星载SAR影像的定位与几何纠正

Geopositioning and geometric rectification of spaceborne SAR images

高精度几何纠正算法对SAR影像的广泛应用具有重要意义,而SAR影像纠正中的一个重要问题是建立影像定位模型。在阐述了距离多普勒定位模型的基础上,利用一景高分辨率的Terra SAR-X影像进行了地理定位实验,实验结果表明采用2次参数方程和3次参数方程描述卫星轨道位置所得的定位精度相差不大,且都能满足精度要求,为了计算方便和减少控制点的数目,通常可以采用二次参数方程来描述卫星位置。定位参数解算完成后,又采用了间接纠正法对影像进行了几何纠正,得出纠正精度不超过3个像素,表明该算法合理可行。

The algorithm of high geometric correction precision is significant for the wide application of Terra SAR-X images. Meanwhile, the modeling of Terra SAR-X images geopositioning is the foundation of geometric Terra SAR-X images correction. After describing the range-doppler model, this paper tries to carry out the geopositioning experiment using high-resolution Terra SAR-X images. The results show that the geopositioning accuracy of the two parameter equations and three parameter equations is similar and can meet the need of the practical applications. To calculate conveniently and reduce the amount of the control points, it is common that the two parameter equations should be used to describe the geopositioning of the satellite. After calculating the geopositioning parameters, the indirect rectification method of the images is introduced to rectify the images and the rectification accuracy is within 3 pixels. This shows that the algorithm is reasonable and feasible.