reduction of its signature with respect to active sonar the communication channel 24 of the beacon co ordinates with either a radio link a satellite communication link or an infra red or laser data transmission link the device for determining local geographical co ordinates 25 is a satellite positioning receiver gps glonass or galileo or any other means of localization the beacon according to the invention can integrate a pressure sensor 36 and means of coding of the emissions for sending by an acoustic channel the telemetry of e g the depth of immersion of the beacon for reasons of covertness it is interesting to design the beacon with a form resulting in reducing its signature with respect to active sonar such a form 42 is presented in fig4 for this purpose the envelope of the beacon may also be covered with absorbing materials 41 according to other modes of implementation of the method of the invention the vehicle from which the beacon is deployed is not an aircraft but a ship or a submarine with or without crew one stresses that one can install in the compartment of carrier 1 a relay transmitter of radio positioning signals to allow fast start up of the radio positioning receiver before dropping the beacon alternatively the beacon localization means in geographical co ordinates could be installed on board the launcher itself advantageously specific buoys a boat or an underwater vehicle could be deployed on the mission area at a later stage to improve the localization accuracy of the beacons once anchored on the.