disclosed is mobile station system and a method for operating a mobile station to reduce the power consumption thereof as a function of a presence or absence of motion , and as a function of a duration of a period over which motion above a motion threshold is not detected . the system includes cellular system reception circuitry and circuitry implementing a cellular system positioning function and a satellite - based positioning function . the circuitry includes a controller that operates in accordance with a stored program for obtaining and combining a plurality of received signal - derived parameters of the cellular system , a position of the mobile station derived from the cellular system positioning function , and a position of the mobile station derived from the satellite - based positioning function to derive a value that is indicative of a presence or absence of motion of the mobile station . the controller compares the value to a motion threshold and , when an absence of motion is detected , the controller is responsive for reducing the power consumption of the mobile station by selectively decreasing the usage of the mobile station cellular system reception circuitry , the cellular system positioning function and the satellite - based positioning function . the received signal - derived parameters of the cellular system include received signal parameters for a currently serving cell and for at least one adjacent cell , and include one or more of a received signal strength indicator , a signal to interference ratio , a received signal code power , a block error rate and a bit error rate .