Synthetic Aperture Radar (SAR), as a kind of activeremotesensor, is a system that can scan and image earth surface object in a high resolution using its EM wave.
合成孔径雷达（SAR）作为主动式遥感器，是一种利用雷达本身发射的电磁波进行高分辨率成像的系统。
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Spaceborne radar altimeter is an important active microwave remotesensor which is able to measure the oceans with high accuracy.