desirably be stored in the SDV. The trip route may be determined from the route map. The SDV may transmit a route request to the dynamic digital map over a wireless communications network for the trip portion from the dynamic digital map.

[00142] The summary portion of the route data may be updated on a predetermined schedule; or it may be updated prior to each trip, in response to an update signal from the dynamic digital map, at the operators request, in response to a discrepancy between the summary portion and more complete route data downloaded from the dynamic digital map, and/or in response to a discrepancy between the summary portion and route data determined by the SDV. The summary portion of the route data in this example embodiment may desirably include position data for a reduced number of the centerline points of the SDV route(s), without additional data such as width data, traffic congestion, speed limits, etc. Alternatively, in another example embodiment, the summary portion of the route data may include some, desirably limited, information, such as speed limits; average congestion; route type, e.g. toll routes, unpaved routes; etc., that may be used by the SDV to determine a preferred trip route. Additionally, in this alternative embodiment, the operator may be able to specify route options, including, for example: route types, such as toll roads or high traffic areas, to avoid; scenic routes to include in the trip route; mid-route stops; the shortest route; and/or the fastest route.

[00143] In example embodiments in which the trip route is determined by the SDV using a route map, it is noted that the SDV may determine multiple potential trip routes, in step 1404, from which a final trip route may be selected by the operator before the local portion is requested from the dynamic digital map; or the SDV may send information for the multiple potential trip routes to the dynamic digital map and the final trip route may be selected (and the corresponding trip portion of the dynamic digital map determined) by the dynamic digital map based on the more complete, and possibly more recently updated, route data available to the dynamic digital map.

[00144] Once, determined, the trip portion of the dynamic digital is transmitted to the SDV over a wireless communications network, and stored, step 1406. The trip portion of the dynamic digital may be desirably stored in a trip module of the SDV adapted for this purpose.

[00145] ID signals from a predetermined emitter number (at least three) of nearby RF emitters is received by the SDV, step 1206. Emitter data for these RF emitters was desirably stored as part of the trip portion of the dynamic digital map in step 1406, and, by comparing the received ID signal to the stored emitter data, each received ID signal may be associated with the position data of its RF emitter. For each ID signal received in step 1206, the emitter angle is determined using the received ID signal, step 1208. Using the multiple emitter angles determined in step 1208 and the emitter data of the corresponding RF emitters stored in step 1406, the local map position and the forward map direction of the SDV in the local portion of the dynamic digital map is determined, step 1210.

[00146] This local map position is compared to the destination received from the SDV operator in step 1402, to determine if the local map position is within a predetermined locus of the destination, step 1408. The predetermined locus may desirably be a sphere with a radius of about 1.0m centered on the destination. It is noted that there may be situations in which it may not be desirable for the SDV to navigate this close to the destination; for example, the destination may be located off of the SDV route(s), such as in a building, or another SDV may already be at the destination. In such situations the locus may extend to the nearest practical location to the destination.

[00147] If the SDV is determined to be within the predetermined locus, the destination has been reached and the SDV navigation is complete, step 1410. In some cases, the SDV may be immediately stopped at this point, or it may enter a parking subroutine (not shown). In either of these cases, it may be desirable for navigation of the SDV in step 1216 to include slowing down as the destination is approached to make this stopping (or parking) more comfortable for the SDV occupant(s).

[00148] If the SDV is determined not to be within the predetermined locus in step 1408, the local map position is compared to the route data stored in step 1406 to determine the current position of the SDV along the current route and the error distance between the local map position of the SDV and the current route, step 1212. In parallel with step 1212, the forward map direction of the SDV is compared to the tangent line of the current route at the current position to determine the error angle from the forward map direction of the SDV to the tangent line of the current route, step 1214. Then navigation instructions for the SDV are determined based on the error distance and the error angle, step 1216.

[00149] After the navigation instructions are determined and used to navigate the SDV another interval along the trip route, the method returns to step 1206, and new ID signals are received and processed in a loop of steps 1208, 1210, 1408, 1210, 1212, and 1216 to continue navigating the SDV along the trip route until the destination is determined to be reached in step 1408 and the trip completed in step 1410. Desirably this navigation loop is repeated with a predetermined route correction rate greater than about 100Hz, and possibly greater than about 10 kHz as discussed in detail above with reference to FIGs 12 and 13. [00150] FIG 15 illustrates a further example navigation method 1500 of navigating an SDV using: a number of fixed (permanent) RF emitters, as in example navigation methods 1200, 1300, and 1400; and one or more temporary RF emitters (TRFEs). This example navigation method includes many of the steps of example navigation method 1200, as illustrated by the use of a number of identical step numbers, and one skilled in the art may understand that many of the alternative example embodiments of navigation method 1200 may be similarly applied to example navigation method 1500. It is also contemplated that the recursive methods of the example embodiments of navigation methods 1300, and 140 may be combined with the embodiments of example navigation method 1500.

[00151] Example navigation method 1500 begins with the step of determining the initial absolute global position of the SDV, step 1202. Then a local portion of the dynamic digital map is then stored by SDV, step 1204.

[00152] ID signals used by the fixed RF emitters for which emitter data was stored in step 1204 are received, step 1502. These ID signals are transmitted on frequencies within a first predetermined bandwidth. In an alternative embodiment, received ID signals that have a received intensity greater than a minimum detection intensity are separated for further signal processing, step 1510. As part of this separation step, the RF emitters associated with the predetermined emitter number of separated ID signals having the greatest received intensity may be identified, based on the emitter data stored in step 1204, and the other received ID signals may be discarded.

[00153] For each ID signal received in step 1502 (or for each ID signal separated and identified in step 1510 in the alternative embodiments that include that step), the emitter angle may be determined using the received ID signal, step 1208. Using the multiple emitter angles determined in step 1208 and the emitter data of the corresponding RF emitters stored in step 1204, the local map position and the forward map direction of the SDV in the local portion of the dynamic digital map is determined, step 1210. This local map position is compared to the route data stored in step 1204 to determine the current position of the SDV along the current route and the error distance between the local map position of the SDV and the current route, step 1212, and the forward map direction of the SDV is compared to the tangent line of the current route at the current position to determine the error angle from the forward map direction of the SDV to the tangent line of the current route, step 1214.

[00154] In parallel to steps 1502, (1510,) 1208, and 1210, temporary ID signals from TRFEs are received, step 1504. These temporary ID signals may be transmitted on frequencies within the first bandwidth used by the fixed RF emitters, and identified by the encoding of their temporary ID signals. Alternatively, the temporary ID signals may be transmitted on frequencies within a second bandwidth used exclusively by TRFEs. In an alternative embodiment, received temporary ID signals that have a received intensity greater than the minimum detection intensity may be separated for further signal processing, step 1512.

[00155] Each received (or separated) temporary ID signal is processed to determine the temporarily closed portion of an SDV route in the local portion of the dynamic digital map associated with that temporary ID signal, step 1506. This determination may be based on closure information, including the TRFE map location of the corresponding TRFE, encoded in each temporary ID signal; or the determination may be made using closure information included in the local portion of the dynamic digital map stored by the SDV in step 1204 (described in detail below). Whether encoded directly in the temporary ID signal or stored in the dynamic digital map, the closure information desirably includes data identifying the temporarily closed section. [00156] Alternatively, the determination of the temporarily closed SDV route portion associated with each temporary ID signal may be accomplished using the local map position and the forward map direction of the SDV in the local portion of the dynamic digital map determined in step 1208 and the temporary ID signal received in step 1504 (and separated in example embodiments including step 1512). For each temporary ID signal received (and separated): the TRFE map location of the corresponding temporary emitter is determined in the local portion of the dynamic digital map; he SDV route in the local portion of the dynamic digital map nearest to the TRFE map location is identified as the corresponding SDV route; and the portion of the corresponding SDV route that lies within a closure locus of the estimated TRFE map location is determined to be the temporarily closed portion of the corresponding SDV route.

[00157] It is contemplated that the closure locus may be defined in a number of ways. In one example embodiment, the closure locus may be predetermined for all TRFEs. In some other example embodiments, the closure locus may vary based on location of the TRFE or may be encoded in the temporary ID signal of the TRFE.

For example, in local portion of the dynamic digital map where the SDV route is formed of blocks that have no intersections with other SDV routes within the block (i.e. sections of the SDV route defined by intersections), the closure locus may be the block of the corresponding SDV route nearest to the estimated TRFE map location. Such a closure locus may be desirable to simplify rerouting of the SDV around a temporarily closed portion. As another example, the closure locus may be a sphere having a set radius. A smaller radius, e.g. 2m, may be useful to cause SDVs to avoid a temporary hazard, such as a pothole or disabled vehicle, which a larger radius, e.g.50m, may be useful to close an entire area that is hazardous, such as SDV route next to a building fire. The closure locus may dependent on the temporary ID signal of the corresponding TRFE, which may have multiple ID signal settings for different situations.

[00158] In an example embodiment of the present invention, the TRFE map location may be estimated by determining the direction to the TRFE and estimating its distance from the SDV. The TRFE angle between the forward direction of the SDV and the TRFE associated with that temporary ID signal is determined using the received TRFE signal in a similar manner to the emitter angles determined for the ID signals of fixed RF emitters in step 1208. The TRFE distance from the SDV of each TRFE may be estimated by comparing the received TRFE intensity with a predetermined TRFE power level. The TRFE map location of the corresponding TRFE in the local portion of the dynamic digital map may be estimated using this determined TRFE angle and estimated TRFE distance, the local map position and the forward map direction of the SDV in the local portion of the dynamic digital map determined in step 1210, and the route data stored in step 1204.

[00159] Once all nearby temporarily closed portions of the SDV route(s) are determined in step 1506 and the error distance and the error angle are determined in steps 1210 and 1212, respectively, navigation instructions for the SDV are determined, step 1508. These navigation instructions, which (as in other example methods of the present invention) are based on the error distance and the error angle, are determined so as to avoid any temporarily closed portion of the SDV route(s).

[00160] As described in detail above with reference to example embodiments of FIG 14, the dynamic digital map may be stored and maintained at a central map facility; a route map that includes a summary portion of the position data for the SDV route(s) may be stored in a map module of the SDV; and before the beginning of a trip, a destination for the trip may be received from the operator of the SDV. In such example embodiments, a trip route along the SDV route(s) of the dynamic digital map may be determined from the stored route map based on the initial absolute global position of the SDV and the received destination, and the local portion of the dynamic digital map may be selected to include a subset of the route data corresponding to the trip route and emitter data for a set of RF emitters within an emitter distance of the trip route.

[00161] It is contemplated that these example embodiments may be combined with example method 1500. In such example combinations, the dynamic digital map may include reported closure information identifying temporarily closed portions of the SDV route(s) that have been reported to the central facility. This closure information desirably includes route data of temporarily closed portions of SDV routes and emitter data of the associated TRFEs. The closure information may be reported to the central facility by users initializing the TRFEs when they are deployed, or by feedback from SDVs when they receive ID signals of unreported TRFEs (described in detail below). Feedback from SDVs may be particularly useful for TRFEs deployed by public safety officials, who may not have time to perform an initialization process during deployment.

[00162] In these example embodiments, the route map stored in the map module of the SDV may desirably include at least a portion of the reported closure information. The trip route determined by the SDV may desirably be determined so as to avoid the reported temporarily closed portions of SDV routes included in the route map of the SDV. As the summary portion of the route data stored in the route map may not include information of all temporary route closures, when the SDV transmits a route request to the dynamic digital map based on its determined trip route, the central facility may determine that the trip route requested include temporarily closed portions and respond to the route request by sending an update for the route map rather than the local portion. The SDV may then redetermine the trip route using the updated route map.

[00163] These example combination methods may also include a navigation loop from step 1508 back to steps 1502 and 1504 (not shown in FIG 15). Once the local portion is determined and stored, the example method may proceed through the steps of the navigation loop to navigate the SDV along the trip route as described in detail above with reference to FIGs 13 and 14, with the additional element of determining, at step 1508 of each loop, whether any temporarily closed portions of the SDV route(s) determined in step 1506 not included in the stored local portion of the dynamic digital map, step 1514, and additionally, whether these new temporarily closed portions of the SDV route(s) are on the trip route. If any temporarily closed portions of SDV routes are not included in the stored local portion, the closure information for these temporarily closed portions of SDV routes may be reported to the central map facility over the wireless communications network, step 1516. It is noted that the SDV may not be able to determine all of the closure information and that some of the closure information may not be determined accurately, particularly the position of the TRFE. The central facility, however, may use multiple such imperfect feedback reports from multiple SDVs to determine more complete and accurate closure information before including the resulting closure information in the dynamic digital map.

[00164] If any temporarily closed portions of the SDV route(s) determined in step 1506 are determined to be on the trip route in step 1514, in addition to reporting the new temporarily closed portion(s) of SDV route(s) to the central map facility over the wireless communications network in step 1516, a new trip route is desirably determined using the most recently determined map position of the SDV as the initial position. The local portion of the dynamic digital map for this new trip route may then be requested over the wireless network. Alternatively, unstored regions of the local portion of the dynamic digital map for which route data is not stored in the trip module may be identified; and the route data and the emitter data for only these unstored regions of the local portion of the dynamic digital map requested) from the central map facility. Either way, it may be desirable to also request updated closure information of the local portion of the dynamic digital map from the central map facility and verifying that the new trip route does not include any temporarily closed route portions.

[00165] Example navigation method 1600 illustrated in FIG 16 includes the use of additional vehicle mounted sensors to assist in SDV navigation. Such vehicle mounted sensors may be particularly desirable for sensing temporary obstacles, such as debris in the road; dynamic road conditions, such as rain, ice, or traffic congestion; and moving objects, such as pedestrians, animals, and other vehicles. Vehicle mounted sensors may also be used to provide feedback in the event of damage to the infrastructure used by the various example navigation methods of the present invention. Example navigation method 1600 includes many of the steps of example navigation method 1200, as illustrated by the use of a number of identical step numbers. Additionally, one skilled in the art may understand that many of the alternative example embodiments of navigation methods 1200, 1300, 1400, and 1500 may be applied to example navigation method 1600. Example navigation method 1600 begins with the step of determining the initial absolute global position of the SDV, step 1202. Then a local portion of the dynamic digital map is then stored by SDV, step 1204.

[00166] ID signals from the predetermined emitter number (at least three) of nearby RF emitters is received by the SDV, step 1206. For each ID signal received in step 1206, the emitter angle may be determined using the received ID signal, step 1208. Using the multiple emitter angles determined in step 1208 and the emitter data of the corresponding RF emitters stored in step 1204, the local map position and the forward map direction of the SDV in the local portion of the dynamic digital map is determined, step 1210. This local map position is compared to the route data stored in step 1204 to determine the current position of the SDV along the current route and the error distance between the local map position of the SDV and the current route, step 1212, and the forward map direction of the SDV is compared to the tangent line of the current route at the current position to determine the error angle from the forward map direction of the SDV to the tangent line of the current route, step 1214.

[00167] In parallel with the reception and processing of ID signals from nearby RF emitters to determine the error distance and the error angle, local conditions of the SDV are sensed by vehicle mounted sensors, step 1602. The local conditions of the SDV sensed for desirably include at least one of: fixed obstacles near the SDV in the current route; moving objects near the SDV; and/or unsafe surface conditions of the SDV route. These local conditions of the SDV may be sensed in step 1602 using one or more known method, such as: optical sensing using a vehicle-mounted active optical sensor system; optical sensing using a vehicle-mounted passive optical sensor system; image recognition using a vehicle-mounted digital camera based system; Infrared (IR) sensing using a vehicle-mounted active IR sensor system; IR sensing using a vehicle-mounted passive IR sensor system; image recognition using a vehicle-mounted IR camera based system; image recognition using a vehicle-mounted sonar based system; range-finding using a vehicle-mounted laser range-finding system, and/or range-finding using a vehicle-mounted sonar based range-finding system. [00168] Once the selected local conditions have been sensed in step 1602 and the error distance and the error angle are determined in steps 1210 and 1212, respectively, navigation instructions for the SDV are determined, step 1604. The error distance and the error angle are determine to accurately navigate the SDV along the current SDV route, but safe and comfortable navigation of SDVs may involve more than merely tracking along a predetermined SDV route. Moving objects, including other SDVs, and recent changes to the SDV route, not yet included in the dynamic digital map, such as: wet or icy conditions; road damage; debris; and/or traffic congestion, may also desirably impact the safety and comfort of SDV navigation. Therefore, in example navigation method 1600, the navigation instructions may be initially determined using the error distance and the error angle determined in step 1212 and 1214, respectively, as in other example embodiments of the present invention, and then may be desirably modified based the local conditions sensed in step 1602. Such modification of the navigation instructions may include steering instructions to navigate around obstacles (fixed or moving), or to avoid obstacles by changing lanes in the case of multi-lane SDV routes; and/or acceleration instructions to assist in avoiding obstacles or to reduce the speed of the SDV for safety in sections of SDV routes with excessive traffic congestion and/or unsafe surface conditions.

[00169] As in the example navigation methods described above with reference to FIGs 12, 13, 14, and 15, the dynamic digital map may desirably be stored and maintained at a central map facility. It is contemplated that, in example method 1600, the dynamic digital map may include emitter data, route data, and information indicative of local conditions in the area of dynamic digital map. This local condition information may include, but is not limited to: local traffic congestion parameters; an obstacle map of the positions of non-permanent fixed obstacles in the SDV route(s); and/or caution sections of the SDV route(s) that have unsafe surface conditions. In these example embodiments, the local portion of the dynamic digital map stored in the map module of the SDV in step 1204 may desirably include at least a portion of this local condition information corresponding to the local portion. Additionally, it may be desirable for the local condition information stored by the SDV to be updated using a wireless

communications network periodically during navigation.

[00170] In an alternative example embodiment of example navigation method 1600, the local conditions sensed in step 1602 are compared to the local condition information for the current local map position stored in the map module of the SDV, step 1606. If there is a significant discrepancy between the sensed local conditions and the stored local condition information, then the SDV may report this discrepancy between the sensed local conditions and the stored local condition information to the dynamic digital map, step 1608. For example, if the SDV determines that there is a difference between the stored local traffic congestion parameter and the sensed local traffic congestion parameter that exceeds a predetermined variance, then the sensed local traffic congestion parameter may be reported to the dynamic digital map over the wireless communications network. The dynamic digital map may use the local traffic congestion parameters reported by multiple SDV during a moving time window to update its stored local traffic congestion parameter. In another example, if the SDV determines that sensed local conditions conflict with stored reported safety information, such as locations of fixed obstacles or unsafe surface conditions, then updated safety information may be reported to the dynamic digital map over the wireless communications network.

[00171] In another alternative example embodiment of example navigation method 1600, the local conditions sensed in step 1602 further include a sensed approximate relative position of the SDV to the current route and a sensed approximate relative angle of the SDV to the tangent of the current route. The sensed approximate relative position of the SDV may be compared to the error distance determined in step 1212 to generate a position difference, step 1610. If the generated position difference is greater than a predetermined positional uncertainty (e.g. about 1.0m), the local map position and the position difference may be reported to the dynamic digital map over a wireless communications network, step 1612. And the sensed relative angle of the SDV may be compared to the error angle determined in step 1214 to generate an angle difference, step 1614. If the generated angle difference is greater than a predetermined angular uncertainty (e.g. about 5°), the local map position and the angle difference may be reported to the dynamic digital map over a wireless communications network, step 1616.

[00172] In a further alternative example embodiment of example navigation method 1600 (not shown) in which the local conditions sensed in step 1602 further include the sensed approximate relative position and the sensed approximate relative angle of the SDV, the sensed approximate relative position and the sensed approximate relative angle of the SDV may be used to determine if there may be an issue with one or more of the RF emitters. As in example embodiment just discussed, in this example embodiment, the approximate relative position is compared to the error distance to generate a position difference and the sensed relative angle is compared to the error angle to generate an angle difference.

[00173] If the position difference is greater than the predetermined positional uncertainty, the number (X) of emitter angles used in step 1210 to determine the local map position and the forward map direction of the SDV are determined and X unique subsets of these emitter angles are selected such that each unique subset leaves out a different one of the emitter angles (i.e. each subset has X-1 members). For each of these unique subsets: a subset map position and a subset forward direction of the SDV are determined; a subset error distance and a subset error angle are determined using the determined subset map position and subset forward direction; and the sensed approximate relative position is compared to the subset error distance to generate a subset position difference. If exactly one of these subset position differences is less than the predetermined positional uncertainty, the error distance determined in step 1212 and the error angle determined in 1214 are replaced with that subset error distance and subset forward direction, respectively. The RF emitter associated with the emitter angle not included in that subset is identified and reported to the dynamic digital map over a wireless communications network as potentially damaged. If none, or multiple, of the subset position differences are less than the predetermined positional uncertainty, the local map position and the position difference may desirably be reported to the dynamic digital map over the wireless communications network.

[00174] Similarly, if the angle difference is greater than the predetermined angular uncertainty, the sensed approximate relative angle of the SDV may be compared to the subset error angle for each of the X unique subsets to generate X subset angle differences. If exactly one of these subset angle differences is less than the predetermined angular uncertainty, the error distance determined in step 1212 and the error angle determined in 1214 are replaced with that subset error distance and subset forward direction, respectively. The RF emitter associated with the emitter angle not included in that subset is identified and reported to the dynamic digital map over the wireless

communications network as potentially damaged. If none, or multiple, of the subset angle differences are less than the predetermined angular uncertainty, the local map position and the angle difference may desirably be reported to the dynamic digital map over the wireless communications network. [00175] As described in detail above with reference to example embodiments of FIGs 14 and 15, a route map that includes a summary portion of the position data for the SDV route(s) may be stored in a map module of the SDV; and before the beginning of a trip, a destination for the trip may be received from the operator of the SDV. In such example embodiments, a trip route along the SDV route(s) of the dynamic digital map may be determined from the stored route map based on the initial absolute global position of the SDV and the received destination, and the local portion of the dynamic digital map may be selected to include a subset of the route data corresponding to the trip route and emitter data for a set of RF emitters within an emitter distance of the trip route. It is contemplated that these example embodiments may be combined with example method 1600, as well. In such example combinations, the trip route may desirably be chosen to substantially avoid sections of the SDV route(s) with unfavorable local conditions, such as, for example, heavy traffic or icy surfaces. Such example embodiments may use algorithms designed to estimate and optimize criteria such as: travel time; safety; passenger comfort; fuel consumption; etc., based on the current information stored in the dynamic digital map.

[00176] These example combination methods may also include a navigation loop from step 1604 back to steps 1206 and 1602 (not shown in FIG 16). Once the local portion is determined and stored, the example method may proceed through the steps of the navigation loop to navigate the SDV along the trip route as described in detail above with reference to FIGs 13 and 14, with the additional element of determining, at step 1602 of each loop, whether to modify the navigation instructions based on the sensed local conditions.

[00177] Example navigation method 1700 illustrates a method for an SDV to navigate an SDV route. This example navigation method includes many of the steps of example navigation method 1200, as illustrated by the use of a number of identical step numbers, but including a more specific and detailed scheme for determining the local map position and forward direction of the SDV from the emitter angles. It is contemplated that one skilled in the art may understand that many of the alternative example embodiments of navigation method 1200, as well as those of example navigation methods 1300, 1400, 1500, and 1600, may be similarly applied to example navigation method 1700.

[00178] Example navigation method 1700 begins with determining the initial absolute global position of the SDV, step 1202. Then a local portion of the dynamic digital map is then stored by SDV, step 1204. ID signals from the predetermined emitter number (at least three) of nearby RF emitters is received by the SDV, step 1206. For each ID signal received in step 1206, the emitter angle may be determined using the received ID signal, step 1208.

[00179] For each pair of emitter angles determined in step 1208, an inter-emitter angle between the corresponding RF emitters is calculated using the pair of emitter angles, step 1702. An emitter pair locus in the local portion of the dynamic digital map is determined for each RF emitter pair for which an inter-emitter angle was calculated in step 1702 using the emitter data of the RF emitter pair stored in step 1204 and the inter-emitter angle, step 1704. Each emitter pair locus is the set of possible SDV positions based on the determined inter-emitter angle of the corresponding RF emitter pair, i.e. the set of points in the local portion where a pair of rays separated by the inter emitter angle intersect with stored locations of the pair of RF emitters.

[00180] Once all of the emitter pair loci are determined, the local map position of the SDV may be determined to be a position in the local portion of the dynamic digital map having the minimum mean separation from the emitter pair loci, step 1706. It is contemplated that it is necessary to calculate the mean separation from the multiple emitter pair loci for every location in the local portion, as the approximate local map position of the SDV may be known from the absolute global position determined in step 1202 (or the previously determined local map position in example embodiments including a navigation loop). Numerous optimization routines may be used to minimize the mean separation based on a survey of nearby locations beginning from the determined absolute global position (or the previously determined local map position). The mean separation of each surveyed position in the local portion of the dynamic digital map from the emitter pair loci may be determined based on the separations between that position and the closest point of each emitter pair locus to it. The local map position of the SDV may be determined by treating the separation a positional error and minimizing its mean using any of a number of error minimization techniques, including, but not limited to: root mean squared error (RMSE) techniques; weighted RMSE techniques; mean absolute error (MAE) techniques; or weighted MAE techniques.

[00181] The forward map direction of the SDV in the local portion of the dynamic digital map may then be determined, step 1708, using the emitter angles determined in step 1208 and the emitter data of their corresponding RF emitters stored in step 1204, as well the local map position of the SDV determined in step 1706.

[00182] The local map position is compared to the route data stored in step 1204 to determine the current position of the SDV along the current route and the error distance between the local map position of the SDV and the current route, step 1212; and the forward map direction of the SDV is compared to the tangent line of the current route at the current position to determine the error angle from the forward map direction of the SDV to the tangent line of the current route, step 1214. Then navigation instructions for the SDV are determined based on the error distance and the error angle, step 1216.

[00183] Example navigation method 1800 illustrates another method for an SDV to navigate an SDV route. This example navigation method includes all of the steps of example navigation method 1700, as illustrated by the use of a number of identical step numbers, but includes scheme for determining potential errors in emitter data received from the dynamic digital map and reporting such potential errors to desirably update the dynamic digital map. These potential errors may include damaged or displaced RF emitters, or possibly inaccurate and/or incorrect emitter data previously reported to the dynamic digital map. It is contemplated that one skilled in the art may understand that many of the alternative example embodiments of navigation method 1700, as well as those of example navigation methods 1200, 1300, 1400, 1500, and 1600, may be similarly applied to example navigation method 1800.

[00184] Example navigation method 1800 begins with determining the initial absolute global position of the SDV, step 1202. Then a local portion of the dynamic digital map is then stored by SDV, step 1204. ID signals from the predetermined emitter number (at least three) of nearby RF emitters is received by the SDV, step 1206. For each ID signal received in step 1206, the emitter angle may be determined using the received ID signal, step 1208.

[00185] For each pair of emitter angles determined in step 1208, an inter-emitter angle between the corresponding RF emitters is calculated using the pair of emitter angles, step 1702. An emitter pair locus in the local portion of the dynamic digital map is determined for each RF emitter pair for which an inter-emitter angle was calculated in step 1702 using the emitter data of the RF emitter pair stored in step 1204 and the inter-emitter angle, step 1704. Once all of the emitter pair loci are determined, the local map position of the SDV may be determined to be a position in the local portion of the dynamic digital map having the minimum mean separation from the emitter pair loci, step 1706. The forward map direction of the SDV in the local portion of the dynamic digital map may then be determined, step 1708, using the emitter angles determined in step 1208 and the emitter data of their corresponding RF emitters stored in step 1204, as well the local map position of the SDV determined in step 1706.

[00186] For each of the emitter angles determined in step 1208, an emitter ray in the local portion of the dynamic digital map is determined, step 1802. Each emitter ray is the ray originating from the corresponding RF emitter in a direction equal 180° plus the corresponding emitter angle measured from the forward direction of the SDV determined in step 1708. The ray offset distance is then determined for each of these emitter rays, step 1804. The ray offset distance is the minimum distance (absolute value magnitude) between the corresponding emitter ray in step 1802 and the local map position of the SDV determined in step 1706. The largest ray offset distance from the ray offset distances determined in step 1804 is selected, step 1806, and the corresponding RF emitter identified. If multiple ray offset distances are identical, the value may be used in further steps and all corresponding RF emitters identified.

[00187] The largest ray offset distance is compared to a predetermined positional uncertainty (e.g. about 1 0m), step 1808. If the largest ray offset distance is greater than the predetermined positional uncertainty, the emitter angle(s) corresponding to the RF emitter(s) having the largest ray offset distance is removed from the set of determined emitter angles, step 1810; and steps 1702, 1704, 1706, and 1708 may be repeated using the reduced set of determined emitter angles to redetermine the local map position and forward direction of the SDV; and steps 1802, 1804, 1806, and 1808 may be repeated to determine the accuracy of the redetermined local map position and forward direction of the SDV. Additionally, if the largest ray offset distance is determined to be greater than the predetermined positional uncertainty, the identified RF emitter(s) corresponding the emitter angles removed from the set of determined emitter angles (the removed RF emitters) may be reported to the dynamic digital map over a wireless communications network as potentially damaged (or as having potentially inaccurate or incorrect emitter data), step 1812.

[00188] If the number of emitter angles remaining in the set of determined emitter angles following step 1812 is less than three, the example navigation method may issue a flag indicating a navigation issue to the SDV and/or the SDV operator and bring the SDV to a stop (not shown). Alternatively (or additionally), the method may return to step 1206 to receive new ID signal and try again to determine the local map position and forward direction of the SDV with sufficient certainty to allow safe navigation of the SDV to continue.

[00189] If the largest ray offset distance is less than or equal to the predetermined positional uncertainty, the local map position determined in step 1706 is compared to the route data stored in step 1204 to determine the current position of the SDV along the current route and the error distance between the local map position of the SDV and the current route, step 1212; and the forward map direction of the SDV determined in step 1708 is compared to the tangent line of the current route at the current position to determine the error angle from the forward map direction of the SDV to the tangent line of the current route, step 1214. Then navigation instructions for the SDV are determined based on the error distance and the error angle, step 1216.

[00190] As described in detail above with reference to example embodiments of FIGs 14, 15, and 16, a route map that includes a summary portion of the position data for the SDV route(s) may be stored in a map module of the SDV; and before the beginning of a trip, a destination for the trip may be received from the operator of the SDV. In such example embodiments, a trip route along the SDV route(s) of the dynamic digital map may be determined from the stored route map based on the initial absolute global position of the SDV and the received destination, and the local portion of the dynamic digital map may be selected to include a subset of the route data corresponding to the trip route and emitter data for a set of RF emitters within an emitter distance of the trip route. It is contemplated that these example embodiments may be combined with example methods 1700 and 1800, as well. In such example combinations, the trip route may desirably be chosen to substantially avoid sections of the SDV route(s) with unfavorable local conditions, such as, for example, heavy traffic or icy surfaces. Such example embodiments may use algorithms designed to estimate and optimize criteria such as: travel time; safety; passenger comfort; fuel consumption; etc., based on the current information stored in the dynamic digital map.

[00191] These example combination methods may also include a navigation loop from step 1216 back to steps 1206 (not shown in FIGs 17 and 8). Once the local portion is determined and stored, the example method may proceed through the steps of the navigation loop to navigate the SDV along the trip route as described in detail above with reference to FIGs 13 and 14 until the destination has been reached.

[00192] Example SDV Navigation System Embodiments

[00193] Another example embodiment of the present invention is a navigation system for an SDV. FIG 19 illustrates example architecture for such an example navigation system. In the example navigation system of FIG 19, antenna array 1900, local map memory 1902, and navigation system signal processing modules 1904 are coupled to the SDV (not shown). SDV control systems 1906, which are illustrated in FIGs 19-22, are separate sub-systems of the SDV. These SDV control systems, which may include steering control systems 1918 and/or acceleration control systems 1920, are coupled to navigation system signal processing modules 1904 to receive navigation instructions for navigation of the SVD. One skilled in the art may understand that each of these SDV control systems may, in turn, include multiple sub-systems, e.g., acceleration control system 1920 may include a throttle, a brake system, and a transmission.

[00194] Local map memory 1902 is a dynamic digital data storage element adapted to store the local portion of the dynamic digital map, which is coupled to each of the navigation system signal processing modules, such that it may communicate with these, and other components of the example SDV navigation system as described in detail below. This dynamic digital data storage element may include, but is not limited to: electronic random access memory (RAM); dynamic magnetic data storage media; or optomagnetic data storage media. As described above in detail (see particularly FIG 11 ), the dynamic digital map includes: position data for a multitude of RF emitters flagged with identification (ID) information indicative of the particular ID signal associated with each RF emitter (emitter data); and position data for the SDV route(s) (route data), the route data having a predetermined route accuracy and the position data of the emitter data having a predetermined emitter accuracy.

[00195] In some example embodiments, the route data may desirably include centerline position data for a multitude of centerline points located along a centerline of each SDV route and may also desirably include width data for the SDV route at each of these centerline points. The local portion of the dynamic digital map includes the local portion of the route data and the emitter data. In such example embodiments, each RF emitter may be associated with one of the centerline points (its associated center point); and the emitter data may include information identifying the associated center point and the position data included in the emitter data for each RF emitter may be measured relative to its associated center point (i.e. relative position data). [00196] Antenna array 1900 is adapted to receive the ID signals from the current subset of the RF emitters, separate these ID signals into the signals corresponding to each RF emitter, and generate a raw data stream for each separated ID signal. Example antenna arrays of the present invention desirably include a multitude of individual antennae 800, each adapted to receive the ID signals of the current subset of RF emitters. Each antenna 800 is coupled to the SDV and located relative to the center of the SDV with a predetermined antenna accuracy, as described above in detail with reference to FIGs 8, 9A, and 9B. Antenna array 1900 may also desirably include signal preprocessing circuitry 1908 coupled to antennae 800 and ID module 1910 of the navigation system signal processing modules that is adapted to separate (demultiplex) the ID signals received by each antenna and generate a multiplexed raw data stream with each separated ID signal on its own channel. Each channel of this raw data stream desirably includes antenna data linked to the ID signal identifying the receiving antenna for that ID signal in addition to the received ID signal. Signal preprocessing circuitry 1908 may be embodied in at least one of: special purpose circuitry; one or more application specific integrated circuits (ASICs); a dedicated special-purpose computing system; or a general-purpose computer programmed with software instructions to perform its operations.

[00197] Navigation system signal processing modules 1904 include: ID module 1910; emitter angle module 1912; map position module 1914; and navigation module 1916. one skilled in the art may understand that the single connection illustrated in FIGs 19, 20, 21 , and 22 coupling local map memory 1902 to navigation system signal processing modules 1904 is used for simplicity and clarity of illustration; each of these signal processing is desirably coupled to local map memory 1902 to access the map data stored therein. Each of these navigation system signal processing modules may be embodied in at least one of: special purpose circuitry; one or more ASICs; a dedicated special-purpose computing system; or a general-purpose computer programmed with software instructions to perform operations of that signal processing module. It is noted that these individual signal processing modules are described separately in example embodiments herein to clarify and simplify understanding of the numerous signal processing functions performed by navigation system signal processing modules 1904; however, one skilled in the art may understand that these navigation system signal processing modules, as well as signal preprocessing circuitry 1908, may be separate modules or one or more may be combined into a single signal processing apparatus that combines the functions of those signal processing modules. If the navigation system signal processing modules are embodies as separate signal processing modules, they may be serially coupled, as illustrated in FIGs 19, 20, 21 , and 22, or they may be coupled together in a bus architecture.

[00198] ID module 1910 is coupled to, and adapted to receive the raw data stream from, antenna array 1900. The ID module is also coupled to local map memory 1902 and adapted to access the ID information of the local portion of the emitter data stored in it. Using the raw data stream and this ID information, ID module 1910 identifies the ID information of the RF emitter associated with each channel of the raw data stream and links the identified ID information to that channel of the raw data stream.

[00199] Emitter angle module 1912 is coupled to ID module 1910 and adapted to receive the raw data stream and the linked ID information for each channel from it. Emitter angle module 1912 is also coupled to local map memory 1902 and adapted access the ID information of the local portion of the emitter data stored in it. Using the raw data stream and the linked ID information, emitter angle module 1912 determines the emitter angle of the ID signal received from the RF emitter associated with each channel relative to the forward direction of the SDV. The linked ID information may be used to group the channels in the raw data stream into a number of single emitter channel subsets, corresponding to the RF emitters in the current subset of RF emitters. The ID signals received on each of the channels of a single emitter channel subset may be processed by the emitter angle module to determine the emitter angle of the corresponding RF emitter.

[00200] In example embodiments of the present invention in which antenna array 1900 includes multiple antennae 800 and signal preprocessing circuitry 1908 adapted to link antenna data to the ID signal, emitter angle module 1912 is also adapted to receive the linked antenna data of each channel of the raw data steam. Using this linked antenna data, determine the fixed position of the receiving antenna relative to the center of the SDV may be determined for each channel in each single emitter channel subset. For each single emitter channel subset of the raw data stream, the emitter angle of the corresponding RF emitter relative to the forward direction of the SDV may then be determined using ID signals, the fixed position of the receiving antenna relative to the center of the SDV, and the linked ID information of each channel of that single emitter channel subset.

[00201] Emitter angle module 1912 is further adapted to generate an emitter angle signal for each RF emitter associated with one of the channels of the received raw data signal. Each emitter angle signal includes the determined emitter angle and the emitter data of the associated RF emitter. These emitter angle signals are transmitted to map position module 1914.

[00202] Map position module 1914 is coupled to, and adapted to receive every emitter angle signal for the current subset of the plurality of RF emitters from, emitter angle module 1912. Map position module 1914 may also be coupled to local map memory 1902 and adapted to access the emitter data stored in it. Using these received emitter angles and their associated emitter data the map position module determines a map position of the SVD and a forward map angle of the forward direction of the SDV. Map position module 1914 may be adapted to use any of the example algorithms for determining the map position and forward map angle of the SDV described above with example methods 1200, 1700, and 1800.

[00203] In one example embodiment, map position module 1914 may be adapted to calculate an inter-emitter angle between each pair of RF emitters, using the pair of corresponding emitter angles received in the emitter angle signal. Using the inter-emitter angle and the emitter data of the pair of RF emitters stored in local map memory 1902 an emitter pair locus in the local portion of the dynamic digital map may be determined for every pair of RF emitters. This emitter pair locus is defined as the set of points in the local portion where each of a pair of rays originating at the point and separated by the inter-emitter angle intersect the stored location of one of the corresponding pair of RF emitters. The local map position of the SDV may then be determined to be the position in the local portion of the dynamic digital map that has the minimum mean separation from the set emitter pair loci. The separation of each emitter pair locus measured from the position to the nearest point within that emitter pair locus. The local map position of the SDV may be determined by minimizing the mean separation using various minimization algorithms such as: root mean squared error (RMSE) techniques; weighted RMSE techniques; mean absolute error (MAE) techniques; or weighted MAE techniques. The forward map direction of the SDV in the local portion of the dynamic digital map may then be determined using the emitter angles, the emitter data of the corresponding RF emitters stored in local map memory 1902, and this local map position of the SDV. [00204] In another example embodiment, map position module 1914 may further adapted to determine an emitter ray in the local portion of the dynamic digital map originating from each RF emitter using: the most recently determined forward map direction of the SDV; the emitter data of the corresponding RF emitter stored in local map memory 1902; and its emitter angle determined by emitter angle module 1912. Using these emitter rays, determine the ray offset distance between the emitter ray and the most recently determined local map position of the SDV, where the ray offset distance is the minimum distance between the emitter ray and the local map position. The largest of these ray offset distances is selected and compared to a predetermined positional uncertainty, desirably less than about 1 0m. If it is greater than the predetermined positional uncertainty, the emitter angle, or emitter angles, and emitter data of the corresponding RF emitter(s) (removed RF emitter) may be removed from the emitter angle signal and the local map position and the forward map direction of the SDV redetermined using the remaining emitter angles of the emitter angle signal. As described in detail below with reference to some of the example embodiments of FIGs 21 and 22, removed RF emitters may be report to the dynamic digital map over wireless communications network 110 as potentially damaged.

[00205] In some example embodiments of the present invention, each of the emitter angles determined by emitter angle module 1912 may include a horizontal emitter angle and an elevation emitter angle. In such example embodiments, the position data included in the emitter data and the route data may desirably include both two dimensional horizontal position data and a height, measured relative to a predetermined zero height, (i.e. 3D position data). In example embodiments in which the position data included in the route data includes centerline position data for centerline points along each SDV route and the emitter data includes relative position data, the height of the centerline points may be measured relative to the zero height, while the height of its associated center point may desirably be used as the zero height for each RF emitter. In such example embodiments, the map position determined by map position module 1914 desirably includes 3D position data for the center of the SDV.

[00206] Once the map position and the forward map angle of the SDV have been determined, map position module 1914 generates a map position signal for the SVD that includes the determined map position and the determined forward map angle of the SVD.

[00207] Navigation module 1916 is coupled to map position module 1914 and adapted to receive the map position signal from it. Navigation module 1916 is also coupled to local map memory 1902 and adapted to access the route data stored in it. The navigation module determines navigation instructions for the SVD based on the map position and forward map angle of the SVD received from map position module 1914, and the stored route data accessed in local map memory 1902. The determined navigation instructions are transmitted to SDV control systems 1906 to control navigation of the SVD along the SDV route.

[00208] In some example embodiments, navigation module 1916 compares the local map position of the SDV to the route data stored in local map memory 1902 to determine the current position of the SDV along the closest SDV route (the current route) and then determines an error distance between the local map position of the SDV and the current route. The navigation module also compares the forward map direction of the SDV to the tangent line of the current route at the current position to determine an error angle from the forward map direction of the SDV to the tangent line of the current route. The navigation instructions for the SVD may then be determined based on the error distance and the error angle. These navigation instructions for the SDV may desirably include steering instructions to turn the SDV an amount equal to the error angle and a distance correction factor based on the error distance.

Additionally, navigation module 1916 may calculate the curvature of the current route at the current position, and this curvature may be used in determining the steering instructions. Once determined, the steering instructions may be transmitted to steering control systems 1918 to control steering of the SDV.

[00209] In example embodiments in which the position data included in the route data includes centerline position data for centerline points along each SDV route, navigation module 1916 may determine the current position of the SDV along the current route by comparing the local map position of the SDV determined by map position module 1914 to the route data accessed from local map memory 1902 to determine the closest centerline point to the local map position. The error distance may be calculated using the local map position and the centerline position data of the current position and the tangent line of the current route at the current position may be calculated using the centerline position data of the current position and of one, or more, adjacent centerline points of the current route.

[00210] If the curvature of the current route at the current position is used in calculating the steering instructions, the curvature may be calculated using the centerline position data of the current position and that of at least the two centerline points of the current route nearest to the current position. It may be desirable use at least the four nearest centerline points in this calculation. The navigation instructions for the SDV determined by the navigation module 1916 may include steering instructions to turn the SDV an amount equal to the error angle, plus a distance correction factor based on the error distance and a curvature correction factor based on the curvature of the current route at the current position.

[00211] It is contemplated that an example SDV navigation system that uses fewer steering corrections may lead to a more comfortable ride for SDV passengers. In some example embodiments of the present invention, the route data stored in local map memory 1902 may further include route widths of the SDV route at each centerline point. In these example embodiments, if the SDV route is wide enough, it may not be necessary for the SDV to track the centerline of the SDV route exactly to be safely navigated within the SDV route; however, it is desirable for the edge of the SDV to have some clearance from the edge of the SDV route. Therefore, it may be desirable for example SDV navigation systems to have a minimum clearance parameter. Local map memory 1902 may be adapted to include a vehicle width of the SDV and navigation module 1916 may be further adapted to calculate an outer edge offset of the SDV by summing half of the vehicle width of the SDV and the magnitude of the error distance. This outer edge offset represents the farthest distance from the centerline to the edge of the SDV. Half of the route width of the current route at the current position minus the calculated outer edge offset of the SDV is how far the edge of the SDV is within the edge of the SDV route. (A negative distance means that the SDV edge is outside of the edge of the SDV route.) Navigation module 1916 may compare this difference to the minimum clearance parameter; and if the difference is greater than the minimum clearance parameter, the distance correction factor of the steering instruction may desirably be set to zero.

[00212] The minimum clearance parameter may be a set distance, e.g. about 1 5m or may be dependent on the route width of the current route at the current position or the vehicle width of the SDV. In further example embodiments of the present invention, the route data stored in local map memory 1902 may further include a route speed limit of the SDV route at each centerline point. As the minimum clearance parameter is intended to provide for safe navigation of the SDV within the SDV route(s), in such example embodiments the minimum clearance parameter of the current route at the current position may be dependent on the route speed limit of the current route at the current position.

[00213] In some example navigation systems according to the present application, the ID signal associated with each RF emitter may be a periodic analog ID signal. In such example embodiments, these periodic analog ID signals may desirably include at least three carrier waves having different wavelengths, with the wavelengths of every carrier wave of every RF emitter being within a predetermined wavelength band, as described above in detail with reference to FIG 7. Additionally, the carrier waves associated with a given RF emitter may have a simultaneous amplitude, or frequency, modulation. The ID information indicative of the ID signal associated with each RF emitter may include the wavelengths of each of the carrier waves and/or may be encoded in the simultaneous modulation of these carrier waves. Antennae 800 of antenna array 1900 are adapted to receive ID signals within the predetermined wavelength band. Signal preprocessing circuitry 1908 is adapted to separate the ID signals received by each antenna by wavelength and generate the raw data stream with a channel corresponding to each carrier wave of each received ID signal. Each channel of this raw data stream desirably includes antenna data identifying the receiving antenna for that ID signal in addition to the received ID signal.

[00214] In example embodiments in which the amplitude (or frequency) of each of the carrier waves of periodic analog ID signal of each RF emitter has a simultaneous modulation, ID module 1910 is further adapted to identify amplitude (frequency) modulations of the channels in the raw data stream and group the channels of different carrier waves the have simultaneous amplitude modulations into single emitter-antenna channel groups. If the ID information of the RF emitters is encoded in this simultaneous modulation, then ID module 1910 compares the modulation to the stored ID information to identify the RF emitter associated with that single emitter-antenna channel group. If the ID information is the wavelengths of the carrier waves, ID module 1910 compares the wavelengths of the carrier waves in each single emitter-antenna channel group to identify the ID information of the RF emitter associated with that single emitter-antenna channel group. The identified ID information is then linked to that single emitter-antenna channel group of the raw data stream.

[00215] In example embodiments in which the set of wavelengths of the carrier waves of periodic analog ID signal of is the ID information of each RF emitter, ID module 1910 is further adapted to identify the wavelengths of the channels in the raw data stream and link corresponding wavelength data to each channel. For each channel in the raw data stream, ID module 1910 compares the wavelength data of the channel to the stored ID information and uses the antenna data of the channel to form a single emitter-antenna channel groups, each single emitter-antenna channel group corresponding to ID signals emitted from one RF emitter and received by one antenna. The ID information for each single emitter-antenna channel group is identified and then linked to it.

[00216] Emitter angle module 1912 uses the linked ID information to group the identified single emitter-antenna channel groups associated with each RF emitter in the raw data stream into a single emitter channel subset of the raw data stream. The emitter angle module then uses the phase differences between the carrier waves in each single emitter-antenna channel group of the single emitter channel subset to determine the arrival time delay between each pair of single emitter-antenna channel groups in the single emitter channel subset. The emitter angle of that RF emitter relative to the forward direction of the SDV may then be determined using the determined arrival time delay between each pair of single emitter-antenna channel groups in the single emitter channel subset and the fixed position of each antenna relative to the center of the SDV.

[00217] In some other example navigation systems according to the present application, the ID signal associated with each RF emitter may be a periodic digital ID signal. In such example embodiments, the periodic digital ID signal of each RF emitter desirably has a known repetition period and bit rate. Further, each periodic digital ID signal is desirably selected to have an autocorrelation signature that is unique for each bit step delay across its repetition period, as described above in detail with reference to FIGs 6A and 6B. Additionally, the ID information of each RF emitter includes information identifying the periodic digital ID signal of that RF emitter. This identifying information may include one or more of: the repetition period of the periodic digital ID signal; its bit rate; its periodic digital ID signal, or the carrier wavelength of the periodic digital ID signal. Antennae 800 of antenna array 1900 are adapted to receive digital ID signals. Signal preprocessing circuitry 1908 is adapted to separate the ID signals received by each antenna by wavelength and generate the raw data stream with a channel corresponding to each received ID signal. Each channel of this raw data stream desirably includes antenna data identifying the receiving antenna for that ID signal in addition to the received ID signal.

[00218] Emitter angle module 1912 uses the linked ID information to group the channels in the raw data stream into single emitter channel subsets of the raw data stream. For each single emitter channel subset of the raw data stream, the emitter angle module then calculates the correlation signature between each pair of channels in the single emitter channel subset corresponding to a pair of antennae 800 in antenna array 1900. These calculated correlation signatures for each pair of channels is compared to the autocorrelation signature of the periodic digital ID signal of the associated RF emitter to determine the bit delay between the pair of channels. The arrival time delay between the ID signals received by the corresponding pair of antennae 800 in the antenna array 1900 may be calculate by dividing the determined bit delay by the bit rate of the periodic digital ID signal. The emitter angle of that RF emitter relative to the forward direction of the SDV may then be determined using the determined arrival time delay between each pair of single emitter-antenna channel groups in the single emitter channel subset and the fixed position of each antenna relative to the center of the SDV.

[00219] In another example embodiment, the navigation system of FIG 19 further includes coarse absolute positioning system 1922 that may include one or more sub systems, such as, but not limited to a GPS absolute positioning system or a cellular tower triangulation system. Coarse absolute positioning system 1922 is coupled to ID module 1910, and is adapted to determine a coarse absolute position of the SDV with a coarse positional accuracy, which is greater than the fine positional accuracy with which the map position of the SVD is determined by map position module 1914, which is in turn greater than the predetermined emitter accuracy of the emitter data stored in local map memory 1902. Coarse absolute positioning system 1922 generates a coarse position signal that includes the coarse absolute position of the SDV and transmits it to ID module 1910, which may be adapted to receive this coarse position signal and use it to assist in identifying the ID information of the RF emitter associated with each channel of the raw data stream.

[00220] FIG 20 illustrates a further example navigation system adapted to determine a trip route and to navigate the SDV along the trip route. The trip route may desirably extend from the initial coarse absolute position of the SDV determined by coarse absolute positioning system 1922 to a destination that has been entered by an SDV operator. [00221] The example navigation system of FIG 20 may include the various elements of the example embodiments described above with reference to FIG 19, and in addition, includes route map memory 2000, local map portion determination module 2002, wireless input/output (I/O) module 2006, and in at least some example embodiments, an SDV operator I/O interface 2004. Route map memory 2000, which is coupled to the SDV and local map portion determination module 2002, is adapted to store a route map that including a summary portion of the position data for the SDV route(s) of the dynamic digital map. This summary portion of the route data may desirably include position data for a reduced number of the centerline points of the SDV route(s), without additional data such as width data, traffic congestion, speed limits, etc. Alternatively, in another example embodiment, the summary portion of the route data may include some, desirably limited, information, such as speed limits; average congestion; route type, e.g. toll routes, unpaved routes; etc., that may be used by the SDV to determine a preferred trip route. Additionally, in this alternative embodiment, the operator may be able to specify route options, including, for example: route types, such as toll roads or high traffic areas, to avoid; scenic routes to include in the trip route; mid-route stops; the shortest route; and/or the fastest route. As described in detail below with reference to FIG 22, route map memory 2000 may be coupled to wireless I/O module 2006 and the summary portion of the route data may be updated periodically from the route data of dynamic digital map through wireless communications network 110.

[00222] Local map portion determination module 2002 is coupled to coarse absolute positioning system 1922, and in some example embodiments may be coupled to SDV operator I/O interface 2004, in addition to route map memory 2000. In embodiments including SDV operator I/O interface 2004, it may desirably include input interface 2008, which is coupled to local map portion determination module 2002, and display 2010, which is coupled to route map memory 2000 and input interface 2008, and may be coupled to map position module 1914. Input interface 2008 may include a keyboard, mouse or other cursor pointing device, and/or a voice-activated input device adapted to accept operator inputs including a destination and other trip-related information. Such trip-related information may include operator-specified route preferences, including, for example: route types, such as toll roads or high traffic areas, to avoid; scenic routes to include in the trip route; mid-route stops; the shortest route; and/or the fastest route. Additionally, input interface 1008 may include a touchscreen portion of display 2010 and/or onscreen menus. Display 2010 may access route map memory 2000 to the display the route map to assist the operator with inputting trip- related information. SDV operator I/O interface 2004 generates a destination signal based on the operator input trip- related information and transmits it to local map portion determination module 2002.

[00223] Local map portion determination module 2002 is adapted to receive the coarse position signal from coarse absolute positioning system 1922 and access the route map stored in the route map memory 2000, then to determine the local portion of the dynamic digital map using the coarse absolute position of the SDV from the coarse position signal and the summary portion of the route data of the route map, and in embodiments including SDV operator I/O interface 2004, to receive the destination signal. The local portion of the dynamic digital map determined by the local map portion determination module 2002 includes the coarse absolute position of the SDV, and in embodiments including SDV operator I/O interface 2004, includes the operator input destination and may be modified based on additional trip-related information included in the destination signal.

[00224] The local map portion determination module then generates a local map portion request signal that include information identifying the desired local map portion. Wireless I/O module 2006 is coupled to local map portion determination module 2002 to receive the local map portion request signal, and is adapted to transmit this local map portion request signal to the central map facility over wireless communications network 110. Wireless I/O module 2006 is also adapted to receive the map update signal, which includes the requested local portion of the dynamic digital map, from the central map facility over wireless communications network 1 10 and transmit this map update signal to local map memory 1902. Local map memory 1902 is further adapted to receive this map update signal and store the received local portion of the dynamic digital map that is included in the map update signal.

[00225] In example embodiments including SDV operator I/O interface 2004, it may be adapted to receive the local map portion request signal from the local map portion determination module 2002 and generate a trip map based on the local map portion request signal using the route map. The resulting trip map may be displayed on display 2010 with the destination of the SVD superimposed on the displayed trip map. SDV operator I/O interface 2004 may further be coupled to map position module 1914 and adapted to receive the map position signal and display the determined map position and the determined forward map angle of the SVD superimposed on the displayed trip map.

[00226] In an alternative example SDV navigation system of FIG 19 includes local condition sensor module 1924, which desirably includes one or more vehicle mounted sensors, and is coupled to navigation module 1916 to assist in SDV navigation. Such vehicle mounted sensors may be particularly desirable for: sensing temporary obstacles, such as debris in the road; sensing dynamic, and potentially unsafe, surface conditions of the SDV route, such as rain, ice, or uneven road surface; or traffic congestion; identifying fixed obstacles near the SDV in the SDV route; and/or moving objects, such as pedestrians, animals, and other vehicles near the SDV. These vehicle mounted sensors may also be used to provide feedback in the event of damage to the infrastructure used by the various example navigation systems of the present invention, as described in detail below with reference to FIG 21. Local condition sensor module 1924 may also include one or more processing units to process information from the vehicle mounted sensor(s) and generate a local condition signal and transmit it to navigation module 1916. The local condition signal desirably includes information identifying the various sensed local conditions and the locations of these sensed local conditions. Navigation module 1916 may be further adapted to receive the local condition signal and modify the navigation instructions based on the local condition signal to improve safety and comfort of the SDV navigation.

[00227] The vehicle mounted sensors of local condition sensor module 1924, may include sensors such as: an active optical sensor system; a passive optical sensor system; a digital camera based system; an active infrared (IR) sensor system; a passive IR sensor system; an IR camera based system; a sonar based system; a laser range finding system, and/or a sonar based range-finding system.

[00228] Local condition sensor module 1924 may also include one or more SDV monitoring systems typical to vehicles that may provide information to assist in navigation of the SDV, such as a speed module to monitor the speed of the SDV, e.g. the speedometer of the SDV. In an alternative example embodiment, map position module 1914 may be further adapted to update the map position of the SVD and the forward map angle of the forward direction of the SDV at a predetermined route correction rate, which is desirably greater than about 100Hz, and possibly greater than about 10 kHz, and navigation module 1916 is further adapted to update the navigation instructions for the SVD and transmit the navigation instructions SDV control system 1906 to control navigation of the SVD at the predetermined route correction rate. The speed module of local condition sensor module 1924 may be adapted to determine the speed of the SDV each time map position module 1914 updates the map position of the SVD by multiplying the predetermined route correction rate by the distance between the updated local map position and the stored previous vehicle position and then storing the updated local map position of the SDV as the previous vehicle position.

[00229] In example SDV navigation systems including a speed module, the route data of each SDV route stored in local map memory 1902 may include a route speed limit of the SDV route for each centerline point. In such an example embodiment, local condition sensor module 1924 may desirably include a speed module, coupled the navigation module 1916 and adapted to determine the speed of the SDV. The navigation instructions for the SDV determined by the navigation module 1916 may include acceleration instructions determined maintain the speed of the SDV within a predetermined range of the route speed limit of the current route. Once determined, the acceleration instructions may be transmitted to acceleration control systems 1920 to control acceleration of the SDV.

[00230] Additionally, the navigation instructions for the SDV determined by navigation module 1916 may further include steering instructions to turn the SDV and acceleration instructions determined to maintain an estimated safe speed based on a magnitude of the steering instructions. Additionally, in example embodiments in which navigation module 1916 is adapted to calculate the curvature of the current SDV route, the estimated safe speed may also be based on the magnitude of the curvature of the current SDV route. For example, these acceleration instructions may be determined such that: the transverse acceleration magnitude of the SDV remains less than a predetermined transverse acceleration level chosen for SDV passenger comfort, e.g. about 5m/s²; or the total acceleration magnitude of the SDV remains less than a predetermined total acceleration level, e.g. about 9.8m/s². In another example embodiment, the navigation instructions may be determined such that the forward acceleration magnitude of the SDV remains less than about 9.8m/s² and the transverse acceleration magnitude of the SDV remains less than about 5m/s². It is noted that in some, e.g. emergency, situations the navigation instructions may allow these acceleration magnitudes may be exceeded. Local condition sensor module 1924 may desirably include information identifying such situation in the local condition signal.

[00231] FIG 21 illustrates further example SDV navigation systems that utilizes local condition sensor module 1924. It may be understood by one skilled in the art that example SDV navigation systems incorporating some, or all, of the various example embodiments described above with reference to the example SDV navigation systems of FIGs 19 and 20 in conjunction with the various example embodiments of FIG 21 would also be within the scope of the present application.

[00232] In example embodiments illustrated in FIG 21 , local condition sensor module 1924 is coupled to wireless I/O module 2006 in addition to navigation module 1916, and is adapted to sense an approximate relative position of the SDV to the current route and an approximate relative angle of the SDV to the tangent of the current route as part of the sensed local conditions. As noted above, it may be difficult, or even impossible, to determine these relative position and angle using these vehicle mounted sensors, depending on local conditions, such as snow covered surfaces, that may obscure the indicia used to determine these relative position and angle. In such a situation, (described in detail below) local condition sensor module 1924 may generate a local condition signal including information identifying sensed local conditions and locations of these sensed local conditions and transmit this local condition signal to wireless I/O module 2006 to be reported to the dynamic digital map, via wireless communication network 1 10.

[00233] Navigation module 1916 may be further adapted to receive local condition signal and the compare the approximate relative position sensed by local condition sensor module 1924 to the error distance, prior to determining the navigation instructions, and to generate a position difference. If this position difference is greater than a predetermined positional uncertainty (e.g. about 1 0m, or less) the number (X) of emitter angles used by map position module 1914 to determine the local map position and the forward map direction of the SDV are determined and X unique subsets of these emitter angles are selected such that each of these unique subsets leaves out a different one of the emitter angles (i.e. each subset has X-1 members). As describe in detail above with reference to example SDV navigation method 1600 of FIG 16, the subset error distance and the subset error angle of each of these subsets are determined and the approximate relative position sensed by local condition sensor module 1924 is compared to the subset error distance to generate a subset position difference. If exactly one of these subset position differences is less than the predetermined positional uncertainty, the corresponding error distance and the error angle are replaced with that subset error distance and subset forward direction, respectively. The RF emitter associated with the emitter angle not included in that subset is identified and ID information associated with the identified RF emitter is transmitted to wireless I/O module 2006 to be reported to the dynamic digital map, via wireless communication network 1 10, flagged as potentially damaged. If none, or multiple, of the subset position differences are less than the predetermined positional uncertainty, the local map position and the position difference may desirably reported to the dynamic digital map, via wireless communication network 1 10.

[00234] Similarly, if the angle difference is greater than a predetermined angular uncertainty (e.g. about 5°, or less), the sensed approximate relative angle of the SDV may be compared to the subset error angle for each of the X unique subsets to generate X subset angle differences. If exactly one of these subset angle differences is less than the predetermined angular uncertainty, the error distance and the error angle may be replaced with that subset error distance and subset forward direction, respectively. The RF emitter associated with the emitter angle not included in that subset is identified and ID information associated with the identified RF emitter is transmitted to wireless I/O module 2006 to be reported to the dynamic digital map, via wireless communication network 1 10, flagged as potentially damaged. If none, or multiple, of the subset angle differences are less than the predetermined angular uncertainty, the local map position and the position difference may desirably be reported to the dynamic digital map, via wireless communication network 1 10.

[00235] Alternatively, local condition sensor module 1924 may be further adapted to generate a relative position signal for the SVD including the sensed approximate relative position and the sensed approximate relative angle of the SVD. Navigation module 1916 may further adapted to receive the relative position signal. The navigation module may compare the local map position of the SDV to the route data stored in local map memory 1902 to determine the current position of the SDV along the closest SDV route (the current route) and the error distance between the local map position of the SDV and the current route and compare the forward map direction of the SDV to the tangent line of the current route at the current position to determine the error angle from the forward map direction of the SDV to the tangent line of the current route. Then navigation module 1916 compares the sensed approximate relative position to the determined error distance to generate position difference and compares the sensed approximate relative angle to the determined error angle to generate an angle difference. If the position difference is greater than a predetermined positional uncertainty or if the angle difference is greater than a predetermined angular uncertainty, navigation module 1916 generates a difference signal including the position difference, the angle difference. Wireless I/O module 2006 may be coupled to the navigation module 1916 and adapted to receive the difference signal, which it may report along with the local map position to the dynamic digital map over a wireless communications network 110.

[00236] In additional example SDV navigation systems of FIG 21 , local condition sensor module 1924 may be adapted to sense local conditions of the SDV such as, but not limited to: fixed obstacles near the SDV in the SDV route; moving objects near the SDV; or unsafe surface conditions of the SDV route, and then to generate a local condition signal including information identifying the sensed local conditions and the locations of these sensed local conditions. Unsafe surface conditions of the SDV route may include, but are not limited to, one or more of: potholes; icy conditions; snow and/or water on the surface; downed power lines; and/or uneven surfaces.

[00237] Navigation module 1916 may be adapted to receive this local condition signal and modify the navigation instructions based on it.

[00238] In yet other example SDV navigation systems of FIG 21 , wireless I/O module 2006, which is coupled to local map memory 1902; map position module 1914; and the navigation module 1916, may be adapted to receive the map position signal from map position module 1914 and to receive a traffic congestion signal over wireless communications network 1 10. Wireless I/O module 2006 may then determine a local traffic congestion parameter corresponding to the local map position using the map position signal and the traffic congestion signal and generate a local traffic congestion signal corresponding to the local map position.

[00239] Additionally, local condition sensor module 1924 may be coupled to wireless I/O module 2006, and adapted to sense a traffic congestion parameter and transmit this sensed traffic congestion parameter to wireless I/O module 2006. Prior to generating the local traffic congestion signal, wireless I/O module 2006 may be adapted to receive the sensed traffic congestion parameter from local condition sensor module 1924 and compare it to the traffic congestion signal received from the dynamic digital map. If the difference between the traffic congestion parameter corresponding to the local map position exceeds a predetermined variance, the sensed traffic congestion parameter may be used as the local traffic congestion parameter to generate the local traffic congestion signal and the local traffic congestion signal may be reported to the dynamic digital map over wireless communications network 1 10 in addition to being transmitted to navigation module 1916 to modify the navigation instructions based on the local traffic congestion parameter.

[00240] In yet further example SDV navigation systems of FIG 21 , wireless I/O module 2006 may be adapted to receive route data, including reported safety information associated with the local portion of the dynamic digital map, over wireless communications network 110. This reported safety information may desirably include an obstacle map position of fixed obstacles reported in the SDV route(s) and/or caution sections of the SDV route(s) having reported unsafe surface conditions. Local map memory 1902 may be further adapted to store this received route data, including reported safety information associated with the local portion of the dynamic digital map.

[00241] Wireless I/O module 2006 may be further adapted to receive the local condition signal from local condition sensor module 1924 and receive the map position signal from map position module 1914, then compare the local conditions signal to the reported safety information for the map position of the SVD stored in local map memory 1902. If the sensed local conditions conflict with the stored reported safety information, wireless I/O module 2006 may desirably report updated safety information, including the local condition signal and the local map position, to the dynamic digital map over wireless communications network 1 10.

[00242] FIG 22 illustrates further example SDV navigation systems that utilize closure information identifying temporarily closed portions of SDV routes. These example embodiments may include: temporary RF emitter (TRFE) module 2200; route map memory 2000; local map portion determination module 2002; and SDV operator I/O interface 2004. It may be understood by one skilled in the art that example SDV navigation systems incorporating some, or all, of the various example embodiments described above with reference to the example SDV navigation systems of FIGs 19, 20, and 21 in conjunction with the various example embodiments of FIG 22 would also be within the scope of the present application.

[00243] In example embodiments illustrated in FIG 22, the dynamic digital map may desirably include closure information identifying temporarily closed portions of SDV routes and the route map stored in the route map memory 2000 may desirably include accumulated closure information that has been stored previously. The summary portion of the route data stored in route map memory 2000 may be updated on a predetermined schedule; or it may be updated prior to each trip, in response to a map update signal from the dynamic digital map, at the operators request, in response to a discrepancy between the summary portion and more complete route data downloaded from the dynamic digital map, and/or in response to a discrepancy between the summary portion and route data determined by the SDV.

[00244] As described above with reference to example embodiments of FIG 20, wireless I/O module 2006 may be adapted to receive map update signals, which includes updated map information of the dynamic digital map, from the central map facility over wireless communications network 110. These map update signals may be in response to local map portion request signals sent by wireless I/O module 2006, or may be transmitted by the dynamic digital based on map updates received by the dynamic digital map. The map update signal may further desirably include a relevant portion of the closure information corresponding to the SDV route(s) in the local portion of the dynamic digital map.

[00245] Wireless I/O module 2006 may be coupled to route map memory 2000, and further adapted to separate the relevant portion of the closure information included in map update signals received from the central map facility and transmit the separated relevant portion of the closure information to the route map memory 2000. Route map memory 2000 may be adapted to compare the relevant portion of the closure information to the corresponding portion of the accumulated closure information. If the relevant portion of the closure information is different than the corresponding portion of the accumulated closure information, the accumulated closure information included in the route map may be updated based on the relevant portion of the closure information received from wireless I/O module 2006 and a route update flag may be generated.

[00246] Local map portion determination module 2002 may be further adapted to receive route update flags generated by route map memory 2000 and, responsive to each received route update flag, redetermine the local portion of the dynamic digital map and, if the redetermined local portion has is different from the previously determined local portion, regenerate a new local map portion request signal. Wireless I/O module 2006 may receive this new local map portion request signal and transmit it to the central map facility over wireless communications network 1 10 and receive a new map update signal in response. Local map memory 1902 may then receive this new map update signal and store the received local portion of the dynamic digital map that is included in it.

[00247] In other example SDV navigation systems of FIG 22, the closure information may include TRFE position data, as well as a temporary ID signal and a temporarily closed portion of the SDV route(s) associated with each TRFE. Additionally, each temporary ID signal may further include TRFE information indicative of at least one temporary route closure parameter. These temporary route closure parameters may include, but are not limited to: single lane closures; complete SDV route closures; the lengths of associated SDV route closures; and/or SDV route temporary reduced speed limits. Navigation system signal processing modules 1904 of these example navigation systems may further include TRFE module 2200 which is coupled to emitter angle module 1912, map position module 1914, wireless I/O module 2006, and the route map memory 2000.

[00248] Antenna array 1900 may be further adapted to receive temporary ID signals from a second bandwidth used by TRFEs, separate these temporary ID signals from other received ID signals and generate a TRFE channel corresponding to each separated temporary ID signal as part of the raw data stream. ID module 1910 is further adapted to, for each TRFE channel of the raw data stream, identify the received temporary ID signal and link a temporary ID flag corresponding to the identified temporary ID signal to that TRFE channel of the raw data stream. And emitter angle module 1912 is further adapted to group TRFE channels by their linked temporary ID flag from the raw data stream and determine the emitter angle associated with each temporary ID flag relative to the forward direction of the SDV using the temporary ID signals of grouped TRFE channels. This determination may be made using any of the example methods described above for determining emitter angle of RF emitters. Emitter angle module 1912 is also adapted to generate a TRFE signal including the determined emitter angle associated with each temporary ID flag.

[00249] TRFE module 2200 is adapted to receive the TRFE signal from emitter angle module 1912 and the map position signal from map position module 1914. For each received temporary ID flag, TRFE module 2200 is adapted to determine whether the temporary ID flag corresponds to TRFE position data that is included in the accumulated closure information stored in the route map memory 2000 using the associated emitter angle, the determined map position of the SVD, and the determined forward map angle of the SVD. For each temporary ID flag that the TRFE module 2200 determines does not to correspond to any TRFE with position data included in the accumulated closure information (an unrecognized TRFE), TRFE module 2200 sets an unrecognized TRFE flag. If the unrecognized TRFE flag is set, TRFE module 2200 generates a local closure request signal including the determined map position of the SVD and transmits this local closure request to wireless I/O module 2006.

[00250] Wireless I/O module 2006 is adapted to receive this local closure request signal and transmit it to the central map facility via wireless communication network 1 10, then receive a closure update signal from the central map facility via wireless communication network 110, the closure update signal including a local portion of the closure information including closure information within a predetermined TRFE locus of the determined map position of the SVD (e.g. a sphere with a radius of 1 km centered on the SDV). Wireless I/O module 2006 then transmits the local portion of the closure information received from the central map facility to the route map memory 2000.

[00251] Route map memory 2000 is further adapted to compare this local portion of the closure information to the corresponding portion of the accumulated closure information. If the local portion of the closure information is different than the corresponding portion of the accumulated closure information, route map memory 2000 may desirably update the accumulated closure information included in the route map based on the local portion of the closure information received from wireless I/O module 2006 and generate a route update flag. Local map portion determination module 2002 may then redetermine the local portion of the dynamic digital map as described in detail above.

[00252] In further example SDV navigation systems of FIG 22, when the unrecognized TRFE flag is set, after the accumulated closure information is updated based on the local portion of the closure information received from the wireless I/O module 2006, TRFE module 2200 may be further adapted to determine whether each unrecognized TRFE is associated with TRFE position data included in the updated accumulated closure information using the associated emitter angle and the determined map position and the determined forward map angle of the SVD, then unset the unrecognized flag. If any one of the unrecognized TRFEs is does not correspond to any TRFE with position data included in the accumulated closure information (an unregistered TRFE), TRFE module 2200 sets an unregistered TRFE flag. And if the unregistered TFRE flag is set, TRFE module 2200 generates a TRFE update signal that includes the determined map position and the determined forward map angle of the SVD, the emitter angle associated with each unregistered TRFE, and the TRFE information of each unregistered TRFE. Wireless I/O module 2006 is further adapted to: receive the TRFE update signal; transmit the TRFE update signal to the central map facility via wireless communication network 1 10; and, after transmitting the TRFE update signal, unset the unregistered flag.

[00253] Although illustrated and described herein with reference to certain specific embodiments, the present invention is nevertheless not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention, including, but not limited to combinations of the elements of the various example embodiments.

Claims

CLAIMS What is Claimed:

1. A global positioning system for self-driving vehicle (SDV) navigation comprising:

at least one SDV route;

a plurality of radio-frequency (RF) emitters, each RF emitter:

located near at least one of the at least one SDV routes; and

emitting a predetermined periodic identification (ID) signal having an ID signal intensity; and

a dynamic digital map including: position data for each RF emitter and ID information indicative of the predetermined periodic ID signal associated with each RF emitter (emitter data); and position data for the at least one SDV route (route data), the route data having a predetermined route accuracy and the position data of the emitter data having a predetermined emitter accuracy.

2. The global positioning system of claim 1 , wherein the route data of the dynamic digital map for each of the at least one SDV routes include: centerline position data for a plurality of centerline points along the SDV route; and width data for the SDV route at each of the plurality of centerline points.

3. The global positioning system of claim 2, wherein the width data for each of the plurality of centerline points include: a width of the SDV route at that centerline point; and a horizontal angle of a normal line to the SDV route at that centerline point.

4. The global positioning system of claim 3, wherein: each of the plurality of RF emitters is located a set distance along the normal line of an associated centerline point of the at least one SDV routes; and the set distance being equal to the half-width of the SDV route at the associated centerline point plus a predetermined setback distance.

5. The global positioning system of claim 3, wherein: each of the plurality of RF emitters is co-located at an associated centerline point of the at least one SDV routes.

6. The global positioning system of claim 3, wherein each of the plurality of RF emitters is located along the normal line of an associated centerline point of the at least one SDV routes (an associated center point); and the emitter data includes information identifying the associated center point and an offset distance between the RF emitter and the associated center point.

7. The global positioning system of claim 6, wherein the offset distance between each RF emitter and its associated center point has a predetermined offset accuracy.

8. The global positioning system of claim 7, wherein the predetermined offset accuracy is less than about 1cm.

9. The global positioning system of claim 2, wherein the dynamic digital map includes: two dimensional horizontal position data for: each of the plurality of centerline points along each SDV route; and each of the plurality of RF emitters.

10. The global positioning system of claim 9, wherein:

the at least one SDV route is a plurality of SDV routes including a plurality of intersections at which at least two of the SDV routes intersect; and

the plurality of RF emitters includes at least one RF emitter located near each intersection.

1 1. The global positioning system of claim 1 , wherein each of the plurality of RF emitters is: mounted in a dedicated structure precisely located near the at least one SDV route; affixed to a pre-existing structure near the at least one SDV route; or set within a structure of the at least one SDV route.

12. The global positioning system of claim 1 , wherein at least one of the plurality of RF emitters is mounted within an electrically powered SDV-route-side structure located near the at least one SDV route.

13. The global positioning system of claim 12, wherein the electrically powered SDV-route-side structure is one of: a streetlight; a lighted billboard; an electronic billboard; or a traffic signal.

14. The global positioning system of claim 12, wherein the electrically powered SDV-route-side structure includes at least one of: a battery; a solar power source; or a wind powered generator.

15. A navigation method for a self-driving vehicle (SDV) comprising the steps of:

a) determining an initial absolute global position of the SDV using at least one of: a GPS absolute positioning system, or a cellular tower triangulation system, wherein the absolute global position of the SDV has a predetermined global accuracy;

b) storing at least a local portion of a dynamic digital map, the dynamic digital map including: position data for a plurality of RF emitters flagged with identification (ID) information indicative of an ID signal associated with each RF emitter (emitter data); and position data for at least one SDV route (route data), wherein: the local portion of the dynamic digital map includes the initial absolute global position determined in step (a), at least a local portion of the route data, and at least a local portion of the emitter data; and the route data have a predetermined route accuracy and the position data of the emitter data have a predetermined emitter accuracy;

c) receiving ID signals from a predetermined emitter number of RF emitters for which emitter data was stored in step (b), wherein the predetermined emitter number is at least three;

d) for each ID signal received in step (c), determining an emitter angle between a forward direction of the SDV and the stored emitter associated with that ID signal using the received emitter signal;

e) determining a local map position and a forward map direction of the SDV in the local portion of the dynamic digital map using the plurality of emitter angles determined in step (d) and the emitter data of the corresponding RF emitters stored in step (b), wherein the local map position of the SDV has a predetermined local accuracy;

f) comparing the local map position of the SDV to the route data stored in step (b) to determine a current position of the SDV along a closest one of the at least one SDV route (the current route) and an error distance between the local map position of the SDV and the current route;

g) comparing the forward map direction of the SDV to a tangent line of the current route at the current position to determine an error angle from the forward map direction of the SDV to the tangent line of the current route; and h) determining navigation instructions for the SDV based on the error distance and the error angle.

16. The navigation method of claim 15, wherein: the predetermined global accuracy of the absolute global position is less than about 10m; the predetermined emitter accuracy of the emitter data of the dynamic digital map is less than about 10m; the predetermined route accuracy of the route data of the dynamic digital map is less than about .50 m; and the predetermined local accuracy of the local map position is less than about 1 0m.

17. The navigation method of claim 15, wherein: step (a) occurs before the beginning of a trip and further includes receiving a destination for the trip from an operator of the SDV; and

the local portion of the dynamic digital map stored in step (b) further includes the destination.

18. The navigation method of claim 17, wherein:

the dynamic digital map is stored and maintained at a central map facility;

a route map including a summary portion of the position data for the at least one SDV route is stored in the SDV; step (a) further includes:

determining a trip route along the at least one SDV route of the dynamic digital map from the stored route map based on the initial absolute global position of the SDV and the received destination; and

selecting the local portion of the dynamic digital map to consist of a subset of the route data corresponding to the trip route and emitter data for a set of RF emitters within an emitter distance of the trip route;

step (b) further includes:

requesting the local portion of the dynamic digital map from the central map facility over a wireless communications network;

receiving the requested local portion of the dynamic digital map from the central map facility over the wireless communications network; and

storing the received local portion of the dynamic digital map in a trip module of the SDV.

19. The navigation method of claim 18, further including the step of:

i) repeating steps (c), (d), (e), (f), (g), and (h) at a predetermined route correction rate until the local map position determined in step (e) is within a predetermined locus of the destination.

20. The navigation method of claim 15, wherein:

for each of the at least one SDV routes in the local portion of the dynamic digital map, the route data stored in step (b) include centerline position data for a plurality of centerline points along the SDV route;

step (f) includes the substeps of:

f1) comparing the local map position of the SDV to the route data stored in step (b) to determine a closest centerline point to the local map position (the current position of the SDV along the current route); and

f2) calculating the error distance using the local map position and the centerline position data of the current position; and

step (g) includes the substeps of:

g1) calculating the tangent line of the current route at the current position using the centerline position data of the current position along the current route and the centerline position data of at least one centerline point of the current route adjacent to the current position; and

g2) comparing the forward map direction of the SDV to the tangent line calculated in step (g1 ) to determine the error angle from the forward map direction of the SDV to the tangent line of the current route.

21. The navigation method of claim 15, wherein:

for each of the at least one SDV routes in the local portion of the dynamic digital map, the route data stored in step (b) include centerline position data for a plurality of centerline points along the SDV route and a route speed limit of the SDV route at each centerline point; step (e) further includes determining a speed of the SDV; and

the navigation instructions for the SDV determined in step (h) include acceleration instructions determined maintain the speed of the SDV within a predetermined range of the route speed limit of the current route.

22. The navigation method of claim 15, wherein step (c) includes the substeps of:

c1) receiving ID signals from a first bandwidth used by the plurality of RF emitters for which emitter data was stored in step (b);

c2) separating the received ID signals having a received intensity greater than a minimum detection intensity; and

c3) identifying the RF emitters associated with the predetermined emitter number of separated ID signals having the greatest received intensity based on the emitter data stored in step (b).

23. A navigation system for a self-driving vehicle (SDV) comprising:

a local map memory coupled to the SDV and adapted to store a local portion of a dynamic digital map, the dynamic digital map including: position data for a plurality of radio frequency (RF) emitters flagged with identification (ID) information indicative of an ID signal associated with each RF emitter (emitter data); and position data for at least one SDV route (route data), wherein: the local portion of the dynamic digital map includes at least a local portion of the route data and at least a local portion of the emitter data; and the route data have a predetermined route accuracy and the position data of the emitter data have a predetermined emitter accuracy;

an antenna array coupled to the SDV and adapted to: receive the ID signals from at least a current subset of the plurality of RF emitters; separate the ID signals; and generate a raw data stream for each separated ID signal; an ID module coupled to the local map memory and the antenna array, and adapted to: receive the raw data stream from the antenna array; access the ID information stored in the local map memory; identify the ID information of the RF emitter associated with each channel of the raw data stream using the ID signal of that channel and the ID information; and link the identified ID information to that channel of the raw data stream;

an emitter angle module coupled to the local map memory and the ID module, and adapted to: receive the raw data stream and the linked ID information for each channel of the raw data stream from the ID module; access the ID information stored in the local map memory; determine an emitter angle of the RF emitter associated with each channel relative to a forward direction of the SDV using the raw data stream and the linked ID information; and generate an emitter angle signal for each RF emitter associated with one of the channels, the emitter angle signal including the determined emitter angle and the emitter data of the RF emitter;

a map position module coupled to the local map memory and the emitter angle module, and adapted to: receive every emitter angle signal for the current subset of the plurality of RF emitters from the emitter angle module; access the emitter data stored in the local map memory; determine a map position of the SVD and a forward map angle of the forward direction of the SDV using the received emitter angles and their associated emitter data; and generate a map position signal for the SVD including the determined map position and the determined forward map angle of the SVD; and

a navigation module coupled to: the local map memory; the map position module; and the SDV, and adapted to: receive the map position signal from the map position module; access the route data stored in the local map memory; determine navigation instructions for the SVD based on the received map position and forward map angle of the SVD, and the stored route data; and transmit the navigation instructions to control navigation of the SVD.

24. The navigation system of claim 23:

further comprising a coarse absolute positioning system coupled to the ID module and adapted to: determine a coarse absolute position of the SDV with a coarse positional accuracy and to generate a coarse position signal; wherein:

the map position of the SVD determined by the map position module has fine positional accuracy that is: less than the coarse positional accuracy of the coarse absolute position; and greater than the predetermined emitter accuracy of the emitter data stored in the local map memory;

the ID module is further adapted to receive the coarse position signal from the coarse absolute positioning system, and further uses the coarse position signal to identify the ID information of the RF emitter associated with each received ID signal.

25. The navigation system of claim 24:

further comprising:

a route map memory coupled to the SDV and adapted to store a route map including a summary portion of the position data for the at least one SDV route of the dynamic digital map;

a local map portion determination module coupled to the route map memory and the coarse absolute positioning system, and adapted to: receive the coarse position signal; access the route map stored in the route map memory; determine the local portion of the dynamic digital map using the coarse position signal and the route map stored in the route map memory; and generate a local map portion request signal; and

a wireless input/output (I/O) module coupled to the local map portion determination module and the local map memory, and adapted to: receive the local map portion request signal; transmit the local map portion request signal to a central map facility over a wireless communications network; receive a map update signal from the central map facility over the wireless communications network, the map update signal including the local portion of the dynamic digital map from the central map facility over the wireless communications network; and to transmit the map update signal to the local map memory;

wherein:

the local portion of the dynamic digital map determined by the local map portion determination module includes the coarse absolute position of the SDV; and

the local map memory is further adapted to: receive the map update signal from the wireless I/O module; and store the received local portion of the dynamic digital map included in the map update signal.

26. The navigation system of claim 25 further comprising an SDV operator I/O interface coupled to the route map memory and the local map portion determination module, and adapted to: access the route map stored in the route map memory; accept a destination input from an SVD operator; generate a destination signal; receive the local map portion request signal; generate a trip map based on the local map portion request signal using the route map; display the trip map;

wherein: the local portion of the dynamic digital map determined by the local map portion determination module includes the coarse absolute position of the SDV and the destination input from the SVD operator; and

the local map portion determination module is further adapted to: receive the destination signal; and determine the local portion of the dynamic digital map using the coarse position signal, the destination signal, and the route map stored in the route map memory; and generate a local map portion request signal.

27. The navigation system of claim 23, wherein:

the antenna array includes: a plurality of antennae, each antenna coupled to the SDV, located relative to a center of the SDV with a predetermined antenna accuracy, and adapted to receive the ID signals of the current subset of RF emitters; and signal preprocessing circuitry coupled to the plurality of antennae and the ID module, and adapted to separate the ID signals received by each antenna and generate the raw data stream with a channel corresponding to each received ID signal, the raw data stream further including antenna data linked to the ID signal identifying the receiving antennae for each channel; and

the emitter angle module is further adapted to:

for each RF emitter in the current subset of RF emitters, use the linked ID information to group the plurality of channels in the raw data stream into a single emitter channel subset of the raw data stream; and

for each single emitter channel subset: determine the fixed position of the receiving antenna for each channel relative to the center of the SDV using the antenna data linked to the ID signal of that channel and determine the emitter angle of the corresponding RF emitter relative to the forward direction of the SDV using the single emitter channel subset of the raw data stream, the fixed position of the receiving antenna of each channel relative to the center of the SDV, and the linked ID information of each channel.

28. The navigation system of claim 23, wherein the navigation module is further adapted to:

compare the local map position of the SDV to the route data stored in the local map memory to determine a current position of the SDV along a closest one of the at least one SDV route (the current route) and an error distance between the local map position of the SDV and the current route;

compare the forward map direction of the SDV to a tangent line of the current route at the current position to determine an error angle from the forward map direction of the SDV to the tangent line of the current route; and determine the navigation instructions for the SVD based on the error distance and the error angle.

29. The navigation system of claim 28 further comprising a speed module coupled the navigation module and adapted to determine a speed of the SDV, wherein:

for each of the at least one SDV routes stored in the local map memory, the route data include centerline position data for a plurality of centerline points along the SDV route and a route speed limit of the SDV route at each centerline point; and

the navigation instructions for the SDV determined by the navigation module include acceleration instructions determined maintain the speed of the SDV within a predetermined range of the route speed limit of the current route.