基于区域网平差的干涉合成孔径雷达数字高程模型校正

合成孔径雷达干涉测量（InSAR）是获取数字高程模型（DEM）的常规手段，而通过干涉技术获得DEM后，其精度会受到轨道定位、影像的配准、干涉图获取、相位解缠等精度的影响。已有的利用区域网平差提升DEM精度的研究忽略了DEM的初始平面定位误差的影响。引入DEM的平面高程一体化区域网平差，将区域网平差分解为平面定位六参数的优化和高程误差模型的平差求解两个独立的平差过程，同时利用激光测高数据作为高程控制。从哨兵干涉生成的20 m分辨率DEM实验结果看，平差后DEM的高程均方根误差（RMSE）从平差前的19.372 m提升到了3.459 m。DEM对应连接点的平面内符合精度RMSE从初始182.462 m提升至14.887 m。而传统的不考虑平面误差的DEM优化方法在平差后高程精度提升至7.865 m，远低于所提出的方法，验证了提出的考虑平面误差的区域网平差方法的有效性。

Interferometric Synthetic Aperture Radar DEM Correction Based on Block Adjustment

Interferometric synthetic aperture radar (InSAR) is a conventional method to obtain digital elevation model (DEM).After DEM is obtained by interferometry,its accuracy will be affected by orbital positioning,images registration,interferogram acquisition,phase unwrapping,etc.The influence of the initial DEM positioning error is ignored in existing researches of employing block adjustment to improve DEM accuracy.The plane-elevation integrated block adjustment of DEM is introduced,and the block adjustment is decomposed into two independent processes: the optimization of the six parameters of positioning and the block adjustment of the elevation error model.At the same time,the laser altimetry data is used as elevation control.From experimental results of the sentinel InSAR DEMs,the root mean square error (RMSE) of DEM after adjustment has increased from 19.372 m to 3.459 m.The in-plane coincidence accuracy RMSE of the corresponding connection point of the DEM is improved from the initial 182.462 m to 14.887 m.However,the traditional DEM optimization method without considering the plane error improves the elevation accuracy to 7.865 m,which is much lower than the proposed method,and verifies the effectiveness of the proposed block adjustment method considering the plane error.