Patent ID: 7512095

Claim:
A communication system comprising several moving participants ( 20 , 21 , 22 , 23 , 24 , 25 ) that are each equipped with a communication device ( 10 ) for exchanging information having a transmitter, transmissions from said transmitter, and receiver ( 1 , 2 ) characterized by a method, for detecting free transmission periods ( 8 ) which control the transmissions of the transmitter ( 1 ); means for detecting transmission periods by a transmission detector ( 8 ), its input ( 15 ) being connected to a first output ( 16 ) of the receiver ( 2 ) and its output ( 14 ) being connected with a first input ( 13 ) of the transmitter ( 1 ); the transmission detector ( 8 ) scanning, within a predictable window of time, for the appearance of transmissions initiated by other participants with the receiver ( 2 ) and releases the transmitter ( 1 ) for communicating navigational data if such transmissions do not appear.