Method for testing GNSS-based positioning systems in obstructed environments

• US 9,377,535 B2
• Filed: 12/02/2011
• Issued: 06/28/2016
• Est. Priority Date: 12/02/2010
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Popovic, Zeljko
• Primary Examiner(s): Issing, Gregory C
• Application Number:
  US13/309,932
• Publication Number:
  US 20120139775A1
• Time in Patent Office: 1,670 Days
• US Class Current: 1/1
• CPC Class Codes: G01S 19/23 Testing, monitoring, correcting or calibrating of receiver elements

Abstract

Methods of testing GNSS-based positioning systems in obstructed environments may include specifying a required accuracy threshold for use in determining a reference trajectory. One or more difficult areas of relatively poor or missing GNSS availability may be located within the obstructed environment. Positioning information may be established for first reference points outside the difficult areas. Subsequently, by surveying with respect to the first reference points, positioning information may be established for second reference points within the difficult areas. The first and second reference points may then be used to determine a true path associated with the reference trajectory. When an improved GNSS-based positioning system is navigated along the reference trajectory, a set of measured points may be gathered, and errors between the true path and a measured path (derived from the measured points) may thereby be evaluated with respect to statistical characteristics, or to other improved GNSS-based positioning systems.

Claims

1. A method for testing at least one Global Navigation Satellite System (GNSS)-based positioning system, which is incorporated in a vehicle, along a reference trajectory within an obstructed environment having a first area and a second area, a GNSS availability within the first area being greater than a GNSS availability within the second area, the method comprising:

establishing positioning information using a GNSS receiver of a first GNSS-based positioning system for each of a plurality of first reference points in the first area of the obstructed environment;

selecting a plurality of second reference points within the second area of the obstructed environment to ensure that an accuracy of surveyed positioning information for the second reference points is within a selected accuracy range for the reference trajectory;

surveying from the first reference points to establish positioning information for each of the plurality of second reference points;

gathering positioning information for a plurality of measured points corresponding to the reference trajectory based on the plurality of first and second reference points using the first GNSS-based positioning system; and

determining a statistical characteristic of the measured points, wherein the statistical characteristic is selected from a group consisting of an average value, a median value, a mode value, and a standard distribution value.

2. The method of claim 1, wherein the selection of the second reference points includes spacing the second reference points to ensure that the accuracy of the positioning information for the second reference points is within the selected accuracy range for the reference trajectory.

3. The method of claim 1, wherein the surveying further includes defining a first lane boundary and a second lane boundary, and the second reference points are along a lane centerline between the first lane boundary and the second lane boundary.

4. The method of claim 1, wherein the plurality of second reference points comprise a plurality of points positioned between surveyed points.

5. The method of claim 1, wherein a GNSS availability of a first portion of the measured points is greater than a GNSS availability of a second portion of the measured points.

6. The method of claim 5, wherein the GNSS availability of the first portion is configured to have both (a) a number of visible satellites that is 5 or more, and (b) a horizontal dilution of precision that 1 or less.

7. The method of claim 5, wherein the GNSS availability of the second portion is configured to have at least one of (a) a number of visible satellites that is 3 or less, and (b) a horizontal dilution of precision that is at 8 or more.

8. The method of claim 5, wherein a GNSS availability of a third portion of the measured points is configured to have at least one of (a) GNSS availability being missing, or (b) GNSS availability being indeterminate.

9. The method of claim 1, further comprising using a second GNSS-based positioning system to gather a plurality of additional measured points corresponding to with the reference trajectory.

10. The method of claim 9, further comprising determining (a) a first error data set that includes a separation between each of the second reference points and an interpolation among the plurality of measured points, and (b) a second error data set that includes a separation between each of the second reference points and an interpolation among the additional plurality of measured data points.

11. The method of claim 10, further comprising selecting one of the first and second GNSS-based positioning systems based upon a comparison of the first error data set and the second error data set.

12. The method of claim 11, wherein a statistical characteristic of the first error data set is compared to a statistical characteristic of the second error data set, and wherein the statistical characteristic is selected from a group consisting of an average value, a median value, a mode value, and a standard distribution value.

13. The method of claim 11, wherein the GNSS availability within the second area is configured to have at least one of (a) a number of visible satellites that is 3 or less, and (b) a horizontal dilution of precision that is at 8 or more, and the GNSS availability within the first area is configured to have both (a) a number of visible satellites that is 5 or more, and (b) a horizontal dilution of precision that 1 or less.

14. The method of claim 1, further comprising:

determining a route for the reference trajectory; and

selecting a sub-set of the first reference points and a sub-set of the second-reference points corresponding with the route.

15. The method of claim 1, further comprising:

using a third GNSS-based positioning system to gathering a plurality of comparison points; and

determining an error data set that includes a separation between each of the comparison points and one of (a) an interpolation among the plurality of measured points and (b) a corresponding point of the plurality of measured points.

16. A method for producing a reference trajectory for testing at least one Global Navigation Satellite System (GNSS)-based positioning system, which is incorporated in a vehicle, in obstructed environments, the method comprising:

specifying an accuracy range for the reference trajectory;

locating within the obstructed environment a plurality of first areas and a plurality of second areas outside the first areas, a GNSS availability within the first areas being greater than a GNSS availability within the second areas, and an accuracy of GNSS-based positioning information within the second areas not being within the accuracy range;

establishing positioning information using a GNSS receiver of a first GNSS-based positioning system for a plurality of first reference points, the first reference points being within the first areas, and the positioning information for the first reference points being within the accuracy range;

selecting a plurality of second reference points inside the second areas to enable surveyed positioning information for the second reference points to be within the accuracy range;

surveying to establish positioning information for the plurality of second reference points, the positioning information for the second reference points being based on the positioning information for the first reference points;

determining a plurality of true path points corresponding to a lane centerline based upon the positioning information for at least the second reference points;

gathering (a) a plurality of first measured points using the first GNSS-based positioning system by navigating the reference trajectory with the first GNSS-based positioning system, and (b) a plurality of second measured points using a second GNSS-based positioning system by navigating the reference trajectory with the second GNSS-based positioning system;

interpolating (a) a first measured path from the first measured points, and (b) a second measured path from the second measured points;

determining (a) a first error data set based upon a distance from each of the true path points to the first measured path, and (b) a second error data set based upon a distance from each of the true path points to the second measured path; and

selecting one of the first and second GNSS-based positioning systems based upon a comparison of the first error data set to the second error data set.

17. The method of claim 16, wherein the obstructed environment is an interconnected plurality of streets.

18. The method of claim 16, wherein the positioning information includes a longitude and a latitude.

19. The method of claim 16, wherein the configuration of the second reference points includes a spacing.

20. The method of claim 16, wherein both the first reference points and the second reference points include points along each of a first lane boundary and a second lane boundary.

21. The method of claim 20, wherein the true path points are along a lane centerline between the first lane boundary and the second lane boundary.

22. The method of claim 16, wherein a GNSS availability of a first portion of the measured points is greater than a GNSS availability of a second portion of the measured points, and a GNSS availability of a third portion of the measured points is either (a) missing or (b) indeterminate.

23. A method for testing at least one Global Navigation Satellite System (GNSS)-based positioning system, which is incorporated in a vehicle, along a reference trajectory within an obstructed environment having a first area and a second area, a GNSS availability within the first area being greater than a GNSS availability within the second area, the method comprising:

specifying an accuracy range for the reference trajectory;

establishing positioning information using a GNSS receiver of a first GNSS-based positioning system for a plurality of first reference points within the first area of the obstructed environment;

selecting a plurality of second reference points within the second area of the obstructed environment to ensure that an accuracy of surveyed positioning information for the second reference points is within the accuracy range;

surveying from the first reference points to establish positioning information for the plurality of second reference points;

gathering a plurality of measured points corresponding to the reference trajectory based on the plurality of first and second reference points using the first GNSS-based positioning system;

determining an error data set based upon a distance from each of the second reference points to a linear interpolation among the plurality of measured data points; and

determining a statistical characteristic of the error data set, wherein the statistical characteristic is selected from a group consisting of an average value, a median value, a mode value, and a standard distribution value.

24. The method of claim 23, wherein the plurality of second reference points comprise a plurality of points positioned between surveyed points.

25. The method of claim 23, further comprising comparing a statistical characteristic of the error data set to statistical characteristic of an additional error data set, wherein the statistical characteristic is selected from a group consisting of an average value, a median value, a mode value, and a standard distribution value.