Measurement in L-band (1.275 GHz) in HH polarization. The instrument consists of the following subsystems: antenna, transmitter/receiver, and signal processor. The SAR antenna is composed of eight 2.2 m x 1.5 m panels, measuring 2.2 m x 11.9 m in total. A honeycomb sandwich structure is used. The signal processor performs several functions. First, it performs the A/D conversion of I and Q video signals from the transmitter/receiver. Secondly, after formatting the A/D converted I and Q data plus other data necessary for processing on the ground, it transmits the I and Q channel data. Finally, it controls itself and the transmitter/receiver based on commands received from the ground stations. The range of incidence angles within a typical image is fixed at between 32º at near range and 38º at far range. SAR transmits 1,500 pulses/s from the antenna with a mean off-nadir angle of 35º to right side of satellite. - The L-band SAR of JERS-1 demonstrated also two-pass SAR-interferometry for change detection