ICESat激光高程点辅助的天绘一号卫星影像立体区域网平差

无地面控制点（简称无控）区域网平差是实现卫星影像无控测图的一项重要技术，对于境外和外业测控困难区域的测图具有重要意义。然而，无控区域网平差的定位精度一般难以满足对应比例尺测图规范要求。利用公开、可稳定获取的公众地理信息数据辅助区域网平差，是提高卫星影像无控定位精度的有效途径，其中ICESat激光高程点便是一种良好的高程控制数据。为了提高天绘一号卫星影像无控定位精度，本文提出ICESat激光高程点辅助的卫星影像模型法立体区域网平差方法。首先，以30 m分辨率SRTM估算的地形坡度作为限制条件，结合激光高程点自身质量评价信息，自动提取高质量ICESat激光高程点；其次，利用自动匹配的连接点进行模型法自由网平差，实现卫星影像几何定位精度的相对一致性（内部一致性）；最后，将激光高程点自动量测至卫星影像作为控制点，其平面坐标根据自由网平差结果前方交会计算而得，高程坐标取自激光点高程，再次进行区域网平差精化定向参数，提高卫星影像的绝对高程精度。最后本文利用山东全省的天绘一号卫星影像进行试验，验证了本文方法的有效性和可行性。

ICESat Laser Points Assisted Block Adjustment for Mapping Satellite-1 Stereo Imagery

Block adjustment without ground control points(GCPs)is an important technique for satellite images surveying and mapping without GCPs.It has great significance for mapping the areas which are in overseas and difficult to get GCPs.However,the positional accuracy of block adjustment without GCPs is generally hard to meet the requirements of the corresponding scale mapping specification.Making use of readily available,public geographic data as the reference,is an effective way to improve the accuracy of block adjustment without GCPs.ICESat/GLAS data is one of the good vertical control data.To improve the positional accuracy of mapping Satellite-1 imagery without GCPs,an ICESat laser points assisted block adjustment method for stereo satellite images is proposed in this study.First,high quality ICESat laser points are extracted automatically based on multi-criteria constraints.Then,free net adjustment is performed by using tie points obtained from automatic matching to realize the internal consistency in block areas.Finally,the ICESat laser points are used as control points after measured on the satellite images automatically,the horizontal coordinates of ICESat control points are calculated by intersection based on free net adjustment results,while the vertical coordinates of ICESat control points are got from the elevations of ICESat laser points themselves,then the orientation parameters are refined again based on free net adjustment to improve the vertical accuracy of satellite images.Experiments on the Mapping Satellite-1 images of Shandong province proved the effectiveness and feasibility of the presented method.