Formation-flying sar as a spaceborne distributed radar based on a microsatellite cluster

Formation Flying Synthetic Aperture Radar (FF-SAR) is defined as a SAR in which the signal emitted by the transmitter and scattered from the area of interest is not collected by a single receiver but by many, conveniently distributed, formation flying, receivers. The concept of distributed aperture can enable new SAR working modes, but more important, thanks to passive operations, can achieve very high performance through a series of very compact, low weight, agile, satellite platforms. Such a distributed space system can be regarded as a system in which the payload functionality is broken apart and distributed among the different elements of the system. While fractionation and formation flying may lead to many advantages, distributed space systems pose a number of technological and operational issues at system and subsystem level. Signal modeling, radar processing, system operations and formation flying aspects are analysed in this paper and an end-to-end space system demonstrator concept is also proposed including 3 satellites working in X-band, flying in a LEO close formation. Mission operations and system budgets are performed at a preliminary level showing the possibility to achieve mission objective by platforms of micro-satellite class (