System design of wide swath, high resolution, full polarimietoric L-band SAR onboard ALOS-2

This paper describes SAR system design of the Advanced Land Observing Satellite-2 (ALOS-2), which is a next-generation Japanese L-band SAR satellite. Since one of an important mission of ALOS-2 is a global monitoring using its unique frequency of L-band, a capability of wider coverage is required. On the contrary, in the point of disaster monitoring especially for urban area, relatively higher spatial resolution is essential. To comply with such a contradictive requirement of wide swath and high resolution, ALOS-2 utilizes a dual-receive channel (DRC) technique, and achieved a coverage area of up to 50km with a spatial resolution of down to 3m. In the paper, the H/W design of ALOS-2 DRC mode is explained. For a wider coverage of polarimetric observation, ALOS-2 installs the fully redundant and “quad-receive channel” system to full-polarimetric mode, achieving a maximum coverage of 50km at 6m resolution. As an experimental mode, new polarimetric mode called “compact polarimetry” is installed for a wide coverage of polarimetric observation.