针对弱交会条件下卫星遥感影像区域网平差无法正确求解的问题，提出利用数字高程模型（DEM）作为高程约束的平面区域网平差方法提高其对地目标定位精度的策略。首先，选取带仿射变换项的有理函数模型（RFM）作为卫星影像平面区域网平差的数学模型。其次，在平差过程中更新连接点的地面坐标时仅求解地面点的平面坐标，高程值利用DEM进行内插获得。最后，在布设少量控制点的情况下通过平面区域网平差求解所有参与平差的卫星影像定向参数和连接点的地面平面坐标。利用两个地区的资源三号正视影像的平面区域网平差以及前正后三视影像的立体区域网平差的对比试验表明，对于资源三号卫星影像在1∶50000 DEM的支持下，平面平差可以达到和立体平差相当平面精度。对于近似垂直正视的资源三号影像，全球1 km格网的 DEM和90 m格网的 SRTM可以取代1∶50000 DEM作为高程控制，平面精度几乎没有损失。试验结果证明了平面区域网平差方法的有效性和可行性。%In response to the problem that block adjustment for satellite images cannot be solved with weak convergence geometric conditions ,a plane block adjustment method is proposed that utilizing DEM as height constraint plane block adjustment method to improve the targeting precision of images .First ,rational function model (RFM) with affine transformation is selected as the mathematical model of the satellite image plane block adjustment .Second ,to update the ground coordinates of tie points(TPs) ,the plane coordinates of TPs are only solved in the adjustment process .Elevation values obtained using DEM interpolation .Finally ,the plane coordinates of all TPs and orientation parameters of all satellite images are solved through plane block adjustment with a few ground control points(GCPs) .ZY-3 nadir images of two regions are tested for plane block adjustment and ZY-3 forward-nadir-back images of the same two regions are tested for stereo block adjustment .Comparison indicates that almost the same accuracy can be obtained by plane block adjustment support with 1 ∶ 50 000 DEM and stereo block adjustment for ZY-3 images .For ZY-3 nadir images ,when global DEM with 1 km grid and SRTM with 90 m grid repl aced 1∶50 000 DEM as elevation control ,It is almost no loss of accuracy of plane block adjustment The test results proved the effectiveness and feasibility of the plane block adjustment method .
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