ALTITUDE CORRECTION OF A NAVIGATIONAL DEVICE

• US 20070093962A1
• Filed: 10/19/2006
• Published: 04/26/2007
• Est. Priority Date: 10/24/2005
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Swope, Charles, Tealdi, Daniel
• Granted Patent: US 7,792,640 B2
• Time in Patent Office: Days
• US Class Current: 701/220
• CPC Class Codes: G01C 21/183 Compensation of inertial measurements, e.g. for temperature effects
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices
• CPC Class Codes: G01C 5/06 by using barometric means

Abstract

A method of altitude correction of an inertial navigational device, the method comprising the steps of: receiving (205) a relative altitude of the inertial navigational device; obtaining (210) a rate of change of the relative altitude of a reference device; and calculating (215) an absolute altitude of the inertial navigational device based on the relative altitude of the inertial navigational device and the rate of change of the relative altitude of the reference device. The invention also provides for a device (505) such as base station, computer or a laptop to enable altitude correction of an inertial navigational device.

Claims

1. A method of altitude correction of an inertial navigational device, the method comprising:

receiving a relative altitude of the inertial navigational device;

obtaining a rate of change of the relative altitude of a reference device; and

calculating an absolute altitude of the inertial navigational device based on the relative altitude of the inertial navigational device and the rate of change of the relative altitude of the reference device.

2. The method of claim 1, wherein the receiving step further comprises:

adjusting the relative altitude of the inertial navigational device by an altitude calibration factor corresponding to the inertial navigational device.

3. The method of claim 1, wherein the obtaining step further comprises:

correlating a relative altitude of the reference device with an absolute altitude of the reference device to obtain the rate of change of the relative altitude of the reference device.

4. The method of claim 3, wherein the absolute altitude of the reference device is obtained from one of a historical database and a global positioning system.

5. The method of claim 3, wherein the relative altitude of the reference device is obtained based on climatic influences at the reference device.

6. The method of claim 1, wherein the absolute altitude of the inertial navigational device is calculated based on a difference between the relative altitude of the inertial navigational device and the rate of change of the relative altitude of the reference device, the rate of change of the relative altitude of the reference device being same as the rate of change of the relative altitude of the inertial navigational device.

7. The method of claim 1, wherein the relative altitude of the inertial navigational device is obtained based on a temperature and a pressure at the inertial navigational device.

8. A device for altitude correction of an inertial navigational device, the device comprising:

a transceiver, and

a processor operatively coupled to the transceiver and adapted for;

receiving a relative altitude of the inertial navigational device; and

obtaining a rate of change of the relative altitude of a reference device; and

calculating an absolute altitude of the inertial navigational device based on the relative altitude of the inertial navigational device and the rate of change of the relative altitude of the reference device.

9. The device of claim 8, wherein the device is adapted for correlating a relative altitude of the reference device with an absolute altitude of the reference device to obtain the rate of change of the relative altitude.

10. The device of claim 9, wherein the absolute altitude of the reference device is obtained from one of a historical database and a global positioning system.

11. The device of claim 8, wherein the relative altitude of the inertial navigational device is adjusted by an altitude calibration factor corresponding to the inertial navigational device.

12. The device of claim 11, wherein the altitude calibration factor is one of an offset and a gain.

13. The device of claim 11, wherein the altitude calibration factor is a real-time adjustment, the real-time adjustment being determined at the device.

14. The device of claim 8, wherein the absolute altitude of the inertial navigational device is sent to the inertial navigational device.

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

16. The device of claim 8, wherein the reference device is located within the device.

17. The device of claim 8, wherein the device is coupled to a display to provide a dimensional model of a predefined area corresponding to the inertial navigational device.

18. A method of altitude correction of an inertial navigational device, the method comprising:

receiving a relative altitude of the inertial navigational device;

correlating a relative altitude of a reference device with an absolute altitude of the reference device to obtain a rate of change of the relative altitude of the reference device;

calculating the absolute altitude of the inertial navigational device based on the relative altitude of the inertial navigational device and rate of change of the relative altitude of the reference device.

19. The method of claim 18, wherein the receiving step further comprises:

adjusting the relative altitude of the inertial navigational device by an altitude calibration factor corresponding to the inertial navigational device.

20. The method of claim 18, wherein the rate of change of the relative altitude of the reference device is calculated at predefined intervals, the rate of change of the relative altitude of the reference device being same as the rate of change of the relative altitude of the inertial navigational device.