Method for accelerometer-assisted navigation

• US 10,209,077 B2
• Filed: 07/18/2017
• Issued: 02/19/2019
• Est. Priority Date: 08/20/2015
• Status: Active Grant

• Current Assignee: Credit Karma LLC (Intuit, Inc.)
• Original Assignee: Zendrive, Inc.
• Inventors: Choudhury, Romit Roy, Pal, Jayanta, Risbood, Pankaj, Matus, Jonathan
• Primary Examiner(s): Troost, Aaron L
• Assistant Examiner(s): Schneider, Paula L
• Application Number:
  US15/652,558
• Publication Number:
  US 20170314929A1
• Time in Patent Office: 581 Days
• Field of Search: 701447
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01C 21/30 Map- or contour-matching

Abstract

A method for primarily sensor-based navigation includes: in a first time period, collecting geophysical position data using a GPS receiver of a navigation device; in the first time period, collecting a first set of accelerometer data using an accelerometer of the navigation device; analyzing the first set of accelerometer data to produce a first set of vertical vehicular motion data; generating a mapping association between the first set of vertical vehicular motion data and the geophysical position data; in a second time period after the first time period, collecting a second set of accelerometer data using the accelerometer; analyzing the second set of accelerometer data to produce a second set of vertical vehicular motion data; and calculating an estimated location of the vehicle by analyzing the second set of vertical vehicular motion data in light of the mapping association.

Claims

1. A method for primarily sensor-based navigation of a vehicle on a road surface, the method comprising:

in a first time period, collecting geophysical position data using a GPS receiver of a navigation device;

in the first time period, collecting a first set of supplementary data using a supplementary sensor of the navigation device;

determining a first set of vertical vehicular motion data based on the first set of supplementary data;

generating a mapping association between the first set of vertical vehicular motion data and the geophysical position data;

in a second time period after the first time period, collecting a second set of supplementary data using the supplementary sensor;

determining a second set of vertical vehicular motion data based on the second set of supplementary data; and

determining an estimated location of the vehicle based on the second set of vertical vehicular motion data and the mapping association.

2. The method of claim 1, wherein the supplementary sensor comprises an inertial measurement unit (IMU), wherein the first and second sets of supplementary data are collected by the IMU.

3. The method of claim 1, wherein vertical vehicular motion data describes motion of the vehicle perpendicular the road surface.

4. The method of claim 1, further comprising:

determining a set of previously traveled routes, each previously traveled route of the set of previously traveled routes associated with geophysical positions previously mapped to vertical vehicular motion data;

receiving, at the navigation device, a travel source and a travel destination;

determining that a first previously traveled route from the set of previously traveled routes intersects the travel source, the travel destination, and the estimated location of the vehicle; and

navigating the vehicle according to the first previously traveled route.

5. The method of claim 4, further comprising, in response to identifying the first previously traveled route, switching off the GPS receiver;

wherein navigating the vehicle according to the first previously traveled route comprises navigating based on vertical vehicular motion data without collecting additional GPS data.

6. The method of claim 1, wherein determining the estimated location of the vehicle comprises:

inferring a GPS-measured initial vehicular location from a second set of geophysical position data collected by the GPS receiver;

wherein the geophysical position data is collected at a first time between the first time period and the second time period;

generating a set of potential locations, each potential location of the set of potential locations associated with a vertical vehicular motion profile; and

calculating the estimated location of the vehicle from the set of potential locations based on;

proximities of the set of potential locations to the GPS-measured initial vehicular location and correlations of the vertical vehicular motion profiles to the second set of vertical vehicular motion data.

7. The method of claim 1, wherein determining the estimated location of the vehicle comprises:

inferring a GPS-measured initial vehicular location from a second set of geophysical position data collected by the GPS receiver;

wherein the geophysical position data is collected at a first time between the first time period and the second time period;

collecting a third set of supplementary data between the first time and a second time in the second time period;

analyzing the third set of supplementary data to produce a first set of horizontal vehicular motion data;

calculating a vehicle position change from the first set of horizontal vehicular motion data;

calculating a GPS-and-supplemental-sensor-derived location by adding the vehicle position change to the GPS-measured initial vehicular location;

generating a set of potential locations, each potential location of the set of potential locations associated with a vertical vehicular motion profile; and

calculating the estimated location of the vehicle from the set of potential locations based on both of proximities of the set of potential locations to the GPS-and-supplemental-sensor-derived location and correlations of the vertical vehicular motion profiles to the second set of vertical vehicular motion data.

8. The method of claim 1, further comprising:

in the first time period, collecting a first vehicle speed;

in the second time period, collecting a second vehicle speed;

wherein determining the estimated location of the vehicle comprises time-scaling the second set of vertical vehicular motion data based on a difference between the first vehicle speed and the second vehicle speed.

9. The method of claim 1, further comprising:

in the first time period, collecting a first vehicle suspension profile;

in the second time period, collecting a second vehicle suspension profile;

wherein determining the estimated location of the vehicle comprises analyzing the second set of vertical vehicular motion data based on;

the mapping association, the first vehicle suspension profile, and the second vehicle suspension profile.

10. The method of claim 1, wherein the second set of vertical vehicular motion data describes motion of the vehicle perpendicular a road surface supporting the vehicle.

11. The method of claim 1, further comprising, before collecting the set of accelerometer data:

in a time period, collecting the set of geophysical position data using a GPS receiver of a navigation device;

in the time period, collecting a second set of accelerometer data using an accelerometer of the navigation device;

analyzing the second set of accelerometer data to produce the first set of vertical vehicular motion data; and

generating the mapping association based on the first set of vertical vehicular motion data and the set of geophysical position data.

12. A method for navigation of a vehicle, the method comprising:

receiving a mapping association between a first set of vertical vehicular motion data and a set of geophysical position data;

after receiving the mapping association, collecting a set of accelerometer data;

analyzing the set of accelerometer data to produce a second set of vertical vehicular motion data; and

determining an estimated location of the vehicle based on the second set of vertical vehicular motion data and the mapping association.

13. The method of claim 12, further comprising determining a set of vehicle suspension calibration data, wherein determining the estimated location comprises analyzing the second set of vertical vehicular motion data in light of:

the mapping association and the set of vehicle suspension calibration data.

14. The method of claim 13, wherein the set of accelerometer data is collected during a time period, wherein determining the set of vehicle suspension calibration data comprises:

collecting a set of geophysical position data, the set of geophysical position data received by a GPS receiver during the time period;

deriving a GPS-derived location based on the set of geophysical position data;

generating a reference vertical vehicular motion profile from the mapping association and the GPS-derived location;

determining a comparison between the reference vertical vehicular motion profile and the second set of accelerometer data; and

generating the set of vehicle suspension calibration data based on the comparison.

15. The method of claim 13, wherein the set of accelerometer data is collected at an accelerometer of a navigation device, the method further comprising, at the navigation device, detecting a vehicle type of the vehicle, wherein the set of vehicle suspension calibration data is determined based on the vehicle type.

16. The method of claim 12, further comprising:

determining a set of previously traveled routes, each previously traveled route of the set of previously traveled routes associated with geophysical positions previously mapped to vertical vehicular motion data;

receiving a travel source and a travel destination;

determining that a first previously traveled route from the set of previously traveled routes intersects the travel source, the travel destination, and the estimated location of the vehicle; and

navigating the vehicle according to the first previously traveled route.

17. The method of claim 12, wherein the set of accelerometer data is collected at an accelerometer of a navigation device, the method further comprising:

determining a location estimate error; and

in response to the location estimate error falling below a location estimate error threshold, disabling a GPS receiver of the navigation device and navigating based on vertical vehicular motion data without collecting additional GPS data.

18. The method of claim 17, wherein the set of accelerometer data is collected during a time period, wherein determining the location estimate error comprises:

collecting a set of geophysical position data, the set of geophysical position data received by the GPS receiver during the time period;

determining a GPS-derived location based on the set of geophysical position data;

determining a comparison between the GPS-derived location and the estimated location of the vehicle; and

calculating the location estimate error based on the comparison.

19. The method of claim 12, wherein calculating an estimated location of the vehicle comprises:

inferring a GPS-measured initial vehicular location from a second set of geophysical position data collected by the GPS receiver;

wherein the geophysical position data is collected at a first time between the first time period and the second time period;

collecting a third set of accelerometer data between the first time and a second time in the second time period;

analyzing the third set of accelerometer data to produce a first set of horizontal vehicular motion data;

calculating a vehicle position change from the first set of horizontal vehicular motion data;

calculating a GPS-and-accelerometer-derived location by adding the vehicle position change to the GPS-measured initial vehicular location;

calculating a vertical-accelerometer-derived location and a vertical-accelerometer confidence by analyzing the second set of vertical vehicular motion data in light of the mapping association; and

selecting one of the GPS-and-accelerometer-derived location and the vertical-accelerometer-derived location as the estimated location of the vehicle based on the vertical-accelerometer-derived confidence.

20. The method of claim 12, wherein the set of accelerometer data is collected during a time period at an accelerometer of a navigation device, the method further comprising:

collecting a second set of geophysical position data using a GPS receiver of the navigation device during the time period;

deriving a GPS-derived location based on the second set of GPS geophysical position data;

calculating a GPS accuracy confidence in the GPS-derived location;

wherein;

calculating an estimated location of the vehicle comprises calculating an estimated location of the vehicle from a weighted combination of an initial estimated location and the GPS-derived location;

the initial estimated location is calculated from analysis of the second set of vertical vehicular data alone; and

the GPS-derived location is weighted by the GPS accuracy confidence.

21. The method of claim 20, further comprising modifying a duty cycle of the GPS receiver based on the GPS accuracy confidence.

22. The method of claim 20, wherein calculating a GPS accuracy confidence comprises computing a geometric dilution of precision rating and comparing the geometric dilution of precision rating to a geometric dilution of precision rating threshold.