System and method for vehicle location information correction based on another vehicle

Abstract

A system for determining vehicle location information includes a receiver supported on a first vehicle for receiving communications from a second vehicle and signals from each of a plurality of satellites. A detector is configured to detect a positional relationship between the first vehicle and the second vehicle. A processor is configured to determine a location of the first vehicle from the received satellite signals, determine a location of the second vehicle based on the received communications from the second vehicle, determine a corrected location of the first vehicle based on the location of the second vehicle and the positional relationship between the vehicles, and determine a correction map for a plurality of segments of a field of view of the receiver. Each segment has a correction factor for correcting a subsequently determined location of the first vehicle based on satellite signals received from satellites appearing in the respective segment.

Description

Background Technology

[0001] Modern motorized vehicles incorporate an increasing amount of electronic technology, such as sensors or detectors that provide driver assistance or control for autonomous vehicles. For such assistance or control, information related to the vehicle's movement or heading is useful or necessary. Various methods exist to obtain this information. For example, GNSS satellite technology allows for the determination and tracking of vehicle movement or heading information based on the detection of multiple satellites and the use of known algorithms. However, in some cases, satellite signals may not allow for location determination with the desired accuracy. For instance, atmospheric delay can introduce differential errors affecting the pseudorange determined by satellites, introducing inaccuracies in location determination. Summary of the Invention

[0002] An illustrative example embodiment of a system for determining vehicle location information includes at least one receiver configured to be supported on a first vehicle. The receiver is configured to receive communications from a second vehicle and signals from each of a plurality of satellites. At least one detector is supported on the first vehicle. The detector is configured to detect the positional relationship between the first and second vehicles. At least one processor is associated with the first vehicle and configured to: determine the location of the first vehicle based on satellite signals received by the receiver; determine the location of the second vehicle based on communications received from the second vehicle; determine a corrected location of the first vehicle based on the location of the second vehicle and the positional relationship between the first and second vehicles; and determine a correction mapping of a plurality of segments of the receiver's field of view. Each segment has an associated correction factor, which the processor uses to correct the subsequently determined location of the first vehicle based on satellite signals received from satellites appearing in the corresponding segment.

[0003] In an example embodiment of a system having at least one feature of the aforementioned paragraphs, the associated correction factor of the first segment in the paragraphs is different from the associated correction factor of the second segment in the paragraphs.

[0004] In an example embodiment of a system having at least one feature of any of the preceding paragraphs, the at least one receiver includes a first antenna for receiving communications from a second vehicle and a second antenna for receiving signals from each of a plurality of satellites; and a correction mapping is used for the field of view of the second antenna.

[0005] In an example embodiment of a system having at least one feature of any of the preceding paragraphs, communication from the second vehicle includes indications of: the location of the second vehicle, the reliability of the location of the second vehicle, the speed of the second vehicle, the size of the second vehicle, and the shape of at least a portion of the second vehicle.

[0006] In an example embodiment of a system having at least one feature of any of the preceding paragraphs, communication from the second vehicle includes a Basic Safety Message (BSM) that includes an indication of the reliability of the location of the second vehicle.

[0007] In an example embodiment of a system having at least one feature of any of the preceding paragraphs, the at least one detector includes at least one of a radar detector, a lidar detector, a vision-based detector, or an ultrasonic detector.

[0008] In an example embodiment of a system having at least one feature of any of the preceding paragraphs, the at least one processor updates the correction mapping based on: a subsequently determined location of a first vehicle based on subsequently received satellite signals, a subsequently determined location of a second vehicle based on subsequently received communications from a second vehicle, and a subsequently determined corrected location of the first vehicle; and the at least one processor replaces the correction mapping with the updated correction mapping.

[0009] In an example embodiment of a system having at least one feature of any of the preceding paragraphs, the at least one processor updates or cancels the correction mapping within a predetermined time period.

[0010] In an example embodiment of a system having at least one feature of any of the preceding paragraphs, the associated correction factors each have a value; the value of the associated correction factor varies across the corresponding segment; the value of the associated correction factor of the first segment in the segment gradually changes toward the value of the associated correction factor of the second segment in the segment near the transition between the first segment and the second segment in the segment; and the second segment in the segment is adjacent to the first segment in the segment.

[0011] In an example embodiment of a system having at least one feature of any of the preceding paragraphs, the at least one processor determines whether the second vehicle is within a predetermined distance of the first vehicle as a prerequisite for using communications received from the second vehicle.

[0012] An illustrative example embodiment of a method for determining location information of a first vehicle includes: receiving communications from a second vehicle; receiving signals from each of a plurality of satellites by at least one receiver associated with the first vehicle; detecting the positional relationship between the first and second vehicles; determining the location of the first vehicle based on the received satellite signals; determining the location of the second vehicle based on the received communications; determining a corrected location of the first vehicle based on the location of the second vehicle and the positional relationship between the first and second vehicles; and determining a correction mapping of a plurality of segments of the field of view of at least one receiver, each segment having an associated correction factor for correcting the subsequently determined location of the first vehicle based on satellite signals received from satellites appearing in the respective segment.

[0013] In an example embodiment of the method having at least one feature of the aforementioned paragraphs, the associated correction factor of the first segment in the paragraphs is different from the associated correction factor of the second segment in the paragraphs.

[0014] In an example embodiment of the method having at least one feature of any of the preceding paragraphs, communication from the second vehicle includes indications of: the location of the second vehicle, the reliability of the location of the second vehicle, the speed of the second vehicle, the size of the second vehicle, and the shape of at least a portion of the second vehicle.

[0015] In an example embodiment of the method having at least one feature of any of the preceding paragraphs, communication from the second vehicle includes a Basic Safety Message (BSM) that includes an indication of the reliability of the location of the second vehicle.

[0016] An exemplary embodiment of the method having at least one feature of any of the preceding paragraphs includes updating the correction mapping based on: a subsequently determined location of a first vehicle based on subsequently received satellite signals, a subsequently determined location of a second vehicle based on subsequently received communications from a second vehicle, and a subsequently determined corrected location of the first vehicle; and the exemplary embodiment further includes replacing the correction mapping with the updated correction mapping.

[0017] An example embodiment of a method having at least one feature of any of the preceding paragraphs includes updating or canceling the correction mapping within a predetermined time.

[0018] In an example embodiment of the method having at least one feature of any of the preceding paragraphs, the associated correction factors each have a value; the value of the associated correction factor varies across the corresponding segment; the value of the associated correction factor of the first segment in the segment gradually changes toward the value of the associated correction factor of the second segment in the segment near the transition between the first segment and the second segment in the segment; and the second segment in the segment is adjacent to the first segment in the segment.

[0019] An example embodiment of a method having at least one feature of any of the preceding paragraphs includes: determining whether a second vehicle is within a predetermined distance of a first vehicle as a prerequisite for using communications received from the second vehicle.

[0020] Another illustrative example embodiment of a system for determining vehicle location information includes: a receiver device configured to be supported on a first vehicle for receiving communications from a second vehicle and signals from each of a plurality of satellites; a detector device supported on the first vehicle for detecting a positional relationship between the first and second vehicles; and a device associated with the first vehicle for: determining the location of the first vehicle based on satellite signals received by the receiver device; determining the location of the second vehicle based on communications received by the receiver device; determining a corrected location of the first vehicle based on the location of the second vehicle and the positional relationship between the first and second vehicles; and determining a correction mapping of a plurality of segments of the receiver device's field of view, each segment having an associated correction factor, the device using the associated correction factors to correct a subsequently determined location of the first vehicle based on satellite signals received from satellites appearing in the respective segments.

[0021] In an example embodiment of a system having at least one feature of the foregoing paragraphs, the means for determining is further configured to: determine whether the second vehicle is within a predetermined distance of the first vehicle as a prerequisite for using communications received from the second vehicle; and update or cancel the correction mapping within a predetermined time.

[0022] From the following detailed description, at least one of the disclosed exemplary embodiments will become apparent to those skilled in the art. The accompanying drawings accompanying the detailed description can be briefly described below. Attached Figure Description

[0023] Figure 1 An example system for determining the location information of vehicles is illustrated schematically.

[0024] Figure 2 This is a flowchart outlining an example method for determining the location information of vehicles.

[0025] Figure 3 The correction mapping feature of an example embodiment is illustrated schematically.

[0026] Figure 4 This is a flowchart outlining an example embodiment of a method for processing satellite and vehicle-to-vehicle communications to determine vehicle location information. Detailed Implementation

[0027] Figure 1 A system 20 for determining vehicle location information on a first vehicle 22 is schematically illustrated. System 20 includes at least one receiver comprising at least one antenna 24 configured to receive signals from each of a plurality of satellites 26 and 28. Two satellites are shown for discussion purposes. In many cases, signals from more than two satellites will be received by antenna 24. An example receiver includes another antenna 30 configured to receive communications from a second vehicle 32. In the illustrated embodiment, the receiver is a transceiver including bidirectional communication capability. The communications received by antenna 30 are vehicle-to-vehicle (V2V) communications, cellular vehicle-to-vehicle (C-V2V) communications, or dedicated short-range communication (DSRC).

[0028] The system 20 associated with the first vehicle 22 includes at least one detector 40 configured to detect the positional relationship between the first vehicle 22 and the second vehicle 32. In some embodiments, the detector 40 includes a radar detector. In other embodiments, the detector 40 includes a lidar detector, an ultrasonic detector, or a vision-based detector.

[0029] Processor 42 receives indications relating to: detected satellite signals, communications from the second vehicle 32, and the detected positional relationship between vehicles 22 and 32. Based on these indications, processor 42 determines vehicle location information relating to the location of the first vehicle 22. Processor 42 is capable of correcting for potential inaccuracies in the location of the first vehicle 22 that could occur if the location of the first vehicle 22 is determined solely using satellite signals received by antenna 24.

[0030] The second vehicle 32 includes a system 20', which is functionally identical to the system 20 on the first vehicle 22. In the example shown, system 20' includes a receiver comprising an antenna 25 configured to receive signals from satellites 26 and 28. Another receiver portion includes an antenna 31 configured for vehicle-to-vehicle communication. Detector 41 is similar to detector 40, and processor 43 is similar to processor 42.

[0031] Figure 2 The flowchart 44 outlines an example method for determining vehicle location information. At 46, the receiver of system 20 detects satellite signals, for example, via antenna 24. At 48, processor 42 determines a first vehicle location based on the detected satellite signals. Figure 1 The location of the first vehicle 22 in the example.

[0032] At position 50, system 20, for example, via antenna 30, from... Figure 1 In the example shown, the second vehicle 32 receives communication. In this example, the communication from the second vehicle 32 is a V2X Basic Safety Message (BSM). The communication from the second vehicle 32 includes information relating to: the GNSS location of the second vehicle 32, the current speed of the second vehicle 32, the dimensions of the second vehicle 32, the shape of the second vehicle 32, and a quality indication of the GNSS location information. The processor 42 uses the quality indication of the GNSS location information to determine whether to potentially correct the location information of the first vehicle 22 using the communication from the second vehicle 32. At various times, different vehicles (including those according to...) Figure 1 The system designed according to the illustrated embodiment will be able to provide accurate or reliable vehicle location information, which is useful for accurately locating other vehicles.

[0033] At point 52, detector 40 provides processor 42 with information for determining the positional relationship between the first vehicle 22 and the second vehicle 32. The information received in the communication at point 50 allows processor 42, associated with the first vehicle 22, to use the information from detector 40 to make an accurate determination of the relative position or positional relationship between vehicles 22 and 32.

[0034] Processor 42 is configured to determine that the second vehicle 32 is within an appropriate distance from the first vehicle 22 as a prerequisite for using communications from the second vehicle 32. Assuming that the information from the second vehicle 32 is reliable, processor 42 determines the location of the second vehicle 32 at point 54. In other words, processor 42 makes a determination at point 54 regarding whether to accept and rely on GNSS location information within communications received from the second vehicle 32.

[0035] At point 56, processor 42 determines the corrected location of first vehicle 22 based on the location of second vehicle 32 and the positional relationship between vehicles 22 and 32. For example, if the detected satellite signals received by the receiver of system 20 associated with vehicle 22 are affected by atmospheric delay, the pseudorange determined by processor 42 based on these signals may not provide a precise or accurate location of first vehicle 22. If GNSS location information from second vehicle 32 and the relative position between vehicles 22 and 32 are given, processor 42 can correct the location of first vehicle 22 based on this information if necessary.

[0036] Detector 40 provides information related to the vehicle dynamics of the second vehicle 32. Processor 42 converts the absolute position information received from communications since the second vehicle 32 into relative position information. Processor 42 uses any positional deviation between the two positions as a basis to determine a position offset to be applied to the determined position of the first vehicle 22. Since the GNSS dynamics of both vehicles 22 and 32 are nearly identical, the position offset is useful for correcting various potential positional errors in determining the location of the first vehicle 22 based on satellite signals. Both vehicles 22 and 32 travel essentially along the same path, and the distance between them is relatively small. In this case, the position offset information allows for the correction of any errors in the satellite-based position of the first vehicle 22 using positional information related to the second vehicle 32.

[0037] At position 58, processor 42 determines the correction mapping for multiple segments of the field of view of antenna 24. Figure 1 In the embodiment shown, the field of view of antenna 24 corresponds to the sky, and the correction mapping is a gradient mapping of the sky, which has different correction values ​​for different segments or portions of the field of view.

[0038] At position 60, processor 42 utilizes a correction map to determine the subsequent location of the first vehicle 22 based on subsequently received satellite signals. The correction map helps correct for pseudoranges of satellites appearing in the corresponding segment of the field of view of antenna 24, providing more accurate vehicle location information.

[0039] Figure 3 The correction mapping technique according to an example embodiment is illustrated schematically. Antenna 24 has a field of view 64 corresponding to the viewpoint of the sky above antenna 24. For discussion purposes, the field of view 64 is divided into segments 66, 68, 70, 72, 74, and 76. Each of these segments corresponds to a portion of the sky above the vehicle's location and has a corresponding correction factor, which is used by processor 42 to correct for pseudoranges determined based on satellites detected within the corresponding segments of segments 66-76. The position of segments 66-76 relative to a geocentric reference frame can be considered such that segments 66-76 do not rotate around the center of the field of view 64 when the vehicle turns. In other words, segments 66-76 in the sky maintain the same heading.

[0040] Figure 3 The lines between segments 66 and 76 are used for illustrative and discussion purposes to visualize the corrected mapping of field of view 64. These lines do not represent any physical boundaries between segments. Many embodiments will include segments that are also longitudinally separated from different segments corresponding to different angles above the horizon; however, for the sake of simplicity, such divisions are not shown.

[0041] The correction map 64 in this example includes a corresponding correction factor for each segment, and at least two of segments 66-76 have correction factors that are different from each other. For example, the direction of movement of the first vehicle 22 can affect the type of atmospheric delay or error associated with the received satellite signal based on known GNSS pull effects. The different correction factors or values ​​for different segments 66-76 of the field of view 64 address the different ways in which satellite signals may be delayed depending on the location and direction of movement of the first vehicle 22. For example, Global Navigation Satellite System (GNSS) satellite signals may have differential errors based on the different atmospheric conditions these signals pass through.

[0042] When vehicles 22 and 32 are within range and transmitting position data, the corrected location of the first vehicle can be determined using pseudoranges from currently visible satellites. In an example embodiment, the correction pseudorange begins with the satellite in the nearest one or more segments within 180° of the direction of position change. Satellites in the opposite direction of the change contribute the most to the error when satellite signals are slowed by ionospheric and tropospheric interference.

[0043] The correction mapping facilitates corrections based on the satellite's position in the sky, which will fall within one of the segments 66-76. The mapping allows for correction of pseudorange information for different satellites appearing in segments where another satellite might be visible. Satellites in the same segment (which may not all appear simultaneously) will have very similar correction factors.

[0044] Processor 42 is configured or otherwise programmed to utilize the correction map over a finite amount of time. As the vehicle moves and as atmospheric conditions change, the correction factor of the corresponding segment of the correction map tends to degrade in terms of availability over time. For example, the amount of free ions in the ionosphere always changes slowly. The correction for any satellite present in a particular segment will be the same at the same time. Within a certain amount of time, the corresponding corrections will be very similar, but only within a finite amount of time. In the illustrative example, processor 42 is configured to update the correction map to reduce the effect of the correction factor over time, or to cancel the correction map after an appropriate amount of time has elapsed since it was determined. Processor 42 updates the correction map in the same manner as described above based on subsequently received communications from the second vehicle, the corresponding determined positional relationships, and satellite signals.

[0045] A feature of the example embodiment shown is that the correction factor varies within or across segments to provide a gradient effect or smoothing of the correction factor between adjacent segments with different correction factors. For example, the correction factor of segment 66 varies between a value near the center of segment 66 and a different value near the transition 78 between segment 66 and segment 76. In this example, as a position within segment 66 approaches transition 78, the value of the correction factor gradually changes to become closer to the correction factor within segment 76.

[0046] Figure 4 This includes a flowchart 80 that describes an example process for determining location information and correcting mappings. Figure 4 The process begins at 82, which may be used for initialization of system 20, or when the available time for a previously determined correction map expires. At 84, the existing correction map is cancelled, and the correction factors for each segment of the correction map are downgraded or removed from the memory used by processor 42.

[0047] At point 86, processor 42 determines whether a calibrated DSRC or CV2X source exists within a pre-selected distance of the first vehicle 22. In this example, at point 86, it is determined whether such a source, such as the second vehicle 32, is within 3 meters of the current location of the first vehicle 22. If not, the process proceeds to step 84.

[0048] When a usable source (such as the second vehicle 32) that meets the decision criteria at point 86 is available, processor 42 makes another decision: whether detector 40 detected an object at the approximate location of the source identified at point 86. This occurs at point 88. If the determination at point 88 is no, the process returns to the step at point 84. If the determination at point 88 is yes, the epoch match value is set to zero at point 90. At point 92, the positional relationship between the first vehicle 22 and the second vehicle 32 is determined, including calculating the relative movement based on the DSRC signal information of the two vehicles. At point 94, it is determined whether the relative movement based on the DSRC signal information matches the relative movement detected by detector 40, thus confirming that the source of the DSRC or CV2X signal is the same object detected by detector 40. If there is no match at point 94, the process returns to the step at point 84. If there is a match at point 94, the epoch match value is incremented at point 96.

[0049] At 98, the epoch-matched value is compared with the required minimum match value. If the current epoch-matched value is not higher than the minimum, the process returns to step 92. If the epoch-matched value is higher than the minimum, it indicates that the information from detector 40 and the location information based on the communication received from the second vehicle 32 are reliable because a match has occurred over a sufficiently long period of time.

[0050] When sufficient matches are found, processor 42 calculates the instantaneous differential position at 100 based on communications received from the second vehicle and information from detector 40. The differential position information determined at 100 indicates whether correction is needed regarding the location information of the first vehicle 22. At 102, processor 42 applies the instantaneous differential correction information determined at 100 to the current location information of the first vehicle 22. Processor 42 also retains the uncorrected location information and an error ellipse, which shows all possible true locations of the receiver in a manner known in the GNSS field.

[0051] At 104, processor 42 determines whether the source of the DSRC or CV2X communication is still within the appropriate range and detected by detector 40. In this embodiment, when these conditions are met, it can be considered V2V-detector fusion. If the fusion condition is not met at 104, the process returns to the step at 84. When appropriate fusion is present, processor 42 utilizes a learning algorithm to determine the correction factor for the currently detected satellite based on the raw pseudorange from the currently received satellite signal and the error ellipse of the uncorrected location. At 108, processor 42 determines which of the detected satellites is in the opposite direction of the GNSS pull and temporarily reduces the pseudorange by a predetermined amount. Processor 42 also recalculates the vehicle position and error ellipse at 108.

[0052] At 110, processor 42 determines whether the correction information is reliable by determining whether the vehicle location calculated at 108 is closer to the transient difference decomposition from steps 100 and 102. If the newly determined vehicle location is not closer to the transient difference decomposition, the temporary correction is removed at 112. On the other hand, if the newly determined vehicle location is closer to the transient difference decomposition, the temporary correction is considered permanent for the new correction mapping of the field of view of the satellite receiver of system 20.

[0053] At 116, processor 42 determines whether the error ellipse meets the criterion corresponding to the maximum design ellipse size. If the error ellipse is smaller than this maximum value, the correction considered permanent at 114 will be used as an extrapolated correction at 118. On the other hand, if the error ellipse is equal to or greater than the allowable maximum value, differential correction is used at 120.

[0054] Figure 4 The example process shown illustrates that in, for example Figure 2 The flowchart 44 shows how various checks and determinations are performed during the process to ensure that reliable information is being used to correct the location information related to the first vehicle 22 and to develop the correction map.

[0055] The embodiments described above and illustrated in the accompanying drawings provide enhanced vehicle location information by utilizing a correction mapping that takes into account potential differential errors in the received GNSS satellite signals to correct for errors that may occur in vehicle location determination. Such errors may be caused by differential errors in the GNSS satellite signals. Utilizing a correction mapping based on information from another vehicle and location information determined according to the received satellite signals facilitates more accurate subsequent vehicle location determination over an appropriate timeframe. Updating or canceling the correction mapping within an appropriate timeframe contributes to sustained accuracy in vehicle location determination.

[0056] The foregoing description is exemplary in nature and not restrictive. Variations and modifications to the disclosed examples, without departing from the spirit of the invention, will become apparent to those skilled in the art. The scope of legal protection afforded to this invention can only be determined by examining the appended claims.

Claims

1. A system for determining vehicle location information, the system comprising: at least one receiver configured to be supported on a first vehicle, the at least one receiver configured to receive a communication from a second vehicle and a signal from each of a plurality of satellites; at least one detector supported on the first vehicle, the at least one detector configured to detect a positional relationship between the first vehicle and the second vehicle; and at least one processor associated with the first vehicle, the at least one processor configured to: determine a location of the first vehicle based on the satellite signals received by the at least one receiver, determine a location of the second vehicle based on the communication received by the at least one receiver, determine a corrected location of the first vehicle based on the location of the second vehicle and the positional relationship between the first vehicle and the second vehicle, and determine a correction gradient map for a plurality of segments of the sky within a field of view of the at least one receiver, the correction gradient map having an associated correction factor for each of the segments, the at least one processor using the associated correction factor to correct for atmospheric delay of the satellite signals received from a satellite appearing in a respective segment when determining a subsequent position of the first vehicle based on the satellite signals.

2. The system of claim 1, wherein, the associated correction factor for a first segment of the segments is different than the associated correction factor for a second segment of the segments.

3. The system of claim 1, wherein: the at least one receiver comprises a first antenna to receive the communication from the second vehicle and a second antenna to receive the signal from each of the plurality of satellites; and the correction gradient map is for the field of view of the second antenna.

4. The system of claim 1, wherein, the communication from the second vehicle includes an indication of the location of the second vehicle, a reliability of the location of the second vehicle, a speed of the second vehicle, a size of the second vehicle, and a shape of at least a portion of the second vehicle.

5. The system of claim 1, wherein, the communication from the second vehicle includes a basic safety message (BSM) including an indication of the reliability of the location of the second vehicle.

6. The system of claim 1, wherein, the at least one detector includes at least one of a radar detector, a lidar detector, a vision-based detector, or an ultrasonic detector.

7. The system of claim 1, wherein, the at least one processor: updates the correction gradient map based on a subsequently determined location of the first vehicle based on subsequently received satellite signals, a subsequently determined location of the second vehicle based on subsequently received communications from the second vehicle, and a subsequently determined corrected location of the first vehicle; and replacing the correction gradient map with the updated correction gradient map.

8. The system of claim 7, wherein, the at least one processor updates or cancels the correction gradient map at predetermined times.

9. The system of claim 1, wherein: the associated correction factors each have a value; the values of the associated correction factors vary across the respective segments; the value of the associated correction factor of a first one of the segments gradually changes toward a value of the associated correction factor of a second one of the segments near a transition between the first one of the segments and the second one of the segments; and the second one of the segments is adjacent to the first one of the segments.

10. The system of claim 1, wherein, the at least one processor determines whether the second vehicle is within a predetermined distance of the first vehicle as a prerequisite for using a communication received from the second vehicle.

11. A method of determining location information of a first vehicle, the method comprising: receiving a communication from a second vehicle; receiving, by at least one receiver associated with the first vehicle, a signal from each of a plurality of satellites; detecting a positional relationship between the first vehicle and the second vehicle; determining a location of the first vehicle based on the received satellite signals; determining a location of the second vehicle based on the received communication; determining a corrected location of the first vehicle based on the location of the second vehicle and the positional relationship between the first vehicle and the second vehicle; and determining a correction gradient map for a plurality of segments of the sky within a field of view of the at least one receiver, the correction gradient map having, for each of the segments, an associated correction factor to correct for atmospheric delay of the satellite signals received from satellites appearing in the respective segment when determining a subsequent position of the first vehicle based on the satellite signals.

12. The method of claim 11, wherein, the associated correction factor of a first one of the segments is different than the associated correction factor of a second one of the segments.

13. The method of claim 11, wherein, the communication from the second vehicle includes an indication of the location of the second vehicle, a reliability of the location of the second vehicle, a speed of the second vehicle, a size of the second vehicle, and a shape of at least a portion of the second vehicle.

14. The method of claim 11, wherein, the communication from the second vehicle includes a basic safety message (BSM) including an indication of the reliability of the location of the second vehicle.

15. The method of claim 11, wherein, comprising: updating the correction gradient map based on a subsequently determined location of the first vehicle based on subsequently received satellite signals, a subsequently determined location of the second vehicle based on subsequently received communications from the second vehicle, and a subsequently determined corrected location of the first vehicle; and replacing the correction gradient map with the updated correction gradient map.

16. The method of claim 15, wherein, updating or cancelling the correction gradient map within a predetermined time.

17. The method of claim 11, wherein: the associated correction factors each have a value; the values of the associated correction factors vary across the respective segments; the value of the associated correction factor of a first one of the segments gradually changes towards the value of the associated correction factor of a second one of the segments near a transition between the first one of the segments and the second one of the segments; and the second one of the segments is adjacent to the first one of the segments.

18. The method of claim 11, wherein, comprises: determining whether the second vehicle is within a predetermined distance of the first vehicle as a prerequisite for using a communication received from the second vehicle.

19. A system for determining vehicle location information, the system comprising: a receiver device configured to be supported on a first vehicle for receiving a communication from a second vehicle and a signal from each of a plurality of satellites; a detector device supported on the first vehicle for detecting a positional relationship between the first vehicle and the second vehicle; and a processor device associated with the first vehicle for: determining a location of the first vehicle based on satellite signals received by the receiver device, determining a location of the second vehicle based on the communication received by the receiver device, determining a corrected location of the first vehicle based on the location of the second vehicle and the positional relationship between the first vehicle and the second vehicle, and determining a correction gradient map for a plurality of segments of the sky within a field of view of the receiver device, the correction gradient map having an associated correction factor for each of the segments, for use by the processor device for determining in correcting atmospheric delays of the satellite signals received from satellites appearing in a respective segment when determining a subsequent position of the first vehicle based on the satellite signals.

20. The system of claim 19, wherein, the processor device for determining is further for: determining whether the second vehicle is within a predetermined distance of the first vehicle as a prerequisite for using a communication received from the second vehicle; and updating or cancelling the correction gradient map within a predetermined time.

Images