Position detection system integrated into mobile terminal

• US 6,437,735 B1
• Filed: 09/07/2000
• Issued: 08/20/2002
• Est. Priority Date: 09/07/2000
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: McMahan, David
• Primary Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US09/657,367
• Time in Patent Office: 712 Days
• Field of Search: 342/357.01, 342/357.03, 342/357.06, 342/357.12, 342/357.1, 342/357.05, 342/450, 342/457, 342/357.11, 342/357.15, 342/352, 342/358, 701/213, 701/215, 701/207, 701/214, 701/226, 455/12.1, 455/422, 455/13.2, 455/427, 455/435, 455/456
• US Class Current: 342/357.66
• CPC Class Codes: G01S 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
• CPC Class Codes: G01S 19/27 creating, predicting or correcting ephemeris or almanac data within the receiver

Abstract

A mobile terminal stores almanac information relating to the position of satellites within a position detection system by converting selective portions of ephemeris information to almanac information. The ephemeris information may be provided by a mobile network continuously or on demand from the mobile terminal. Alternatively, the mobile terminal may secure the ephemeris information from satellites.

Claims

1. A mobile terminal comprising:

a location detector adapted for use with a satellite based position detection system;

a receiver adapted for use with a mobile network;

memory;

a controller operatively connected to said location detector, said receiver, and said memory, wherein said controller receives ephemeris information for use by said location detector and converts said ephemeris information to almanac information and stores said almanac information in said memory.

2. The mobile terminal of claim 1 wherein said location detector is adapted for use with GPS satellites.

3. The mobile terminal of claim 1 wherein said receiver comprises a transceiver.

4. The mobile terminal of claim 3 wherein said controller requests said ephemeris information from the mobile network through said transceiver.

5. The mobile terminal of claim 1 wherein said controller receives said ephemeris information periodically from the mobile network.

6. The terminal of claim 1 wherein said controller receives said ephemeris information periodically from the mobile network over a control channel.

7. The terminal of claim 1 wherein said controller converts said ephemeris information to said almanac information by discarding one or more ephemeris parameters.

8. The terminal of claim 1 wherein said controller converts said ephemeris information to said almanac information by scaling one or more ephemeris parameters.

9. The terminal of claim 1 wherein said controller converts said ephemeris information to said almanac information by reducing a number of bits required to contain the information.

10. The terminal of claim 1 wherein said controller converts said ephemeris information to said almanac information according to the following table:

11. A method of assisting a mobile terminal determine a position at which the mobile terminal is located, comprising:

receiving ephemeris information at said mobile terminal;

converting said ephemeris information to almanac information; and

storing said almanac information for later use.

12. The method of claim 11 wherein said converting said ephemeris information to almanac information comprises discarding one or more ephemeris parameters.

13. The method of claim 11 wherein said converting said ephemeris information to almanac information comprises scaling one or more ephemeris parameters.

14. The method of claim 11 wherein converting said ephemeris information to almanac information comprises reducing a number of bits required to contain the information.

15. The method of claim 11 wherein converting said ephemeris information to almanac information comprises converting according to the following table:

16. The method of claim 11 wherein receiving ephemeris information at said mobile terminal comprises receiving ephemeris information broadcast by a mobile network.

17. The method of claim 11 wherein receiving ephemeris information at said mobile terminal comprises receiving ephemeris information in response to a request from the mobile terminal.

18. The method of claim 11 wherein storing said almanac information for later use comprises storing said almanac information in a memory device.

19. The method of claim 11 wherein receiving ephemeris information at said mobile terminal comprises receiving ephemeris information from one or more satellites.

20. The method of claim 11 wherein storing said almanac information for later use comprises storing said almanac information for later use when a mobile network is incapable of providing information from which the mobile terminal may locate satellites to determine a present position.

21. A method of locating a mobile terminal, comprising:

receiving ephemeris information at the mobile terminal while in communication with a mobile network;

converting said ephemeris information to almanac information;

storing the almanac information in memory associated with the mobile terminal; and

subsequently, when said mobile terminal is no longer in communication with the mobile network using the almanac information to assist the mobile terminal determine the mobile terminal'"'"'s location.

22. The method of claim 21 wherein using the almanac information comprises using the almanac information while the mobile terminal is in communication with a second mobile network incapable of providing assistance to the mobile terminal in the form of almanac information.

23. The method of claim 21 wherein using the almanac information comprises using the almanac information while the mobile terminal is in communication with a second mobile network incapable of providing assistance to the mobile terminal in the form of ephemeris information.

24. The method of claim 21 wherein using the almanac information comprises using the almanac information while the mobile terminal is not in communication with any mobile network.