Estimating an initial position and navigation state using vehicle odometry

Patent metadata

Field	Value
Publication number	US-9677887-B2
Application number	US-201314087743-A
Country	US
Kind code	B2
Filing date	Nov 22, 2013
Priority date	Mar 22, 2013
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

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.

First claim

What is claimed is:

1. A method for estimating at least an initial position of a mobile device using vehicle odometer readings, comprising:
retrieving, by the mobile device, a last known position associated with a vehicle at a first odometer value associated with the vehicle in response to the mobile device establishing a link with the vehicle, wherein the last known position and the first odometer value associated with the vehicle are stored in association in a memory accessible to the mobile device;
reading, by the mobile device, a current odometer value from the vehicle via the established link with the vehicle;
comparing, by the mobile device, the first odometer value associated with the last known position to the current odometer value read from the vehicle; and
using, by a navigation unit incorporated into the mobile device, the last known position associated with the vehicle at the first odometer value as the initial position of the mobile device at navigation start-up for subsequent positioning by the mobile device in response to the comparing indicating that the current odometer value has not changed from the first odometer value associated with the last known position, the mobile device including a receiver or transceiver to receive signals for deriving position information from the signals for aiding the subsequent positioning by the mobile device.

2. The method recited in claim 1 , wherein the initial position of the mobile device has an estimated error that substantially corresponds to an estimated error associated with the last known position at the first odometer value in response to the comparing indicating that the current odometer value has not changed from the first odometer value.

3. The method recited in claim 2 , further comprising:
retrieving, from the memory, a last known heading associated with the vehicle at the first odometer value; and
using, by the navigation unit incorporated into the mobile device, the last known heading at the first odometer value as an initial heading of the mobile device for the subsequent positioning by the mobile device in response to the comparing indicating that the current odometer value has not changed 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 , further comprising defining a radius around the last known position in response to the comparing indicating a non-zero difference between the first odometer value and the current odometer value, wherein the defined radius limits a distance from the last known position that can be used for the subsequent positioning by the mobile device.

6. The method recited in claim 5 , further comprising estimating, by the navigation unit incorporated into the mobile device, the initial position of the mobile device 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 an estimated error associated with the initial position according to the difference between the first odometer value and the current odometer value; and
determining whether to use the initial position or calculate a different initial position based on data from the one or more satellites based on the scaled estimated error.

8. The method recited in claim 1 , wherein the memory further stores the last known position and the first odometer value associated with the vehicle in association with an identifier corresponding to the vehicle.

9. The method recited in claim 1 , further comprising:
retrieving, by the mobile device, one or more models associated with the vehicle from the memory accessible to the mobile device; and
using, by the navigation unit incorporated into the mobile device, the one or more models associated with the vehicle to perform dead reckoning based on the 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, by the navigation unit incorporated into the mobile device, the initial position of the mobile device 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, by the mobile device, the last known position from the server; and
transferring, by the first mobile device, the last known position retrieved from the server and a last known heading associated with the vehicle at the first odometer value to a second mobile device, wherein an estimated error associated with the last known position and the last known heading is based on a difference between the first odometer value and the current odometer value.

14. The method recited in claim 1 , further comprising initializing, by the navigation unit incorporated into the mobile device, a navigation route based on the last known position at the first odometer value and a last known heading associated with the vehicle at the first odometer value in response to the comparing indicating that the current odometer value has not changed from the first odometer value.

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 last known heading 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 retrieving a last known position associated with a vehicle at a first odometer value associated with the vehicle from a memory accessible to the apparatus in response to the apparatus establishing a link with the vehicle, wherein the last known position and the first odometer value associated with the vehicle are stored in association in the memory;
means for reading a current odometer value from the vehicle via the established link with the vehicle;
means for comparing the first odometer value associated with the last known position to the current odometer value read from the vehicle;
means for using the last known position associated with the vehicle at the first odometer value as an initial position of the apparatus at navigation start-up for subsequent positioning by the apparatus in response to the comparing indicating that the current odometer value has no

Assignees

• Qualcomm Inc

Inventors

• Werner Benjamin A
• Morrison William James
• Riley Wyatt Thomas
• Czompo Joseph

Classifications

• G01C22/00 Primary

  Measuring distance traversed on the ground by vehicles, persons, animals or other moving solid bodies, e.g. using odometers, using pedometers · CPC title

• G01C21/00 Primary

  Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 (measuring distance traversed on the ground by a vehicle G01C22/00; control of position, course, altitude or attitude of vehicles G05D1/00; traffic control systems for road vehicles involving transmission of navigation instructions to the vehicle G08G1/0968) · CPC title

• G01C21/20 Primary

  Instruments for performing navigational calculations (G01C21/24, G01C21/26 take precedence) · CPC title