RU2419808C1 - Positioning device, method and program with absolute and relative positioning modes - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: propose positioning device may be operated in two modes: first, using data mainly from absolute positioning system, and second, using data, mainly from relative positioning system. Primary data source is selected proceeding from predetermined position and quality of absolute positioning system signal, as well as data stored in digital card data base. Note here that said data comprises data on threshold distances for various geographical objects and that, on approaching said objects with their threshold distances known, operating mode changes into that using mainly the data received from relative positioning system before quality of absolute positioning system signal drops drastically.

EFFECT: higher range-finding data accuracy.

18 cl, 5 dwg

Description

Technical field

The present invention relates to a positioning apparatus and method for determining a location using an absolute positioning system and a relative positioning system, to a computer program and a storage medium.

State of the art

Global Navigation Satellite Systems (GNSS), such as the Global Positioning System (GPS), are used globally by users to determine their location (longitude, latitude, altitude) on the earth.

The GPS system includes a number of satellites orbiting the earth, each satellite transmitting radio signals containing accurate time information about the time when the radio signals are transmitted by the satellite. Radio signals also contain location information (orbital information), including the location information of the corresponding satellite, and satellite identification, which is unique to a particular satellite.

Positioning devices, such as GPS receivers, are configured to receive these signals and calculate their location based on the received signals. Such positioning devices provide absolute positioning information with respect to the absolute coordinate system and therefore can also be referred to as absolute positioning systems.

The positioning devices are adapted to receive these transmitted radio signals and calculate the transit time of such a radio signal based on the time information contained in the radio signal and the measured time of arrival of the radio signal using the clock (hours) contained in the positioning device. The transit time is usually 65-85 milliseconds. Based on the travel time, the distance from the positioning device to the satellite can be calculated simply by multiplying the travel time by the speed of light (c = 299,792,458 m / s).

Based on the received orbital information contained in the radio signal, the positioning device can calculate the location of the satellite. By combining information about the distance to the satellite and the location of the satellite, the positioning device is placed on an imaginary sphere whose radius is equal to the distance and in the center of which the satellite is located.

By repeating this calculation process for at least four satellites, the positioning device can calculate four of these imaginary spheres, determining one intersection that determines the location of the positioning device.

Positioning devices are often used in navigation devices containing digital map data. Such navigation devices may be configured to display a location, as determined on a digital map, using a display. Such a navigation device may be referred to as a map display device, where a portion of the displayed map is determined by the actual location, as determined by the positioning device.

In addition, such navigation devices may be configured to calculate navigation instructions from a starting location (e.g., a current location) to a position of a destination in order to direct the user to the destination address. Since the positioning device can place the current location on a digital map, the navigation device is able to provide detailed navigation instructions, for example: "after 100 meters, turn left." It should be understood that accurate positional information is necessary for such applications in order to guarantee optimal navigation and optimum comfort for the user.

To increase the accuracy of the location, as determined by the positioning device using the absolute positioning system, the positioning device can use more than four satellites. In general, a positioning device uses information from all satellites from which it receives radio signals. In general, the more satellites used, the more accurate a particular location is.

The accuracy of the location, as determined by the positioning device, is influenced by a number of factors, such as the computed satellite location, the calculated transit time of the radio signal, the current time, as determined by the clock of the positioning device. A number of methods are known that can reduce the effects of these system errors, such as WAAS (Advanced Extended Area System) and DGPS (differential GPS), as is known to a person skilled in the art.

The accuracy of a specific location can be further enhanced by using a method called map matching. This method provided a further increase in the accuracy of a specific location by mapping the location, as determined, to a street or the like, as stored in the map database.

However, a number of additional errors that reduce the accuracy of a specific location, such as ionospheric effects, satellite clock errors, etc., can also be identified. One special type of error is the so-called multipath distortion.

Multipath occurs in situations in which a radio signal transmitted by a satellite is reflected by an object, such as a building, and the positioning device receives the radio signal after reflection, possibly together with an unreflected radio signal. As a result, the calculated distance between the satellite and the positioning device introduces an error into the calculated location of the positioning device.

The positioning devices may also comprise or cooperate with a relative positioning system in order to in principle improve the positioning accuracy of the absolute positioning system or to determine a location in situations in which radio signals cannot be received, or insufficient radio signals are received. Relative positioning systems provide local and relative positioning information.

These relative positioning systems may, for example, be at least one of a gyroscope, accelerometer, compass, distance meter (such as an odometer), and an inclinometer. In case the positioning device is used in a vehicle, such as a car or a motorcycle, the relative positioning device may also be a distance / speed measuring module, which is usually present in such a vehicle, and / or a module detecting steering actions of the steering wheel, and / or other sensors that may be present in the vehicle.

Situations in which greater emphasis can be placed on relative positioning systems (i.e. information from a relative positioning system is weighed with more weight) are situations where, for example, a positioning device enters a tunnel or underground parking. The positioning device will no longer be able to determine its location using the absolute positioning system, since not enough radio signals are received. In a tunnel or in an underground parking positioning device uses information received or received from the relative positioning system.

For example, a gyroscope provides information about relative rotational motion. In combination with the last obtained location based on the absolute positioning system and a distance meter, this can be used to calculate the current position inside the tunnel or in the underground parking lot.

US Pat. No. 5,311,195 describes a navigation system using a combination of an absolute positioning system, such as a GPS receiver, and relative positioning systems, such as an on-board wheel sensor and / or magnetic compass. According to U.S. Pat. So, in case the accuracy of the relative positioning system is low, the absolute positioning system can be used to update the relative positioning system.

According to the prior art, positioning devices are arranged to determine a location using an absolute positioning system and a relative positioning system and are further operable

- in a first mode in which a location is determined using an absolute positioning system and possibly a relative positioning system, and

- in the second mode, in which the location is determined using a relative positioning system and, possibly, an absolute positioning system,

in the first mode, the absolute positioning system is weighed with a greater weight to determine the location than in the second mode. The positioning devices are configured to switch from the first mode to the second mode and vice versa, based on certain accuracy of the absolute and / or relative positioning systems.

Based on the foregoing, the aim is to provide a positioning device and method that provides more accurate location information.

SUMMARY OF THE INVENTION

According to one aspect, there is provided a positioning device configured to determine a location using an absolute positioning system and a relative positioning system and further configured to operate

- in a first mode in which a location is determined using an absolute positioning system and possibly a relative positioning system, and

- in the second mode, in which the location is determined using a relative positioning system and, possibly, an absolute positioning system,

in the first mode, the absolute positioning system is weighed with a greater weight than in the second mode to determine the location, and the positioning device is configured to switch from the first mode to the second mode, characterized in that the positioning device includes or has access to a digital database cards, and the decision to switch from the first to the second mode is made based on at least a specific location in combination with the information stored in the digital map database . Such a positioning device provides a more accurate positioning, since switching from one mode to another mode can be performed before the quality of one mode deteriorates too much.

According to an embodiment, the absolute positioning system is one of a satellite positioning system and a ground positioning system.

According to an embodiment, the relative positioning system is at least one of a gyroscope, accelerometer, compass, speed measurement module, distance meter, inclinometer and a module detecting steering wheel actions.

According to an embodiment, the information stored in the digital map database contains a plurality of geographic features having threshold distances associated with them.

According to an embodiment, the positioning device is configured to calculate at least one distance from a specific location to a selection from a plurality of geographical objects having threshold distances associated with them, and switching from the first mode to the second mode is carried out if at least at least one of the calculated distances is below the corresponding associated threshold.

According to an embodiment, the absolute positioning system is configured to determine a location based on signals received from a plurality of transmitters that are part of a satellite positioning system or a terrestrial positioning system.

According to an embodiment, the digital map database is a three-dimensional digital map database, and the information includes three-dimensional information about geographical objects, wherein the positioning device is configured to calculate location quality as determined by the absolute positioning system based on at least one of a specific location, the location of the transmitters and the database of a three-dimensional digital map.

According to an embodiment, the positioning device is configured to determine the respective locations of the transmitters based on the location information contained in the respective signals.

According to an embodiment, the decision to further switch from the second to the first mode of the method is made based on a specific location in combination with the information stored in the digital map database.

According to an embodiment, the positioning device is configured to maintain a history file including previously determined locations and associated accuracy as determined according to the absolute positioning system, and if switching from the first mode to the second mode is performed, the positioning device is configured to select an initial location for relative positioning systems from a history file.

According to an embodiment, the positioning device is configured to determine the accuracy of certain locations in one mode, compare a certain accuracy of locations with a threshold value and, if the accuracy is below a threshold value, save these locations as a geographical feature with a recommended mode associated with it, and the recommended mode different from the one mode mentioned.

According to one aspect, a method is provided, the method comprising determining a location using an absolute positioning system and a relative positioning system, wherein the location can be determined

- in a first mode in which a location is determined using an absolute positioning system and possibly a relative positioning system, and

- in the second mode, in which the location is determined using a relative positioning system and, possibly, an absolute positioning system,

in the first mode, the absolute positioning system is weighed with a greater weight than in the second mode, the method further comprising switching from the first mode to the second mode,

characterized in that the method comprises an action for deciding whether to switch from the first mode to the second mode, based on a specific location in combination with information stored in the digital map database.

According to one aspect, a computer program is provided that, when downloaded to a computer device, acts to perform any one of the methods according to the above.

According to one aspect, a storage medium is provided comprising a computer program according to the above.

Brief Description of the Drawings

The present invention is described below in more detail using a number of exemplary embodiments with reference to the drawings, which are intended to illustrate the present invention, and not limiting its scope, which is limited only by the attached claims:

figure 1 schematically depicts a positioning device according to the prior art,

figure 2 schematically depicts a positioning device that interacts with satellites, and

3, 4, and 5 schematically depict flowcharts according to embodiments.

Detailed description

As already briefly described above, the positioning device can be configured to operate in a first mode in which locations are determined using an absolute positioning system, and in a second mode in which locations are determined using a relative positioning system. Such a positioning device may include a PU processing unit including or interacting with such an absolute and relative positioning system. The PU processing unit may also be configured to switch from the first to the second mode and vice versa. First, the PU processing unit of such a positioning device is described in more detail below.

Processing unit

The PU processing unit is shown schematically in FIG. 1, but it should be understood that the PU processing unit can be formed as a computer unit, for example, comprising a processor for performing arithmetic operations and a memory, the memory comprising program lines read and executed by the processor to provide PD positioner functionality described here.

The memory may be a magnetic tape unit, a hard disk, read-only memory (ROM), an electrically erasable read-only programmable memory (EEPROM), and random access memory (RAM).

The PU processing unit may further comprise or be configured to communicate with

- input devices such as keyboard, mouse, touch screen, loudspeaker,

- output devices such as display, printer,

- reading devices for reading storage media such as floppy disks, CD-ROMs, DVDs, flash cards, USB sticks, etc., and

- communication devices configured to communicate with other computer systems via a communication network, such as a mobile telephone network, a GSM network, a UMTS network, an RF network, (wireless) Internet, etc.

The PU processing unit may be configured to receive information from a relative positioning system (also called an autonomous positioning system), as explained in more detail below, using suitable input devices or readers.

However, it should be understood that more such devices can be provided, and / or other memory units, input devices, output devices, and reading devices known to those skilled in the art can be provided. In addition, one or more of them may be physically located remotely from the PU processing unit, if required. The PU processing unit is shown as one unit, however, it may include several processing units operating in parallel or controlled by one main processing unit, which can be located remotely from one another, as is well known to specialists in this field of technology.

The PU processing unit may further include or be configured to communicate with the CL clock and the AN antenna. CL watches can be used in combination with an absolute positioning system. The AN antenna can be used to receive signals, for example, from satellites of the absolute positioning system.

Note that the connections between the various hardware elements can be physical connections, but one or more of these connections can be made wireless.

The PU processing unit may be a computer system, but may be any signal processing system of analog and / or digital technology and / or software technology configured to perform the functions described herein.

Absolute positioning system

2 shows a PD positioning device, as already described above, using an absolute positioning system to determine its location. The PD positioning device includes a PU processing unit, an antenna AN, and a clock CL. Antenna AN is designed to receive radio signals transmitted by satellites SA1, SA2, and transmit these received radio signals to the processing unit PU. Although the antenna AN is depicted as an element extending from the PD positioning device, it is understood that the AN antenna can also be formed inside the PD positioning device. The CL watch is designed to provide accurate time information to the PU processing unit.

As already described above, the processing unit PU can be configured to receive radio signals from satellites SA1, SA2 through the antenna AN. From these radio signals, the PU processing unit receives information, such as time information about the time when the radio signals were transmitted by the satellite, orbital information including the location information of the corresponding satellite and satellite identification for the satellites SA1, SA2.

The processing unit PU can be configured to determine the time of arrival of radio signals using time information received from the clock CL. Based on the time information about the time when the radio signals were transmitted by the satellite and the time information from the CL clock, the PU processing unit can calculate the transit time of the radio signal (by subtracting one from the other) and the distance between the PD positioning device and the corresponding satellite (multiplying the transit time by the speed of light) .

By combining information from multiple satellites (at least four), the location of the PD positioning device can be calculated.

Figure 2 further shows that the positioning device PD is located near the entrance of the tunnel or underground parking. In fact, the PD positioning device can be located near an object of any kind that can block the radio signals transmitted by the satellite, such as a building, tree, hill, mountain, viaducts, etc. 2 further schematically shows a first satellite SA1, a second satellite SA2 and a third satellite SA3 orbiting around the Earth. It is understood that although only three satellites SA1, SA2, SA3 are shown in FIG. 2, in fact, there will usually be more than three satellites SA1, SA2, SA3.

The first satellite SA1 transmits the radio signals indicated by a dotted line. You can see that the radio signals can be detected by the positioning device PD. The processing unit PU can now calculate the distance from the positioning device PD to the first satellite SA1.

The second satellite SA2 also transmits radio signals, also indicated by a dotted line. However, these radio signals experience multipath distortion, since the radio signal from the second satellite SA2 enters the antenna of the PD positioning device directly (see radio signal a in figure 2), as well as indirectly (see radio signal b), that is, through reflection from the tunnel input TU.

If the processing unit PU now calculates the distance between the positioning device PD and the second satellite SA2, calculating the travel time, it is clear that the result will be an erroneous distance due to distortion of multipath propagation. This erroneous distance will lead to an erroneous determined position of the PD positioning device even when used in combination with information received from a plurality of satellites SA1, SA2.

Radio signals from the third satellite SA3 cannot be received at all by the positioning device, since they are completely blocked by the TU tunnel.

It is understood that the examples of the absolute positioning system described herein are not limited to GPS systems. The described embodiments may be used in combination with any kind of absolute positioning system using signals sent wirelessly from multiple transmitters to a receiver, such as a PD positioning device, allowing the receiver to calculate its location based on the received signals.

It is understood that such signals typically have a low power level, which makes their detection relatively difficult by positioning devices.

The absolute positioning system may be a satellite positioning system or a global navigation satellite system (GNSS) such as a GPS system, GLONASS and Galileo.

The absolute positioning system may also be a ground-based positioning system using beacons located on land or at sea, which transmit signals containing information that can be used by the receiver to determine its location. An example of such a ground based system is the LORAN Long Range Navigation System. Another example of such a system may be a terrestrial system using mobile telephone masts (such as GSM masts) as beacons.

In general, an absolute positioning system includes a plurality of transmitters, such as satellites or beacons, for wirelessly transmitting signals, such as radio signals that can be received by a receiver, such as a PD positioning device, which is configured to calculate its location based on the received signals.

Relative positioning system

According to the embodiments described herein, the PD positioning device may include or interact with an RPS relative positioning system, as shown schematically in FIG. As described above, such an RPS relative positioning system can be, for example, at least one of a gyroscope, accelerometer, compass, distance meter (such as an odometer), and an inclinometer. In case the PD positioning device is used in a vehicle such as a car or a motorcycle, the RPS relative positioning system may also be the distance / speed measuring unit that is normally present in such a vehicle and / or a steering wheel control detecting unit, and / or other sensors that may be present in the vehicle.

It will be appreciated that other RPS relative positioning systems may also be used. In addition, a combination of various RPS relative positioning systems may be used.

For example, the PD positioning device may be configured to receive input from a speed measuring unit and a (electronic) compass. Based on the inputs received from these modules, the processing unit PU of the PD positioning device can calculate the relative position because it can calculate how far the PD positioning device has traveled and in which direction.

According to the prior art, the PD positioning device may be operable

- in a first mode in which a location is determined using an absolute positioning system and possibly a relative positioning system, and

- in the second mode, in which the location is determined using a relative positioning system and, possibly, an absolute positioning system,

in the first mode, the absolute positioning system is weighed with a larger weight to determine the location than in the second mode. Switching from the first mode to the second mode can be triggered by comparing estimates of the accuracy of the location, as determined by both systems. In addition, when no absolute position determination is possible, for example, when the PD positioning device enters a tunnel or underground parking, the positioning device can switch from the first mode to the second mode.

From the foregoing, it should be clear that in the first mode and the second mode, the location information, as obtained from the absolute and relative positioning system, can be combined by weighing, filtering, mixing, etc., to obtain a specific location of the positioning device.

Of course, additional modes can be applied using different weightings of the absolute positioning system and the relative positioning system, other than in the first and second modes. Furthermore, it is understood that according to an embodiment, the relative positioning system is not taken into account in the first mode at all, and / or the absolute positioning system is not taken into account in the second mode at all.

In the second mode, the PD positioning device uses the relative positioning information provided by the RPS relative positioning system. Relative positioning information is used in combination with the starting location (for example, the most recent location, as determined by the absolute positioning system or the previous mode) to determine the current location.

However, it was found that switching from the first to the second mode and / or vice versa, according to the prior art, can lead to inaccurate positioning information, since the switching is usually performed at a point in time at which the location, as determined according to the initial mode, is already relatively inaccurate.

For example, an error in the initial location used by the RPS relative positioning system, as determined by the first mode before switching from the first to the second mode, will affect all subsequent locations determined in the second mode, since the initial location is used as the base for them. Therefore, an improvement is provided to ensure the calculation of more accurate positioning information.

Digital map database

PD positioning devices may include or access DMD digital card databases. The PD positioning device may be configured to present the current location on a digital map using a display. However, the PD positioning device may also be configured to provide navigation instructions from a starting location (e.g., a current location) to a destination position in order to direct a user to a destination address.

It is understood that the term “digital map database”, as used here, does not necessarily refer to the database structure in the traditional way, that is, it does not imply a relational structure between the database records or the database administrator coordinating the database. The digital map database, as used here, refers to any set of geospatial information, regardless of the exact way the information is structured.

The term “geographic feature”, as used here, may correspond to a real feature, such as a tunnel, building, tree, hill, etc., but also corresponds to a specific position in general.

DMD digital map databases, also known as geospatial databases, navigation maps, or electronic maps, are known in the prior art. In general, DMD digital map databases can currently include geographic features (also called geographic locations) associated with geographic location (s), and possibly include some form of geographically related information, such as places of interest (museum, restaurant), (underground) parking, tunnels, bridges, etc. In this application, the term "DMD Digital Card Database" is used to refer to all kinds of electronic and digital cards.

DMD digital map databases can include a set of geographic features and a set of vectors representing (parts of) a road connecting geo-spatial features. The DMD digital map database may also include additional information, for example, regarding the type of road (highway, footpath), maximum permissible speed (50 km / h, 100 km / h), street names, the presence of objects such as tunnels and underground parking, etc. The DMD digital map database may also include information about the type of environment (urban, rural, forest, agriculture), etc.

A DMD digital map database can be used to compute navigation instructions to guide the user to a destination, as mentioned above. Depending on the user's current location, as determined by the positioning device, part of the digital database of the DMD card may be displayed.

The digital map database may be a database of a three-dimensional digital map 3DMD containing three-dimensional information, for example, about geographical objects such as buildings, trees, rocks, mountains, tunnels, (underground) parking lots, etc. The 3DMD digital map database may further include information on city canyons and / or city models.

Such a database of a three-dimensional digital map 3DMD may include information about the location of objects, including the horizontal and vertical sizes of such objects. The 3DMD digital map database may also include information about the shape of such geographic features that may, for example, be relevant in the case of a building having a gabled roof.

Options for implementation

According to an embodiment, the PD positioning device is configured to switch from a first mode to a second mode using information from a database of a digital map DMD or a database of a three-dimensional digital map 3DMD.

According to another embodiment, the PD positioning device is configured to switch from the second mode to the first mode based on the information of the DMD digital map database or the 3DMD digital map database.

It is understood that the second mode can also exclusively use information from the relative positioning system and not use any information from the absolute positioning system. This can, for example, take place in situations where no absolute positioning is possible, for example in a tunnel, etc. In such a case, when the PD positioning device is in the second mode, the relative positioning information, as determined by the RPS relative positioning system, can only be converted to an absolute location using the starting location described above, for example, being the previously determined absolute location determined in the first mode, or absolute positioning system.

According to the prior art, switching from the first mode to the second mode was started based on the identification that the quality or accuracy of the location was determined to be relatively low, for example, because fewer radio signals were received. However, as a result of switching from the first mode to the second mode, when the specific position is not accurate enough, the initial location used as the base for the relative positioning system is of relatively poor quality or is relatively inaccurate. This may, for example, take place because the switching from the first to the second mode was performed at the moment when the positioning device PD has already entered the TU tunnel. Therefore, all locations determined using the relative positioning system are relatively inaccurate due to the relatively inaccurate starting location.

According to the embodiments provided herein, switching from the first mode to the second mode is performed in a more complex way, that is, before the quality of the location, as determined in the first mode, decreases too much. Switching from the first to the second mode is started using information from the database of the digital map DMD or the database of the three-dimensional digital map 3DMD.

Furthermore, according to the embodiments provided herein, switching from the second to the first mode is performed when the quality of the location, as determined by the first mode, is high enough. Switching from the second to the first mode is started using information from the database of the digital map DMD or the database of the three-dimensional digital map 3DMD.

Using information from the digital map database, the switching time from one mode to another can be calculated more accurately, leading to more accurate positioning information.

Embodiment 1

According to an embodiment, the DMD digital map database may include a geographical object, such as the location of, for example, a TU tunnel, or the position of a tree, building, viaduct, and the like. At the same time, a threshold distance of, for example, 50 meters can be stored in the DMD digital map database, indicating that the positioning quality in the first mode is low within this distance from the TU tunnel, and the PD positioning device should switch from the first mode to the second mode when located at a distance less than, for example, a distance of 50 meters from the TU tunnel.

Each specific geographic feature may have its own threshold associated with it. Thus, standard threshold distances can be provided for a certain type of geographical objects, such as 50 meters for tunnels and 30 meters for trees.

According to such an embodiment, the PD positioning device may have access to a DMD digital map database. Based on the information stored in the DMD digital map database, for each location of the PD positioning device, the PD positioning device can calculate whether it is too close to a geographic object, and the quality of the locations, as determined in the first mode, is likely to deteriorate too much . When the PD positioner determines that it is too close to the object, the PD positioner switches to the second mode.

Also, when the PD positioning device is in the second mode and the PD positioning device detects that it is no longer within the threshold distance from the geographical feature, it can switch back from the second mode to the first mode.

Of course, this embodiment could also work in combination with a database of a three-dimensional 3DMD digital map containing threshold distances.

Flowchart 1

3 is a schematic flowchart depicting actions that may be performed by a PD positioning device or a PU processing unit according to an embodiment.

In the first step 100, the PD positioning device may start executing a flowchart as described herein. The start may be manually triggered by the user, or may, for example, be triggered by switching on the PD positioning device.

In the second step 101, the PD positioning device determines its location in the first mode using input from the APS absolute positioning system and, possibly, from the RPS relative positioning system.

Once the location is determined, the PD positioning device can calculate its distance to the nearest geographic features having a threshold associated with it, for example, all such geographic features within a range of 100 meters. This is done in step 102. To perform this step, the input from the database of the DMD digital card is used.

In the next step 103, the calculated distances to the nearest geographical features are compared with the corresponding distance thresholds associated with the geographical features.

If the PD positioning device is not too close to the geographic feature, then in step 104, a decision is made to return to step 101 and determine the updated location in the first mode. If the PD positioning device is too close to the geographic feature, then in step 104 a decision is made to proceed to step 105 and determine the updated location in the second mode.

After actions 101 and 105, steps 102, 103 and 104 are performed. This ensures that the positioning device PD automatically switches from the first mode to the second mode and vice versa, when necessary and possible.

Embodiment 2

According to another embodiment, the PU processing unit may have access to a 3DMD digital map database. According to such an embodiment, the PD positioning device can calculate, based on three-dimensional information about geographic features stored in the 3DMD digital map database for each position of the PU processing unit, whether the quality of the absolute locations, as determined by the absolute positioning system, is such that the block processing PU will have to switch to the second mode, in which the absolute positioning system APS is weighed with less weight.

Thus, while the first embodiment uses predetermined threshold distances that are stored in the digital map database or the three-dimensional digital map database, according to this embodiment, the switching from one mode to another is determined locally using information from the three-dimensional database digital cards.

The PU processing unit may, for example, calculate when it reaches or has reached a position where multipath distortion is likely to occur. It is clear that the processing unit PU has information about the current locations of the satellites SA1, SA2, SA3 from which the signals are received, since this information is contained in the signals (orbital information). Using this information in combination with the shape and size of geographic features close to the last determined position stored in the 3DMD digital map database, the PU processing unit can calculate for which satellites multipath distortion is likely to occur by applying simple geometric relationships.

According to an alternative, the PU processing unit can, for example, calculate when it reaches or has reached a location where too few signals can be received directly (i.e., without multipath distortion) from satellites SA1, SA2, SA3 to calculate the location with sufficient accuracy. To do this, the PU processing unit is configured to calculate which satellites do not experience multipath distortion and which satellites do experience multipath distortion. This calculation is explained in more detail below. Based on the result, the PU processing unit may decide to switch from the first mode to the second mode, in which the RPS relative positioning system is more emphasized.

Again, the PU processing unit has information about the current locations of satellites SA1, SA2 from which the signals are received (with or without multipath distortion), since this information is contained in the signals (orbital information). Using this information in combination with the shape and size of geographic features close to the last determined location that is stored in the 3DMD digital map database, the PU processing unit can calculate which satellites the signals can be received without multipath distortion using simple geometric relationships.

Thus, according to this embodiment, the PD positioning device can predict, based on information from the 3DMD digital map database, that it will reach a location where it is preferable to be in a particular mode (first mode or second mode). In response to this positioning device, the PD can switch the mode when this location is soon to be reached or has been reached.

Signal quality determination

As described above, the PU processing unit may be configured to determine which of the satellites SA1, SA2, SA3 are observable, which are invisible or experience multipath distortion. The PU processing unit can calculate this using information about the following:

a) the location of the PD positioning device,

b) the location of the satellite concerned and

c) a database of a three-dimensional digital map 3DMD.

The location of the PD positioning device used to calculate which satellites SA1, SA2, SA3 are observed, invisible or experiencing multipath distortion is the most recent location determined by the PD positioning device, for example, in the previous positioning. The location may also be an estimated location, that is, a location that is estimated to be reached after one second. This can be done based on extrapolation of speed and direction of movement, possibly in combination with the methods of matching with the map, and using information about the planned route.

The location of the corresponding satellite SA1, SA2 can be calculated based on the orbital information, as received from the respective satellites SA1, SA2. Using this information, an elevation angle α can be calculated that indicates at what angle the corresponding satellite SA1, SA2 can be observed relative to the horizontal. It can also be determined in which direction β the corresponding satellite SA1, SA2 can be observed, for example, in the western direction (270 ° relative to the north direction).

The 3DMD digital map database is located in memory, on a storage medium, etc., as described above.

All this information can be used to calculate whether direct communication is possible between the positioning device PD and satellite SA1, SA2, and whether multipath distortion can occur when using basic goniometric mathematics. It is understood that if the positioning system is a ground-based system, the locations of the transmitters may be fixed and may be known to the positioning device PD. In this case, their location must be determined once, and not determined periodically.

In addition, the surface properties of objects stored in a 3DMD digital map database (for example, buildings) can be contained in a three-dimensional digital map database and used to decide on the expected multipath intensity.

Based on this calculation, a measure of the quality of the absolute location, as determined by the APS absolute positioning system, can be calculated and compared with the threshold quality. If the quality of the absolute location, as determined by the absolute positioning system APS, below the threshold quality, the positioning device PD can switch from the first mode to the second mode. When in the second mode, and if the quality of the absolute location, as determined by the absolute positioning system APS, is higher than the threshold quality, the positioning device PD can switch from the second mode to the first mode.

The quality of the APS absolute positioning system can be determined taking into account the number of satellites from which direct signals can be received, their angle above the horizon (satellites at low angles usually provide information of relatively low quality), and their spatial distribution in the celestial sphere.

This information can be used to switch from the first mode to the second mode before the quality or accuracy of the location determined in the first mode is likely to decrease too much, for example, to fall below a predetermined threshold. In addition, this information can be used to switch from the second mode to the first mode, if possible.

Flowchart 2

4 schematically depicts a flowchart depicting actions as may be performed by a PD positioning device or a PU processing unit according to an embodiment.

In the first step 200, the PD positioning device may begin to execute a flowchart as described herein. The start may be manually triggered by the user or may, for example, be triggered by the inclusion of the PD positioning device.

In the second step 201, the positioning device PD determines its location in the first mode, as shown schematically in FIG.

Once a location is determined, the PD positioner can calculate the quality of the APS absolute positioning system for that location. This is done in step 202. To perform this action, the input from the database of a three-dimensional digital map 3DMD of geographical objects is used, in combination with the locations of satellites SA1, SA2, using simple geometric ratios.

In the next step 203, the computed quality of the location determined based on the APS absolute positioning system is compared with the threshold quality.

If the quality is high enough, in step 204 a decision is made to return to step 201 and determine the updated position in the first mode. If the quality is too poor, in step 204 a decision is made to proceed to step 205 and determine the updated location in the second mode.

After actions 201 and 205, actions 202, 203 and 204 are performed. This ensures that the positioning device PD automatically switches from the first mode to the second mode and vice versa, when necessary and possible.

Embodiment 3

According to another embodiment, the PD positioning device may be configured to support a history file containing specific locations and associated accuracy, as determined according to the APS absolute positioning system, as well as measurements determined by the RPS relative positioning system.

For example, a PD positioning device may be configured to support a history file over a specific distance, for example, the last 200 meters. Or, the PD positioning device may be configured to support a history file during a specific time interval, for example, in the last minute.

This history file can be used when switching from the first mode to the second mode. Since the second method relies heavily on information from the RPS relative positioning system, its accuracy is largely dependent on the location that is used as the starting location for the RPS relative positioning system.

When switching from the first mode to the second mode, the PD positioning device can be configured to check the history file and select, based on the information contained in the history file, which position should be used as the starting location for the second mode.

For example, if the accuracy of the first location determined 50 meters before the switch is very high, and the second location determined close to the switch (for example, 5 meters) has very low accuracy, it may be more correct to use the first location as starting location, not the second location, although this second location is much closer to the switch position from the first to the second mode.

To use this first location as a starting location, it is also necessary for the PD positioning device to store measurements of the RPS relative positioning system between the first position and the switching position in order to be able to calculate further locations in the second mode.

It will be appreciated that the PD positioning device may be configured to support a history file if a geographic feature that may cause switching is approaching. The PD positioning device can calculate whether such a geographic feature is approaching based on extrapolation of speed and direction or based on a planned route.

Flowchart 3

5 schematically depicts a flowchart that may be performed by a PD positioning device to perform the embodiment described here.

In a first step 300, a flowchart begins to run. In the next step 301, it is determined whether a geographical feature is approaching, which may cause switching between modes. If not, then the PD positioner returns to step 301. If yes, then the PD positioner starts supporting the history file in step 302.

At act 303, it is determined whether the positioning device PD switches from the first mode to the second mode. If no switching is performed within a predetermined time interval or distance of the path, the positioning device PD returns to step 303.

If the switch is made from the first mode to the second mode, in step 304, the PD positioning device determines what is the best starting location for the RPS relative positioning system.

Embodiment 4

As described above, geographic features can be used to decide when to switch between the first and second mode. These geographic features may correspond to a real feature that may affect the APS absolute positioning system, such as a tunnel, building, tree, hill, etc.

Geographic features (also called geographical locations) can also be a location for which it is known that one mode is more preferable than another, and the location does not necessarily correspond to or is associated with a real object, such as a tunnel, building, tree, hill, etc. d.

According to an embodiment, the PD positioning device is configured to add geographic features to the DMD digital map database based on measurements of absolute and relative positioning systems and associated accuracy in the past. According to such an embodiment, the PD positioning device is configured to calculate and record the accuracy of certain locations and the mode in which the locations were determined.

If it is found that the accuracy of a specific location or range of locations (for example, in a tunnel), for example, in the first mode is below a certain threshold, this location can be saved as a geographic feature, with a recommended mode (for example, the second mode) associated with it. The PD positioning device may also be configured to save a location such as a geographic feature with a recommended mode assigned to it only if the specified accuracy of a specific location in one mode is below the threshold more than a predetermined number of times (e.g., 5 times) or more than a predetermined percentage time (for example, more than 50% of cases of positioning).

This embodiment provides a self-learning PD positioning device that can add locations to a DMD digital map database or a 3DMD digital map database, for which it is known from previous measurements that positioning in a particular mode will most likely result in relatively low accuracy, and therefore, the PD positioning device can switch to another mode before such a location is reached. This can lead to more accurate positioning.

Weighted accuracy information can be linked to the DMD / 3DMD 3D map database and returned to the map provider for inclusion in newer generations of the DMD / 3DMD 3D map database or broadcast to the service provider for distribution back to new users. In addition, information can be broadcast directly to users in the vicinity for sharing by drivers.

So, other drivers who are not aware of the upcoming signal failures of absolute positioning systems (in tunnels, due to power lines) can find out about this and take the necessary precautions: switch to the second mode.

Information can be entered into the DMD digital map database by the card provider or quickly distributed to a service center, which then distributes it to other drivers. In addition, this information can be broadcast directly to vehicles in the vicinity, which can store information in their local DMD digital map database for future use, as described above.

Additional notes

In both embodiments described above, the decision to switch from the first mode to the second mode and vice versa is made based on a previously determined location in combination with the information stored in the digital map database. According to one embodiment, satellite location information may also be used.

It is understood that although the embodiments described above describe a PD positioning device using the first and second mode, the PD positioning device can also be configured to operate in additional modes such as third, fourth, etc. mode. In these additional modes, the weighting for absolute and relative positioning systems may be different from that used in the first and second modes. In addition, the modes may differ in that a different set of relative positioning systems RPS is used. For example, in the second mode, the PD positioning device can use a compass and a speed meter, and in the third mode, an accelerometer is also used. It is clear that changes of any kind are possible.

Therefore, it should be understood that the PD positioning device can also be configured to switch between the first, second and additional modes based on a specific location in combination with information stored in a digital map database (DMD, 3DMD). Geographic features may also have a recommended mode associated with them, indicating which mode the PD positioning device should switch to when approaching such a geographical feature.

The information stored in the database of the digital DMD card, 3DMD, which causes a switch from the first mode to the second mode or vice versa, may also include a time parameter indicating that the switch should be performed only at certain points in time. For example, the presence of foliage on trees can block the reception of signals for use by the APS absolute positioning system only from spring to autumn or from spring to summer.

It is understood that although the above-described embodiments are presented as separate embodiments, combinations thereof may also be used in practice.

It is understood that the described embodiments may be provided as a computer program, which, when downloaded to a computer device, enables any of the embodiments described above to be executed. Such a computer program may be provided on a storage medium such as a computer-readable medium, for example, a floppy disk, memory card, compact disc (CD), digital video disc (DVD), etc.

In order to study the invention, preferred embodiments of the method and device according to the invention have been described. For a person skilled in the art it should be clear that other alternative and equivalent embodiments of the invention can be created and put into practice without departing from the essence of the invention, while the scope of the invention is limited only by the attached claims.

Claims (18)

1. A positioning device (PD) configured to determine a location using an absolute positioning system and a relative positioning system and further configured to work
in a first mode in which a location is determined using an absolute positioning system and possibly a relative positioning system, and
in the second mode, in which the location is determined using a relative positioning system and, possibly, an absolute positioning system,
moreover, in the first mode, the absolute positioning system is weighed with a greater weight than in the second mode to determine the location, and the positioning device is configured to switch from the first mode to the second mode,
characterized in that the positioning device (PD) includes or has access to a digital map database (DMD, 3DMD), and the decision to switch from the first to the second mode is made based on at least a specific location in combination with the information, stored in a digital map database (DMD, 3DMD), and the information mentioned contains many geographic features having data associated with them, which is one of:
threshold distance
data from which the threshold distance can be calculated,
wherein said threshold distances indicate an area in which the quality of positioning in the first mode may be relatively low,
and the positioning device (PD) is further characterized in that it is configured to calculate at least one distance from a specific location to at least one of the plurality of geographical objects, and switch from the first mode to the second mode, if, at least one of the calculated distances is less than the corresponding threshold distance. 2. The positioning device (PD) according to claim 1, wherein the absolute positioning system (APS) is one of a satellite positioning system (GNSS) and a ground-based positioning system. 3. The positioning device (PD) according to claim 1, wherein the relative positioning system (RPS) is at least one of a gyroscope, accelerometer, compass, speed measuring module, distance meter, inclinometer and a module detecting steering wheel actions . 4. The positioning device (PD) according to claim 2, in which the absolute positioning system (APS) is configured to determine the location based on signals received from multiple transmitters (SA1, SA2, SA3) that are part of a satellite positioning system (GNSS) or ground positioning system. 5. The positioning device (PD) according to claim 4, in which the digital map database (3DMD) is a three-dimensional digital map database (3DMD), and the information includes three-dimensional information about geographical objects,
moreover, the positioning device (PD) is configured to calculate the quality of the location, as determined by the absolute positioning system (APS), based on at least one of the determined location, the location of the transmitters (SA1, SA2, SA3) and the database of the three-dimensional digital map ( DMD, 3DMD). 6. The positioning device (PD) according to claim 4 or 5, in which the positioning device (PD) is configured to determine the respective locations of the transmitters (SA1, SA2, SA3) based on the location information contained in the respective signals. 7. The positioning device (PD) according to claim 1, in which the decision on the additional switching from the second to the first mode is made based on a specific location in combination with information stored in the digital map database. 8. The positioning device (PD) according to claim 1, wherein the positioning device (PD) is configured to maintain a history file including previously determined locations and associated accuracy, as determined according to the absolute positioning system (APS), and if switching is performed from the first mode to the second mode, the positioning device (PD) is configured to select an initial location for the relative positioning system (RPS) from the history file. 9. The positioning device (PD) according to claim 1, in which the positioning device (PD) is configured to determine the accuracy of certain locations in one mode, comparing a certain accuracy of locations with a threshold value and, if the accuracy is below a threshold value, storing these locations as a geographical feature with a recommended mode associated with it, and the recommended mode is different from the one mode. 10. A method for determining a location, the method comprising determining a location using an absolute positioning system and a relative positioning system, wherein the location can be determined
in a first mode in which a location is determined using an absolute positioning system and possibly a relative positioning system, and
in the second mode, in which the location is determined using a relative positioning system and, possibly, an absolute positioning system,
in the first mode, the absolute positioning system is weighed with a greater weight to determine the location than in the second mode, the method further comprising switching from the first mode to the second mode, characterized in that the method comprises the action of deciding whether to switch from the first mode to the second mode based on a specific location in combination with information stored in a digital map database (DMD, 3DMD), said information containing many geographical objects having boiling data associated with them, which are one of:
threshold distance
data from which the threshold distance can be calculated,
wherein said threshold distances indicate an area in which the quality of positioning in the first mode may be relatively low,
and the method of determining the location is further characterized in that it comprises calculating at least one distance from a specific location to at least one of the many geographical features, and switching from the first mode to the second mode, carried out if at least one of the calculated distances is less than the corresponding threshold distance. 11. The method of claim 10, wherein the absolute positioning system (APS) is one of a satellite positioning system (GNSS) and a terrestrial positioning system. 12. The method of claim 10, wherein the relative positioning system (RPS) is at least one of a gyroscope, accelerometer, compass, speed measurement module, distance meter, a module detecting steering actions of the steering wheel, and an inclinometer. 13. The method of claim 10, wherein the absolute positioning system (APS) is configured to determine a location based on signals received from a plurality of transmitters (SA1, SA2, SA3) that are part of a satellite positioning system (GNSS) or a terrestrial positioning system. 14. The method according to item 13, in which the digital map database (3DMD) is a three-dimensional digital map database (3DMD), and the information includes three-dimensional information about geographical objects, and the method comprises
calculating the quality of the location, as determined by the absolute positioning system (APS), based on at least one of the determined location, the location of the transmitters (SA1, SA2, SA3) and the database of a three-dimensional digital map (DMD, 3DMD). 15. The method according to item 13 or 14, the method further comprising determining the respective locations of the transmitters (SA1, SA2, SA3) based on the location information contained in the respective signals. 16. The method according to claim 10, wherein the method further comprises
maintaining a history file including previously determined locations and associated accuracy, as determined according to the absolute positioning system (APS) and the relative positioning system (RPS), and if switching from the first mode to the second mode is performed,
Selection of the starting location for the relative positioning system (RPS) from the history file. 17. The method according to claim 10, wherein the method further comprises
determining the accuracy of certain locations in one mode,
comparing a certain accuracy of locations with a threshold value and if the accuracy is lower than the threshold value,
maintaining these locations as a geographic feature with a recommended mode associated with it, the recommended mode being different from the one mode. 18. A computer-readable storage medium containing a computer program, which, when downloaded to a computer device, ensures that the computer device performs a location method according to any one of claims 10-17.

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