利用轨道参数修正的无控制点星载SAR图像几何校正方法

Spaceborne SAR Image Geometric Rectification Method without Ground Control Points Using Orbit Parameters Modulation

使用距离多普勒模型进行SAR图像几何校正时,卫星轨道误差、系统成像参数误差和DEM高程的误差会影响几何校正精度。本文提出了一种基于轨道参数修正的星载SAR图像几何校正方法。首先利用多项式对卫星轨道进行参数化,然后使用模拟SAR图像与真实SAR图像进行匹配得到控制点来修正轨道参数,最后利用修正后的参数进行几何精校正,从而提高几何校正精度。该方法无需地面控制点,适用于不易于人工测量获取地面控制点地区的SAR图像几何校正,与基于模拟SAR图像匹配并使用多项式改正的几何校正方法相比,本文方法具有更高的精度。使用Radarsat-2图像进行试验,并使用地面实测GPS控制点验证了本方法的有效性。

When using the Range-Doppler model for SAR image geometric correction,the error of satellite orbit,imaging parameter and DEM elevation will affect the geometric correction accuracy.A new geometric rectification method has been presented for spaceborne SAR image.First,polynomial was used for parameterizing SAR orbit.Then orbit parameters were corrected by control points that acquired by matching of simulated SAR image and real SAR image.Finally,the precise geometric rectification using corrected parameters was accomplished.The presented method can be applied for SAR image geometric rectification where the ground control points are difficult to be acquired.It has higher precision compared to the geometric rectification based on image simulation and polynomial correction.The Radarsat-2image was used in experiments,and the ground control points measured by GPS validated the proposed approach.