Preliminary outline of a distributed radar based on very large baselines for parasitic remote sensing

The concept of a sparse radar for parasitic remote sensing is presented. The receiving antenna is distributed on a formation of small satellites and exploits the backscattered echoes of existing low Earth orbit transmitters. The passive devices are conceived to orbit at very low altitudes, below the illuminators. This paper explores the mission feasibility and assesses preliminarily the radar performance. A scenario with a specific transmitter and a compact receiver is thus considered. The analysis focuses on the piece of relative trajectory with satellites in the proximity of their “conjunction”, when the signal acquisition becomes possible. The impact of acquisition geometry on imaging performance is evaluated and the ex-pected spatial resolution estimated. The coverage potential of the radar is then computed in terms of ac-cessible ground areas. Finally, the sparse receiving-only antenna is verified to be compliant with the se-lected bus class.