APPARATUS AND METHODS FOR CALIBRATING DYNAMIC PARAMETERS OF A VEHICLE NAVIGATION SYSTEM

• US 20120022780A1
• Filed: 07/22/2010
• Published: 01/26/2012
• Est. Priority Date: 07/22/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kulik, Victor, Czompo, Joseph
• Granted Patent: US 8,843,290 B2
• Time in Patent Office: Days
• US Class Current: 701/220
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments
• CPC Class Codes: G01C 22/025 Differential odometers
• CPC Class Codes: G01C 25/00 Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass testing, calibrating or compensating compasses G01C17/38

Abstract

Apparatus and methods for calibrating dynamic parameters of a vehicle navigation system are presented. One method may include determining whether reference position data of a vehicle is available, and measuring composite accelerations of the vehicle. The method may further include generating distance and turn angle data based upon a wheel speed sensors data, computing distance and turn angle errors based upon the independent position data, and associating the distance and turn angle errors with composite accelerations. A second method presented includes calibrating an inertial navigation sensor within a vehicle navigation system. The second method may include determining reference position data and Inertial Navigation System (INS) data, aligning an IMU with the vehicle, and aligning the IMU with an Earth fixed coordinate system. The second method may further include computing the vehicle alignment with respect to a horizontal plane, and determining calibration parameters for distance sensors associated with the vehicle.

Claims

1. A method for calibrating distance sensors within a vehicle navigation system, comprising:

determining that reference position data of a vehicle is available;

measuring composite accelerations of the vehicle;

generating distance and turn angle data based upon a wheel speed sensors data;

computing distance and turn angle errors based upon the independent position data; and

associating the distance and turn angle errors with composite accelerations.

2. The method of claim 1, further comprising:

determining that the composite accelerations are substantially constant.

3. The method of claim 1, wherein the associating further comprises:

storing the distance and turn angle errors in look-up tables; and

indexing the look-up tables with the composite accelerations.

4. The method of claim 3, wherein the associating further comprises:

approximating a relationship between the distance errors and the composite accelerations with a first mathematical function; and

approximating a relationship between the turn angle errors and the composite accelerations with a second mathematical function.

5. The method of claim 4, wherein the first mathematical function and the second mathematical function are linear functions.

6. The method of claim 1, wherein the composite accelerations include composite forward acceleration and composite lateral acceleration.

7. The method of claim 6, further comprising

associating the distance error with the composite forward acceleration;

and

associating the turn angle error with the composite lateral acceleration.

8. The method of claim 1, wherein the distance sensors are wheel speed sensors, and the reference position data is satellite position system data.

9. The method of claim 1, further including applying corrections to the distance sensor data, comprising:

determining distance and turn angle data using the wheel speed sensors;

measuring composite forward and lateral accelerations;

determining that calibration data is available;

determining distance and turn angle corrections based upon measured composite accelerations; and

applying distance and turn angle corrections to the distance and turn angle data.

10. An apparatus for calibrating a distance sensor within a vehicle navigation system, comprising:

an accelerometer;

a reference position determination system;

at least two wheel speed sensors;

a processor coupled to the accelerometer, the wheel speed sensors, and the reference position determination system; and

a memory coupled to the processor, wherein the memory stores instructions causing the processor to

receive measured composite accelerations of the vehicle from the accelerometer,

determine when the composite accelerations are substantially constant,

compute distance and turn angle data based upon the wheel speed sensors,

computing distance and turn angle errors based upon data provided by the independent position determination system,

receive composite accelerations from the accelerometer, and

associate the distance and turn angle errors with the composite accelerations.

11. The apparatus of claim 10, wherein the reference position determination system is a Satellite Position System (SPS) and/or a map matching system.

12. The apparatus of claim 10, wherein the at least two wheel speed sensors are tick sensors.

13. The apparatus of claim 11, wherein the accelerometer, the SPS, the processor, and the memory reside within a mobile device.

14. The apparatus of claim 10, wherein the memory stores instructions further causing the processor to

store the distance and turn angle errors in look-up tables, and

index the look-up tables with the composite accelerations.

15. The apparatus of claim 14, wherein the memory stores instructions further causing the processor to

approximate a relationship between the distance errors and the composite accelerations with a first mathematical function;

and

approximate a relationship between the turn angle errors and the composite accelerations with a second mathematical function.

16. The apparatus of claim 15, wherein the first mathematical function and the second mathematical function are linear functions.

17. The apparatus of claim 10, wherein the composite accelerations include composite forward acceleration and composite lateral acceleration.

18. The apparatus of claim 17, wherein the memory stores instructions further causing the processor to

associate the distance error with the composite forward acceleration;

and

associate the turn angle error with the composite lateral acceleration.

19. The apparatus of claim 10, wherein the memory stores instructions further causing the processor to

receive distance data from the wheel speed sensors;

receive composite forward and lateral accelerations from the accelerometer;

determine that calibration data is available;

determine distance and turn angle corrections based upon measured composite accelerations; and

apply distance and turn angle corrections to the distance sensor data.

20. An apparatus for calibrating a distance sensor within a vehicle navigation system, comprising:

means for determining that reference position data of a vehicle is available;

means for measuring composite accelerations of the vehicle;

means for generating distance and turn angle data based upon a wheel speed sensors data;

means for computing distance and turn angle errors based upon the independent position data; and

means for associating the distance and turn angle errors with composite accelerations.

21. The apparatus of claim 20, wherein the means for associating further comprises:

means for storing the distance and turn angle errors in look-up tables; and

means for indexing the look-up tables with the composite accelerations.

22. The apparatus of claim 21, wherein the means for associating further comprises:

means for approximating a relationship between the distance errors and the composite accelerations with a first mathematical function; and

means for approximating a relationship between the turn angle errors and the composite accelerations with a second mathematical function.

23. The apparatus of claim 20, wherein the composite accelerations include composite forward acceleration and composite lateral acceleration.

24. The apparatus of claim 23, further comprising

means for associating the distance error with the composite forward acceleration;

and

means for associating the turn angle error with the composite lateral acceleration.

25. The apparatus of claim 20, comprising means for applying corrections to the distance sensor data, further comprising:

means for determining distance and turn angle data using the wheel speed sensors;

means for measuring composite forward and lateral accelerations;

means for determining that calibration data is available;

means for determining distance and turn angle corrections based upon measured composite accelerations; and

means for applying distance and turn angle corrections to the distance and turn angle data.

26. A non-transitory machine-readable medium comprising instructions, which, when executed by a machine, cause the machine to perform operations, comprising:

instructions to determine that reference position data of a vehicle is available;

instructions to measure composite accelerations of the vehicle;

instructions to generate distance and turn angle data based upon a wheel speed sensors data;

instructions to compute distance and turn angle errors based upon the independent position data; and

instructions to associate the distance and turn angle errors with composite accelerations.

27. The non-transitory machine-readable medium of claim 26, wherein the instructions to associate further comprise:

instructions to store the distance and turn angle errors in look-up tables; and

instructions to index the look-up tables with the composite accelerations.

28. The non-transitory machine-readable medium of claim 26, further including instructions to apply corrections to the distance sensor data, comprising:

instructions to determine distance and turn angle data using the wheel speed sensors;

instructions to measure composite forward and lateral accelerations;

instructions to determine that calibration data is available;

instructions to determine distance and turn angle corrections based upon measured composite accelerations; and

instructions to apply distance and turn angle corrections to the distance and turn angle data.

29. A method for calibrating an inertial navigation sensor within a vehicle navigation system, comprising:

determining reference position data and Inertial Navigation System (INS) data;

aligning an IMU with the vehicle;

aligning the IMU with an Earth fixed coordinate system;

computing the vehicle alignment with respect to a horizontal plane; and

determining calibration parameters for distance sensors associated with the vehicle.

30. The method of claim 29, further comprising:

measuring data using distance sensors; and

applying calibration parameters to the measured distance data.

31. An apparatus for calibrating an inertial sensor within a navigation system residing within a vehicle, comprising:

an accelerometer;

at least two distance sensors;

a vehicle inertial navigation system (INS) which includes an inertial measurement unit (IMU);

a processor coupled to the accelerometer;

the at least two distance sensors, and the INS;

a memory coupled to the processor, wherein the memory stores instructions causing the processor to

determine reference position data and INS data;

align the IMU with the vehicle;

align the IMU with an Earth fixed coordinate system;

compute the vehicle alignment with respect to a horizontal plane;

determine calibration parameters for the at least two distance sensors;

measure data using distance sensors; and

apply calibration parameters to the measured distance data.

32. An apparatus for calibrating an inertial sensor within a navigation system residing within a vehicle, comprising:

means for determining reference position data and Inertial Navigation System (INS) data;

means for aligning an IMU with the vehicle;

means for aligning the IMU with an Earth fixed coordinate system;

means for computing the vehicle alignment with respect to a horizontal plane; and

means for determining calibration parameters for distance sensors associated with the vehicle.

33. The apparatus of claim 32, further comprising:

means for measuring data using distance sensors; and

means for applying calibration parameters to the measured distance data.

34. A non-transitory machine-readable medium comprising instructions, which, when executed by a machine, cause the machine to perform operations, comprising:

instructions to determining reference position data and Inertial Navigation System (INS) data;

instructions to aligning an IMU with the vehicle;

instructions to aligning the IMU with an Earth fixed coordinate system;

instructions to computing the vehicle alignment with respect to a horizontal plane; and

instructions to determining calibration parameters for distance sensors associated with the vehicle.

35. The non-transitory machine-readable medium 34, further comprising:

instructions to measuring data using distance sensors; and

instructions to applying calibration parameters to the measured distance data.