AUTOMATED SAR REFERENCE IMAGE PREPARATION FOR NAVIGATION

The preparation of good navigational synthetic aperture radar (SAR) reference image is critical to the SAR scene matching aided navigation system, especially for complex terrain. However, few papers discuss the problem, and almost none of the methods proposed by them are fully automatic. Based on the practical requirements, a fully automated method of SAR reference image preparation is introduced. Firstly, a number of distinctive control points (CP) in the simulated SAR image is detected based on a method of image segmentation and clustering. Then, the corresponding tie-points in the real SAR image are searched based on local similarity by means of template matching. To improve the accuracy of CP, a method for segmentation threshold calculation, outlier screening and sub-pixel location computation is presented. Finally, the real SAR image is warped to the simulated one, and then projected to the frame of digital elevation model (DEM) by the polynomial mapping function. Experimental results on real data sets demonstrate the accuracy and efficiency of the proposed method.