New solution to location of spaceborne synthetic aperture radar image
ZHANG Bo ZHANG Hong WANG Chao WU Fan (Key Laboratory of China Remote Sensing Ground Station, CAS, Beijing 100086, China)
Directly locating pixel in SAR image is based on RangeDoppler model without tie points. In general, transforms among different coordinates used to solve RangeDoppler equations, are complex and depend on many projection parameters. In this paper, a new method is developed to solve RD equations. Firstly, the RD equations are expanded by Taylor expansion while the distance between SAR satellite and target is viewed as a variable parameter. Then the absolute location is retrieved iteratively by leastsquare adjustment for linear RD equations. Test is conducted using ERS2 SAR imagery of Suzhou area, China, comparing with topographic map with a scale of 1∶100,000. The results indicated an accuracy of 200 meters is attainable independent of any reference or GCP point.