Patent ID: 8471765

Claim:
A method, in a mobile device configured to obtain position information from a position broadcast system, the position broadcast system comprising a plurality of transmitters that each broadcast a respective signal containing position information for the respective transmitter, the method comprising: measuring signal strengths of signals from each of a plurality of the transmitters of the position broadcast system; determining that the mobile device is out of range of the position broadcast system if the measured signal strengths satisfy an out of range criterion; if the mobile device is determined to be out of range, operating the mobile device according to an out of range profile for conservation of power; and if the mobile device is not determined to be out of range, attempting to lock on to a position using the position broadcast system, wherein the out of range criterion differs from criteria used to determine whether or not it is possible to lock on to a position, and wherein determining that the mobile device is out of range based on the out of range criterion comprises at least one of: determining that fewer than a predetermined number of the measured signal strengths are above a threshold value; determining that a sum of highest measured signal strengths of signals from each of a predetermined number of transmitters is below a threshold value; and determining that the signal strength of fewer than a predetermined number of visible transmitters is above a threshold value; and wherein operating the mobile device according to an out of range profile for conservation of power comprises turning off a position broadcast receiver in the mobile device.