Method and system for the geolocation of a radio beacon in a search and rescue system

A system for the geolocation of a device able to transmit a message to a plurality of relay satellites, said system comprising:

• a first module for determining the times of reception TRi of the message by each of a number Nvis of relay satellites,
• a second module for determining, from said times of reception TRi and with resect of a time Te of transmission of the message by the device, the pseudo-distances Di between the device and each of the Nvis relay satellites,
• a third module for searching for and acquiring a number N of satellite radio navigation signals, N being at least equal to 2+m−Nvis where m is a number of space coordinates of the device and Nvis is the number of relay satellites visible from the device,
• a fourth module for determining an information on the time lag between the time of transmission of each radio navigation signal j and the time of reception TRi, by the device, of each radio navigation signal j, and transmitting said information to a fifth module for determining, from said information, the pseudo-distances Dj(GNSS) between the device and each of the N radio navigation satellites,
• a sixth module for determining the position of the device from the pseudo-distances Di between the device and each of the Nvis relay satellites and from the pseudo-distances Dj(GNSS) between the device and each of the N radio navigation satellites.