Abstract: The present invention relates to a satellite communication system for extending communications between a vehicle and a satellite in an area of non-visibility of the satellite. The satellite communication system comprises a fixed transceiver system and a mobile transceiver system. The fixed transceiver system includes a first antenna intended to be positioned outside the area of non-visibility of the satellite, and at least one second antenna coupled with the first antenna and intended to be positioned in the area of non-visibility of the satellite. The fixed transceiver system is configured to receive through the first antenna downlink signals transmitted by the satellite on at least one downlink carrier frequency and to transmit the received downlink signals on the at least one downlink carrier frequency in the area of non-visibility of the satellite through the at least one second antenna.

Abstract: In a synthetic aperture radar system (1) monitoring an area containing at least one moving target (2) for identification, the target (2) is equipped with an identification device (3), which receives the radar signal (RS) transmitted by the radar system (1), and transmits a processed radar signal (ES) obtained by modulating the incoming radar signal (RS) with a modulating signal (MODS) containing target (2) information (ID, MSG), such as identification (ID) and status (MSG) information, and by amplifying the modulated radar signal (RS); the radar echo signal (RES) reflected by the monitored area and containing the processed radar signal (ES) is received and processed by a control station (8) of the radar system (1) to locate the target (2) on a map of the monitored area, and to extract the target (2) information (ID, MSG) to identify the target (2).

Abstract: The present invention is directed to a multibeam antenna reflector distortion compensation system comprising at least one remote reference radio frequency transmitter cooperating with a feed cluster of a beam forming network which includes one central and at least two peripheral feed elements, means for producing error signals including a circuit for consecutively connecting each peripheral cluster feed element to one input of an adding circuit, and the central feed element to the other input after appropriate attenuation and phase compensation of the central feed signal, and means for down-converting linear and non-linear distortion correction signals based on the down-converter output.

Abstract: The invention relates to multi-mission orbital spacecraft of the kind comprising a platform and several different payloads including several telecommunication antenna feed systems.The problem is to avoid antenna interference, obtain bigger effective antenna aperture, avoid the necessity for replacing main antennae when replacing payloads, and make maximum use of longer platofrm life.In accordance with the invention, the antenna system comprises a common primary reflector which is a permanent integral part of the platform while the feed systems are mounted on the payloads, which may be launched separately, and are assembled with the platform to cooperate with the common platform antenna system in operation.The invention is mainly applicable to multi-mission satellites.