Overview of ALOS-2 and ALOS-4 L-band SAR

ALOS-2 and ALOS-4 (Advanced Land Observing Satellite-2/4) are Japanese earth observation satellites with L-band SAR (Synthetic Aperture Radar) sensors. ALOS-2 has been operating since 2014, and its observations have been utilized for disaster mitigation, environmental monitoring such as forest and sea/land ice, land monitoring such as agriculture and natural resources, and technology development. ALOS-4 is now being developed for launch in JFY2022. The ALOS-4 aims to expand swath width and increasing observation frequency while keeping the high spatial resolution of ALOS-2 for improving the response of disaster monitoring, early detection of anomalies on the earth’s surface, and enabling time-series analysis. In this paper, the ALOS-2/4 mission summary and SAR system design are introduced.