GPS based search and rescue system

A Search and Rescue System, comprising:

• a survival radio, said survival radio comprising a GPS receiver, a transceiver, and a controller, said survival radio having a unique identification code associated therewith, said survival radio controller responding to interrogation messages received over a substantially line of sight first communication path by said transceiver and having contained therein said unique identification code by causing said transceiver to transmit location information generated by said GPS receiver and said identification code over said first communication path;
• a first interrogation unit comprising a second controller and a second transceiver, said second controller being operable to cause said second transceiver to transmit interrogation messages containing said survival radio identification code, said second controller being further operable to identify messages received by said second transceiver as being from said survival radio;
• and
• a second interrogation unit comprising a third controller and a third transceiver, said third controller being operable to cause said third transceiver to generate said interrogation messages and to transmit said interrogation messages to said first interrogation unit, said first interrogation unit being responsive to said interrogation messages to re-transmit said interrogation messages to said survival radio, at least some of said interrogation messages including GPS position correction data that can be used by said survival radio to correct a local position determined by said GPS receiver, said at least some interrogation messages being among said interrogation messages that are re-transmitted to said survival radio to cause said survival radio to transmit said location information over said first communication path.

A method of operating a Search and Rescue system, said system comprising at least one survival radio, at least one first interrogation unit, and a second interrogation unit, said method comprising the steps of:

• generating an interrogation message at said second interrogation unit, said interrogation message containing a unique identification code corresponding to a first survival radio;
• transmitting said interrogation message to said first interrogation unit, wherein said first interrogation unit is carried on an airborne vehicle;
• utilizing said first interrogation unit to relay said interrogation message to said first survival radio;
• responding to said interrogation message, at said first survival radio, by generating and transmitting a response message containing said unique identification code and geographic location information;
• receiving said response message at said first interrogation unit;
• and
• relaying said response message from said first interrogation unit to said second interrogation unit.