Synthetic aperture radar can calculate and analyze the flying fights' doppler shifts with its hunreds of meter-long virtual synthetic aperture antennas and advanced signal processing, its resolution is far higher than the traditional radars.It can work efficiently both in nighttime and worse weathers, it can also cut through the clouds, fog and battle field shelters, imaging in large range with high resolution. However, its weight and energy consumption are very large, which limit its application with the UAV, now, only large-sized UAV has the ablity to carry the SAR. With the development of the light antennas and the compact signal processors and the lower cost of the SAR, it can be applied in tactical UAV.
UAV can't process the data provided by SAR by its own processing capacity, hence, it needs to transmit the data of the images with high resolution to the ground stations through the high-capacity data chains. The tactical use of the SAR is that it can extract additional information form the radar images. Another promising development refers to combine the SAR data and the data provided by other sensors.By detecting the objectives with some specific operating modes, we can obtain more useful information through the radar images and provide the SAR's value of tactical utility.