System and method for dual-mode location determination

• US 20050261833A1
• Filed: 01/28/2005
• Published: 11/24/2005
• Est. Priority Date: 07/12/1999
• Status: Active Grant

• Current Assignee: SkyBitz, Inc. (Ametek Incorporated)
• Original Assignee: SkyBitz, Inc. (Ametek Incorporated)
• Inventors: Kilfeather, James B., Brosius, Jay, Burtner, Richard
• Granted Patent: US 8,255,149 B2
• Time in Patent Office: Days
• US Class Current: 701/213
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/256 relating to timing, e.g. time of week, code phase, timing offset
• CPC Class Codes: G01S 19/40 Correcting position, velocity or attitude
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location

Abstract

A geographic tracking system with minimal power and size required at the mobile terminal collects observation data at the mobile terminal, forwards the data to a processor, which calculates the position. The mobile terminal needs only to gather a few milliseconds of observation data, and to relay this observation data to the processor. In one embodiment, the observation data is communicated to the processor using either a satellite communication network or through a mobile telephone network.

Claims

1. A location determination system, comprising

a. a mobile terminal operative to take code phase measurements from signals received from a plurality of GPS satellites, said mobile terminal further being operative to receive location area information from a mobile telephone system signal communicating over an area of interest;

b. a communication satellite; and

c. a service operations center operative to receive said code phase measurements and said location area information from said mobile terminal via said communication satellite, and to iteratively calculate a position solution using an initial position estimate based on said area of interest identified by said location area information and said plurality of code phase measurements.

2. The system of claim 1, wherein said area of interest has a size that is less than a size of a convergence zone of the position solution process using said iterative calculations.

3. The system of claim 1, wherein said location area information includes a location area code.

4. The system of claim 3, wherein said location area information further includes a country code.

5. The system of claim 1, wherein said mobile terminal is not configured for voice communication over said mobile telephone system.

6. A location determination system, comprising

a. a mobile terminal operative to take code phase measurements from signals received from a plurality of GPS satellites, and to receive location area information from a mobile telephone system signal communicating over an area of interest, wherein said mobile terminal is not configured to communicate voice communication over said mobile telephone system;

b. a communication satellite; and

c. a service operations center operative to receive said code phase measurements and said location area information from said mobile terminal via said communication satellite, and to iteratively calculate a position solution using an initial position estimate based on said area of interest identified by said location area information and said plurality of code phase measurements.

7. The system of claim 6, wherein said area of interest has a size that is less than a size of a convergence zone of the position solution process using said iterative calculations.

8. The system of claim 6, wherein said location area information includes a location area code.

9. The system of claim 8, wherein said location area information further includes a country code.

10. A location determination method in a mobile terminal, comprising

a. taking a plurality of observation measurements from a respective plurality of GPS signals received by the mobile terminal;

b. if the mobile terminal is in view of a communication satellite, then transmitting said plurality of observation measurements to a service operations center via a communication satellite for determination of a location of the mobile terminal; and

c. if the mobile terminal is in view of a mobile telephone network, then transmitting said plurality of observation measurements along with location area information received from said mobile telephone network to a service operations center via said mobile telephone network for determination of a location of the mobile terminal.

11. The method of claim 10, wherein said observation measurements include code phase measurements.

12. The method of claim 10, wherein said observation measurements include carrier phase measurements.

13. The method of claim 10, wherein said observation measurements include doppler shift measurements.

14. The method of claim 10, wherein said observation measurements include bit phase measurements.

15. The method of claim 10, wherein the mobile terminal transmits to said communication satellite only if it is not in view of said mobile telephone network.

16. The method of claim 10, wherein the mobile terminal transmits to said mobile telphone network only if it is not in view of said communication satellite.

17. The method of claim 10, wherein said location area information is based on a location area identifier.

18. The method of claim 10, wherein said location area information is based on a base station identifier.