Position detection system integrated into mobile terminal

• US 6,937,865 B1
• Filed: 09/12/2000
• Issued: 08/30/2005
• Est. Priority Date: 09/12/2000
• Status: Expired due to Term

• Current Assignee: Unwired Planet LLC (JP Morgan Chase & Co)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Koorapaty, Havish, Bloebaum, Leland S.
• Primary Examiner(s): Perez-Gutierrez, Rafael
• Assistant Examiner(s): Iqbal, Khawar
• Application Number:
  US09/660,519
• Time in Patent Office: 1,813 Days
• Field of Search: 4554561-4566, 455/414.2, 342/357.03, 342/357.05, 342/357.15, 342/357.06, 342/357.6, 701213-215
• US Class Current: 455/456.1
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view

Abstract

A wireless communications mobile terminal conserves bandwidth by determining which position detection assisting devices within a position detection system are available for use and limiting ephemeris information inquiries to only those devices that are available. To make this determination, mobile terminals are provided with an almanac of position information relating to the position detection system. Once the ephemeris information is provided to the mobile terminal, the mobile terminal may determine its location relatively quickly and with a minimal imposition on the mobile network.

Claims

1. A method of facilitating location detection, comprising:

storing information relating to position detection assisting devices in a mobile terminal;

referencing said information to determine, by said mobile terminal, a subset of the position detection assisting devices which are available from which to determine location, wherein referencing said information to determine a subset of the position detection assisting devices which are available comprises determining, by said mobile terminal, a subset consisting of only the position detection assisting devices necessary and sufficient from which to determine location;

requesting contemporary information about said subset from a mobile network; and

after said determining by said mobile terminal, beginning acquisition of position location assistance signals from said subset of the position detection devices.

2. The method of claim 1 further comprising receiving an inquiry as to the present location of the mobile terminal.

3. The method of claim 2 wherein receiving an inquiry as to the present location of the mobile terminal originates in the mobile terminal.

4. The method of claim 2 wherein receiving an inquiry as to the present location of the mobile terminal originates in a mobile network associated with the mobile terminal.

5. The method of claim 2 wherein receiving an inquiry as to the present location of the mobile terminal originates in a server communicatively connected to a mobile network associated with the mobile terminal.

6. The method of claim 1 wherein requesting contemporary information about said subset from a mobile network comprises evaluating a time stamp to determine whether the mobile terminal already has contemporary information about one or more position detection assisting devices in said subset.

7. The method of claim 6 wherein requesting contemporary information comprises requesting contemporary information about only those in said subset about whom contemporary information is not available in the mobile terminal.

8. The method of claim 6 wherein evaluating a time stamp comprises evaluating a time stamp to determine if said time stamp falls within a predetermined threshold.

9. The method of claim 8 wherein evaluating a time stamp to determine if said time stamp falls within a predetermined threshold comprises evaluating if said time stamp is more than four hours old.

10. The method of claim 1 wherein requesting contemporary information about said subset from a mobile network comprises requesting contemporary information from a server within the mobile network.

11. The method of claim 1 wherein requesting contemporary information about said subset from a mobile network comprises requesting contemporary information from a server communicatively connected to said mobile network.

12. The method of claim 1 further comprising receiving the contemporary information at the mobile terminal and subsequently locating said mobile terminal based on information received from said subset of position detection assisting devices.

13. The method of claim 12 further comprising reporting the location of the mobile terminal as determined by said locating step.

14. The method of claim 1 wherein said requesting contemporary information occurs prior to said beginning acquisition of position location assistance signals from said subset of the position detection devices.

15. A mobile terminal comprising:

a transceiver;

a control system operatively connected to said transceiver, wherein said control system stores information relating to a plurality of position detection assisting devices within a position detection system and solicits contemporary information from a mobile network via said transceiver relating to a subset of said position detection assisting devices; and

wherein said control system further determines, at said mobile terminal, a subset of the position detection assisting devices which are available from which to determine location based on said information, said subset consisting of only the position detection assisting devices necessary and sufficient from which to determine location, and wherein said control system thereafter causes acquisition of position assisting signals from said subset to be initiated.

16. The mobile terminal of claim 15 wherein said control system determines a present location of the mobile terminal after soliciting said contemporary information.

17. The mobile terminal of claim 15 wherein information relating to a plurality of position detection assisting devices comprises information about a satellite-based position detection system.

18. The mobile terminal of claim 17 wherein said information comprises information relating to a plurality of satellites within a GPS.

19. The mobile terminal of claim 15 wherein said information relating to a plurality of position detection assisting devices comprises information about a terrestrial position detection system.

20. The mobile terminal of claim 15 wherein said information relating to a plurality of position detection assisting devices comprises information relating to a mixed satellite based and terrestrial position detection system.

21. A communication system comprising:

a server comprising contemporary information relating to a position detection system;

a mobile network;

a mobile terminal communicatively connected to said server through said mobile network, said mobile terminal storing local information relating to the position detection system and soliciting a subset of said contemporary information from said server based in part on said local information; and

wherein said mobile terminal determines a subset of the position detection assisting devices which are available from which to determine location based on said local information, said subset consisting of only the position detection assisting devices necessary and sufficient from which to determine location; and

wherein said mobile terminal thereafter initiates acquisition of position assisting signals from said subset.

22. The communication system of claim 21 wherein said local information comprises an almanac.

23. The communication system of claim 21 wherein said contemporary information comprises satellite ephemeris.

24. The communication system of claim 21 wherein said mobile terminal determines a number of available position detection assisting devices within the position detection system based on a coarse location of the mobile terminal.

25. The communication system of claim 21 wherein said server forms a part of said mobile network.

26. The communication system of claim 21 wherein said server is communicatively connected to said mobile network.

27. A method of facilitating location detection, comprising:

storing information relating to position detection assisting devices in a mobile terminal;

referencing said information to determine, at said mobile terminal, a subset of the position detection assisting devices which are theoretically visible from which to determine location, wherein referencing said information to determine a subset of the position detection assisting devices which are available comprises determining, by said mobile terminal, a subset consisting of only the position detection assisting devices necessary and sufficient from which to determine location;

after said determining at said mobile terminal, beginning acquisition of position location assistance signals from said subset of the position detection devices;

receiving signals from position detection assisting devices which are actually visible to the mobile terminal; and

requesting contemporary information about the position detection assisting devices which are actually visible from a mobile network.

28. A method of facilitating location detection using a satellite based positioning system, comprising:

evaluating an almanac within a mobile terminal to determine which satellites are theoretically available based on a coarse location and time of the mobile terminal;

securing at the mobile terminal, from a mobile network accurate time information for satellites that are theoretically available;

deriving, at the mobile terminal, doppler and code phase information for the satellites that are theoretically available;

thereafter, acquiring a signal from one or more of the satellites that are theoretically available and, based thereon, determining at the mobile terminal which of said one or more satellites from which signals are acquired from a subset of the theoretically available satellites consisting of only the satellites necessary and sufficient from which to determine location; and

requesting ephemeris information only for those satellites in said subset.

29. The method of claim 28 wherein requesting ephemeris information comprises requesting ephemeris information for only those satellites whose previously stored ephemeris information is stale.

30. The method of claim 28 wherein acquiring a signal comprises evaluating a signal quality measurement.