利用国产卫星影像开展全球范围地理信息资源建设的前提条件之一是提升卫星影像无地面控制条件下几何精度水平。2020年7月成功发射资源三号03星（ZY3-03）是资源三号系列卫星中的第三颗高分辨率立体测绘卫星，主要用于全球范围1:5万比例尺测图应用。卫星搭载了三台全色线阵推扫式光学相机和一台多光谱相机，可获取优于2.5米分辨率的三线阵立体影像和5.8米分辨率的多光谱影像。为了提升卫星影像的高程精度，卫星还设计搭载了一台单波束激光测高仪，可同步获取高精度激光测高点。本文提出了一种ZY3-03星激光测高点与立体影像联合区域网平差处理方法。利用激光测高点和同轨获取的正视影像相对平面误差较小的特性，准确获取激光测高点在立体影像上的像方位置；将激光测高点作为立体影像高程控制，并以整轨立体影像为单位开展立体影像与激光测高点的联合区域网平差，实现立体影像高程精度大幅提升。选取黑龙江省中部地区和河北省太行山地区的ZY3-03星三线阵立体影像及其同轨获取的激光测高点开展联合区域网平差试验，结果表明，平地和丘陵地形区域的ZY3-03星立体影像的高程中误差从5.27米降低至2.58米，山地地形区域的ZY3-03立体影像的高程中误差从11.25米降低至4.45米，均能满足我国1:5万比例尺立体测图的精度要求。

Objective: Using domestic satellite for global geographic resources construction, one of the most important promise is to improve the geometry accuracy of satellite imagery without ground control points (GCPs). Ziyuan3-03 (ZY3-03) satellite, launched on July 25th, 2020, was the third high-resolution stereo mapping satellite of Ziyuan3 series. And it mainly used for the global application of 1:50000-scale mapping. Triple linear-array push-broom panchromatic cameras (resolution<=2.5 m) and one multi-spectral camera (resolution =5.8 m) were loaded on this satellite. Moreover, in order to improve the vertical accuracy, an additional single-beam laser altimeter was loaded on the ZY3-03 satellite. This addition enables the satellite to simultaneously obtain high vertical accuracy laser altimetry points (LAPs). Integrating stereo images and LAPs to improve the vertical accuracy of the stereo images is considered the key to realize the application of 1:50,000-scale stereo mapping of ZY3-03 images with sparse or no GCPs. Method: This study proposed a combined block adjustment method using ZY3-03 triple linear-array stereo images and synchronous orbit LAPs to improve the elevation accuracy of the images. First, a method able to accurately obtain the image coordinates of LAPs on the stereo images was designed. By fully using this advantage that the relative planar error between LAPs and the synchronous nadir image was minimal, the image coordinate of LAPs on synchronous orbit nadir images could be correctly acquired through the image rational function model (RFM) and ground geodetic coordinates of the LAPs. Then the accurate pixel coordinates of the LAPs on triple linear-array stereo image were obtained by high-precision image matching between the forward/backward image and nadir image. Subsequently, using the whole orbit stereo image as the operation unit, a combined block adjustment model based on RFM and combined block adjustment strategy were constructed. Result: Twelve ZY3-03 satellite triple linear-array stereo image pairs and 81 synchronous orbit LAPs of plain and hilly terrains located in Heilongjiang province (China) were selected as experimental data. Simultaneously, 270 Global Positioning System (GPS) points were collected as checkpoints. Through combined adjustment with stereo images and LAPs, the vertical root mean square error (RMSE) of the images was reduced from 5.27 m to 2.58 m. Seven ZY3-03 satellite triple linear-array stereo images pairs and 6 synchronous orbit LAPs of mountainous terrains in Hebei province were selected as experimental data, with 115 GPS points as checkpoints. After the combined block adjustment, the vertical RMSE of images was reduced from 11.25 m to 4.45 m. The experimental results showed that the vertical accuracy of ZY3-03 images was enhanced significantly, satisfying the precision requirements of 1:50,000-scale stereo mapping in China. Conclusion: The experiments discussed above demonstrated that the combined block adjustment method proposed in this study was effective regardless of whether the terrain is flat, hilly, or mountainous. And the vertical accuracy of stereo images can be greatly improved so that it satisfies the accuracy requirements of 1:50000-scale stereo mapping in China.