A new method of SAR images geometric rectification under undulate areas based on the application of navigation

The guidance precision can be improved greatly when the synthetic aperture radar (SAR) is used in the navigation system of aircraft or missile. However, the inherent geometric distortion of SAR images under undulate areas makes the matching navigation error to be increased. So, it is necessary to research geometric rectification methods for SAR images under undulate areas. A new method of SAR image geometric correction under undulate areas based on the application of navigation is presented in the paper. Firstly, it rectifies the range position error caused by elevation in the slant range plane. Secondly, it corrects the position error caused by the scale difference between slant range and ground range in the ground plane. Lastly, it transforms the reference frame of the real-time image to the map according to the course angle. In the end, a simulation using the DEM data of GUIZHOU of China is given, which gets perfect results, to testify the validity and accuracy of the method.