METHODS AND APPLICATIONS FOR ALTITUDE MEASUREMENT AND FUSION OF USER CONTEXT DETECTION WITH ELEVATION MOTION FOR PERSONAL NAVIGATION SYSTEMS

• US 20110106449A1
• Filed: 10/30/2009
• Published: 05/05/2011
• Est. Priority Date: 10/30/2009
• Status: Active Grant

• Current Assignee: CSR Technology Holdings Inc. (Qualcomm, Inc.)
• Original Assignee: CSR Technology Holdings Inc. (Qualcomm, Inc.)
• Inventors: Jain, Mahaveer, Narula, Gagan, Agarwal, Chinmay, Chowdhary, Mahesh, Kumar, Arun, Paul, Kolin, Sharma, Manish, Pande, Ashutosh
• Granted Patent: US 8,566,032 B2
• Time in Patent Office: Days
• US Class Current: 701/214
• CPC Class Codes: G01C 21/005 with correlation of navigation data from several sources, e.g. map or contour matching G01C21/30 takes precedence
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled

Abstract

Methods and apparatuses for estimating a user'"'"'s altitude with respect to the mean sea level are provided. According to some aspects, the present invention is able to estimate altitude in both open sky as well as in degraded GPS signal environments such as dense urban canyon environments where GPS performance is affected by fewer available satellites and/or multipath error. According to other aspects, the present invention uses data from a pressure sensor to estimate altitude, either with or without the use of GPS aiding data. According to further aspects, estimated altitude is integrated with other types of dead reckoning data to provide user context detection pertaining to changes of altitude.

Claims

1. A method comprising:

receiving information corresponding to a user'"'"'s position in altitude;

automatically determining the user'"'"'s context based on the received information, the context including whether or not the user'"'"'s altitude is changing, and if it is changing, a type of motion associated with the changing altitude.

2. A method according to claim 1, wherein the type of motion includes one of moving at the same altitude, moving on a ramp, stair or escalator, and riding an elevator.

3. A method according to claim 1, wherein the receiving step includes obtaining samples of data from a pressure sensor.

4. A method according to claim 3, wherein the automatically determining step includes filtering the sampled data using windows with a plurality of different numbers of samples.

5. A method according to claim 4, wherein the automatically determining step further includes comparing the outputs of certain of the filters to determine that the person is moving on the same floor.

6. A method according to claim 4, wherein the automatically determining step further includes comparing the outputs of certain of the filters to determine that the person is moving on a ramp, staircase or escalator.

7. A method according to claim 4, wherein the automatically determining step further includes comparing the outputs of certain of the filters to determine that the person is moving on an elevator.

8. A method according to claim 4, further comprising comparing the outputs of certain of the filters to determine that altitude drift correction is needed.

9. A method according to claim 1, wherein the automatically determining step is further based on information about the user'"'"'s acceleration.

10. A method according to claim 3, wherein the step of receiving information further includes receiving additional information from an external source, and using the additional information to adjust the pressure sensor data.

11. A method according to claim 10, wherein the additional information includes approximate altitude based on the user'"'"'s location.

12. A method according to claim 10, wherein the additional information includes atmospheric conditions based on the user'"'"'s location.

13. A method according to claim 10, wherein the additional information includes indoor pressure conditions based on the user'"'"'s location.

14. A method according to claim 10, further comprising:

calibrating the pressure sensor using the additional information.

15. A method according to claim 3, further comprising:

receiving satellite positioning information; and

determining a navigation solution for the user using the received satellite positioning information and the altitude information, the navigation solution including estimated altitude.

16. A method according to claim 15, wherein the step of determining the navigation solution includes supplying the altitude information from the pressure sensor to a Kalman filter.

17. A computing apparatus that implements the method of claim 1.

18. A computing apparatus that implements the method of claim 3.

19. A computing apparatus that implements the method of claim 10.

20. A computing apparatus that implements the method of claim 15.