Methods and apparatus for providing location data with variable validity and quality

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 to a required accuracy of the location fix required by the device;
• receiving the location assist information from the system including receiving a message that includes the location assist information, 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;
• and
• constructing, 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 those triangulation sources that are visible during a time period associated with a service offered to or provided by the device.

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;
• 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;
• and
• delivering the message to the requesting device.

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;
• and
• constructing a message that includes information required by the listening device to assist a location service to locate the listening device during the time period.

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;
• and
• using the broadcast message to assist in a determination of a location of the listening device, where the location is accurate at the selected quality and accuracy during the valid time period.

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;
• receiving the location assist information;
• requesting ephemerides for one or more visible sources;
• and
• using the location assist information to determine the location of the device until the device has received and decoded the ephemerides.