WO2003023435A2

WO2003023435A2 - Apparatus and methods for locating points of interest

Info

Publication number: WO2003023435A2
Application number: PCT/US2002/028319
Authority: WO
Inventors: Bo Ake Sture Gustafson
Original assignee: Bo Ake Sture Gustafson
Priority date: 2001-09-11
Filing date: 2002-09-06
Publication date: 2003-03-20
Also published as: AU2002331818A1; WO2003023435A3

Abstract

An apparatus for locating a point of interest at a point in time includes a processor (240), an antenna (210) having a receiving point, and an orientation sensor (230). The processor uses coordinate information received by the antenna (210) for the receiving point, the orientation of the orientation sensor (230) and a distance between the receiving point and the point of interest to determine coordinate information of a point of interest at a point in time. The processor (240) also uses predetermined coordinate information, coordinate information received by the antenna (210) for the receiving point and the orientation of the orientation sensor (230) to locate a predetermined point of interest.

Description

APPARATUS AND METHODS FOR LOCATING POINTS OF INTEREST

BACKGROUND OF THE INVENTION

1. Field of Invention

[0001] This invention is generally related to locating apparatus and methods that use global positioning system data to locate a point of interest.

2. Description of Related Art

[0002] Traditional surveying involves leveling and plumbing a transit, or more recently a theodolite, on a tripod. Additionally, a separate rod is required to identify the local x and y coordinates of a point of interest as well as its local elevation, or z coordinate. Generally, three men are required to perform a survey, one man to operate the transit or theodolite, one man to operate the data collector, and a third man to move the rod to place the rod at the points of interest.

[0003] More recently, global positioning system equipment has been used in order to locate the coordinates of a point of interest. There are a number of different global positioning systems, such as the original U.S. based Global Positioning System, the Russia- based GLONASS (Global Navigation Satellite System) system, and the European-based Galileo system, which is expected to come on line in the near future. Specifically, a global positioning system receptor is mounted on a tripod at each point of interest. The global positioning system antenna must be very precisely positioned relative to a desired point of interest so that it is vertically directly above the point of interest. This is usually done using a tripod or a bipod. The x, y, and z coordinates of the global positioning system antenna are determined using satellite signals. The grid coordinates, or x and y coordinates, of the points of interest are calculated as well as the elevation, or z coordinate. The distance between the global positioning system antenna phase center and a point of interest is determined along the local coordinate axis and then combined with the known coordinates of the global positioning system antenna to yield the location of the point of interest.

[0004] Figure 1 illustrates such a contemporary global positioning system survey instrument 100 utilized in order to define the coordinates of a point of interest 150. Specifically, as shown in Figure 1, the global positioning system survey instrument 100 includes a tripod 105 supporting a global positioning system receiver antenna 110. Additionally, the global positioning system survey instrument 100 includes a global positioning system data collector 140 and a 2-dimensional bubble level 130 located below the global positioning system receiver antenna 110. The 2-dimensional bubble level 130 is used to orient a rod 135 vertically over the point of interest 150. An end point 120 of the rod 135 is used to locate the point of interest 150 by precisely placing the tripod 105 and rod 135 into a predefined relationship between the point of interest 150 and the global positioning system receiver antenna 110. Locating a point of interest 150 involves determining the grid coordinate of the point of interest 150, i.e., the local x and y coordinates, and the elevation, i.e., the local z coordinate. However, using the global positioning system survey instrument 100 shown in Figure 1 is cumbersome and time consuming because the global positioning system survey instrument must be carefully setup into the predefined orientation relative to each point of interest 150.

[0005] As shown in Figure 2, a global positioning system, such as the GPS, GLONASS, or Gahleo systems, includes a series of satellites 500 orbiting the earth. Each of these satellites emits signals that may be received by an antenna and used to determine the antenna's location. The conventional global positioning system survey instrument 100 uses the global positioning system receiver, or antenna 110, to receive these signals and to determine the location of the global positioning system receiver 110. The global positioning system survey instrument 100 is then able to determine the coordinates and elevation of points of interest.

SUMMARY OF THE INVENTION

[0006] The procedure for using contemporary global positioning system equipment requires numerous setups, is very labor intensive, and cannot be used to determine the location of points of interest that are located in difficult-to-access areas.

[0007] This invention separately provides apparatus and methods for locating mobile or stationery points of interest.

[0008] This invention separately provides methods and apparatus that locate a point of interest using a point of interest locating device that can be arbitrarily oriented relative to the point of interest and relative the vertical direction.

[0009] This invention provides methods and apparatus that require only one person for operation to locate points of interest.

[0010] In various exemplary embodiments, the apparatus and methods of the invention includes a locating device that can be used to locate points of interest, particularly points of interest that are difficult to access. [0011] In various other exemplary embodiments, the apparatus and method of this invention use a supporting rod having a global positioning system receiver antenna on one end and a point at the other end. Additionally, the apparatus of this invention includes a data collector, a processor and an orientation sensor. The global positioning system receiver location is determined by using satellite global positioning system data, and the location of the point of interest defined by the point of the rod is determined using the orientation sensor and the data collector. The data collector processes the raw position data and optionally stores and/or displays the desired coordinate information.

[0012] In various other exemplary embodiments, a global positioning system receiver is coupled with a global positioning system data collector, an orientation sensor, and a range finder. The range finder is used to determine the location of points of interest. In various exemplary embodiments, the range finder comprises a distance-measuring device, such as an acoustic or electro-magnetic based distance-measuring device, although any suitable known or later-developed device usable to determine the location of points of interest can be used as the range finder. The orientation sensor determines the orientation of the range finder relative to the point of interest. In various exemplary embodiments, the orientation sensor finds the direction from the range finder to the point to interest. The data collector processes that information and displays and stores the desired data.

[0013] These and other features and advantages of this invention are described in or are apparent from the following detailed description of various exemplary embodiments of the systems and methods according to this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Various exemplary embodiments of this invention will be described in detail with respect to the following drawings, in which like reference numerals indicate like elements, and wherein:

[0015] Figure 1 shows a profile view of conventional theodolite and/or global positioning system equipment used to locate a point of interest;

[0016] Figure 2 shows a side plan view of a conventional theodolite and/or global positioning system equipment receiving signals from global positioning system satellites;

[0017] Figure 3 shows a side plan view of a first exemplary embodiment of a locating apparatus according to this invention that uses a constant length rod; [0018] Figure 4 illustrates one exemplary embodiment of a global positioning system receiver and gi bal usable as the global positioning system antenna of the locating apparatus of Figure 3;

[0019] Figure 5 illustrates a second exemplary embodiment of a global positioning system receiver and gimbal usable as the global positioning system antenna of the locating apparatus of Figure 3;

[0020] Figure 6 illustrates the difference in location between the global positioning system antenna and the point of interest located by the locating apparatus of Fig. 3;

[0021] Figure 7 is a block diagram outlining in greater detail one exemplary embodiment of the global positioning system data collector of Figure 3;

[0022] Figure 8 shows a perspective view of a third exemplary embodiment of a locating apparatus according to this invention that uses a range finder;

[0023] Figure 9 is a flowchart outlining one exemplary embodiment of a method for using a global positioning system locating apparatus according to this invention;

[0024] Figure 10 is a block diagram outlining in greater detail a second exemplary embodiment of the global positioning system data collector of Figure 3; and

[0025] Figure 11 is a flowchart outlining a second exemplary embodiment of a method for using a global positioning system locating apparatus according to this invention. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0026] The following detailed description refers in general to global positioning systems. Such systems take their name from the original U.S.-created Global Positioning System. However, it should be appreciated that there are now competing global positioning systems, such as the Russian "GLONASS" global positioning system and the European "Galileo" global positioning system, in addition to the "Global Positioning System". Thus, as used herein, the term "global positioning system" encompasses all such systems or combinations of systems, whether currently operational, likely to be operational soon, or later developed, that allow a location of a receiver to be determined based on wireless communications with a number of transceivers that each has a position that can be determined for the time of communication with the receiver.

[0027] The following detailed description also refers in general to "orientation sensors". However, it should be appreciated that the following detailed description does not make a distinction between "orientation" and "direction". In general, mathematically, opposite directions are antiparallel while the orientation could be the same. Thus, it is possible to instead refer to the devices, disclosed herein as "orientation sensors", as "direction sensors". However, those skilled in the art generally refer to these devices as orientation sensors.

[0028] Fig. 3 shows a first exemplary embodiment of a point of interest locator 200 according to this invention that is usable to determine the local coordinates of a point of interest 250 on an x-y plane, the elevation z of the point of interest 250, and to find the location of a predetermined point of interest 250 with known coordinates. The point of interest locator 200 includes a global positioning system antenna 210 mounted on a gimbal 212 that is in turn mounted on a support rod 235.

[0029] The global "positioning system antenna 210 receives signals emitted from a number of satellites orbiting the earth to determine the local x, y and z coordinates of a receiving point 214 of the antenna 210.

[0030] It should be appreciated that, regardless of the arrangement of the gimbal 212 and the support rod 235, the receiving point 214 of the antenna 210 should be in a known location relative to the support rod 235, regardless of the orientation of the support rod 235.

[0031] As shown in Fig. 3, the support rod 235 has a length 237, a first end 222 and a point of interest locating end 220. The support rod 235 also comprises a high precision orientation sensor 230, which can be implemented using a gyroscope and/or a magnetometer (including a magnetometer/accelerometer combination), and a data collector 240.

[0032] It should be appreciated that a simple three-axis magnetometer gives the orientation of the support rod 235 with respect to a local magnetic field vector of the geomagnetic field. Since the magnetic field is a vector, having only magnitude and direction, the orientation information given by such a simple three-axis magnetometer is the angle between the support rod 235 and the magnetic field vector. Accordingly, a second direction, such as the direction given by the local geogravity field, is used in various exemplary embodiments of the magnetometer-based orientation sensor according to this invention.

[0033] In various exemplary embodiments, the vertical direction, that is, the direction of the local gravity field, can be measured using, for example, a three-axis accelerometer or any other suitable known or later-developed device or technique. Similarly, any known or later-developed device or technique that is usable to determine the orientation of the support rod 235 to any other predefined direction can be used with, or possibly in place of, the simple three-axis magnetometer. Often, such magnetometer-based orientation sensors that include accelerometers or the like as well as magnetometers are also referred to by those skilled in this art as magnetometers.

[0034] It should further be appreciated that, in various exemplary embodiments, one or more gyroscopes can be used to keep track of two directions. Accordingly, in various exemplary embodiments of the point of interest locator 200, the orientation sensor can include one or more gyroscopes without a magnetometer. The one or more gyroscopes of such an orientation sensor may also be combined with other appropriate types of sensors. In general, so long as the orientation sensor can adequately locate the location of the global positioning system receiving point 214 relative to the point of interest, such that the offset in the implemented coordinate system between the receiving point 214 and the point of interest can be determined, any desired combination of sensor elements, whether known or later developed, can be used.

[0035] As shown in Fig. 3, the point of interest locating end 220 of the support rod 235 can be shaped to define a point 224. The point 224 should be small enough to accurately identify a given point of interest 250. The point of interest locator 200 can also contain a tag reading sensor 221. The tag reading sensor 221 may be any type of conventional sensor that automatically reads a tag containing information about a particular point of interest, such as, a point of interest description and local x, y and z coordinates.

[0036] It should be appreciated that the support rod 235 may be made of any material so long as it is capable of supporting the gimbal 212 and can withstand the loads and stresses of use. Additionally, it should be appreciated that the supporting rod 235 may be solid or hollow, and may be of any fixed length suitable for purposes of the methods and apparatus of this invention. For example, in various exemplary embodiments, the supporting rod 235 may be telescoping to known length settings to be manually entered into or automatically read by the data collector.

[0037] The orientation sensor 230 defines the orientation of the supporting rod 235. The orientation sensor 230 allows a measurement to be obtained when the point 224 is maneuvered to identify a particular point of interest 250. A location is recorded when the trigger 239 is operated.

[0038] It should be appreciated that, in various exemplary embodiments, the trigger 239 can be activated so that the point of interest locator 200 is continuously operated to record the locations of a series of closely-spaced points of interest. For example, these closely-spaced points of interest could be located on the surface of an object. In this way, the point of interest locator 200 could be used to record data for a plurality of points that define a shape of an object.

[0039] It should also be appreciated that, in various exemplary embodiments, the trigger 239 could be relocated to different locations within the point of interest locator 200. For example, in various exemplary embodiments, the trigger 239 could be attached to or located with the point of interest locating end 220 of the support rod 235. In this case, the act of placing the point of interest locating end 220 at a desired point of interest could itself activate the trigger 239 to record the location and orientation of the support rod 235.

[0040] For example, the trigger 239 can be implemented, in various exemplary embodiments, using a mechanical contact switch that is closed when the point of interest locating end 220 is placed at a desired point of interest. In this case, the contact switch is connected to a movable element that forms the point 224. When the movable point 224 is placed at the desired point of interest, it moves within the rod 235 to close (or open) the mechanical contact switch.

[0041] In various other exemplary embodiments, the trigger 239 can be implemented as a solid-state switch, such as a piezoelectric switch, that is activated by placing the point of interest locating end 220 at or against the desired point of interest, fn some exemplary embodiments, the support rod 235 is designed to transmit pressure against the piezoelectric switch. In other exemplary embodiments, the solid-state switch is proximity switch that activates whenever it is brought into proximity with a predetermined device, material or the like. Of course, it should be appreciated that such piezoelectric or proximity switches need not be implemented using solid-state elements.

[0042] The antenna 210 is mounted in the gimbal 212. As shown in Fig. 4, the gimbal 212 comprises two rings 216 and 218 mounted on axes at right angles to each other so that the antenna 210 remains suspended in a horizontal plane between the rings 216 and 218 regardless of any motion of the support rod 235. It is convenient, but not necessary, to mount the antenna 210 with its phase center, i.e., the receiving point 214, along the rod axis. It should be appreciated that such a location eliminates any error due to imperfection in the balance of the gimbal 212. However, even if there is a known vertical offset in the location of the phase center, this can be accounted for in the data reduction if the gimbal 212 is assumed to keep the antenna 210 in the horizontal plane. Placing the receiving point 214 in a fixed location along the axis of the support rod 235 eliminates one projection in the calculation, thus simplifying the data reduction. This also tends to reduce any error introduced due to any imperfection in the balance of the gimbal 212, but it is not strictly necessary.

[0043] As shown in Fig. 4, the support rod 235 is secured to the gimbal 212 at the first end 222 using a threaded screw 223. It should be appreciated that the first end 222 can be secured to the gimbal 212 in any manner that securely connects the gimbal 212 to the support rod 235.

[0044] Figure 5 illustrates a second exemplary embodiment of a point of interest locator 200 according to the apparatus and methods according to this invention that is usable to determine coordinates and elevations of select locations. The second exemplary embodiment of the point of interest locator 200, as shown in Fig. 5, includes substantially the same elements as the first exemplary embodiment of the point of interest locator 200 shown in Fig. 3. Except as outlined below, a detailed description of the method of determining the coordinates of a particular point of interest 250 using the second exemplary embodiment of the point of interest locator 200 is not necessary because the operation is substantially the same as outlined above with respect to the first exemplary embodiment of the point of interest locator 200.

[0045] In the second exemplary embodiment, the point of interest locator 200 includes a gimbal 212 rotatably attached to a support rod 235, such that the gimbal 212 swivels about the support rod 235. The gimbal 212 may rotate clockwise and/or counter clockwise about the support rod 235. Additionally, the antenna 210 is mounted in the gimbal 212 so that the antenna 210 rotates about a single axis.

[0046] It should be appreciated that the gimbal 212 may be rotatably attached to the support rod 235 in any fashion, as long as the gimbal 212 rotates in a counterclockwise direction and/or a clockwise direction about the support rod 235. Further, the gimbal 212 should be rotatably attached to the support rod 235 so that it can withstand the loads and stresses of use. It should also be appreciated that mounting the antenna 210 in the gimbal 212 so that the antenna 210 rotates about a single axis simplifies the gimbal 212 mount.

[0047] Fig. 6 illustrates an orientation of the point of interest locator 200 shown in Fig. 3. Specifically, as shown in Fig. 6, the local coordinates of the receiving point 214 are xi, yi, and zj, and the local coordinates of the point of interest 250 are x , y₂, and z₂. Further, as shown in Fig. 6, the difference in the local x, y and z coordinates between the receiving point 214 and the point of interest 250 are Δx, Δy, and Δz, respectively, and are used to determine the local coordinates of the point of interest 250. [0048] It should be appreciated that, as indicated, these are local coordinates and are defined in a Cartesian coordinate system. It is also possible to define the global positioning system data using a global coordinate system defined for that global positioning system. For example, the Global Positioning System uses a global coordinate system having an origin that is located at the center of the earth. Standard global positioning system data processing techniques allow the measured position to be defined in these global coordinates or in local coordinates. It should be appreciated that these local coordinates, while often defined in terms of grid and elevation, can also be defined in any desired coordinate system, such as polar coordinates or the like. Standard data processing techniques also allow the data to be easily transformed from one local or global coordinate system to another desired local or global coordinate system. Thus, while the detailed description set forth herein may refer to a particular local coordinate system, the systems and methods according to this invention are not limited to any specific local or global coordinate system.

[0049] The orientation sensor 230 is, in various exemplary embodiments, a three- axis magnetometer that measures the magnitude as well as the direction of the magnetic field along three orthogonal axes. In various exemplary embodiments, this magnetometer- based orientation sensor 230 has a nominal angular accuracy of about 0.1 degrees. It should be appreciated that a lower-cost 1 -degree accuracy version may also be adequate for some applications. In various exemplary embodiments, an accelerometer, or inner ear, which measures the magnitude and direction of the acceleration, can be attached to, or incorporated into, the magnetometer.

[0050] In various exemplary embodiments, such as those used for hand-held devices, the orientation sensor can be read at a rate of about 10 times per second or more and the latest data sets are stored in a buffer of the data collector 240. In various exemplary embodiments, numerical smoothing techniques and/or physical stabilization techniques may be used to mitigate the effects of low stability in hand-held and other low-stability embodiments. Thus, in various exemplary embodiments, the point of interest locator 200 itself can be mechanically and/or electronically stabilized. Such stability-improving techniques reduce the timing requirements for recording the position data relative to a trigger being activated.

[0051] In various other exemplary embodiments, the orientation sensor 230 is implemented using a gyroscope. In still other exemplary embodiments, the orientation sensor 230 is implemented using a combination of a gyroscope and a three- axis magnetometer. Moreover, in some exemplary embodiments, the gyroscope and or three-axis magnetometer may also be combined with an accelerometer to help define the direction of the gravity field.

[0052] The known global positioning system coordinates can be used to compare the measured magnetic field to a model of the Earth's magnetic field so that the measured field tensor may directly be translated to any Earth based coordinate system. Local magnetic disturbances are generally recognized based on the magnitude of the field and on the direction relative the gravity field. It should be appreciated that local magnetic fields can be separated from the global fields in this way. Thus, in various exemplary embodiments, the point of interest locator 200 can be used to recognize and/or measure local magnetic fields at a known or previously-located point of interest, rather than using the known magnetic field structures to determine the location of a desired point of interest. Similarly, it should be appreciated that, in various exemplary embodiments, the point of interest locator 200 can be used to recognize and/or measure deviations in the local geo-gravity field. In general, obtaining such information about the local geo-magnetic and/or geo-gravity fields is difficult. In contrast, such often-sought-after information can be readily obtainable when using various exemplary embodiments of the point of interest locator 200 according to this invention.

[0053] Thus, in various exemplary embodiments, for a given point of interest, the orientation of the point of interest locator 200 can be used to compare the measured magnetic field with expected values based on a model of the Earth's global magnetic field. In exemplary embodiments, such as where the global positioning system coordinates are effectively continually recorded, a measure of the magnetic field gradient, that is, a change in the magnitude and/or in the direction around the point of interest, can be determined and used to indicate magnetic disturbances. It should be appreciated that this gradient also can be used to separate local magnetic fields from the global field values that are characterized by a known (practically vanishing) gradient.

[0054] It should also be appreciated that the support rod 235 can be held in any orientation relative to the point of interest 250 so long as the point 224 is placed at or near the point of interest. Thus, there is no need to precisely locate the global positioning system antenna 210 relative to the point of interest 250 or place the global positioning system antenna 210 at a predefined orientation and distance from the point of interest 250, as in the prior art. Thus, the point of interest locator 200 can be easily used without necessarily requiring any significant training in its use and without requiring a significant amount of setup time and/or effort. [0055] Moreover, contemporary global positioning system equipment cannot be used to determine the location of points of interest that are located in difficult- to-access areas or in areas where there is interference, multipath signal reception, or that have poor or no reception of the signals from the global positioning satellites. Examples of such points include points near walls, points under trees, and points below ground or in water. In contrast, in various exemplary embodiments, the point of interest locator 200 can be used to determine the location of such points.

[0056] That is, it is possible to make measurements of such points using various exemplary embodiments of the point of interest locator 200 according to this invention since the global positioning system antenna 210 is located some distance away from the point of interest being measured. For example, if the actual point of interest is located somewhere where there is no global positioning system reception, or even only poor global positioning system reception, since the antenna 210 of the point of interest locator 210 will be spaced some distance from that point of interest, such as by the length of the support rod 235, then the antenna 210 can be located relative to the point of interest at a point where there is sufficient global positioning system reception.

[0057] As shown in Fig. 7, the data collector 240 of the first and second exemplary embodiments includes an input/output interface circuit or software interface 425, a control circuit, routine or application 430, a memory 440, a coordinate determination circuit, routine or application 450, an orientation determination circuit, routine or application 460, an orientation decomposition circuit, routine or application 470 and a point of interest coordinate determination circuit, routine or application 480.

[0058] It should be understood that each of the circuits, routines or applications shown in Fig. 7 can be implemented as portions of a suitably programmed general-purpose computer. Alternatively, each of the circuits, routines or applications shown in Fig. 7 can be implemented as physically distinct hardware circuits within an ASIC, or using a FPGA, a PDL, a PLA, or a PAL, or using discrete logic elements or discrete circuit elements. The particular form each of the circuits, routines or applications shown in Fig. 7 will take is a design choice and will be obvious and predictable to those skilled in the art.

[0059] The input/output interface circuit or software interface 425 receives signals sent to the data collector 240 from sources such as the orientation sensor 230, the global positioning system antenna 210, a display/input device 415, or other types of user input devices 420. Additionally, the input/output interface circuit or software interface 425 can output data produced by the data collector 240.

[0060] The control circuit, routine or application 430 coordinates communication between all of the circuits, routines or applications 425, 440, 450, 460, 470, and 480 during operation of the data collector 240.

[0061] As shown in Fig. 7, the memory 440 can include one or more of a variable length portion 442, a fixed length portion 444, a point of interest point identification portion 445, a point of interest coordinate portion 446, a position data storage portion 447, a point of interest description portion 448, and a buffer portion 449. The fixed length portion 444 stores a value corresponding to the fixed length of the support rod 235. The point of interest point identification portion 445 stores an identification value corresponding to each point of interest located. The point of interest coordinate portion 446 stores each set of the local x, y, and z coordinates that correspond to the one or more located points of interest 250 located using the point of interest locator 200. In various exemplary embodiments, the position data storage portion 447 can store in excess often hours of global positioning system data. The point of interest description portion 448 stores a description corresponding to each located point of interest 250. For example, the description could describe the point of interest 250 as being "top of curb," "24-inch diameter tree", or "24-inch diameter pipe invert elevation". The buffer portion 449 stores one or more orientation data sets generated by the orientation sensor 230.

[0062] In the third exemplary embodiment outlined below with respect to Fig. 8, the rod 235 that has a known length 237 is replaced with a measurement device that allows the distance from the receiving point 214 to the measurement end of the measurement device to vary. In this case, it is desirable to record the value of that variable distance when a measurement is taken by triggering the point of interest locator 200. In this case, the fixed length portion 444 can be replaced or supplemented with the variable length portion 442. The variable length portion 442 stores distances to points of interest determined using the variable length measurement device, such as the range finder 260, of the third exemplary embodiment of the point of interest locator 200 shown in Fig. 8.

[0063] The memory 440 can be implemented using any appropriate combination of alterable, volatile or non-volatile memory or non-alterable, or fixed, memory. The alterable memory, whether volatile or non- volatile, can be implemented using any one or more of static or dynamic RAM, a floppy disk and disk drive, a writeable or re-writeable optical disk and disk drive, a hard drive, flash memory or the like. Similarly, the non-alterable or fixed memory can be implemented using any one or more of ROM, PROM, EPROM, EEPROM, an optical ROM disk, such as a CD-ROM or DVD-ROM disk, and disk drive or the like.

[0064] The coordinate determination circuit, routine or application 450 determines the lateral local coordinates in an x-y plane, and the elevation, or z coordinate, of the receiving point 214 of the antenna 210. The orientation determination circuit, routine or application 460 determine the orientation of the supporting rod 235 with respect to the receiving point 214 of the antenna 210 based on data generated by the orientation sensor 230.

[0065] The orientation decomposition circuit, routine or application 470 determines the local coordinate differences Δx, Δy, and Δz in the x, y, and z coordinates, respectively, between the receiving point 214 of the antenna 210 and the point 224 of the supporting rod 235. Specifically, the orientation decomposition circuit, routine or application 440 uses the orientation of the supporting rod 235, determined by the orientation determination circuit, routine or application 460, in conjunction with the fixed length value stored in the fixed length portion 444, or the variable length value stored in the variable length portion 442, of the memory 440 to determine the local coordinate differences Δx, Δy, and Δz.

[0066] The point of interest coordinate determination circuit, routine or application 480 determines the coordinates of the particular point of interest 250 currently located by the point 224 of the support rod 235. Specifically, the point of interest coordinate determination circuit, routine or application 480 combines the local x, y, and z coordinates of the receiving point 214 of the antenna 210 with the local coordinate differences Δx, Δy, and Δz, respectively, determined by the orientation decomposition circuit, routine or application 470.

[0067] Figure 8 shows a third exemplary embodiment of the point of interest locator 200 according to this invention that is usable to determine coordinates and elevations of select locations. The third exemplary embodiment of the point of interest locator 200, as shown in Fig. 8, includes substantially the same elements as the first exemplary embodiment of the point of interest locator 200 shown in Fig. 3. Consequently, similar numbers are used to identify corresponding elements. Except as outlined below, a detailed description of the method of determining the coordinates of a particular point of interest 250 using the third exemplary embodiment of the point of interest locator 200 is not necessary because the operation is substantially the same as outlined above with respect to the first and second exemplary embodiments of the point of interest locator 200.

[0068] In the third exemplary embodiment, the point of interest locator 200 includes a range finder 260 located at the end of the supporting rod 235. The supporting rod 235 of the third exemplary embodiment of the point of interest locator 200 is shorter than in the first and second exemplary embodiments. The range finder 260 determines the distance from a defined point 262 of the point of interest locator 200 to the point of interest 250.

[0069] It should be appreciated that the range finder 260 may comprise any distance-measuring device capable of determining distances in accordance with the invention. Such distance measuring devices used to implement the range finder 260 may be acoustic or electromagnetic-based. One example of a distance measuring device is a laser or acoustic range finder in which an operator aims a sighting scope cross hair at the point of interest 250. The point of interest 250 to be determined can also be below water. In this case, sonar-based systems and/or depth-sounder-based systems can be used as the distance measuring device. The point of interest 250 may also be under ground. In this case, ground penetrating radar (GPR) can be used as the range finder 260. In accordance with the third exemplary embodiment of the point of interest locator 200, the point of interest 250 does not have to be physically in contact with the rod 235. Accordingly, the point of interest 250 may be on a stationary object or on a moving object. Thus, the position of large objects, such as airplanes or helicopters, may be determined at a distance of 30 km or more with only slightly degraded accuracy.

[0070] It should be appreciated that, in the first, second and third exemplary embodiments of this invention, data is collected allowing phase lock-carrier phase positioning. More than ten hours of global positioning system data can be stored in the position data storage portion 447 of the memory 440 of the data collector 240. The local coordinates x, y, and z of a point of interest 250 are registered by pulling the trigger 239, which causes one or more data sets from the orientation sensor 230 to be sent to the position data storage portion 447. Sets of data blocks corresponding to the data from the orientation sensor 230 are sent to the position data storage portion 447 for a predetermined time interval before and following the operation of the trigger 239. The data in the buffer is used to get pre-trigger information.

[0071] It should also be appreciated that, in various exemplary embodiments, the location and orientation of the point of interest locator 200, relative to a desired point of interest, can be recorded essentially continuously. In this case, it is no longer necessary to trigger the system to record this data. As a result, a particularly accurate or otherwise appropriate recorded set of data can be identified and extracted from all of the recorded data. As indicated above, this can also allow shape information to be extracted from the mass of recorded data.

[0072] J-n various exemplary embodiments, a digital camera or the like can be associated with or incorporated into the point of interest locator 200. In this case, a digital image is captured for at least some of the recorded position data sets. In general, the captured image will include the point of interest whose position is being measured. In various exemplary embodiments, an image is captured for each recorded position data set. The captured images allow later verification that the point of interest whose position was actually measured is in fact the desired point of interest and not some other point.

[0073] The orientation determining circuit, routine or application 460 uses the magnitude of the gravitational field to extract the direction of the gravitational field from the orientation data, even if the orientation sensor 230 is not stationary. It should be appreciated that, in various exemplary embodiments, the data obtained by the orientation sensor 230 includes acceleration data in combination with the magnetic field-based or gyroscope-based orientation data. In various exemplary embodiments, a set of 16 data points over 1600 milliseconds will be a sufficient data set to allow this information to be extracted. However, it should be appreciated that a sufficient number of sets of data points may vary depending on the extraction algorithm used and/or the available processing power.

[0074] The direction of the magnetic field is referenced to the direction of the gravitational field. As discussed above, local magnetic disturbances are generally recognized based on the magnitude of the field and on the direction relative the gravity field. In various exemplary embodiments, the position is also known and can be used to compare the measured magnetic field with expected values based on a model of the Earth's global magnetic field. For example, when the orientation sensor 230 is a magnetometer, whether or not the orientation sensor 230 also includes an accelerometer, the orientation determining circuit, routine or application 460 uses the data from the position data storage portion 447 to determine the magnitude and direction of the local "undisturbed" magnetic field.

[0075] As discussed, above, in those exemplary embodiments where the global positioning system coordinates are continually recorded, a measure of the magnetic field gradient, that is, the change in magnitude and/or the change in direction around the point of interest, can be determined and used to indicate magnetic disturbances. It should be appreciated that this gradient also can be used to separate local magnetic fields from the global field values that are characterized by a known (practically vanishing) gradient. Thus, accounting for field deviations due to the displacement of the magnetic axis from the earth's rotational axis and other known features of the geomagnetic field, the orientation determining circuit, routine or application 460 fits the measured magnetic field to the theoretical magnetic field magnitude and direction and may correct for small deviations by also fitting a model unknown dipole field. Thus, in various exemplary embodiments, the point of interest locator 200 can be used to recognize and/or measure local magnetic fields at a known or previously- located point of interest, rather than using the known magnetic field structures to determine the location of a desired point of interest. In various exemplary embodiments, the orientation sensor may generate sufficient information to determine the coordinates of a point of interest independently of the magnetic field. In this case, the orientation sensor can be used to recognize and/or measure local magnetic fields.

[0076] In various exemplary embodiments, the orientation determining circuit, routine or application 460 immediately alarms the operator if the fit is outside of a preset tolerance. If the fit is within tolerances, the orientation data at the precise moment of triggering the trigger 239 is determined through an interpolation scheme using the number of sets of orientation data at a predefined interval before and after the trigger, such as, for example, a set of orientations at 100-millisecond intervals. This interpolation compensates for any incidental movement of the point of interest locator 200.

[0077] Figure 9 is a flowchart outlining one exemplary embodiment of the method for determining the local coordinates and elevation, i.e., the local x, y, and z coordinates, of a point of interest according to this invention. Beginning in step SI 00, operation continues to step S200, where an operator determines a point of interest to be located. Then, in step S300, the point of interest is located using a locator having a known or determinable length from a known point of reference. Next, in step S400, global positioning system data is obtained for a global positioning system receiver located at the known point of reference. Operation then continues to step S500.

[0078] In step S500, the coordinates and elevation, i.e., the local x, y, and z coordinates, of the receiver are determined using the global positioning system data. Next, in step S600, the orientation of the locator, at the time the local coordinates and elevation of the receiver were obtained, is determined. Then, in step S700, the differences in coordinates, i.e., Δx, Δy, and Δz, between the receiver and the point of interest are determined based on the orientation and on the known length or the determinable length at the time the coordinates and elevation of the receiver were obtained. Thus, in step S700, the orientation of the locator is used in conjunction with the known or determined distance from the receiver to the point of interest to determine the differences in the local coordinates Δx, Δy, and Δz. Operation then continues to step S800.

[0079] In step S800, the coordinates and elevation, i.e., the local x, y, and z coordinates, of the point of interest are deteπnined. Particularly, the differences in the local coordinates Δx, Δy, and Δz determined in step S700 are combined with the local coordinates and elevation x, y and z of the receiver at the time the local coordinates and elevation of the receiver were obtained. Then in step S900, the local x, y, and z coordinates of the point of interest, the corresponding point identification value assigned to the point of interest, and a description of the point of interest are stored and/or output. Next, in step SI 000, a determination is made whether any additional points of interest are to be located. If an additional point of interest is to be located, operation returns to step S200. Otherwise, operation continues to step SI 100, where the operation ends.

[0080] Figure 10 illustrates a fourth exemplary embodiment of the point of interest locator 200 according to the apparatus and methods according to this invention that is usable to determine the location of predetermined points of interest 250. The fourth exemplary embodiment of the point of interest locator 200, as shown in Fig. 10, can be used with any of the physical devices of the first, second, and third exemplary embodiments of the point of interest locators shown in Figs. 3, 4 and 8.

[0081] In the fourth exemplary embodiment, the point of interest locator 200 includes a data collector 240. Except as outlined below, a detailed description of the operation of the data collector 240 is not necessary because the operation is substantially the same as outlined above with respect to the first, second, and third exemplary embodiments.

[0082] In the fourth exemplary embodiment, the data collector 240 contains a memory 440, a locator end point coordinate determination circuit, routine or application 480, a comparison circuit, routine or application 485 and a notification circuit, routine or application 490. As shown in Fig. 10, the memory 440 contains a predetermined point of interest coordinate portion 443. The predetermined point of interest coordinate portion 443 stores the coordinates of points of interest that are to be located. The locator end point coordinate determination circuit, routine or application 480 determines the local x and y coordinates of the point 224 of the support rod 235.

[0083] The comparison circuit, routine or application 485 compares the local x, y. and z coordinates or x and y coordinates of the end point 224 determined by the locator end point coordinate determination circuit, routine or application 480 with a predetermined point of interest stored in the predetermined point of interest coordinate portion 443 of the memory 440, and determines a value corresponding to the comparison. The notification circuit, routine or application 490 produces a distinctive signal based on the value of the local x and y coordinate comparison performed by the comparison circuit, routine or application 485. For example, the distinctive signal may be audible, visual or tactile, or any other signal suitable for purposes of the invention. A characteristic of the distinctive signal changes the closer the point 224 is to the predetermined point of interest. Furthermore, in various exemplary embodiments, the characteristic of the distinctive signal can be used, in addition to or in place of indicating the distance to the predetermined point of interest, to indicate the direction from the current location of the point of interest locator 200 to the predetermined point of interest.

[0084] Figure 11 is a flowchart outlining one exemplary embodiment of the method for determining the location of a predetermined set of local x and y coordinates or x, y, z coordinates for a point of interest. Beginning in step S2000, the operation continues to step S2100, where an operator stores the local x and y coordinates or x, y, z coordinates of a set of one or more predetermined points of interest, a desired tolerance and corresponding point numbers and point descriptions. Then, in step S2200, the operator selects one of the predetermined points for location. In step S2300, the operator locates a selected point using the locator. Operation then continues in step S2400.

[0085] In step S2400, global positioning system data is obtained for the receiver. Next, in step S2500, the local coordinates and elevation, i.e., the local x, y and z coordinates, of the receiver are determined using the global positioning system data. Next, in step S2600, the orientation of the locator is determined. Then, in step S2700, the differences in the local coordinates, i.e., Δx, Δy and Δz, between the receiver and the selected point are determined based on the orientation and on the known or determinable length of the end of the locator from the global positioning system receiver point at the time the coordinates and elevation of the receiver were obtained.

[0086] Next, in step S2800, the local x and y coordinates or x, y, and z coordinates of an arbitrary point are determined. Particularly, the differences in coordinates Δx and Δy determined in step S2700 are combined with the local x and y coordinates or the x, y, _ coordinates of the receiver. Operation then continues to step S2900.

[0087] In step S2900, the local coordinates of the selected point are compared with the local coordinates of the predetermined point of interest. Next, in step S3000, a signal is generated notifying the user how close the selected point is to the predetermined point and/or in which direction the predetermined point lies from the selected point. That is, in various exemplary embodiments, as the selected point is closer to (or farther from) the current predetermined point of interest, one or more characteristics of the signal changes notifying the user that the selected points are becoming closer to (or farther apart) from the current predetermined point of interest. Similarly, in various exemplary embodiments, in addition to or instead of these distance-based changes, one or more characteristics of the signal notify the user of the direction of the selected point to the current predetermined point of interest Then, in step S3100, if the selected point and the current predetermined point of interest are within the desired tolerance, if defined, or a standard tolerance, if not, or by operator command, then operation continues to step S3200. Otherwise, processing returns to step S2300 and repeats until the selected point and the current predetermined point of interest are within required tolerances.

[0088] In contrast, in step S3200, if an additional predetermined point of interest is to be located, operation returns to step S3200. Otherwise, operation continues to step S3300, where the operation ends.

[0089] While the invention has been described with reference to specific embodiments, the description of the specific embodiments is illustrative only and is not to be construed as limiting the scope of the invention. Various other modifications and changes may occur to those skilled in the art without departing from the spirit and scope of the invention.

Claims

WHAT IS CLAIMED IS:

1. A locating apparatus, comprising: an antenna having a receiving point, the antenna usable to receive coordinate information of the receiving point; an orientation sensor that generates a signal corresponding to the orientation of the locating apparatus between a point of interest and the receiving point; and a processor connected to the antenna and to the orientation sensor, the processor usable to determine coordinate information of the point of interest at a point in time based on the coordinate information received by the antenna for the location of the receiving point at the point in time, the orientation of the orientation sensor at the point in time and a distance between the receiving point and the point of interest.

2. The locating apparatus of claim 1, wherein the orientation sensor includes a three-axis magnetometer that measures the magnitude and direction of a magnetic field relative to the locating apparatus.

3. The locating apparatus of claim 2, wherein the orientation sensor further includes means for determining an orientation of the locating apparatus relative to a known second direction.

4. The locating apparatus of claim 2, wherein the means for determining the orientation of the locating apparatus relative to a known second direction comprises at least one of at least one accelerometer and at least one gyroscope.

5. The locating apparatus of claim 2, wherein the orientation sensor further includes at least one of at least one accelerometer and at least one gyroscope.

6. The locating apparatus of claim 1, wherein the processor comprises an orientation determining circuit, routine or application that determines the orientation of the locating apparatus based on the signal from the orientation sensor.

7. The locating apparatus of claim 1, wherein the processor further comprises an orientation decomposition circuit, routine or application that determines location coordinates of the point of interest relative to the receiving point based on the determined orientation of the orientation sensor and the distance between the receiving point and the point of interest.

8. The locating apparatus of claim 1, wherein the processor comprises a memory that stores coordinates of a predetermined point of interest.

9. The locating apparatus of claim 1 , wherein the processor comprises a comparison circuit, routine or application that compares coordinates of a predetermined point of interest with coordinates of the point of interest located by the locating apparatus at the point in time.

10. The locating apparatus of claim 9, wherein the processor further comprises a notification circuit, routine or application that produces a human-perceptible signal based on a value of the comparison.

11. The locating apparatus of claim 1 , further comprising a rod having a length and a first end and a second end, the antenna attached to the first end, the second end defining the point of interest.

12. The locating apparatus of claim 11, wherein a gimbal is rotatably attached to the first end of the rod and the antenna is attached to the gimbal.

13. The locating apparatus of claim 11 , wherein the antenna is a global positioning system antenna.

14. The locating apparatus of claim 1, further comprising a range finder, the range finder usable to determine the distance from the receiving point to the point of interest.

15. A method for locating a point of interest using a locating apparatus having an antenna having a receiving point and an orientation sensor, the method comprising: receiving coordinate information of the receiving point; determining an orientation of the locating apparatus using the orientation sensor; and determining coordinate information of the point of interest at a point in time based on the coordinate information received by the antenna for the location of the receiving point at the point in time, the determined orientation of the locating apparatus relative to the point of interest at the point in time and a distance between the receiving point and the point of interest.

16. The method of claim 15, wherein determining the orientation of the locating apparatus comprises measuring a magnitude and a direction of a magnetic field relative to the locating apparatus.

17. The method of claim 15 , further comprising defining the point of interest with a rod, the rod having a length, and a first end and a second end, the antenna being attached to the first end and the second end defining the point of interest.

18. The method of claim 15, further comprising determining the distance from the receiving point to the point of interest.

19. A method for locating a predetermined point of interest using a locating apparatus having an antenna having a receiving point and an orientation sensor, the method comprising: storing coordinates for the predetermined point of interest in the locating apparatus; moving the locating apparatus to a selected point in a vicinity of the predetermined point of interest; determining coordinates for the selected point; comparing the coordinates of the predetermined point of interest with the coordinates of the selected point; and producing a distinctive signal based on the comparison to notify a user of at least one of a location of the selected point relative to the predetermined point of interest, a direction from the selected point to the predetermined point of interest and the distance from the selected point to the predetermined point of interest.

20. The method of claim 19, further comprising: moving the locating apparatus to another selected point in the vicinity of the predetermined point of interest based on the produced distinctive signal; and repeating the determining, comparing and producing steps to produce another distinctive signal corresponding to the relative location of the another selected point to the predetermined point of interest.