Integrating Stereo Images and Laser Altimetry Points Derived from the Same Satellite for High-Accuracy Stereo Mapping

Abstract

At present, some mapping satellites, such as GaoFen-7 and ZiYuan3-03, are equipped with both optical stereo cameras and laser altimeters that can synchronously obtain stereo images and sparse ground laser altimetry points (LAPs). To effectively improve the geometric accuracy of these satellite stereo images, this study proposed an integrated processing method for LAPs and stereo images derived from the same satellite. This method makes full use of the advantages of synchronously obtaining stereo images and LAPs, and designs measurement technology for accurate pixel coordinates of LAPs in stereo images, which works toward solving a technical difficulty that has restricted their integration to achieve higher accuracy. The method also constructs a combined block adjustment model of LAPs and stereo images. We selected 70 GaoFen-7 stereo images and 463 GaoFen-7 LAPs from Hebei Province, China, and 12 ZiYuan3-03 stereo images and 81 ZiYuan3-03 LAPs from Heilongjiang Province, China, to conduct integrated processing experiments. The vertical accuracy of the GaoFen-7 images in all types of terrain were improved substantially and reached the accuracy requirements of 1:10,000 (even 1:5000) scale mapping in China. The vertical accuracy of the ZiYuan3-03 images in various terrain areas were also improved markedly, satisfying the accuracy requirement of 1:50,000 scale mapping. These experimental results indicate that the working mode of synchronously obtaining LAPs and stereo images using the same satellite is advanced, and the proposed method is correct and effective.