Numerically stable computation of heading without a reference axis

• US 8,914,037 B2
• Filed: 08/11/2011
• Issued: 12/16/2014
• Est. Priority Date: 08/11/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Czompo, Joseph, Kulik, Victor
• Primary Examiner(s): DOAN, PHUOC HUU
• Application Number:
  US13/208,285
• Publication Number:
  US 20130040653A1
• Time in Patent Office: 1,223 Days
• Field of Search: 455/456.1, 455/414.1, 455/556.1, 342/202
• US Class Current: 455/456.1
• CPC Class Codes: G01C 21/1654 with electromagnetic compass

Abstract

Systems and methods are described for computing device motion direction and orientation. A system as described herein includes an orientation sensor configured to collect data relating to orientation of the mobile device; an orientation analysis module communicatively coupled to the orientation sensor and configured to determine a three-dimensional orientation of the mobile device relative to an Earth-based coordinate system based on the data collected by the orientation sensor; and a motion direction tracker module communicatively coupled to the orientation analysis module, configured to compute a first direction, that is a three-dimensional direction of motion of the mobile device relative to a coordinate system of the mobile device, and configured to compute a second direction, that is a direction of motion of the mobile device relative to the Earth-based coordinate system, based on the first direction using the three-dimensional orientation of the mobile device relative to the Earth-based coordinate system.

Claims

1. A system for computing motion direction of a mobile device, the system comprising:

an orientation sensor configured to collect data relating to orientation of the mobile device;

an orientation analysis module communicatively coupled to the orientation sensor and configured to determine a three-dimensional orientation of the mobile device relative to an Earth-based coordinate system based on the data collected by the orientation sensor; and

a motion direction tracker module communicatively coupled to the orientation analysis module, configured to compute a first direction, that is a three-dimensional direction of motion of the mobile device relative to a coordinate system of the mobile device, and configured to compute a second direction, that is a direction of motion of the mobile device relative to the Earth-based coordinate system, based on the first direction using the three-dimensional orientation of the mobile device relative to the Earth-based coordinate system.

2. The system of claim 1 wherein the orientation sensor comprises at least one of an accelerometer, a gyroscope or a magnetometer.

3. The system of claim 1 wherein the orientation sensor is further configured to collect data relating to motion direction of the mobile device and the motion direction tracker module is further configured to determine the first direction based on the data collected by the orientation sensor relating to the motion direction of the mobile device.

4. The system of claim 1 wherein the motion direction tracker module is further configured to relate the coordinate system of the mobile device to the Earth-based coordinate system and to translate the motion direction of the mobile device of the mobile device from the coordinate system of the mobile device to the Earth-based coordinate system.

5. The system of claim 4 wherein the motion direction tracker module is further configured to relate the coordinate system of the mobile device to the Earth-based coordinate system using a rotation matrix or a quatemion.

6. The system of claim 1 wherein the first direction is an angle relative to north in relation to a horizontal plane of the Earth-based coordinate system.

7. The system of claim 6 wherein the first direction is one of an angle relative to magnetic north or an angle relative to true north.

8. The system of claim 6 wherein the motion direction tracker module is further configured to compute the second direction by projecting, to a horizontal plane at Earth'"'"'s surface, a three-dimensional direction of motion of the mobile device relative to the Earth-based coordinate system determined using a three-dimensional direction of motion of the mobile device relative to the coordinate system of the mobile device and the three-dimensional orientation of the mobile device relative to the Earth-based coordinate system.

9. A system for tracking motion direction of a mobile device,

the system comprising:

an orientation sensor configured to collect data relating to orientation of the mobile device;

a satellite positioning system (SPS) receiver configured to determine an initial direction of motion of the mobile device in terms of an Earth-based coordinate system during a calibration time period;

an orientation analysis module communicatively coupled to the orientation sensor and configured to track changes to a three-dimensional orientation of the mobile device in terms of the Earth-based coordinate system over time based on the data collected by the orientation sensor; and

a motion direction tracker module communicatively coupled to the SPS receiver and the orientation analysis module and configured to compute a direction of motion of the mobile device in terms of the Earth-based coordinate system relative to the initial direction of motion of the mobile device using the changes to the three-dimensional orientation of the mobile device in terms of the Earth-based coordinate system.

10. The system of claim 9 wherein the orientation sensor comprises at least one of an accelerometer, a gyroscope or a magnetometer.

11. The system of claim 9 wherein the motion direction tracker module is further configured to compute the direction of motion of the mobile device as an angle relative to north in relation to a horizontal plane of the Earth-based coordinate system.

12. The system of claim 11 wherein the motion direction tracker module is further configured to compute the direction of motion of the mobile device by projecting, to a horizontal plane at Earth'"'"'s surface, a three-dimensional direction of motion of the mobile device relative to the Earth-based coordinate system determined using a three-dimensional direction of motion of the mobile device in terms of a coordinate system of the mobile device, the changes to the three-dimensional orientation of the mobile device in terms of the Earth-based coordinate system over time, and the initial direction of motion of the mobile device in terms of the Earth-based coordinate system.

13. A method of computing motion direction of a mobile device comprising:

determining a three-dimensional orientation of the mobile device relative to a coordinate system of Earth;

computing a first direction, that is a three-dimensional direction of motion of the mobile device relative to a coordinate system of the mobile device;

computing a second direction that is a three-dimensional direction of motion of the mobile device relative to the coordinate system of Earth using the first direction and the three-dimensional orientation of the mobile device relative to the coordinate system of Earth, the second direction be an angle relative to north; and

projecting, to a horizontal plane at Earth'"'"'s surface, the three-dimensional direction of motion of the mobile device relative to the coordinate system of Earth.

14. A method of tracking a motion direction of a mobile device over time comprising:

obtaining an initial motion direction of the mobile device in a coordinate system of Earth from a satellite navigation system during an initial time period;

determining a three-dimensional orientation of the mobile device in the coordinate system of Earth subsequent to the initial time period; and

computing an updated motion direction of the mobile device in the coordinate system of Earth relative to the initial motion direction of the mobile device using the three-dimensional orientation of the mobile device in the coordinate system of Earth.

15. The method of claim 14 further comprising:

determining an initial three-dimensional orientation of the mobile device in the coordinate system of Earth during the initial time period; and

computing a three-dimensional motion direction of the mobile device in a coordinate system of the mobile device using the initial motion direction of the mobile device in the coordinate system of Earth and the initial three-dimensional orientation of the mobile device in the coordinate system of Earth.

16. The method of claim 14 wherein the computing the updated motion direction of the mobile device comprises:

determining an updated three-dimensional motion direction of the mobile device in the coordinate system of Earth using the three-dimensional motion direction of the mobile device in the coordinate system of the mobile device and the three-dimensional orientation of the mobile device in the coordinate system of Earth subsequent to the initial time period; and

projecting, to a horizontal plane at Earth'"'"'s surface, the updated three-dimensional motion direction of the mobile device in the coordinate system of Earth.

17. A mobile wireless communication device comprising:

sensing means for generating orientation information for the device;

orientation means, communicatively coupled to the sensing means, for computing a three-dimensional earth-frame orientation of the device relative to Earth based on the orientation information for the device; and

direction means, communicatively coupled to the orientation means, for computing a three-dimensional sensor-frame direction of motion of the device relative to a sensor coordinate plane of the device defined by at least one sensor axis and

computing an earth-frame direction of motion of the device relative to Earth using the three-dimensional sensor-frame direction of motion of the device and the three-dimensional earth-frame orientation of the device.

18. The device of claim 17 wherein the direction means is further configured to translate the three-dimensional sensor-frame direction of motion of the device to a three-dimensional earth-frame direction of motion using a rotation matrix or a quaternion.

19. The device of claim 17 wherein the earth-frame direction of motion of the device is an angle relative to north and the direction means is configured to compute the earth-frame direction of motion of the device by projecting, to a horizontal plane relative to Earth, a three-dimensional earth-plane direction of motion of the device determined using a three-dimensional sensor-plane direction of motion of the device and the three-dimensional earth-plane orientation of the device.

20. A mobile wireless communication device comprising:

sensing means for generating orientation information for the device;

calibration means for determining an initial earth-frame direction of 4 motion of the device relative to Earth;

orientation means, communicatively coupled to the sensing means, for tracking changes to a three-dimensional earth-frame orientation of the device relative to Earth over time based on the orientation information for the device; and

direction means, communicatively coupled to the calibration means and

the orientation means, for computing changes to an earth-frame direction of motion of the device relative to Earth over time relative to the initial earth-frame direction of motion of the device using the changes to the three-dimensional earth-frame orientation of the device.

21. The device of claim 20 wherein the direction means is configured to compute the earth-frame direction of motion of the device as an angle relative to north.

22. The device of claim 21 wherein the direction means is further configured to compute the earth-frame direction of motion of the device by projecting, to a horizontal plane relative to Earth, a three-dimensional earth-frame direction of motion of the device computed using a sensor-frame direction of motion of the device relative to a sensor coordinate plane of the device defined by at least one sensor axis, the changes to the three-dimensional earth-frame orientation of the device, and the initial earth-frame direction of motion of the device.

23. A non-transitory processor-readable medium comprising processor-readable instructions configured to cause a processor to:

determine a three-dimensional orientation of a mobile device relative to a coordinate system of Earth;

compute a first direction, that is a three-dimensional direction of motion of the mobile device relative to a coordinate system of the mobile device; and

compute a second direction that is a three-dimensional direction of motion of the mobile device relative to the coordinate system of Earth using the first direction and the three-dimensional orientation of the mobile device relative to the coordinate system of Earth, the second direction being an angle relative to north; and

project, to a horizontal plane at Earth'"'"'s surface, the three-dimensional direction of motion of the mobile device relative to the coordinate system of Earth.

24. A non-transitory processor-readable medium comprising processor-readable instructions configured to cause a processor to:

obtain an initial motion direction of a mobile device in a coordinate system of Earth from a satellite navigation system during an initial time period;

determine a three-dimensional orientation of the mobile device in the coordinate system of Earth subsequent to the initial time period; and

compute an updated motion direction of the mobile device in the coordinate system of Earth relative to the initial motion direction of the mobile device using the three-dimensional orientation of the mobile device in the coordinate system of Earth.

25. The non-transitory processor-readable medium of claim 24 further comprising processor-readable instructions configured to cause the processor to:

determine an initial three-dimensional orientation of the mobile device in the coordinate system of Earth during the initial time period; and

compute a three-dimensional motion direction of the mobile device in a coordinate system of the mobile device using the initial motion direction of the mobile device in the coordinate system of Earth and the initial three-dimensional orientation of the mobile device in the coordinate system of Earth.

26. The non-transitory processor-readable medium of claim 24 wherein the instructions configured to cause the processor to compute the updated motion direction of the mobile device are further configured to cause the processor to:

determine an updated three-dimensional motion direction of the mobile device in the coordinate system of Earth using a three-dimensional motion direction of the mobile device in a coordinate system of the mobile device and the three-dimensional orientation of the mobile device in the coordinate system of Earth subsequent to the initial time period; and

project, to a horizontal plane at Earth'"'"'s surface, the updated three-dimensional motion direction of the mobile device in the coordinate system of Earth.