Method and apparatus of obtaining improved location accuracy using magnetic field mapping

• US 20070150195A1
• Filed: 12/22/2005
• Published: 06/28/2007
• Est. Priority Date: 12/22/2005
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola Solutions, Inc.
• Inventors: Swope, Charles, Koskan, Patrick
• Granted Patent: US 8,296,058 B2
• Time in Patent Office: Days
• US Class Current: 701/221
• CPC Class Codes: G01C 21/1654 with electromagnetic compass

Abstract

Method and apparatus of increasing location accuracy of an inertial navigational device is described. The inertial navigation device generates real-time data and transmits the real-time data to a second device so that the second device may obtain a location of the inertial navigational device. The inertial navigational device receives an update message from the second device, wherein the update message is created at the second device based on a comparison of the real-time data generated by the inertial navigational device against a magnetic field database and adjusts the depicted location of the inertial navigational device based on the update message in order to increase the location accuracy of the inertial navigational device.

Claims

1. A method of increasing location accuracy in an inertial navigational device comprising the steps of:

generating real-time data to depict a location of the inertial navigational device, wherein the real-time data comprises at least one of sensor data, motion data, and location data;

transmitting the real-time data generated by the inertial navigational device to a second device;

receiving an update message at the inertial navigational device from the second device, wherein the update message is created at the second device based on a comparison of the real-time data generated by the inertial navigational device against a magnetic field database; and

adjusting the depicted location of the inertial navigational device based on the update message in order to increase the location accuracy of the inertial navigational device.

2. The method of claim 1, wherein the magnetic field database is generated by:

creating at least one magnetic field disturbance map corresponding to at least one predefined area; and

updating the magnetic field database based on the at least one magnetic field disturbance map,

wherein the magnetic field database reflects variations in the magnetic field of the at least one predefined area.

3. The method of claim 2, wherein the magnetic field disturbance map is a dimensional model of the at least one predefined area.

4. The method of claim 3 further comprising:

displaying the dimensional model of the at least one predefined area on a graphical user interface, wherein the at least one predefined area is associated with the inertial navigational device;

correlating the depicted location of the inertial navigational device with the magnetic field disturbance map corresponding to the at least one predefined area; and

providing an indicator of the adjusted depicted location of the inertial navigational device on the dimensional model of the graphical user interface.

5. The method of claim 1, wherein the magnetic field database is predetermined.

6. The method of claim 1, wherein the comparison further comprises calculating an error vector based upon interpolating heading inaccuracies from the real-time data and the magnetic field database.

7. The method of claim 1, wherein the depicted location is displayed in three dimensions.

8. A device comprising

a transceiver,

a processor operatively coupled to the transceiver and adapted for:

obtaining real-time data corresponding to a depicted location of an inertial navigational device from the inertial navigational device, wherein the real-time data comprises at least one of sensor data, motion data, and location data;

comparing the real-time data against a magnetic field database; and

in response to comparing, adjusting the depicted location of the inertial navigational device to increase location accuracy of the inertial navigational device.

9. The device of claim 8, wherein the transceiver is in communication with the inertial navigational device to generate the magnetic field database, wherein the magnetic field database reflects variations in the magnetic field of at least one predefined area.

10. The device of claim 9, wherein the magnetic field database further comprises a magnetic field disturbance map that is a dimensional model of the at least one predefined area.

11. The device of claim 10 wherein the processor is further adapted for:

displaying the dimensional model of the at least one predefined area on a graphical user interface, the at least one predefined area being associated with the inertial navigational device;

correlating the depicted location of the inertial navigational device with the magnetic field disturbance map corresponding to the at least one predefined area; and

providing an indicator of an accurate location of the inertial navigational device in relation to the dimensional model.

12. The device of claim 8, wherein the depicted location is displayed in three dimensions.

13. The device of claim 8, wherein the device is enabled for processing the magnetic field database.

14. The device of claim 8 is one of a personal computer, personal digital assistant and a laptop.

15. A method of increasing location accuracy of an inertial navigational device comprising the steps of:

receiving real-time data to obtain a depicted location of the inertial navigational device from the inertial navigational device, wherein the real-time data comprises at least one of sensor data, motion data, and location data;

comparing the real-time data against a magnetic field database, wherein the magnetic field database comprises at least one magnetic field disturbance map corresponding to a predefined area; and

adjusting the depicted location of the inertial navigational device by calculating an error vector based upon interpolating heading inaccuracies from the real-time data and the magnetic field database.

16. The method of claim 15, further comprising

displaying a dimensional model of the at least one predefined area on a graphical user interface, the at least one predefined area being associated with the inertial navigational device;

correlating the depicted location of the inertial navigational device with the magnetic field disturbance map corresponding to the at least one predefined area; and

providing an indicator of an accurate location of the inertial navigational device in relation to the dimensional model.

17. The method of claim 16, wherein the correlation can be performed using an algorithm.

18. The method of claim 15, wherein the magnetic field database is updated at predetermined intervals.

19. The method of claim 18, wherein the magnetic field database is available off-line.

20. The method of claim 15, wherein the magnetic field disturbance map comprises a dimensional model of the at least one predefined area.