PARAMETER ESTIMATION FOR ACCELEROMETERS, PROCESSES, CIRCUITS, DEVICES AND SYSTEMS

• US 20090259424A1
• Filed: 03/05/2009
• Published: 10/15/2009
• Est. Priority Date: 03/06/2008
• Status: Abandoned Application

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Mukul, Reetesh, Srikantaiah, Hemanth M., B A, Venkatesh, Dutta, Goutam
• Application Number:
  US12/398,775
• Publication Number:
  US 20090259424A1
• Time in Patent Office: Days
• US Class Current: 702/85
• CPC Class Codes: G01C 17/02 Magnetic compasses
• CPC Class Codes: G01C 17/28 Electromagnetic compasses with north seeking magnetic elements and having electric pick-offs G01C17/26
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

An electronic circuit includes accelerometer (1140) sensors mounted on different axes, memory circuitry (1024) and an electronic processor (1030) coupled to the accelerometer (1140) sensors and to the memory circuitry (1024), the electronic processor (1030) operable to generate signals representing at least one calibration parameter for the accelerometer (1140) sensors from signals representing data resulting from the accelerometer (1140) sensors in an imprecise orientation of the accelerometer (1140) sensors. Information storage media, systems for measuring acceleration, and processes of operation and processes of manufacture are also disclosed.

Claims

1. An electronic circuit comprising:

accelerometer sensors mounted on different axes;

memory circuitry; and

an electronic processor coupled to said accelerometer sensors and to said memory circuitry, said electronic processor operable to generate signals representing at least one calibration parameter for the accelerometer sensors from signals representing data resulting from said accelerometer sensors in an imprecise orientation of said accelerometer sensors.

2. The electronic circuit claimed in claim 1 wherein said memory circuitry holds physical representations of instructions executable by said electronic processor to generate the signals representing the calibration parameter through an electronic process representing gradient-related matrix multiplication.

3. The electronic circuit claimed in claim 1 wherein said electronic processor has multiply-accumulate circuitry and is operable to perform an electronic process representing gradient-related matrix multiplication.

4. The electronic circuit claimed in claim 1 further comprising a satellite positioning decoder situated and coupled to said electronic processor on a same single chip.

5. The electronic circuit claimed in claim 1 wherein at least one of the accelerometer sensors is situated and coupled on a same single chip to said electronic processor.

6. The electronic circuit claimed in claim 1 further comprising an environmental sensor coupled to said electronic processor.

7. An information storage medium holding a set of physical representations of instructions executable by an electronic processor to generate signals representing accelerometer calibration parameters from accelerometer data from different imprecise orientations.

8. The information storage medium claimed in claim 7 wherein the instructions include instructions to generate the parameters by gradient-related matrix multiplication.

9. The information storage medium claimed in claim 7 wherein the instructions include instructions for performing a recursive mean square minimization process to generate the accelerometer calibration parameters.

10. A process of accelerometer calibration, the process comprising generating signals representing accelerometer calibration parameters from signals representing multi-axes accelerometer data from different imprecise accelerometer orientations.

11. The process claimed in claim 10 wherein the generating includes generating the signals representing parameters through an electronic process representing gradient-related matrix multiplication.

12. The process claimed in claim 11 wherein the electronic process representing gradient related matrix multiplication includes a gradient of a function of gravitational acceleration with respect to the calibration parameters.

13. The process claimed in claim 10 further comprising executing a first mode to issue a prompt signal for reorientation and a second mode to occasionally acquire signals representing unprompted accelerometer data and automatically generate signals representing updated calibration parameters.

14. The process claimed in claim 10 wherein the generating includes performing an electronic process representing a recursive mean square minimization to generate the signals representing accelerometer calibration parameters.

15. The process claimed in claim 10 further comprising electronically utilizing signals representing environmental sensor data to determine when to perform the generating.

16. A system for measuring acceleration, comprising:

a portable device having accelerometer sensors mounted on different axes and operable to supply accelerometer signals representing accelerometer data;

a transducer associated with the portable device and operable to emit a user-perceptible prompt; and

an electronic processor coupled to said accelerometer sensors and to said transducer, said electronic processor operable to cause said transducer to emit the user-perceptible prompt, and said electronic processor operable to generate signals representing at least one calibration parameter for the accelerometer sensors in response to the accelerometer signals in different freely-establishable orientations of said portable device.

17. The system claimed in claim 16 wherein said signals representing calibration parameters include signals representing bias parameters and axes gain parameters.

18. The system claimed in claim 16 wherein said electronic processor is operable to perform an electronic process representing error feedback-minimization to generate the signals representing calibration parameters for the accelerometer sensors from the accelerometer signals.

19. The system claimed in claim 16 wherein said electronic processor is operable to perform a gradient-related generation of the signals representing calibration parameters for the accelerometer sensors from the accelerometer signals.

20. The system claimed in claim 16 further comprising a timer circuit coupled to said processor and wherein said electronic processor has an additional mode independent of said transducer and responsive at least in part to said timer circuit to occasionally acquire signals representing accelerometer data and automatically generate updated signals representing calibration parameters.

21. The system claimed in claim 16 wherein said processor is operable to ascertain when the signals representing accelerometer data are sufficiently stable in determining whether the signals representing accelerometer data are acceptable to generate calibration parameters.

22. The system claimed in claim 16 wherein said processor is operable to ascertain when the signals representing accelerometer data substantially accord with gravitational acceleration in determining whether the signals representing accelerometer data are acceptable to generate the signals representing calibration parameters.

23. The system claimed in claim 16 further comprising an environmental sensor coupled to said electronic processor, said electronic processor responsive to said environmental sensor for initiation of accelerometer calibration.

24. The system claimed in claim 16 further comprising a satellite positioning decoder coupled to said electronic processor wherein said processor is operable as an electronic position engine to blend signals representing information from said satellite positioning decoder and the signals representing accelerometer data.

25. The system claimed in claim 16 further comprising an electronic compass coupled to said electronic processor wherein said electronic processor is responsive to said accelerometer sensors and to the calibration parameters for tilt compensation of said electronic compass.

26. A process of manufacture comprising attaching to a printed wiring board an electronic processor and an accelerometer and a flash memory holding a set of physical representations of instructions executable by the electronic processor to generate signals representing accelerometer calibration parameters from accelerometer data from different imprecise orientations.