AUTOMATICALLY IDENTIFYING GEOGRAPHIC DIRECTION

• US 20100312519A1
• Filed: 06/03/2009
• Published: 12/09/2010
• Est. Priority Date: 06/03/2009
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Piemonte, Patrick, Huang, Ronald Keryuan
• Granted Patent: US 8,898,034 B2
• Time in Patent Office: Days
• US Class Current: 702/150
• CPC Class Codes: G01C 17/28 Electromagnetic compasses with north seeking magnetic elements and having electric pick-offs G01C17/26
• CPC Class Codes: G01C 17/38 Testing, calibrating, or compensating of compasses

Abstract

Automatically identifying a geographic direction (e.g., a heading relative to true north) is disclosed. Responsive to a correction trigger event, geographic position data that identifies a geographic position of the device can be obtained. A magnetic declination based on the geographic position data can be obtained. A magnetic heading of the device can be obtained. A geographic direction based on the magnetic heading and the magnetic declination can be identified without user intervention.

Claims

1. A device comprising:

one or more processors;

memory coupled to the one or more processors and storing instructions which, when executed by the one or more processors, cause the one or more processors to perform operations comprising;

obtaining geographic position data that identifies a geographic position of the device;

identifying a magnetic declination based on the geographic position data;

obtaining a magnetic heading of the device; and

identifying, without user intervention, a geographic direction based on the magnetic heading and the magnetic declination.

2. The device of claim 1, further comprising a magnetometer, where the magnetic heading is obtained based on measurements made by the magnetometer.

3. The device of claim 1, where identifying the magnetic declination includes:

identifying from declination data, a magnitude of a first magnetic declination that corresponds to the geographic position.

4. The device of claim 3, where the declination data is stored in the memory.

5. The device of claim 4, where the declination data is represented in a geomagnetic model.

6. The device of claim 3, where the declination data is periodically updated, without user intervention.

7. The device of claim 3, further comprising instructions which cause the one or more processors to perform operations including:

obtaining temporal data that is related to the geographic position data and identifies a time, and where the magnitude of magnetic declination also corresponds to the time in the declination data.

8. The device of claim 1, where the device further comprises:

an accelerometer that detects a velocity of the device;

where identifying the magnetic declination and identifying, without user intervention, the geographic direction, occur periodically based on an average velocity.

9. A computer-implemented method, comprising:

obtaining geographic position data that identifies a geographic position of the device;

identifying a magnetic declination based on the geographic position data;

obtaining a magnetic heading of the device; and

identifying, without user intervention, a geographic direction based on the magnetic heading and the magnetic declination.

10. The method of claim 9, further comprising:

presenting a representation of the geographic direction in a user interface.

11. The method of claim 10, where the representation of the geographic direction includes content that identifies a physical location.

12. A computer-implemented method, comprising:

obtaining a geographic position of a device;

identifying magnetic north at the geographic position of the device;

identifying a magnetic declination based on the geographic position; and

identifying, without user intervention, true north based on a combination of magnetic north and the magnetic declination.

13. A computer-implemented method, comprising:

obtaining geographic position data that identifies a geographic position of a device;

identifying a magnetic declination based on the geographic position data; and

without user intervention;

obtaining a magnetic heading of the device, and

identifying a geographic direction based on the magnetic heading and the magnetic declination.

14. The method of claim 13, where the magnetic heading is obtained based on measurements made by a compass.

15. The method of claim 13, where the magnetic heading is obtained based on measurements made by a magnetometer.

16. The method of claim 13, where identifying the magnetic declination includes:

identifying from declination data, a magnitude of a first magnetic declination that corresponds to the geographic position.

17. The method of claim 16, where the declination data is stored in the memory.

18. The method of claim 17, where the declination data is represented in a geomagnetic model.

19. The method of claim 16, where the declination data is periodically updated, without user intervention.

20. The method of claim 16, further comprising instructions which cause the one or more processors to perform operations including:

obtaining temporal data that is related to the geographic position data and identifies a time, and where the magnitude of magnetic declination also corresponds to the time in the declination data.

21. The method of claim 13, where identifying the magnetic declination and identifying, without user intervention, the geographic direction, occur periodically based on an average velocity.