Research And Practise On The Target Location Of Space-borne Synthetic Aperture Radar Image

Spaceborne synthetic aperture radar satellite positioning is using to determine the coordinates of designated targets in spaceborne synthetic aperture radar images under the designated coordinates. It is well known that accurate geographic positioning to the pixels of images is required to apply spaceborne synthetic aperture radar images in various fields of remote sensing effectively. In the post-processing of images, accurate geographic positioning is also required to ensure the geometric accuracy of images, as well as to extract effective mapping information from remote sensing images.In this paper, the basic principles of synthetic aperture radar is introduced first, the mathematical expression of Range-Doppler model is derived in detail. Based on analyzing the effect of Range-Doppler model in positioning of images, the principal and methods of direct positioning using the assistance data in head file of spaceborne synthetic aperture radar. By the positioning experiment of actual ERS-1 image, the detail of the positioning method is studied concretely, and the acquisition methods of all parameters in the algorithm are expatiated in detail. Also the concrete calculation processing is given out. The results of experiment show that the algorithm has a high accuracy. Finally, after analysis, the positioning accuracy of the positioning model in this paper is mainly influenced by effectiveness of the earth model, slant range, and the accuracy of both Doppler parameters measurement and satellite ephemeris data. It is pointed out that the accuracy of absolute positioning could be further improved if the geometric relationship of radar, the effectiveness of earth model and the adjustment accuracy of satellite ephemeris data could be improved.