Inertial sensor aided heading and positioning for GNSS vehicle navigation

• US 9,891,054 B2
• Filed: 12/01/2011
• Issued: 02/13/2018
• Est. Priority Date: 12/03/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Czompo, Joseph, Opshaug, Guttorm R., Joshi, Ashutosh, Luo, Ning
• Primary Examiner(s): Barbee, Manuel L
• Application Number:
  US13/309,522
• Publication Number:
  US 20120173140A1
• Time in Patent Office: 2,266 Days
• Field of Search: 702150, 702151, 702153, 702154, 735033, 7351401
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01C 21/188 for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• CPC Class Codes: G01S 19/393 Trajectory determination or predictive tracking, e.g. Kalman filtering
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: G01S 19/52 Determining velocity

Abstract

An apparatus and method for providing an improved heading estimate of a mobile device in a vehicle is presented. First, the mobile device determines if it is mounted in a cradle attached to the vehicle; if so, inertia sensor data may be valid. While in a mounted stated, the mobile device determines whether it has been rotated in the cradle; if so, inertia sensor data may no longer be reliable and a recalibration to determine a new relative orientation between the vehicle and the mobile device is needed. If the mobile device is mounted and not recently rotated, heading data from multiple sensors (e.g., GPS, gyroscope, accelerometer) may be computed and combined to form the improved heading estimate. This improved heading estimate may be used to form an improved velocity estimate. The improved heading estimate may also be used to compute a bias to correct a gyroscope.

Claims

1. A method in a mobile device for detecting cradle rotation of a cradle on which the mobile device is mounted, the method comprising:

determining a threshold based on a GNSS magnitude;

comparing an angular rotation rate to the threshold;

determining a cradle rotation state based on the comparison; and

declaring, by the mobile device, the cradle rotation state, wherein the cradle rotation state comprises an indication of whether the mobile device mounted on the cradle has been rotated relative to a frame of reference.

2. The method of claim 1, wherein the angular rotation rate is based on gyroscope measurements.

3. The method of claim 1, wherein the determining the threshold comprises:

comparing a magnitude of a velocity to a velocity threshold; and

determining the threshold based on the magnitude comparison.

4. The method of claim 3, wherein the magnitude of the velocity comprises a magnitude of a velocity from a GNSS receiver.

5. The method of claim 3, wherein determining the threshold comprises:

setting the threshold based on a minimum radius of curvature when the magnitude comparison is low and based on a maximum acceleration when the magnitude comparison is high.

6. The method of claim 3, wherein the angular rotation rate is based on gyroscope measurements.

7. The method of claim 1, further comprising writing a parameter based on the cradle rotation state.

8. The method of claim 1, further comprising saving the cradle rotation state.

9. The method of claim 1, further comprising resetting at least one ongoing computation until a redetermination of the cradle rotation state, when the cradle rotation state indicates that the mobile device mounted on the cradle has been rotated relative to the frame of reference.

10. The method of claim 1, further comprising de-weighting results of at least one ongoing computation until a redetermination of the cradle rotation state, when the cradle rotation state indicates that the mobile device mounted on the cradle has been rotated relative to the frame of reference.

11. The method of claim 1, further comprising barring use of sensor measurements until a redetermination of the cradle rotation state, when the cradle rotation state indicates that the mobile device mounted on the cradle has been rotated relative to the frame of reference.

12. A mobile device to detect cradle rotation of a cradle on which the mobile device is mounted, the mobile device comprising:

an inertial measurement unit comprising an accelerometer and a gyroscope;

a Global Navigation Satellite Systems receiver (GNSS receiver);

a processor coupled to the inertial measurement unit and the GNSS receiver; and

memory coupled to the processor, comprising code for;

determining a threshold based on a GNSS magnitude of a velocity;

comparing an angular rotation rate to the threshold;

determining a cradle rotation state based on the comparison; and

declaring, by the mobile device, the cradle rotation state, wherein the cradle rotation state comprises an indication of whether the mobile device mounted on the cradle has been rotated relative to a frame of reference.

13. The mobile device of claim 12, wherein the angular rotation rate is based on gyroscope measurements.

14. The mobile device of claim 12, wherein the determining the threshold comprises:

comparing a magnitude of a velocity to a velocity threshold; and

determining the threshold based on the magnitude comparison.

15. The mobile device of claim 14, wherein the magnitude of the velocity comprises a magnitude of a velocity from a GNSS receiver.

16. The mobile device of claim 14, wherein determining the threshold comprises:

setting the threshold based on a minimum radius of curvature when the magnitude comparison is low and based on a maximum acceleration when the magnitude comparison is high.

17. The mobile device of claim 14, wherein the angular rotation rate is based on gyroscope measurements.

18. A mobile device to detect cradle rotation of a cradle on which the mobile device is mounted, the mobile device comprising:

means for determining a threshold based on a GNSS magnitude of a velocity;

means for comparing an angular rotation rate to the threshold;

means for determining a cradle rotation state based on the comparison; and

means for declaring, by the mobile device, the cradle rotation state, wherein the cradle rotation state comprises an indication of whether the mobile device mounted on the cradle has been rotated relative to a frame of reference.

19. A device mounted on a cradle, the device comprising a processor and a memory wherein the memory includes software instructions for:

determining a threshold based on a GNSS magnitude;

comparing an angular rotation rate to the threshold;

determining a cradle rotation state based on the comparison; and

declaring, by the device, the cradle rotation state, wherein the cradle rotation state comprises an indication of whether the mobile device mounted on the cradle has been rotated relative to a frame of reference.

20. A non-transitory computer-readable storage medium including program code stored thereon for detecting cradle rotation of a cradle on which the mobile device is mounted, the program code comprising instructions for:

determining a threshold based on a GNSS magnitude;

comparing an angular rotation rate to the threshold;

determining a cradle rotation state based on the comparison; and

declare, by the mobile device, the cradle rotation state, wherein the cradle rotation state comprises an indication of whether the mobile device mounted on the cradle has been rotated relative to a frame of reference.