Patent ID: 8467804

Claim:
A method for determining location of a mobile terminal, comprising: repetitively switching power-on and power-off to a GPS receiver circuit which determines location of the mobile terminal using GPS signals; and regulating the power-on to power-off duty cycle of the GPS receiver circuit in response to distance that the mobile terminal has moved from a previously determined location by: detecting when the mobile terminal is GPS isolated in response to insufficient GPS signal strength for the GPS receiver circuit to determine location of the mobile terminal during at least a threshold length of time; powering-off the GPS receiver circuit in response to detecting that the mobile terminal is GPS isolated; determining a present acceleration-based location of the mobile terminal using acceleration information from an accelerometer circuit in the mobile terminal during the power-off cycle of the GPS receiver circuit; extending duration of the power-off cycle of the GPS receiver circuit until a distance between the present acceleration-based location and a previous GPS-determined location of the mobile terminal exceeds a threshold distance; and upon powering-on the GPS receiver circuit, attempting to determine a present GPS-determined location of the mobile terminal.