MIMO SAR formations: Orbital diameter and synchronization tolerances

Multiple-Input-Multiple Output (MIMO) Synthetic Aperture Radar (SAR) along-track formations can be used to fraction the power resources into compact, lightweight and cost-effective satellites, or to extend the swath coverage beyond the limit provided by a small antenna. In this second case, the Pulse Repetition Frequency (PRF) is kept low by implementing an inversion that solves up to N−1 ambiguities, given N observations. The simultaneous illumination - that allows for the N2 gain due to the coherent combination of the N transmitters and the N receivers, is analyzed and shown not to be critical, as the more than NCombining double low line2 sensors are assumed. Performance is evaluated for the NCombining double low line2 and NCombining double low line3 cases and compared with the Single Input Multiple Output formations, where one sensor is transmitting, and all are receiving. Finally, the impact of the across-track deviation from the orbit is modeled and evaluated.