New method for airborne SAR image positioning

Synthetic aperture radar (SAR) geometric positioning obtains the geodetic coordinates of each pixel in a SAR image. However, due to the changes in geometry, position and attitude angle of the sensor and the influence factors such as topography, atmospheric refraction, plus the curvature and rotation of the earth, image deformation will occur. Therefore, there is a great practical significance to explore the precise geometric positioning method for SAR images. It proposed a new positioning method combining range-Doppler model and polynomial model, realising SAR image accurate positioning with the digital elevation model data. The method considers the effects of terrain-height-induced geometric distortions and establishes a practical positioning model based on the geometric relationship of imaging. The result shows that the positioning accuracy of the proposed method is higher than the accuracy of the traditional rang-Doppler model and polynomial model with a small number of ground control points.