A mobile device (MS) is disclosed comprising a GPS receiver (14) and an audible alarm (13, 15) configured to sound, during operation of the GPS receiver, in response to either adverse performance of the GPS receiver or to an event which is adverse or likely to be adverse to the performance of the GPS receiver. The alarm may sound in response to the inability of the GPS receiver to either acquire or track a GPS signal, or obtain or maintain a position fix. Also, the alarm may sound in response to movement of the GPS receiver, including acceleration and higher order movement of the GPS receiver, in so far as that movement is adverse to the performance of the GPS receiver.