基于参考DEM的机载InSAR定标方法

Calibration of Airborne Interferometric SAR Data Based on Reference DEM

研究无人工靶标的干涉定标方法对促进机载InSAR技术在山区等复杂地形的测绘、制图等定量应用有重要的实用价值。提出一种基于参考DEM的干涉定标方法,在InSAR定标中用已知高程精度的参考DEM与待定标的InSAR系统生成的DEM进行比较,利用参考DEM模拟SAR图像,获得大量定标所需的控制点坐标并建立敏感度矩阵,并对敏感度方程的解算进行了改进,同时将干涉处理与定标过程相结合,改进了干涉处理过程,最后得到定标后的干涉参数和校正的DEM。利用中国科学院电子学研究所研制的机载双天线InSAR系统在内蒙古某地获取的试验数据进行试验验证,并分析无人工靶标干涉定标试验结果的误差。

Interferometric calibration without artificial calibrators is significant in terrain mapping and other applications of airborne InSAR especially in mountainous areas. A new calibration method is presented based on referenceDEM without any artificial calibrators. A reference DEM with known accuracy is used to simulate SAR image and compared with the DEM derived by InSAR. According to the relationship of real SAR image and simulated SAR image, a number of tie points are selected to be control points to set up the sensitivity matrix. An improved solving method is described based on sensitivity model and a modified processing of InSAR with calibration, After that the interferometric parameters are calibrated and updated InSAR DEM is generated. This paper illustrates the application of this method to InSAR data in Inner Mongolia autonomous region, derived by the dual-antenna airborne InSAR system developed by Institute of Electronics, Chinese Academy of Sciences, The difference between InSAR DEM and reference DEM is calculated to evaluate the precision of calibration.