Error sources and sensitivity analysis in formation flying synthetic aperture radar

Abstract

Distributed Synthetic Aperture Radar (DSAR) is one of the most promising approaches to enable the utilization of small satellite platforms for gathering radar images as well as reducing the time-to-market and costs. The paper aims at estimating the main imaging properties achievable by a DSAR under realistic satellite trajectories and working conditions. To this end, a simulation environment has been developed in which DSAR performance has been investigated including the most significant error sources, i.e. radar synchronization errors, position and pointing errors, co-registration errors, antenna pattern errors and signal noise. The estimation has been carried out considering satellite formations with both a relevant along-track distance among the receivers and a dominant cross-track/vertical separation, to investigate different application scenarios. The conducted sensitivity analysis provides some valuable insights into the uncertainty in the error sources which can be tolerated. From an application perspective, the results show that the impact of the error sources can be made negligible thus confirming that DSAR enables azimuth ambiguity suppression, SNR improvement and coherent resolution enhancement. Moreover, DSAR can achieve an accuracy in pointing, antenna pattern, coregistration, and the clock error, in line with well-assessed techniques.