Design considerations and performance analysis for RODiO distributed SAR mission

The paper introduces RODiO (Radar for Earth Observation by synthetic aperture DIstributed on a cluster of cubesats equipped with high-technology micro-propellers for new Operative services), an innovative mission concept selected by the Italian Space Agency (ASI) for a phase A study in the framework of Alcor program. The mission relies on a cluster of 4 passive CubeSats flying in formation with ASI PLATiNO-1 (PLT-1) Synthetic Aperture Radar (SAR) mission. The mission is aimed at demonstrating from space the concept of Distributed Synthetic Aperture Radar (DSAR) through the application of multi-platform image synthesis, i.e. the generation of an improved performance image through the coherent combination, so in both amplitude and phase, of a stack of low performance bistatic raw data collected by formation-flying cubesat receivers. RODiO system parameters are discussed and preliminary performance evaluated. Results confirm that multi-static beamforming is able to both improve the Signal-to-Noise Ratio (SNR) and the level of ambiguities in the generated DSAR images, making the relevant values compliant with high-quality SAR imaging standards.