Patent ID: 7453396

Claim:
A radioterminal comprising: a wireless communications transmitter; a wireless communications receiver; a global positioning system (GPS) receiver including a GPS radio frequency (RF) system and a GPS signal processing system; and a controller that is configured to enable the GPS receiver when the wireless communications receiver is receiving wireless communications and to disable the GPS receiver when the wireless communications transmitter is transmitting wireless communications; wherein the controller is further configured to disable the wireless communications transmitter and enable the GPS RF system and the GPS signal processing system to receive and process GPS signals, respectively, when the GPS RF system and the GPS signal processing system have been disabled for a predetermined time, wherein the predetermined time comprises a variable predetermined time, and to send a measure of location of the radioterminal to at least one other radioterminal, wherein an identity of the radioterminal is used to determine the at least one other radioterminal and the measure of location of the radioterminal is sent to the at least one other radioterminal responsive to a change of position of the radioterminal and responsive to a rate of change of position of the radioterminal.