ESTIMATING AN INITIAL POSITION AND NAVIGATION STATE USING VEHICLE ODOMETRY

• US 20140288828A1
• Filed: 11/22/2013
• Published: 09/25/2014
• Est. Priority Date: 03/22/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Werner, Benjamin A., Morrison, William James, Riley, Wyatt Thomas, Czompo, Joseph
• Granted Patent: US 9,677,887 B2
• Time in Patent Office: Days
• US Class Current: 701/527
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 22/00 Measuring distance traversed on the ground by vehicles, persons, animals or other moving solid bodies, e.g. using odometers, using pedometers

Abstract

The disclosure relates to estimating an initial position and navigation state associated with a vehicle using odometry and/or other data obtained from the vehicle to support dead reckoning at start-up. In particular, a last known position and last known heading at a first odometer value associated with the vehicle may be stored and compared to a current odometer value after linking a mobile device with the vehicle. The last known position and last known heading may be used to estimate the initial position and navigation state associated with the vehicle based on a difference between the compared odometer values. For example, the estimated initial position and/or navigation state may substantially correspond to the last known position and last known heading if the difference between the odometer values indicates no change, or a non-zero difference may define a radius to limit an estimated error associated with the initial position estimate.

Claims

1. A method for estimating an initial position and navigation state using vehicle odometry, comprising:

storing, in a memory, a last known position associated with a vehicle at a first odometer value associated with the vehicle;

comparing the first odometer value to a current odometer value associated with the vehicle in response to a mobile device establishing a link with the vehicle; and

using the last known position at the first odometer value to estimate the initial position and navigation state associated with the vehicle based on a difference between the first odometer value and the current odometer value.

2. The method recited in claim 1, wherein the estimated initial position associated with the vehicle substantially corresponds to the last known position at the first odometer value if the current odometer value indicates no change from the first odometer value.

3. The method recited in claim 2, further comprising storing, in the memory, a last known heading associated with the vehicle at the first odometer value, wherein the estimated initial navigation state comprises the last known heading at the first odometer value if the current odometer value indicates no change from the first odometer value.

4. The method recited in claim 3, wherein one or more of a server or the mobile device includes the memory that stores the last known position and the last known heading at the first odometer value.

5. The method recited in claim 1, wherein a non-zero difference between the first odometer value and the current odometer value defines a radius that limits an estimated error associated with the estimated initial position.

6. The method recited in claim 5, further comprising estimating the initial position associated with the vehicle based on the defined radius in combination with one or more of data obtained from one or more satellites or data stored on the vehicle in response to the first odometer value and the current odometer value having a non-zero difference.

7. The method recited in claim 6, further comprising:

scaling the estimated error associated with the estimated initial position according to the difference between the first odometer value and the current odometer value; and

determining whether to use the estimated initial position or calculate the initial position based on data from one or more satellites based on the scaled estimated error.

8. The method recited in claim 1, further comprising associating the last known position associated with the vehicle at the first odometer value with an identifier corresponding to the vehicle.

9. The method recited in claim 1, further comprising:

storing, in the memory, one or more models associated with the vehicle; and

using the estimated initial navigation state and the one or more models associated with the vehicle to perform dead reckoning from the estimated initial position.

10. The method recited in claim 9, further comprising:

using the one or more models to determine whether a current position associated with the vehicle has substantially changed from the last known position despite the current odometer value indicating no change from the first odometer value; and

calculating the initial position associated with the vehicle based on one or more of data from one or more satellites or data stored on the vehicle in response to the one or more models indicating that the current position associated with the vehicle has substantially changed from the last known position.

11. The method recited in claim 9, wherein the one or more models include parameters relating to one or more of a last known sensor bias, an odometry scale factor, an estimated lever arm, turning rate statistics, velocity statistics, or vehicle motion statistics.

12. The method recited in claim 1, wherein the mobile device assumes a beacon role to share at least the last known position at the first odometer value over one or more communication interfaces.

13. The method recited in claim 1, wherein the mobile device comprises a first mobile device, a server includes the memory that stores the last known position at the first odometer value, and the method further comprises:

retrieving the last known position from the server;

comparing the first odometer value to a current odometer value associated with the vehicle in response to a second mobile device establishing a link with the vehicle; and

using the retrieved last known position and a last known heading to estimate the initial position and navigation state associated with the vehicle based on a difference between the first odometer value and the current odometer value.

14. The method recited in claim 1, further comprising initializing a navigation route based on the estimated initial position and navigation state.

15. The method recited in claim 1, wherein one or more of a server or the mobile device includes the memory that stores the last known position and a heading estimate at the first odometer value, and wherein the current odometer value associated with the vehicle comprises a cumulative odometer value stored on the vehicle.

16. An apparatus, comprising:

means for storing a last known position associated with a vehicle at a first odometer value associated with the vehicle;

means for comparing the first odometer value to a current odometer value associated with the vehicle in response to a mobile device establishing a link with the vehicle; and

means for using the last known position at the first odometer value to estimate an initial position and navigation state associated with the vehicle based on a difference between the first odometer value and the current odometer value.

17. The apparatus recited in claim 16, wherein the estimated initial position associated with the vehicle substantially corresponds to the last known position at the first odometer value if the current odometer value indicates no change from the first odometer value.

18. The apparatus recited in claim 17, further comprising means for storing a last known heading associated with the vehicle at the first odometer value, wherein the estimated initial navigation state comprises the last known heading at the first odometer value if the current odometer value indicates no change from the first odometer value.

19. The apparatus recited in claim 16, wherein a non-zero difference between the first odometer value and the current odometer value defines a radius that limits an estimated error associated with the estimated initial position.

20. The apparatus recited in claim 19, further comprising means for estimating the initial position associated with the vehicle based on the defined radius in combination with one or more of data obtained from a satellite or data stored on the vehicle in response to the first odometer value and the current odometer value having a non-zero difference.

21. The apparatus recited in claim 20, further comprising:

means for scaling the estimated error associated with the estimated initial position according to the difference between the first odometer value and the current odometer value; and

means for determining whether to use the estimated initial position or calculate the initial position based on data from one or more satellites based on the scaled estimated error.

22. The apparatus recited in claim 16, further comprising means for associating the last known position associated with the vehicle at the first odometer value with an identifier corresponding to the vehicle.

23. The apparatus recited in claim 16, further comprising:

means for storing one or more models associated with the vehicle; and

means for using the estimated initial navigation state and the one or more models associated with the vehicle to perform dead reckoning from the estimated initial position.

24. The apparatus recited in claim 23, further comprising:

means for using the one or more models to determine whether a current position associated with the vehicle has substantially changed from the last known position despite the current odometer value indicating no change from the first odometer value; and

means for calculating the initial position associated with the vehicle based on one or more of data from one or more satellites or data stored on the vehicle in response to the one or more models indicating that the current position associated with the vehicle has substantially changed from the last known position.

25. The apparatus recited in claim 23, wherein the one or more models include parameters relating to one or more of a last known sensor bias, an odometry scale factor, an estimated lever arm, turning rate statistics, velocity statistics, or vehicle motion statistics.

26. The apparatus recited in claim 16, further comprising means for assuming a beacon role to share at least the last known position at the first odometer value over one or more communication interfaces.

27. The apparatus recited in claim 16, wherein the mobile device comprises a first mobile device and the apparatus further comprises:

means for retrieving the stored last known position;

means for comparing the first odometer value to a current odometer value associated with the vehicle in response to a second mobile device establishing a link with the vehicle; and

means for using the retrieved last known position and a last known heading to estimate the initial position and navigation state associated with the vehicle based on a difference between the first odometer value and the current odometer value.

28. The apparatus recited in claim 16, further comprising means for initializing a navigation route based on the estimated initial position and navigation state.

29. An apparatus, comprising:

a memory configured to store a last known position associated with a vehicle at a first odometer value associated with the vehicle; and

one or more processors configured to compare the first odometer value to a current odometer value associated with the vehicle in response to a mobile device establishing a link with the vehicle and use the last known position stored in the memory to estimate an initial position and navigation state associated with the vehicle based on a difference between the first odometer value and the current odometer value.

30. A non-transitory computer-readable storage medium having computer-executable instructions recorded thereon, wherein executing the computer-executable instructions on one or more processors causes the one or more processors to:

store, in a memory, a last known position associated with a vehicle at a first odometer value associated with the vehicle;

compare the first odometer value to a current odometer value associated with the vehicle in response to a mobile device establishing a link with the vehicle; and

use the last known position at the first odometer value to estimate an initial position and navigation state associated with the vehicle based on a difference between the first odometer value and the current odometer value.