Methods and Apparatus for Providing Location Data with Variable Validity and Quality

• US 20090061898A1
• Filed: 08/15/2008
• Published: 03/05/2009
• Est. Priority Date: 08/16/2007
• Status: Active Grant

• Current Assignee: Cortxt Incorporated
• Original Assignee: Cortxt Incorporated
• Inventors: Scheurman, Brad, Jones, Ryan Scott, Johnson, Roderick Michael, Blackwell, Dane
• Granted Patent: US 8,396,484 B2
• Time in Patent Office: Days
• US Class Current: 455/456.200
• 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
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Methods, systems and computer program products for determining a location of a device based on location information are described. In some implementations, location assist information may be requested so as to determine a location of sufficient quality to satisfy a requesting application. Upon receiving the location assist information, empherides from one or more visible sources may be requested. The location assist information may be used to determine the location of the device until the device has received and decoded the empherides.

Claims

1. A method comprising

receiving a request for location services;

determining a locale associated with a requesting device;

determining a set of visible triangulation sources;

determining a subset of the visible triangulation sources that will provide a location fix at a predetermined accuracy;

constructing a message that includes information required by the requesting device to locate the requesting device; and

broadcasting the message.

2. The method of claim 1 wherein constructing the message includes constructing an SMS message.

3. The method of claim 1 wherein constructing a message includes determining a subset of parameters associated with each triangulation source to be provided in the message.

4. The method of claim 3 wherein the subset includes less than all the available parameters for the triangulation source.

5. The method of claim 3 wherein constructing the message includes providing clock correction along with triangulation source parameter data.

6. The method of claim 3 wherein constructing the message includes integrating harmonic correction factors in the parameters.

7. The method of claim 1 further comprising determining a time period that the location information must be accurate.

8. The method of claim 7 where the time period is less than 4 hours.

9. The method of claim 7 where the time period is substantially one minute.

10. The method of claim 7 where time period is used to determine the locale.

11. The method of claim 7 where the time period is used to determine visible triangulation sources.

12. The method of claim 7 where the time period is used to determine the subset of visible sources.

13. A method comprising:

requesting location assist information so as to determine a location of a device;

receiving the location assist information including receiving a broadcast message that includes the location assist information; and

constructing a location datafile including a minimal set of information required to locate the device and associated with only those triangulation sources that are visible during a time period associated with a service provided by the device.

14. The method of claim 13 further comprising:

specifying a time interval requirement for a service using the location assist information, where the time interval requirement is less than 4 hours.

15. A method comprising:

receiving a request for information to locate a device; and

sending time interval specific spatial coordinate information of less than four hours in duration to the requesting device, where sending includes broadcasting the message.

16. The method of claim 15 further comprising:

incorporating precision correction information with a validity period equal to or greater than the spatial coordinate information into the time interval specific spatial coordinate information.

17. A method comprising:

receiving a request for location services from a requesting device;

constructing a message that includes information required by the requesting device to locate the requesting device within a predetermined accuracy, the predetermined accuracy including a valid time period for use of location data where the valid time period is less than 4 hours; and

delivering the message using a broadcast method.

18. A broadcast method comprising:

determining a broadcast locale;

determining a broadcast time;

determining a broadcast interval;

determining a time validity equivalent in accordance with the broadcast interval;

determining a set of triangulation sources visible from within the broadcast locale during the broadcast interval;

determining a subset of the visible sources that will provide a location fix at a predetermined accuracy; and

constructing a message that includes information required by a listening device to assist a location service to locate the listening device.

19. The method of claim 18 where the location service is a GPS based service.

20. The method of claim 18 wherein constructing a message includes determining a subset of parameters associated with each triangulation source to be provided in the broadcast message.

21. The method of claim 20 wherein the subset includes less than all available parameters for a triangulation source.

22. The method of claim 18 wherein a rough order of broadcast time is known by the listening device and using the rough order of broadcast time to receive and align a broadcast time to GPS Time of Week (TOW) and/or Coordinated Universal Time for input to a GPS associated with the listening device.

23. The method of claim 18 wherein the broadcasted message includes a clock correction along with triangulation source parameter data.

24. The method of claim 18 wherein constructing the message includes integrating harmonic correction factors in triangulation source parameter data.

25. The method of claim 18 wherein the method supports multiple geographically unique broadcast locales.

26. The method of claim 18 wherein the broadcast message is encrypted.

27. The method of claim 26 wherein the broadcast message can be decrypted by a listening device with a valid subscription.

28. A method in a listening device comprising;

determining a time to listen for a broadcast message including using a clock corrected time to activate listening;

receiving a broadcast message at the time that includes triangulation source parameter data of a predetermined quality and accuracy; and

using the broadcast message to assist in a determination of a location of a listening device.

29. A method comprising:

requesting location assist information so as to determine a location of sufficient quality to satisfy a requesting application;

receiving the location assist information;

requesting empherides from one or more visible sources; and

using the location assist information to determine a location of a device until the device has received and decoded the empherides.

30. The method of claim 29 where the quality is accuracy within a predetermined tolerance.

31. The method of claim 29 where the quality is time validity within a predetermined tolerance.

32. The method of claim 29 further comprising using the received and decoded empherides after decoding.

33. The method of claim 29 where the step of receiving the assist information includes receiving an SMS message including the assist information.