METHODS AND DEVICES FOR DETERMINING ORIENTATION

• US 20130245982A1
• Filed: 03/15/2012
• Published: 09/19/2013
• Est. Priority Date: 03/15/2012
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: ALMALKI, Nazih, BUCHANAN, Nathan Daniel Pozniak
• Granted Patent: US 9,279,680 B2
• Time in Patent Office: Days
• US Class Current: 702/93
• CPC Class Codes: G01C 19/00 Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices

Abstract

Methods and electronic devices for determining orientation are described. In one aspect, the present disclosure provides a processor-implemented method of determining a corrected orientation of a gyroscope on an electronic device. The method includes: obtaining a gyroscope reading; determining a first orientation estimate based on the gyroscope reading and a past corrected orientation; determining whether the gyroscope was saturated when the gyroscope reading was obtained; adjusting a saturation correction learning rate for the gyroscope based on the result of the determination of whether the gyroscope was saturated; and determining a corrected orientation based on the first orientation estimate, a second orientation estimate and the saturation correction learning rate.

Claims

1. A processor-implemented method of determining a corrected orientation of a gyroscope on an electronic device, the method comprising:

obtaining a gyroscope reading;

determining a first orientation estimate based on the gyroscope reading and a past corrected orientation;

determining whether the gyroscope was saturated when the gyroscope reading was obtained;

adjusting a saturation correction learning rate for the gyroscope based on the result of the determination of whether the gyroscope was saturated; and

determining a corrected orientation based on the first orientation estimate, a second orientation estimate and the saturation correction learning rate.

2. The method of claim 1, wherein adjusting a saturation correction learning rate for the gyroscope based on the result of the determination of whether the gyroscope was saturated comprises:

increasing the saturation correction learning rate for the gyroscope if the gyroscope was saturated.

3. The method of claim 1, further comprising:

determining the second orientation estimate based on an accelerometer reading and a magnetometer reading,

and wherein determining a corrected orientation based on the first orientation estimate, a second orientation estimate and the saturation correction learning rate comprises determining the corrected orientation by balancing a relative importance of the second orientation estimate and the first orientation estimate using the saturation correction learning rate.

4. The method of claim 3, further comprising:

determining an orientation error as the difference between the first orientation estimate and the second orientation estimate;

determining a saturation correction adjustment amount based on the orientation error and the saturation correction learning rate,

and wherein balancing a relative importance of the second orientation estimate and the first orientation estimate using the saturation correction learning rate comprises;

determining the corrected orientation based on the saturation correction adjustment amount and the first orientation estimate.

5. The method of claim 1, further comprising:

obtaining a second gyroscope reading;

determining whether the gyroscope was saturated when the second gyroscope reading was obtained; and

further adjusting the saturation correction learning rate for the gyroscope based on the result of the determination of whether the gyroscope was saturated when the second gyroscope reading was obtained.

6. The method of claim 5, wherein adjusting a saturation correction learning rate for the gyroscope based on the result of the determination of whether the gyroscope was saturated comprises:

increasing the saturation correction learning rate for the gyroscope if the gyroscope was saturated,

and wherein further adjusting the saturation correction learning rate comprises;

further increasing the saturation correction learning rate for the gyroscope if the gyroscope was saturated during the second gyroscope reading.

7. The method of claim 1, wherein adjusting a saturation correction learning rate for the gyroscope based on the result of the determination of whether the gyroscope was saturated comprises:

decreasing the saturation correction learning rate for the gyroscope if the gyroscope was not saturated.

8. The method of claim 1 wherein the determined saturation correction learning rate is related to the duration of a period of saturation.

9. The method of claim 1 wherein determining whether the gyroscope was saturated when the gyroscope reading was obtained comprises:

retrieving, from memory, a gyroscope saturation value; and

comparing the gyroscope reading to the gyroscope saturation value.

10. The method of claim 9, further comprising:

determining if the gyroscope reading exceeds the gyroscope saturation value; and

when the gyroscope reading exceeds the gyroscope saturation value, replacing the gyroscope saturation value with the gyroscope reading.

11. The method of claim 1, wherein the saturation correction learning rate controls a rate of correction for the first orientation estimate.

12. The method of claim 3, wherein the saturation correction learning rate balances the relative importance of the first orientation estimate and the second orientation estimate when determining the corrected orientation.

13. An electronic device comprising:

a memory;

a gyroscope;

a processor coupled to the memory and the gyroscope, the processor being configured to determine a corrected orientation of the gyroscope by;

obtaining a gyroscope reading;

determining a first orientation estimate based on the gyroscope reading and a past corrected orientation;

determining whether the gyroscope was saturated when the gyroscope reading was obtained;

adjusting a saturation correction learning rate for the gyroscope based on the result of the determination of whether the gyroscope was saturated; and

determining a corrected orientation based on the first orientation estimate, a second orientation estimate and the saturation correction learning rate.

14. The electronic device of claim 13, wherein adjusting a saturation correction learning rate for the gyroscope based on the result of the determination of whether the gyroscope was saturated comprises:

increasing the saturation correction learning rate for the gyroscope if the gyroscope was saturated.

15. The electronic device of claim 13, wherein the processor is further configured to:

determine the second orientation estimate based on an accelerometer reading and a magnetometer reading,

and wherein determining a corrected orientation based on the first orientation estimate, a second orientation estimate and the saturation correction learning rate comprises determining the corrected orientation by balancing a relative importance of the second orientation estimate and the first orientation estimate using the saturation correction learning rate.

16. The electronic device of claim 15, wherein the processor is further configured to:

determine an orientation error as the difference between the first orientation estimate and the second orientation estimate;

determine a saturation correction adjustment amount based on the orientation error and the saturation correction learning rate,

and wherein balancing a relative importance of the second orientation estimate and the first orientation estimate using the saturation correction learning rate comprises;

determining the corrected orientation based on the saturation correction adjustment amount and the first orientation estimate.

17. The electronic device of claim 13, wherein the processor is further configured to:

obtain a second gyroscope reading;

determine whether the gyroscope was saturated when the second gyroscope reading was obtained; and

further adjust the saturation correction learning rate for the gyroscope based on the result of the determination of whether the gyroscope was saturated when the second gyroscope reading was obtained.

18. The electronic device of claim 17, wherein adjusting a saturation correction learning rate for the gyroscope based on the result of the determination of whether the gyroscope was saturated comprises:

increasing the saturation correction learning rate for the gyroscope if the gyroscope was saturated,

and wherein further adjusting the saturation correction learning rate comprises;

further increasing the saturation correction learning rate for the gyroscope if the gyroscope was saturated during the second gyroscope reading.

19. The electronic device of claim 13, wherein adjusting a saturation correction learning rate for the gyroscope based on the result of the determination of whether the gyroscope was saturated comprises:

decreasing the saturation correction learning rate for the gyroscope if the gyroscope was not saturated.

20. A computer readable storage medium comprising computer-executable instructions for determining a corrected orientation for a gyroscope by:

obtaining a gyroscope reading;

determining a first orientation estimate based on the gyroscope reading and a past corrected orientation;

determining whether the gyroscope was saturated when the gyroscope reading was obtained;

adjusting a saturation correction learning rate for the gyroscope based on the result of the determination of whether the gyroscope was saturated; and

determining a corrected orientation based on the first orientation estimate, a second orientation estimate and the saturation correction learning rate.