End-to-end space system demonstration concepts for a distributed SAR by small formation flying satellites

This paper presents a mission concept for an end-to-end space demonstration of Formation Flying Synthetic Aperture Radar (FF-SAR) system. This is realized by means of 3 satellites working in X-band, flying in Low Earth Orbit (LEO) formation. One satellite embarks a Transmitting-Receiving (Tx/Rx) radar, i.e. it is a monostatic SAR. The other two satellites are Receiving-only platforms. From the FF-SAR perspective, starting from the design of a general purpose monostatic SAR, targeted to achieve 8m x 8m resolution on ground from a 550-km orbit, FF-SAR properties are exploited to demonstrate performance improvement, namely the achievement of 4m x 4m resolution with the same Noise Equivalent Sigma Zero (NESZ) requirement, testing suitable combinations of FF-SAR techniques like Signal-to-Noise Ratio (SNR) enhancement, Pulse Repetition Frequency (PRF) reduction, Coherence Resolution Enhancement (CRE). Moreover, at the nominal 8m x 8m resolution, 3D imaging and Ground Moving Target Indication (GMTI) techniques can be also tested. The paper focuses on space system design aspects related to the end-to-end demonstration mission, aiming at showing the feasibility of a FF-SAR with micro-satellite class platforms (~100 kg) .