Positioning With Wireless Local Area Networks And WLAN-Aided Global Positioning Systems

• US 20150304811A1
• Filed: 06/30/2015
• Published: 10/22/2015
• Est. Priority Date: 02/14/2003
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Wang, Yi-Hsiu
• Granted Patent: US 9,571,963 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data
• CPC Class Codes: G01S 19/252 Employing an initial estimate of location in generating assistance data
• CPC Class Codes: G01S 19/28 Satellite selection
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/48 by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04B 7/1851 Systems using a satellite or space-based relay H04B7/18508, H04B7/18521 take precedence; providing specific services H04B7/18523 - H04B7/18576
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

Accurate position capability can be quickly provided using a Wireless Local Area Network (WLAN). When associated with a WLAN, a wireless device can quickly determine its relative and/or coordinate position based on information provided by an access point in the WLAN. Before a wireless device disassociates with the access point, the WLAN can periodically provide time, location, and decoded GPS data to the wireless device. In this manner, the wireless device can significantly reduce the time to acquire the necessary GPS satellite data (i.e. on the order of seconds instead of minutes) to determine its coordinate position.

Claims

1. A method comprising:

determining a location of a wireless device in a communications system based on location information received from one or more access points, wherein the location information includes a position associated with at least one of the one or more access points; and

acquiring a satellite positioning system signal at the wireless device based at least in part on the determined location.

2. The method of claim 1, further including providing the location information from a server of the communications system to the at least one of the one or more access points.

3. The method of claim 1, further including using the acquired satellite positioning system signal to generate a modified location of the wireless device.

4. The method of claim 1, further including periodically receiving the location information from the one or more access points with the wireless device.

5. The method of claim 1, wherein the location information further includes a current time and GPS almanac data.

6. The method of claim 1, further including identifying a first satellite having a highest elevation angle with respect to the wireless device based on the received location information.

7. The method of claim 6, further comprising acquiring the satellite positioning system signal from the first satellite.

8. The method of claim 7, further including using multiple correlators of the wireless device in parallel to acquire the satellite positioning system signal from the first satellite, wherein the multiple correlators have different time and/or frequency offsets.

9. The method of claim 7, further including using multiple pairs of correlators of the wireless device in parallel to acquire the satellite positioning system signal from the first satellite, wherein each pair of correlators includes an in-phase correlator and a quadrature-phase correlator.

10. The method of claim 7, further comprising:

determining a time offset and a frequency offset associated with the satellite positioning system signal acquired from the first satellite; and

using the time offset and the frequency offset to derive time offsets and frequency offsets of other satellites.

11. The method of claim 7, further comprising determining a frequency offset associated with the satellite positioning signal acquired from the first satellite by:

approximating a Doppler effect of the first satellite to be zero; and

specifying the frequency offset as a difference between an oscillator frequency of the first satellite and a receiver frequency of the wireless device.

12. The method of claim 6, wherein identifying the first satellite is further based on a current time.

13. A wireless device comprising:

a wireless local area network (WLAN) baseband for communicating with one or more access points, wherein the WLAN baseband is configured to receive location information from at least one of the one or more access points, and determine a location of the wireless device based on the location information; and

a global positioning system (GPS) baseband configured to acquire a satellite positioning system signal based on the determined location of the wireless device.

14. The wireless device of claim 13, wherein the GPS baseband is configured to generate a modified location of the wireless device using the acquired satellite positioning system signal.

15. The wireless device of claim 13, further including means for identifying a first satellite having a highest elevation angle with respect to the wireless device based on the received location information.

16. The wireless device of claim 15, wherein the GPS baseband is configured to acquire the satellite positioning system signal from the first satellite.

17. The wireless device of claim 16, further comprising multiple correlators configured to operate in parallel to acquire the satellite positioning system signal from the first satellite, wherein the multiple correlators have different time and/or frequency offsets.

18. The wireless device of claim 16, further comprising multiple pairs of correlators configured to operate in parallel to acquire the satellite positioning system signal from the first satellite, wherein each pair of correlators includes an in-phase correlator and a quadrature-phase correlator.

19. The wireless device of claim 16, wherein the GPS baseband is configured to determine a time offset and a frequency offset associated with the satellite positioning system signal acquired from the first satellite, and use the time offset and the frequency offset to derive time offsets and frequency offsets of other satellites.

20. The wireless device of claim 16, wherein the GPS baseband is configured to determine a frequency offset associated with the satellite positioning signal acquired from the first satellite by:

approximating a Doppler effect of the first satellite to be zero, and specifying the frequency offset as a difference between an oscillator frequency of the first satellite and a receiver frequency of the wireless device.

21. The wireless device of claim 13, further comprising a radio frequency (RF) front end, wherein the WLAN baseband and the GPS baseband share the RF front end.

22. The wireless device of claim 21, wherein the RF front end comprises an antenna shared by the WLAN baseband and the GPS baseband.

23. The wireless device of claim 21, wherein the RF front end comprises a frequency synthesizer that is programmable to provide difference frequencies for operating the WLAN baseband and the GPS baseband.

24. A wireless device comprising:

means for determining a location of a wireless device in a communications system based on location information received from one or more access points, wherein the location information includes a position associated with at least one of the one or more access points; and

means for acquiring a satellite positioning system signal at the wireless device based at least in part on the determined location.

25. The wireless device of claim 24, further including means for using the acquired satellite positioning system signal to generate a modified location of the wireless device.

26. The wireless device of claim 24, further including means for storing the location information for use by the wireless device.

27. The wireless device of claim 24, further including means for periodically receiving the location information from the one or more access points.

28. The wireless device of claim 24, further including means for identifying a first satellite having a highest elevation angle with respect to the wireless device based on the received location information.

29. The wireless device of claim 28, wherein the means for acquiring the satellite positioning system signal includes means for acquiring the satellite positioning system signal from the first satellite.

30. The wireless device of claim 28, further including multiple correlators configured to operate in parallel to acquire the satellite positioning system signal from the first satellite, wherein the multiple correlators have different time and/or frequency offsets.

31. The wireless device of claim 28, further including multiple pairs of correlators configured to operate in parallel to acquire the satellite positioning system signal from the first satellite, wherein each pair of correlators includes an in-phase correlator and a quadrature-phase correlator.

32. The wireless device of claim 28, further including:

means for determining a time offset and a frequency offset associated with the satellite positioning system signal acquired from the first satellite; and

means for using the time offset and the frequency offset to derive time offsets and frequency offsets of other satellites.

33. The wireless device of claim 28, further including means for determining a frequency offset associated with the satellite positioning signal acquired from the first satellite by:

approximating a Doppler effect of the first satellite to be zero, and specifying the frequency offset as a difference between an oscillator frequency of the first satellite and a receiver frequency of the wireless device.