Spaceborne Synthetic Aperture Radar Antenna Pattern In-orbit Testing Technology

The antenna pattern uncertainty is the main error of spaceborne SAR system. The technique for inflight antenna pattern measurement of spaceborne SAR is one of the most important technique of SAR calibration. This paper discussed the methods of the inflight antenna pattern measurement of spaceborne SAR, including the method of using standard reflectors, the method of using uniform distrbuted targets and the method of using ground receivers. We analysed the main error source of these method, their advantages and disadvantages. Then we focused on the techniques of inflight antenna pattern measurement of spaceborne SAR using ground receivers. In order to get more reliable results, we developed a computer software system to simulate the whole measure process. Using this simulation system and theoretic analysis we7 researched many factors which affect the precision of the inflight antenna pattern measurement, such as the satellite orbit, the satellite gesture, ground receivers?number and position, the uncertainty of SAR transmit power and ground receivers gain, and so on. In this paper, we use two dimensional arithmetic to recover the antenna pattern. It is much preciser than the methods based on one dimensional arithmetic. In order to cut down the cost of measurement using ground receiver, we also researched the multiple measure technique using multiple satellite orbits.