Optical Satellite Image Geo-Positioning with Weak Convergence Geometry

• Main Authors: Yang Wu, Yongsheng Zhang, Donghong Wang, Delin Mo
• Format: Article
• Language: English
• Published: MDPI AG 2018-06-01
• Series: ISPRS International Journal of Geo-Information
• Subjects: high-resolution optical satellite images; weak convergence; geo-positioning; open source DEM; planar adjustment; linear programming
• Online Access: http://www.mdpi.com/2220-9964/7/7/251

High-resolution optical satellites are widely used in environmental monitoring. With the aim to observe the largest possible coverage, the overlapping areas and intersection angles of respective optical satellite images are usually small. However, the conventional bundle adjustment method leads to erroneous results or even failure under conditions of weak geometric convergence. By transforming the traditional stereo adjustment to a planar adjustment and combining it with linear programming (LP) theory, a new method that can solve the bias compensation parameters of all satellite images is proposed in this paper. With the support of freely available open source digital elevation models (DEMs) and sparse ground control points (GCPs), the method can not only ensure the consistent inner precision of all images, but also the absolute geolocation accuracy of the ground points. Tests of the two data sets covering different landscapes validated the effectiveness and feasibility of the method. The results showed that the geo-positioning performance of the method was better in regions of smaller topographic relief or for satellite images with a larger imaging altitude angle. The best accuracy of image geolocation with weak convergence geometry was as high as to 3.693 m in the horizontal direction and 6.510 m in the vertical direction, which is a level of accuracy equal to that of images with good intersection conditions.