缺少控制点的SPOT-5 HRS影像RPC模型区域网平差

提高稀少甚至无地面控制点的区域网平差精度，是实现境外和外业测控困难区域高精度测图的核心问题之一，也是主要的技术难点。为了充分利用高分七号激光测高数据与立体影像同步获取、相对精度较高、高程精度极高的特点，充分发挥足印影像作用，提出了一种激光测高数据辅助的高分七号卫星立体影像区域网平差方法。通过足印影像实现了激光高程控制点在立体影像上的自动量测，利用其极高的高程精度对区域网立体影像进行高程控制，经过联合区域网平差实现区域网影像高程精度提升。通过覆盖不同地形类型的山东测区激光测高数据与立体影像联合平差实验表明，仅使用激光测高数据作为高程控制，实验区高程中误差可由原始7.97 m提高到0.79 m，高程最大误差优于1.5 m，高程精度改善明显。

Block Adjustment of High-Resolution Satellite Images Described by Rational Functions

  Objectives  Improving the accuracy of block adjustment with few or even no ground control points (GCP) is one of the core issues for high-precision mapping of areas difficult to get GCP, and it is also a major technical difficulty. In order to make full use of the footprint image and the excellent high accuracy of elevation, and the high relative accuracy between the laser altimetry data and stereo images, we propose a combined adjustment method of Gaofen-7 (GF-7) satellite stereo images aided with laser altimetry data.  Methods  In this method, the elevation control points are automatically extracted by registering the laser footprint images and stereo images, and then they are used as the vertical control in the combined adjustment to improve the elevation accuracy.  Results  The combined block adjustment experiments performed in Shandong with different terrains show that using only laser altimetry data as elevation control, the root mean square errors of elevation can be significantly improved from the original 7.97 m to 0.79 m, and the maximum elevation error is better than 1.5 m.  Conclusions  The experimental results reveal that the proposed method can substantially improve the elevation accuracy of satellite imagery. Additionally, with integration of few horizontal control points, the plane accuracy and elevation accuracy can be simultaneously improved. The proposed method is of great significance to reduce the field survey and improve the efficiency of block adjustment.