Satellite positioning receiver and proxy location system

• US 9,354,323 B2
• Filed: 04/04/2012
• Issued: 05/31/2016
• Est. Priority Date: 12/18/2009
• Status: Active Grant

• Current Assignee: Skyhook Holding, Inc. (Liberty Broadband Corp.)
• Original Assignee: TruePosition Incorporated
• Inventors: Anderson, Robert J., Ward, Matthew L.
• Primary Examiner(s): Adams, Tashiana
• Assistant Examiner(s): Mull, Fred H
• Application Number:
  US13/439,287
• Publication Number:
  US 20120194382A1
• Time in Patent Office: 1,518 Days
• Field of Search: 342/357.25, 342/357.29, 342/357.31, 342/357.74, 4553431-3432, 455/456.1
• US Class Current: 1/1
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type

Abstract

To reduce power consumption in a user terminal, especially mobile devices, a system and method are introduced that use terrestrial beacons as a location proxy when satellite positioning signals are not available. The geographic locations of the terrestrial beacons need not be known to use the beacons as a proxy for a satellite positioning signals derived location.

Claims

1. A mobile device, comprising:

a first receiver, comprising a global navigation satellite system (GNSS) receiver configured to receive GNSS signals and to provide updates of GNSS location measurements over time;

a second receiver configured to receive a terrestrial beacon signal; and

a controller operatively coupled to the GNSS receiver and the second receiver;

wherein the mobile device is configured to detect when GNSS signals are unavailable and, in response thereto, to use a received terrestrial beacon signal to determine whether a previous GNSS location measurement is valid, wherein the mobile device is configured to use the beacon as a proxy for a location derived from satellite positioning signals without knowing the geographic location of the terrestrial beacon;

wherein the mobile device is further configured to perform the following steps;

employing the GNSS receiver to develop a first valid GNSS location including latitude,

longitude, altitude, and timing;

in parallel, employing the second receiver to detect and identify one or more radio beacons in predefined transmission bands;

storing the first valid GNSS location and a first list of beacons locally within the mobile device;

entering the GNSS receiver into a low power sleep mode;

upon determining that the GNSS receiver has failed to produce a valid current GNSS location fix, using the second receiver to produce a current beacon list of detectable, identifiable beacons;

comparing the current beacon list to a prior beacon list associated in time with a last valid GNSS location update; and

upon determining the presence of a limited-range beacon in both the current and prior beacon lists, reusing a previously obtained valid GNSS location as the current location of the device, and determining an error radius based on the type of limited-range beacon in both the current and prior beacon lists; and

wherein the mobile device is further configured to passively use received beacon signals from multiple beacons as a proxy for a high accuracy GNSS location estimate by measuring and comparing the strengths of signals received from neighboring beacons during periodic sampling events.

2. A mobile device as recited in claim 1, wherein the controller is further configured to suspend GNSS searches and to power down the GNSS receiver in response to detecting that GNSS signals are unavailable.

3. A mobile device as recited in claim 1, wherein the mobile device is integrated into a mobile phone.

4. A mobile device as recited in claim 1, wherein the mobile device is integrated into a personal or automobile navigation system.

5. A mobile device as recited in claim 1, wherein the mobile device is integrated into a tag device.

6. A mobile device as recited in claim 1, wherein the mobile device is battery powered.

7. A mobile device as recited in claim 1, wherein the GNSS receiver and second receiver are implemented in a software defined radio (SDR).

8. A mobile device as recited in claim 1, wherein the mobile device is further configured to determine network timing from frames transmitted by the beacon.

9. A mobile device as recited in claim 8, wherein the mobile device is further configured to receive at least one of a pilot channel signal and a synchronization channel signal from the beacon.

10. A mobile device as recited in claim 8, wherein the mobile device is further configured to receive beacon transmissions including at least one of a broadcast control channel of a cellular network and a beacon frame of an IEEE 802.11 network.

11. A mobile device as recited in claim 8, wherein the mobile device is further configured to receive beacon identifiers including at least one of a cell-ID in a CDMA or UMTS cellular network, a cell-global-identifier (CGI) in a GSM cellular network, and a base station identifier in an IEEE 802.11 wireless local area network.

12. A mobile device as recited in claim 1, wherein the mobile device is further configured to perform a process including the following steps, whereby the device resumes GNSS locations after a triggering event:

a GNSS retry triggering event is detected;

the controller uploads the current time, last valid location, and stored almanac and ephemeris data to the GNSS receiver;

the GNSS receiver successfully performs positioning and GNSS generated information is stored and passed to a location-consuming application;

the second receiver scans for detectable, identifiable beacons and reports a list to the controller and then goes into the low power sleep mode; and

the refreshed beacon list and a timestamp are stored.

14. A mobile device as recited in claim 1, wherein the second receiver is implemented in a communications transceiver.

15. A mobile device as recited in claim 14, wherein the mobile device is configured to employ the communications transceiver to retry connecting with a cellular network to gather timing and signal data from multiple beacons.

16. A mobile device as recited in claim 14, wherein the mobile device is configured to employ the communications transceiver to create an active session with a cellular network and to use a failed session initiation to receive additional information from the network that is unavailable on a broadcast beacon.

17. A mobile device as recited in claim 16, wherein the additional information comprises at least one of timing advance (TA), a received signal strength indicator (RSSI), and details on frequencies or identifiers of neighboring beacons.

13. A mobile device, comprising:

a first receiver, comprising a global navigation satellite system (GNSS) receiver configured to receive GNSS signals and to provide updates of GNSS location measurements over time;

a second receiver configured to receive a terrestrial beacon signal; and

a controller operatively coupled to the GNSS receiver and the second receiver;

wherein the mobile device is configured to detect when GNSS signals are unavailable and, in response thereto, to use a received terrestrial beacon signal to determine whether a previous GNSS location measurement is valid, wherein the mobile device is configured to use the beacon as a proxy for a location derived from satellite positioning signals without knowing the geographic location of the terrestrial beacon;

wherein the mobile device is further configured to perform the following steps;

employing the GNSS receiver to develop a first valid GNSS location including latitude,

longitude, altitude, and timing;

in parallel, employing the second receiver to detect and identify one or more radio beacons in predefined transmission bands;

storing the first valid GNSS location and a first list of beacons locally within the mobile device;

entering the GNSS receiver into a low power sleep mode;

upon determining that the GNSS receiver has failed to produce a valid current GNSS location fix, using the second receiver to produce a current beacon list of detectable, identifiable beacons;

comparing the current beacon list to a prior beacon list associated in time with a last valid

GNSS location update; and

upon determining the presence of a limited-range beacon in both the current and prior beacon lists, reusing a previously obtained valid GNSS location as the current location of the device, and determining an error radius based on the type of limited-range beacon in both the current and prior beacon lists; and

wherein the mobile device is further configured to use both the GNSS receiver and the second receiver to collect information from each receiver concurrently, and to make a measurement of the beacon'"'"'s transmit power and to compare the measurement to the beacon'"'"'s transmit power recorded at a previous GNSS location fix, and based on the comparison to detect motion toward or away from the beacon.

18. A method for use in determining the location of a mobile device, comprising:

employing a first receiver, comprising a global navigation satellite system (GNSS) receiver associated with the mobile device, to receive GNSS signals;

employing a second receiver associated with the mobile device to receive a terrestrial beacon signal; and

employing a controller associated with the mobile device to detect when GNSS signals are unavailable and, in response thereto, to use a received terrestrial beacon signal to determine whether a previous GNSS location update is valid, wherein the mobile device is able to use the beacon as a proxy for a location derived from satellite positioning signals without knowing the geographic location of the terrestrial beacon;

wherein the second receiver is employed to acquire network parameters from the terrestrial beacon, said network parameters including at least one of timing advance and round-trip-time; and

wherein the method further comprises performing the following steps;

the GNSS receiver is employed to develop a first valid GNSS location including latitude, longitude, altitude, and timing;

in parallel, the second receiver is employed to detect and identify one or more radio beacons in predefined transmission bands;

the first valid GNSS location and a first list of beacons are stored locally within the mobile device;

the GNSS receiver enters a low power sleep mode until a next required update time;

the second receiver enters a low power sleep mode until the next required update time;

upon determining that the GNSS receiver has failed to produce a valid current GNSS location fix, the second receiver produces a current beacon list of detectable, identifiable beacons;

the current beacon list is compared to a prior beacon list associated in time with the last valid GNSS location update; and

upon determining the presence of a limited-range beacon in both the current and prior beacon lists, the mobile device reuses a previously obtained valid GNSS location;

wherein the geographic location of the terrestrial beacon need not be known to use the beacon as a proxy for a location derived from satellite positioning signals; and

wherein the method further comprises passively using received beacon signals from multiple beacons as a proxy for a high accuracy GNSS location estimate by measuring and comparing the strengths of signals received from neighboring beacons during periodic sampling events.

19. A method as recited in claim 18, further comprising suspending GNSS searches and powering down the GNSS receiver in response to detecting that GNSS signals are unavailable.

20. A method as recited in claim 18, wherein the mobile device is integrated into a mobile phone.

21. A method as recited in claim 18, wherein the mobile device is integrated into a personal or automobile navigation system.

22. A method as recited in claim 18, wherein the mobile device is integrated into a tag device.

23. A method as recited in claim 18, wherein the mobile device is battery powered.

24. A method as recited in claim 18, wherein the GNSS receiver and second receiver are implemented in a software defined radio (SDR).

25. A method as recited in claim 18, wherein the method further comprises determining network timing from frames transmitted by the beacon.

26. A method as recited in claim 25, wherein the method further comprises receiving at least one of a pilot channel signal and a synchronization channel signal from the beacon.

27. A method as recited in claim 25, wherein the method further comprises receiving beacon transmissions including at least one of a broadcast control channel of a cellular network and a beacon frame of an IEEE 802.11 network.

28. A method as recited in claim 25, wherein the method further comprises receiving beacon identifiers including at least one of a cell-ID in a CDMA or UMTS cellular network, a cell-global-identifier (CGI) in a GSM cellular network, and a base station identifier in an IEEE 802.11 wireless local area network.

29. A method as recited in claim 18, wherein the method further comprises performing a process including the following steps, whereby the device resumes GNSS locations after a triggering event:

a GNSS retry triggering event is detected;

the controller uploads the current time, last valid location, and stored almanac and ephemeris data to the GNSS receiver;

the GNSS receiver successfully performs positioning and GNSS generated information is stored and passed to a location-consuming application;

the second receiver scans for detectable, identifiable beacons and reports a list to the controller and then goes into the low power sleep mode; and

the refreshed beacon list and a timestamp are stored.

31. A method as recited in claim 18, wherein the second receiver is implemented in a communications transceiver.

32. A method as recited in claim 31, wherein the method further comprises employing the communications transceiver to retry connecting with a cellular network to gather timing and signal data from multiple beacons.

33. A method as recited in claim 31, wherein the method further comprises employing the communications transceiver to create an active session with a cellular network and to use a failed session initiation to receive additional information from the network that is unavailable on a broadcast beacon.

34. A method as recited in claim 33, wherein the additional information comprises at least one of timing advance (TA), a received signal strength indicator (RSSI), and details on frequencies or identifiers of neighboring beacons.

30. A method for use in determining the location of a mobile device, comprising:

employing a first receiver, comprising a global navigation satellite system (GNSS) receiver associated with the mobile device, to receive GNSS signals;

employing a second receiver associated with the mobile device to receive a terrestrial beacon signal; and

employing a controller associated with the mobile device to detect when GNSS signals are unavailable and, in response thereto, to use a received terrestrial beacon signal to determine whether a previous GNSS location update is valid, wherein the mobile device is able to use the beacon as a proxy for a location derived from satellite positioning signals without knowing the geographic location of the terrestrial beacon;

wherein the second receiver is employed to acquire network parameters from the terrestrial beacon, said network parameters including at least one of timing advance and round-trip-time; and

wherein the method further comprises performing the following steps;

the GNSS receiver is employed to develop a first valid GNSS location including latitude, longitude, altitude, and timing;

in parallel, the second receiver is employed to detect and identify one or more radio beacons in predefined transmission bands;

the first valid GNSS location and a first list of beacons are stored locally within the mobile device;

the GNSS receiver enters a low power sleep mode until a next required update time;

the second receiver enters a low power sleep mode until the next required update time;

upon determining that the GNSS receiver has failed to produce a valid current GNSS location fix, the second receiver produces a current beacon list of detectable, identifiable beacons;

the current beacon list is compared to a prior beacon list associated in time with the last valid GNSS location update; and

upon determining the presence of a limited-range beacon in both the current and prior beacon lists, the mobile device reuses a previously obtained valid GNSS location;

wherein the geographic location of the terrestrial beacon need not be known to use the beacon as a proxy for a location derived from satellite positioning signals; and

wherein the method further comprises using both the GNSS receiver and the second receiver to collect information from each receiver concurrently, and to make a measurement of the beacon'"'"'s transmit power and to compare the measurement to the beacon'"'"'s transmit power recorded at a previous GNSS location fix, and based on the comparison to detect motion toward or away from the beacon.

35. A system for use in determining the location of a mobile device, comprising:

a global navigation satellite system (GNSS) receiver associated with the mobile device, configured to receive GNSS signals;

a second receiver associated with the mobile device, configured to receive a terrestrial beacon signal;

means for employing a controller associated with the mobile device to detect when GNSS signals are unavailable and, in response thereto, to use a received terrestrial beacon signal to determine whether a previous GNSS location update is valid, wherein the mobile device is configured to use the beacon as a proxy for a location derived from satellite positioning signals without knowing the geographic location of the terrestrial beacon;

means for employing the second receiver to acquire network parameters from the terrestrial beacon, said network parameters including at least one of timing advance and round-trip-time;

means for determining if a last known GNSS-derived location is still valid;

means for obtaining data from received beacon signals, wherein the data includes identifying information for a beacon and its network;

means for suspending GNSS searches and powering down the GNSS receiver in response to detecting that GNSS signals are unavailable; and

means for performing the following steps;

employing the GNSS receiver to develop a first valid GNSS location including latitude, longitude, altitude, and timing;

in parallel, employing the second receiver to detect and identify one or more radio beacons in predefined transmission bands;

storing the first valid GNSS location and a first list of beacons locally within the mobile device;

entering the GNSS receiver into a low power sleep mode until a next required update time;

upon determining that the GNSS receiver has failed to produce a valid current GNSS location fix, producing with the second receiver a current beacon list of detectable, identifiable beacons;

comparing the current beacon list to a prior beacon list associated in time with the last valid GNSS location update; and

upon determining the presence of a limited-range beacon in both the current and prior beacon lists, reusing a previously obtained valid GNSS location; and

means for passively using received beacon signals from multiple beacons as a proxy for a high accuracy GNSS location estimate by measuring and comparing the strengths of signals received from neighboring beacons during periodic sampling events.

36. A system as recited in claim 35, wherein the mobile device is integrated into one of a mobile phone, a personal or automobile navigation system, and a tag device;

and wherein the mobile device is battery powered.

37. A system as recited in claim 35, wherein the GNSS receiver and second receiver are implemented in a software defined radio (SDR).

38. A system as recited in claim 35, wherein the system further comprises means for determining network timing from frames transmitted by the beacon.

39. A system as recited in claim 38, wherein the system further comprises means for receiving at least one of a pilot channel signal and a synchronization channel signal from the beacon.

40. A system as recited in claim 38, wherein the system further comprises means for receiving beacon transmissions including at least one of a broadcast control channel of a cellular network and a beacon frame of an IEEE 802.11 network.

41. A system as recited in claim 38, wherein the system further comprises means for receiving beacon identifiers including at least one of a cell-ID in a CDMA or UMTS cellular network, a cell-global-identifier (CGI) in a GSM cellular network, and a base station identifier in an IEEE 802.11 wireless local area network.

42. A system as recited in claim 35, wherein the second receiver is implemented in a communications transceiver.

43. A system as recited in claim 42, wherein the system further comprises means for employing the communications transceiver to retry connecting with a cellular network to gather timing and signal data from multiple beacons.

44. A system as recited in claim 42, wherein the system further comprises means for employing the communications transceiver to create an active session with a cellular network and to use a failed session initiation to receive additional information from the network that is unavailable on a broadcast beacon.

45. A system as recited in claim 44, wherein the additional information comprises at least one of timing advance (TA), a received signal strength indicator (RSSI), and details on frequencies or identifiers of neighboring beacons.

46. A system for use in determining the location of a mobile device, comprising:

a global navigation satellite system (GNSS) receiver associated with the mobile device, configured to receive GNSS signals;

a second receiver associated with the mobile device, configured to receive a terrestrial beacon signal;

means for employing a controller associated with the mobile device to detect when GNSS signals are unavailable and, in response thereto, to use a received terrestrial beacon signal to determine whether a previous GNSS location update is valid, wherein the mobile device is configured to use the beacon as a proxy for a location derived from satellite positioning signals without knowing the geographic location of the terrestrial beacon;

means for employing the second receiver to acquire network parameters from the terrestrial beacon, said network parameters including at least one of timing advance and round-trip-time;

means for determining if a last known GNSS-derived location is still valid;

means for obtaining data from received beacon signals, wherein the data includes identifying information for a beacon and its network;

means for suspending GNSS searches and powering down the GNSS receiver in response to detecting that GNSS signals are unavailable; and

means for performing the following steps;

employing the GNSS receiver to develop a first valid GNSS location including latitude, longitude, altitude, and timing;

in parallel, employing the second receiver to detect and identify one or more radio beacons in predefined transmission bands;

storing the first valid GNSS location and a first list of beacons locally within the mobile device;

entering the GNSS receiver into a low power sleep mode until a next required update time;

upon determining that the GNSS receiver has failed to produce a valid current GNSS location fix, producing with the second receiver a current beacon list of detectable, identifiable beacons;

comparing the current beacon list to a prior beacon list associated in time with the last valid GNSS location update; and

upon determining the presence of a limited-range beacon in both the current and prior beacon lists, reusing a previously obtained valid GNSS location; and

means for performing a process including the following steps, whereby the device determines whether a previous GNSS location update is valid;

the GNSS receiver is employed to develop a first valid GNSS location including latitude, longitude, altitude, and timing;

in parallel, the second receiver is employed to detect and identify one or more radio beacons in predefined transmission bands, wherein the radio beacons comprise broadcast signals from cellular network transmitters;

the GNSS location information is passed to a location-consuming application;

the GNSS receiver enters a low power sleep mode until a next required update time as determined by the location-consuming application;

the second receiver enters a low power sleep mode until the next required update time;

upon determining that the GNSS receiver has failed to produce a valid GNSS location fix, the second receiver produces a current beacon list of detectable, identifiable beacons;

the current beacon list is compared to a prior beacon list associated in time with the last valid GNSS location update, and one of relative timing and power differences between beacon signals are used to determine an approximate change in location; and

based on the approximate change in location, the mobile device determines the validity of last valid GNSS location.