Positioning system and method using GPS with wireless access points

• US 9,513,375 B2
• Filed: 04/28/2015
• Issued: 12/06/2016
• Est. Priority Date: 11/14/2007
• Status: Active Grant

• Current Assignee: Uber Technologies, Inc.
• Original Assignee: IP3, Series 100 of Allied Security Trust I (Allied Security Trust)
• Inventors: Moshfeghi, Mehran
• Primary Examiner(s): GALT, CASSI J
• Application Number:
  US14/698,722
• Publication Number:
  US 20150234051A1
• Time in Patent Office: 588 Days
• US Class Current: 1/1
• CPC Class Codes: G01S 19/072 Ionosphere corrections
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type

Abstract

Embodiments of an improved assisted global positioning system (GPS) method and system are described. Wireless access points send assistance data to GPS receivers that are integrated into cellular chipsets and other chipsets. The access points may also act as fixed location references for differential GPS (DGPS) mobile stations. Errors caused by multipath travel of the GPS signals are reduced by using fixed location reference receivers.

Claims

1. A method of determining a position of a mobile device using global positioning system (GPS) signals, the method comprising:

receiving, at the mobile device, GPS information from a plurality of GPS satellites;

receiving, at the mobile device, a plurality of GPS differential data from a plurality of access points comprising a first access point and a second access point, the mobile device communicating with the first access point in a first communication protocol and with the second access point in a second different communication protocol, wherein the first communication protocol is for a shorter range communication than the second communication protocol;

computing, at the mobile device, a combined GPS differential data from a weighted average of said plurality of GPS differential data, the weighted average based on communication protocols the mobile device uses to receive GPS differential data from said plurality of access points, wherein GPS differential data received using the first communication protocol that is for the shorter range communication gets a higher weight than GPS differential data received using the second communication protocol;

sending the GPS information received from the plurality of GPS satellites and the combined GPS differential data from the mobile device to an assistance server;

computing, at the assistance server, a distance from the mobile device to each of the plurality of GPS satellites based on the GPS information received from the plurality of GPS satellites;

compensating, at the assistance server, an error in the computed distance from the mobile device to at least one satellite of the plurality of satellites using said combined GPS differential data;

computing, at the assistance server, the position of the mobile device based on said distance from the mobile device to each of the plurality of satellites; and

sending the computed position of the mobile device from the assistance server to the mobile device.

2. The method of claim 1, further comprising sending the position of the mobile device from the assistance server to an emergency service provider.

3. The method of claim 1, further comprising displaying, at the mobile device, the computed position of the mobile device.

4. The method of claim 1, further comprising sending the position of the mobile device from the mobile device to an emergency service provider.

5. The method of claim 1, wherein the first access point communicates with the mobile device through one of a wireless local area network (WLAN), an 802.11x network, a WiMax network, a Bluetooth network, a RFID network, a ZigBee network, and a UWB network, wherein the second access point communicates with the mobile device through a different one of said wireless local area network (WLAN), said 802.11x network, said WiMax network, said Bluetooth network, said RFID network, said ZigBee network, and said UWB network.

6. The method of claim 1, wherein said error is due to multipath interference, wherein the multipath interference is caused by reflections of signals transmitted by satellites on objects near the mobile device and the plurality of access points.

7. The method of claim 1, wherein the GPS differential data is further for reducing errors due to at least one of (i) variations in a speed of radio waves travelling through the earth'"'"'s atmosphere and (ii) errors due to satellite clock inaccuracies.

8. The method of claim 1 further comprising:

receiving, at the mobile device, the computed position based on the distance from the mobile device to each of the plurality of satellites from the assistance server;

receiving, at the mobile device, a plurality of time of arrival information from said plurality of access points;

computing, at the mobile device, the position of the mobile device using triangulation of said plurality of time of arrival information; and

combining, at the mobile device, the computed position based on the distance from the mobile device to each of the plurality of satellites with the position computed based on the triangulation of the plurality of time of arrival information to compensate for effects of multipath interference.

9. The method of claim 1 further comprising:

receiving, at the mobile device, the computed position based on the distance from the mobile device to each of the plurality of satellites from the assistance server;

receiving, at the mobile device, a plurality of phase information from said plurality of access points;

computing, at the mobile device, the position of the mobile device using triangulation of said plurality of phase information; and

combining, at the mobile device, the computed position based on the distance from the mobile device to each of the plurality of satellites with the position computed based on the triangulation of the plurality of phase information to compensate for effects of multipath interference.

10. The method of claim 1 further comprising:

receiving, at the mobile device, a plurality of assistance data from at least one of said plurality of access points;

computing, at the mobile device, a combined assistance data from said plurality of assistance data; and

sending the combined assistance data from the mobile device to the assistance server,

wherein computing the position of the mobile device further comprises using said combined assistance data.

11. The method of claim 10, wherein computing the position of the mobile device further comprises computing said position based on the GPS information having a first weight and the combined assistance data having a second weight.

12. The method of claim 10, wherein the GPS information includes a final position, velocity, and time solution, wherein computing the position of the mobile device further comprises computing said position based on said final position, velocity and time solution having a first weight and said combined assistance data having a second weight.

13. The method of claim 10, wherein the GPS information includes raw GPS measurements, wherein computing the position of the mobile device further comprises computing said position based on said raw GPS measurements having a first weight and said combined assistance data having a second weight.

14. The method of claim 10, wherein the combined assistance data includes a final position, velocity, and time solution, wherein computing the position of the mobile device further comprises computing said position based on said final position, velocity, and time solution having a first weight and said GPS information having a second weight.

15. The method of claim 10, wherein the combined assistance data includes raw navigation measurements, wherein computing the position of the mobile device further comprises computing said position based on said raw navigation measurements having a first weight and said GPS information having a second weight.

16. The method of claim 10, wherein the combined assistance data includes in-phase and quadrature symbols, wherein computing the position of the mobile device further comprises computing said position based on said in-phase and quadrature symbols having a first weight and said GPS information having a second weight.

17. A system for performing position determination using global positioning system (GPS) signals, the system comprising:

a plurality of access points comprising a first access point and a second access point;

an assistance server; and

a mobile device communicatively coupled to the assistance server, the mobile device comprising;

a GPS receiver configured to receive GPS information from a plurality of GPS satellites;

a wireless communication module, communicatively coupled to said GPS receiver, the wireless communication module configured to receive a plurality of GPS differential data from the plurality of access points, the wireless communication module configured to communicate with the first access point in a first communication protocol and communicate with the second access point in a second different communication protocol, wherein the first communication protocol is for a shorter range communication than the second communication protocol; and

a processor, communicatively coupled to said wireless communication module and said GPS receiver, the processor configured to compute a combined GPS differential data from a weighted average of said plurality of GPS differential data, the weighted average based on communication protocols the mobile device uses to receive GPS differential data from said plurality of access points, wherein GPS differential data received using the first communication protocol that is for the shorter range communication gets a higher weight than GPS differential data received using the second communication protocol;

the wireless communication module further configured to send the GPS information received from the plurality of GPS satellites and the combined GPS differential data from the mobile device to the assistance server;

the assistance server configured to;

compute a distance from the mobile device to each of said plurality of GPS satellites based on the GPS information received from the plurality of GPS satellites;

compensate an error in the computed distance from the mobile device to at least one satellite of the plurality of satellites using said combined GPS differential data;

compute a position of the mobile device based on said distance from the mobile device to each of the plurality of satellites; and

sending the computed position of the mobile device to the mobile device.

18. The system of claim 17, the assistance server further configured to send the position of the mobile device to an emergency service provider.

19. The system of claim 17, the mobile device further configured to display the computed position of the mobile device at the mobile device.

20. The system of claim 17, the mobile device further configured to send the position of the mobile device to an emergency service provider.

21. The system of claim 17, wherein the first access point communicates with the mobile device through one of a wireless local area network (WLAN), an 802.11x network, a WiMax network, a Bluetooth network, a RFID network, a ZigBee network, and a UWB network, wherein the second access point communicates with the mobile device through a different one of said wireless local area network (WLAN), said 802.11x network, said WiMax network, said Bluetooth network, said RFID network, said ZigBee network, and said UWB network.

22. The system of claim 17, wherein said error is due to multipath interference, wherein the multipath interference is caused by reflections of signals transmitted by satellites on objects near the mobile device and the plurality of access points.

23. The system of claim 17, wherein the GPS differential data is further for reducing errors due to at least one of (i) variations in a speed of radio waves travelling through the earth'"'"'s atmosphere and (ii) errors due to satellite clock inaccuracies.

24. The system of claim 17, the mobile device further configured to:

receive the computed position based on the distance from the mobile device to each of the plurality of satellites from the assistance server;

receive a plurality of time of arrival information from said plurality of access points;

compute the position of the mobile device using triangulation of said plurality of time of arrival information; and

combine the computed position based on the distance from the mobile device to each of the plurality of satellites with the position computed based on the triangulation of the plurality of time of arrival information to compensate for effects of multipath interference.

25. The system of claim 17, the mobile device further configured to:

receive the computed position based on the distance from the mobile device to each of the plurality of satellites from the assistance server;

receive a plurality of phase information from said plurality of access points;

compute the position of the mobile device using triangulation of said plurality of phase information; and

combine the computed position based on the distance from the mobile device to each of the plurality of satellites with the position computed based on the triangulation of the plurality of phase information to compensate for effects of multipath interference.

26. The system of claim 17, the mobile device further configured to:

receive a plurality of assistance data from at least one of said plurality of access points;

compute a combined assistance data from said plurality of assistance data; and

send the combined assistance data from the mobile device to the assistance server,

wherein computing the position of the mobile device further comprises using said combined assistance data.

27. The system of claim 26, wherein computing the position of the mobile device further comprises computing said position based on the GPS information having a first weight and the combined assistance data having a second weight.

28. The system of claim 26, wherein the GPS information includes a final position, velocity, and time solution, wherein computing the position of the mobile device further comprises computing said position based on said final position, velocity and time solution having a first weight and said combined assistance data having a second weight.

29. The system of claim 26, wherein the GPS information includes raw GPS measurements, wherein computing the position of the mobile device further comprises computing said position based on said raw GPS measurements having a first weight and said combined assistance data having a second weight.

30. The system of claim 26, wherein the combined assistance data includes a final position, velocity, and time solution, wherein computing the position of the mobile device further comprises computing said position based on said final position, velocity, and time solution having a first weight and said GPS information having a second weight.

31. The system of claim 26, wherein the combined assistance data includes raw navigation measurements, wherein computing the position of the mobile device further comprises computing said position based on said raw navigation measurements having a first weight and said GPS information having a second weight.

32. The system of claim 26, wherein the combined assistance data includes in-phase and quadrature symbols, wherein computing the position of the mobile device further comprises computing said position based on said in-phase and quadrature symbols having a first weight and said GPS information having a second weight.