System and Method for Determining Quality of Calibration Parameters for a Magnetometer

1 . A method of calibrating a magnetometer on a mobile communication device, the method comprising:

applying at least one first test to a new set of calibration parameters;

accepting the new set of calibration parameters as an active set of calibration parameters when the new calibration parameters pass the at least one first test;

applying the active set of calibration parameters to a plurality of magnetometer readings to obtain a plurality of values;

applying at least one second test to the plurality of values; and

calculating a quality measure for the active set of calibration parameters based on an outcome of the at least one second test.

2 . The method according to claim 1 , wherein the at least one first test comprises determining if the new calibration parameters are within predetermined acceptable ranges or limits associated with the magnetometer.

3 . The method according to claim 1 , wherein the at least one second test comprises comparing the plurality of outputs to expected values associated with a location estimate for the mobile device.

4 . The method according to claim 3 , wherein the expected values are obtained from a data model available to the mobile device.

5 . The method according to claim 1 , wherein the a first test is applied to at least one of a gain parameter, an inter-axis misalignment parameter, and a constant bias parameter.

6 . The method according to claim 1 , wherein the at least one second test comprises determining if the outputs are within predetermined acceptable ranges or limits associated with the magnetometer.

7 . The method according to claim 6 , wherein the predetermined acceptable ranges or limits are obtained from data available to the mobile device.

8 . A computer readable storage medium comprising computer executable instructions for calibrating a magnetometer on a mobile communication device, the computer executable instructions comprising instructions for:

applying at least one first test to a new set of calibration parameters;

accepting the new set of calibration parameters as an active set of calibration parameters when the new calibration parameters pass the at least one first test;

applying the active set of calibration parameters to a plurality of magnetometer readings to obtain a plurality of values;

applying at least one second test to the plurality of values; and

calculating a quality measure for the active set of calibration parameters based on an outcome of the at least one second test.

9 . The computer readable storage medium according to claim 8 , wherein the at least one first test comprises determining if the new calibration parameters are within predetermined acceptable ranges or limits associated with the magnetometer.

10 . The computer readable storage medium according to claim 8 , wherein the at least one second test comprises comparing the plurality of outputs to expected values associated with a location estimate for the mobile device.

11 . The computer readable storage medium according to claim 10 , wherein the expected values are obtained from a data model available to the mobile device.

12 . The computer readable storage medium according to claim 8 , wherein the a first test is applied to at least one of a gain parameter, an inter-axis misalignment parameter, and a constant bias parameter.

13 . The computer readable storage medium according to claim 8 , wherein the at least one second test comprises determining if the outputs are within predetermined acceptable ranges or limits associated with the magnetometer.

14 . The method according to claim 13 , wherein the predetermined acceptable ranges or limits are obtained from data available to the mobile device.

15 . A mobile device comprising a processor coupled to a memory, and a magnetometer, the memory comprising computer executable instructions for calibrating the magnetometer, the computer executable instructions comprising instructions for:

applying at least one first test to a new set of calibration parameters;

accepting the new set of calibration parameters as an active set of calibration parameters when the new calibration parameters pass the at least one first test;

applying the active set of calibration parameters to a plurality of magnetometer readings to obtain a plurality of values;

applying at least one second test to the plurality of values; and

calculating a quality measure for the active set of calibration parameters based on an outcome of the at least one second test.

16 . The mobile device according to claim 15 , wherein the at least one first test comprises determining if the new calibration parameters are within predetermined acceptable ranges or limits associated with the magnetometer.

17 . The mobile device according to claim 15 , wherein the at least one second test comprises comparing the plurality of outputs to expected values associated with a location estimate for the mobile device.

18 . The mobile device according to claim 17 , wherein the expected values are obtained from a data model available to the mobile device.

19 . The mobile device according to claim 15 , wherein the a first test is applied to at least one of a gain parameter, an inter-axis misalignment parameter, and a constant bias parameter.

20 . The mobile device according to claim 15 , wherein the at least one second test comprises determining if the outputs are within predetermined acceptable ranges or limits associated with the magnetometer.

21 . The mobile device according to claim 20 , wherein the predetermined acceptable ranges or limits are obtained from data available to the mobile device.