1. INTRODUCTION
The Advanced Land Observing Satellite-2 (ALOS-2) is a next-generation Japanese SAR satellite. As a successor of ALOS/PALSAR, The SAR sensor onboard ALOS-2, named “PALSAR-2”, follows its unique frequency of L-band. Considering a uniqueness of the land in Japan, continuous investigation of the forest, volcanoes, and earthquake activities, based on differential interferometric SAR (DInSAR) and/or polarimetric techniques, become important missions of ALOS-2. In order to conduct continuous investigation by InSAR/DInSAR, acquisition of a base map, including both domestic and global mapping, is indispensable. An L-band sensor is hence required for wide observation width in order to acquire the reference data as much as possible for a short period of time. In a different viewpoint, a demand of the detailed information before and behind the disaster, e.g. East Japan great earthquake, is also increasing. In this case, a finer spatial resolution is preferred. From this viewpoint, surveillance in Japan and the whole world of 3m-class is planned in ALOS-2 mission. To realize a demand of these both sides more efficiently, broadening while maintaining 3m-class high resolution becomes indispensable.