First result from ALOS-2 operation

Abstract

The Advanced Land Observing Satellite-2 (ALOS-2) carries the phased array type Synthetic Aperture Rader (SAR) with the L-band frequency named PALSAR-2. ALOS-2 provides necessary data for disaster management, land and infrastructures management, resource management and so on. For disaster management by satellite based SAR, high resolution and wide swath width observation are needed. The Pulse Repetition Frequency (PRF) must be higher to improve azimuth resolution with less ambiguity caused by aliasing, but lower PRF is necessary to realize wider swath width. From this reason, high resolution and wide swath width are conflicting requirements for SAR. We have realized the requirements by adopting the multi-beam technology. PALSAR-2 has one transmitter and two receivers (dual beam system). This makes possible to reduce PRF and PALSAR-2 enables to receive the back scatterings, which are received in twice in the single beam receiver, at the same time. Therefore PALSAR-2 can realize high resolution and wide swath width capabilities by mean of the dual beam system. Improving resolution and swath width leads to increasing the data volume. Large amount of data need longer time to send the data to ground stations. From this reason the high speed data transmitting system with multi-mode X-band modulator has been developed. The modulator works with 800Mbps in 16QAM mode. This paper presents the initial on-orbit checkout result of ALOS-2.