Development and Performance Evaluation of Small SAR System for 100-kg Class Satellite

This article shows development and performance evaluation of a MicroX-SAR demonstration satellite, scheduled to be launched in 2020 for synthetic aperture radar (SAR) application. This compact SAR system and its instruments are briefly described. The SAR antenna consists of deployable seven panels with a slot array and the antenna size is 4.9 x 0.7 m. This article proposes a simple evaluation method of the SAR antenna. The seven-panel antenna array performance is estimated from isolated single-panel antenna measurement results and synthesized scattering matrix. It is validated by comparing with near-field measurement of a seven-panel antenna array. The on-board SAR system is combined with a single-point source simulator and the point source SAR image is evaluated. The ambiguity to the signal ratio is computed for the bandwidth-integrated seven-panel antenna radiation patterns, and finally the pulse repetition frequency selection is computed along with noise equivalent sigma zero to estimate the SAR image quality based on various requirements of swath-width and ground-range resolution as per the application of interest. The prototype system is capable of 1-m ground-range resolution SAR image acquisition for 28-km swath-width within acceptable limits of signal-to-noise ratio and ambiguity levels.