Method for correcting orientation of magnetometer

• US 9,702,957 B2
• Filed: 07/22/2013
• Issued: 07/11/2017
• Est. Priority Date: 07/25/2012
• Status: Active Grant

• Current Assignee: Huawei Device Company Limited (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Peng, Xu, Liu, Tian
• Primary Examiner(s): Lee, Paul D
• Application Number:
  US13/947,886
• Publication Number:
  US 20140032154A1
• Time in Patent Office: 1,450 Days
• Field of Search: 702104
• CPC Class Codes: G01C 17/38 Testing, calibrating, or compensating of compasses
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments
• CPC Class Codes: G01R 33/0035 Calibration of single magnetic sensors, e.g. integrated calibration
• CPC Class Codes: G01R 35/005 Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references G01R33/0035, G01R35/002 take precedence

Abstract

A method for correcting an orientation of a magnetometer includes obtaining current position information through a global positioning system. A geomagnetic inclination angle list is queried according to the current position information to acquire a geomagnetic inclination angle δ corresponding to a current position. A deviation Δψ of an orientation is calculated according to the geomagnetic inclination angle δ and the orientation is corrected based on the deviation Δψ of the orientation.

Claims

1. A method, comprising:

measuring an orientation of a device by a magnetometer, the orientation being an angle between the magnetic north direction and a component of a magnetic vector measured by the magnetometer, wherein the component of the magnetic vector is on a horizontal surface determined by acceleration of gravity;

determining, by the magnetometer, a current position of the device through a global positioning system, wherein current position information corresponding to the current position is obtained by the magnetometer;

querying, by the magnetometer, a geomagnetic inclination angle list according to the current position information to acquire a geomagnetic inclination angle corresponding to the current position;

calculating, by the magnetometer, a deviation of the measured orientation according to the geomagnetic inclination angle;

correcting the measured orientation based on the calculated deviation of the measured orientation; and

providing a corrected orientation of the device according to the corrected measured orientation.

2. The method according to claim 1, further comprising:

obtaining the geomagnetic inclination angle list from a server before determining the current position of the device, wherein the server updates the geomagnetic inclination angle list in real time.

3. The method according to claim 1, wherein determining the current position of the device through the global positioning system comprises periodically determining the current position of the device through the global positioning system upon a trigger.

4. The method according to claim 1, further comprising:

determining whether the measured orientation of the device needs to be corrected by comparing the current position information with existing position information corresponding to a previous position of the device;

wherein the measured orientation is corrected based on a calculated deviation of the measured orientation when a difference between the current position information and the existing position information exceeds a preset range; and

wherein the measured orientation is not corrected when the difference between the current position information and the existing position information does not exceed the preset range.

5. A magnetometer, comprising:

a processor; and

a non-transitory computer readable storage medium storing programming for execution by the processor, wherein the programming includes instructions to;

measure an orientation of a device, the orientation being an angle between the magnetic north direction and a component of a magnetic vector of the magnetometer, wherein the component of the magnetic vector is on a horizontal surface determined by acceleration of gravity;

determine a current position of the device through a global positioning system, wherein current position information corresponding to the current position is obtained by the magnetometer;

query a geomagnetic inclination angle list according to the current position information to acquire a geomagnetic inclination angle corresponding to the current position;

calculate a deviation of the measured orientation according to the geomagnetic inclination angle;

adjust the measured orientation based on the calculated deviation of the measured orientation; and

provide an adjusted orientation of the device according to the adjusted measured orientation.

6. The magnetometer according to claim 5, wherein the programming comprises further instructions to obtain the geomagnetic inclination angle list from a server before determining the current position of the device, wherein the server updates the geomagnetic inclination angle list in real time.

7. The magnetometer according to claim 5, wherein the current position of the device is determined periodically upon a trigger.

8. The magnetometer according to claim 5, wherein the programming comprises further instructions to determine whether the measured orientation of the device needs to be corrected by comparing the current position information with existing position information corresponding to a previous position of the device, wherein the measured orientation is corrected based on the calculated deviation of the measured orientation when a difference between the current position information and the existing position information exceeds a preset range, and the measured orientation is not corrected when the difference between the current position information and the existing position information does not exceed the preset range.

9. A terminal, comprising a magnetometer, wherein the magnetometer comprises:

a processor; and

a non-transitory computer readable storage medium storing programming for execution by the processor, wherein the programming includes instructions to;

measure an orientation of the terminal, the orientation being an angle between the magnetic north direction and a component of a magnetic vector of the magnetometer, wherein the component of the magnetic vector is on a horizontal surface determined by acceleration of gravity;

determine a current position of the terminal through a global positioning system, wherein current position information of the current position is obtained by the magnetometer;

query a geomagnetic inclination angle list according to the current position information to acquire a geomagnetic inclination angle corresponding to the current position;

calculate a deviation of the measured orientation according to the geomagnetic inclination angle; and

adjust the measured orientation based on the calculated deviation of the measured orientation; and

provide an adjusted orientation of the terminal according to the adjusted measured orientation.

10. The terminal according to claim 9, wherein the programming comprises further instructions to obtain the geomagnetic inclination angle list from a server before determining the current position of the terminal, wherein the server updates the geomagnetic inclination angle list in real time.

11. The terminal according to claim 9, wherein the current position of the terminal is determined periodically upon a trigger.

12. The terminal according to claim 9, wherein the programming comprises further instructions to determine whether the measured orientation of the terminal needs to be corrected by comparing the current position information with existing position information corresponding to a previous position of the terminal, wherein the measured orientation is corrected based on the calculated deviation of the measured orientation when a difference between the current position information and the existing position information exceeds a preset range, and the measured orientation is not corrected when the difference between the current position information and the existing position information does not exceed the preset range.