ALOS-4 System Design and PFM Current Status

The Advanced land observing satellite-4 (ALOS-4) is a follow-on mission of ALOS-2 "Daichi-2" and which will be launched in Japanese Fiscal Year (JFY) 2023 by H3 launch vehicle. ALOS-4 carries the-state-of-the-art L-band SAR (PALSAR-3, Phase Array type L-band Synthetic Aperture Radar-3) to respond higher user requirements than that of ALOS-2. The observation swath is 200 km which is four times wider than that of PALSAR-2 onboard ALOS-2, which is achieved by digital beam forming (DBF) and phase spoiling techniques. ALOS-4 also carries the SPace based Automatic Identification System for ships Experiment (SPAISE3), which is successor of SPAISE2 onboard ALOS-2. The features of SPAISE3 are the antenna composed by eight elements, and Automatic Identification System for ships (AIS) signal processing which adopts ground based DBF system as one of methods to eliminate the AIS signal collision in ship crowded area.