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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 recei

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.

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1. A method comprising receiving a request for location services, the request generated by a requesting device and received by a system separate from the requesting device;determining a locale associated with the requesting device;determining, by the system, an accuracy level required to support the

1. A method comprising receiving a request for location services, the request generated by a requesting device and received by a system separate from the requesting device;determining a locale associated with the requesting device;determining, by the system, an accuracy level required to support the request;determining a set of visible triangulation sources that will provide a location fix at the determined accuracy level;determining a time period associated with the location fix, wherein the location fix is accurate during the time period and wherein the time period is up to one minute;constructing a message that includes information representing the location fix within the determined accuracy level; andproviding the message to the requesting device at the determined accuracy level. 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 available parameters for the triangulation sources. 5. The method of claim 3 wherein constructing the message includes providing clock correction along with the subset of parameters. 6. The method of claim 3 wherein constructing the message includes integrating harmonic correction factors in the subset of parameters. 7. The method of claim 1 wherein time period is used to determine the locale. 8. The method of claim 1 wherein the time period is used to determine the set of visible triangulation sources. 9. A method comprising: requesting, by request to a system separate from a device, location assist information so as to determine a location of the device, wherein the request includes information related to a required accuracy of a location fix required by the device;receiving the location assist information from the system including receiving a message that includes the location assist information and information representing the location fix within the required accuracy, the system having selected an accuracy level based on the request and determined a validity period based on the selected accuracy level, wherein the location assist information is accurate during the validity period; andconstructing, by one or more processors and using the location assist information, a location data file including a minimal set of information required to locate the device and associated with triangulation sources that are visible during a time period associated with a service offered to or provided by the device, wherein the time period is up to one minute. 10. The method of claim 9 further comprising: specifying a time interval requirement for a service using the location assist information, where the time interval requirement is less than that associated with the ephemeris information and specifically less than 4 hours. 11. A method comprising: receiving a request for location services from a requesting device, the request received by a system separate from the requesting device;determining, by the system, an accuracy level based on the request;determining, by the system and based on the determined accuracy level, a valid time period for use of location data, wherein the valid time period is up to one minute;determining the location data using data provided by visible sources;constructing a message that includes the location data that locates the requesting device within the selected accuracy level, wherein the location data is accurate only during the valid time period; anddelivering the message to the requesting device at the determined accuracy level. 12. 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;selecting an accuracy level based on a listening device;determining a set of visible sources that will provide a location fix at the selected accuracy level, the selected accuracy level having a valid time period, wherein the location fix is accurate during the valid time period, wherein the time period is up to one minute; andconstructing a message that includes information required by the listening device to assist a location service to locate the listening device during the time period including information representing the location fix within the selected accuracy level. 13. The method of claim 12 where the location service is a GPS based service. 14. The method of claim 12 wherein constructing a message includes determining a subset of parameters associated with each source to be provided in the broadcast message. 15. The method of claim 14 wherein the subset includes less than all available parameters for a source that is associated with ephemeris information. 16. The method of claim 12 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 Global Positioning System (GPS) Time of Week (TOW) and/or Coordinated Universal Time for input to a GPS associated with the listening device. 17. The method of claim 12 wherein the broadcasted message includes a clock correction along with triangulation source parameter data. 18. The method of claim 12 wherein constructing the message includes integrating harmonic correction factors in triangulation source parameter data. 19. The method of claim 12 wherein the method supports multiple geographically unique broadcast locales. 20. The method of claim 12 wherein the message is encrypted. 21. The method of claim 20 wherein the message can be decrypted by a listening device with a valid subscription. 22. A method in a listening device comprising; requesting location data including providing a request and an data indicative of an accuracy level required to support a location service provided by the listening device;determining a time to listen for a broadcast message after transmission of the request;receiving a broadcast message at the time that includes triangulation source parameter data of a quality and accuracy required by the listening device to support the location service, the selected quality and accuracy being associated with a valid time period, wherein the valid time period is up to one minute; andusing the broadcast message to assist in a determination of a location of the listening device within the required accuracy, where the location is accurate at the selected quality and accuracy during the valid time period. 23. A method comprising: requesting location assist information so as to determine a location of a device that is accurate according to an accuracy level during a time period to satisfy a requesting application, wherein the time period is up to one minute;receiving the location assist information;requesting ephemerides for one or more visible triangulation sources; andusing the location assist information to determine the location of the device within the accuracy level and within the time period until the device has received and decoded the ephemerides. 24. The method of claim 23 where the accuracy of the location assist information degrades outside the time period. 25. The method of claim 23 further comprising using the received and decoded ephemerides after decoding to locate the device. 26. The method of claim 23 wherein receiving the location assist information includes receiving an SMS message including the location assist information. 27. A method comprising receiving a request for location services, the request generated by a requesting device and received by a system separate from the requesting device;determining a locale associated with the requesting device;determining, by the system, an accuracy level required to support the request;determining a set of visible triangulation sources that will provide a location fix at the determined accuracy level;determining a time period associated with the location fix, wherein the location fix is accurate during the time period and wherein the time period is up to one minute;constructing a message that includes information representing the location fix within the determined accuracy level, wherein constructing a message includes determining a subset of parameters associated with each triangulation source to be provided in the message; andproviding the message to the requesting device.