Method and system for validating a mobile station location fix

• US 7,551,931 B2
• Filed: 01/24/2001
• Issued: 06/23/2009
• Est. Priority Date: 01/24/2001
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Alberth, William P. Jr., Walczak, Thomas J.
• Primary Examiner(s): Bhattacharya; Sam
• Application Number:
  US09/769,122
• Publication Number:
  US 20020098851A1
• Time in Patent Office: 3,072 Days
• Field of Search: 455/456.1, 455/12.1, 455/427, 34235701-35714
• US Class Current: 455/456.5
• CPC Class Codes: G01S 19/396 Determining accuracy or reliability of position or pseudorange measurements
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence

Abstract

A method and system for evaluating the validity of location fixes of a mobile station by comparison of a location fix for which a validity determination is desired with one or more prior reference location fixes. In one embodiment, a satellite positioning system based location fix of a satellite positioning system enabled cellular mobile station in a cellular communications network is validated by comparison of the satellite positioning system based location fix to one or more of a plurality of network based location fixes, or to an estimated future location fix of the mobile station.

Claims

1. A method for validating a non-network based location fix of a mobile station, comprising:

generating a non-network based location fix of the mobile station;

evaluating the validity of the non-network based location fix of the mobile station by determining whether the non-network based location fix is within a specified range of a prior location fix,

the specified range based on an estimated velocity of the mobile station and a time interval between the generation of the prior location fix and the non-network based location fix.

2. The method of claim 1, generating the non-network based location fix includes receiving global positioning system signals at the mobile station.

3. The method of claim 1, generating the prior location fix by measuring a time related parameter of signals received at the mobile station from several base stations neighboring the mobile station.

4. The method of claim 3, translating the prior location fix and the non-network based location fix into a common format prior to comparing the prior network and non-network based location fixes.

5. The method of claim 1, the communications network having a plurality of base stations,

generating the prior location fix by measuring at the mobile station several base station signals neighboring the mobile station,

evaluating the validity of the non-network based location fix by determining whether the non-network based location fix is within a specified range of the prior location fix.

6. The method of claim 1, evaluating the validity of the non-networked based location fix by comparing it to at least one of a plurality of prior network based location fixes.

7. The method of claim 1,

estimating a future location fix of the mobile station based on a plurality of prior location fixes,

evaluating the validity of the non-networked based location fix by determining whether the non-network based location fix is within a specified range of the estimated location fix.

8. A method for validating a satellite positioning system based location fix of a satellite positioning system enabled cellular mobile station, comprising:

generating a satellite positioning system based location fix of the mobile station;

ordering a plurality of prior location fixes by applying a corresponding time of acquisition attribute thereto;

evaluating the validity of the satellite positioning system based location fix by comparing the satellite positioning system based location fix to at least one of the plurality of time stamped prior location fixes.

9. The method of claim 8, generating the prior location fixes by measuring at the mobile station a time related parameter of signals received from a plurality of cellular base stations of the cellular communications network neighboring the mobile station.

10. The method of claim 8,

evaluating the validity of the satellite positioning system based location fix by determining whether the satellite positioning system based location fix is within a specified range of the at least one prior location fixes,

defining the specified range based on an estimated velocity of the mobile station and a time interval between generation of the at least one prior network based location fix and the satellite positioning system based location fix.

11. The method of claim 8, evaluating the validity of the satellite positioning system based location fix by comparing it to more than one of the plurality of time stamped prior location fixes.

12. The method of claim 8, generating a subsequent satellite positioning system based location fix of the mobile station if a prior satellite positioning system based location fix is invalid.

13. A method for validating a location fix of a mobile station, comprising:

generating a plurality of location fixes of the mobile station;

estimating a future position fix of the mobile station based on the plurality of location fixes;

evaluating the validity of a recently generated location fix of the mobile station by determining whether it is within a specified range of the estimated future position fix of the mobile station.

14. The method of claim 13, estimating a velocity of the mobile station, defining the specified range based on the estimated velocity and time interval.

15. A cellular mobile station, comprising:

a satellite positioning system signal reception interface in the mobile station for receiving satellite positioning system signals;

a cellular communications network interface in the mobile station for communicating with a cellular communications network;

an information processor coupled to the satellite positioning system signal reception interface and the cellular communications network interface,

the information processor for evaluating the validity of a satellite positioning system based location fix based on at least one prior mobile station location fix stored in memory.

16. The mobile station of claim 15, the at least one prior mobile station location fix is a network based mobile station location fix, the information processor for determining the network based mobile station location fix based on cellular base station signal strength data received by the cellular communications network interface.

17. The mobile station of claim 15, the information processor for determining a network based mobile station location fix based on a timing relationship between cellular communication network signals received by the cellular communications network interface, the information processor for evaluating the validity of a satellite positioning system based location fix by comparing it to at least one prior network based mobile station location fix.

18. The mobile station of claim 15, the information processor for estimating a future position fix of the mobile station and evaluating the validity of the satellite positioning system based location fix by determining whether it is within a specified range of the estimated future position fix.

19. The mobile station of claim 15, the information processor for evaluating the validity of a satellite positioning system based location fix by determining whether it is within a specified range of at least one prior mobile station location fix.

20. The mobile station of claim 15, the information processor for evaluating the validity of the satellite positioning system based location fix by determining whether it is closer to a more recent prior location fix than it is to a less recent prior location fix.