Area target usually covers a large area and it takes a long mission-complete time for a satellite to cover it completely, which makes the image request difficult to satisfy in a reasonable time.
3
星载雷达高度计是一种重要的对海洋进行精确测量的主动式微波遥感器。
Spaceborne radar altimeter is an important active microwave remote sensor which is able to measure the oceans with high accuracy.