A wireless communication system useful in locating users of mobile communication units (MUs) in emergency situations. In one embodiment, the system includes a plurality of aircraft-deployable, wireless position determining equipment (PDE) to generate position information from an emergency call request received from an MU, and a wireless mobile positioning center (MPC) on board an aircraft adapted to determine the location of the MU from the position information received from the PDE. In another embodiment, the PDE are adapted to transmit a message to elicit a response from the MU to acquire position information. In another embodiment, the PDE are adapted to receive periodic messages from the MU to acquire position information. In another embodiment, a mobile switching center (MSC) assists a GPS-capable MU in determining its location by providing it the information on the GPS satellites visible within the area covered by its base station and sector.