Abstract: A survival radio of the type useable in search and rescue operations and carried by the party to be rescued is described. The survival radio includes a GPS receiver, a transceiver and a microcontroller. The microcontroller responds to interrogation messages containing a predetermined identification code for the survival radio to cause a transceiver to transmit a geographic location of the survival radio as derived from GPS signals.

Abstract: A method for organizing a communication system with automatic handoff. The method includes steps of: (i) sending a message from a first remote unit to a monitoring site during a specific time slot within a frame of time slots, wherein the first remote unit has a unique identification code and the message includes the unique identification code from the first remote unit; (ii) relaying the message including the identification code from the monitoring site to a central authority during a reserved time slot within the frame, the reserved time slot reserved for the relaying step; (iii) transmitting an acknowledgment message from the central authority to the monitoring site, wherein the monitoring site is determined from an updated lookup table of communications links between monitoring sites and remote units, during a time slot reserved for the acknowledgment message; and (iv) retransmitting the acknowledgment message from the monitoring site to the remote unit.

Abstract: A GPS based search and rescue system utilizes an airborne interrogation unit for extending the range of a second interrogation unit. The airborne unit relays communication between a survival radio and the second interrogation unit. The second interrogation unit is typically a ground based unit and is arranged to provide GPS correction information to the survival radio. The normal line of sight communication between a survival radio and an interrogation unit is extended to an over the horizon communication path by utilizing the airborne interrogation unit as a relay for communications.