Scansar and spotlight imaging operation study for sar satellite mission

Synthetic Aperture Radar (SAR) has been widely used for remotely sensed on Earth for decades. The advantages of SAR are to provide all weather and all day capability imagery and can be complemented with optical images. In considerations of the applications of SAR, user needs, mission definitions and critical technology preparations, a development of the X-band SAR program was planned and enforced from 2015 to 2018. The goal of the program is to develop a prototype SAR payload, including electronic units, high power amplifier (HPA) modules and high-gain multibeam antenna. This prototype shall present the technology readiness for NSPO (National Space Organization) future SAR small/microsatellite mission. So far, the preliminary assessment based on the designed subsystems and components shows that signal, power amplifiers, power supply, antenna gain pattern, data sampling, compression, recording and downlink system can meet the requirements of Stripmap imaging mode. However, ScanSAR and Spotlight modes are also necessary in order to achieve the goals for the wider swath and high resolution respectively for broader applications. In this study, the imaging operations and corresponding design parameters of the ScanSAR and Spotlight modes are presented. Additional system requirements respect to Stripmap operation are also analyzed to current SAR payload design and specifications.