Geometric Accuracy Analysis of Regional Block Adjustment Using GF-7 Stereo Images without GCPs

As an important means of improving positioning accuracy, block adjustment has been used in the improvement and assessment accuracy for Chinese Gaofen-7 (GF-7) satellite. However, there is little research on what factors affect without ground control points (GCPs). The correlation between images participating not clear. This paper proposes coefficients canonical analysis five indicators three sets ten factors, including topographic image tie (TPs) to quantify influence accuracy. Block GCPs GF-7 stereo imagery verified study areas evaluate relationship factors. results show that can improve direct with average 1.27 m planar direction 0.13 elevation direction. Moreover, plane more easily affected by while balanced. set TP greatest overlap critical than coverage area, number, time periods. Topographic also play role, factor highest coefficient (−0.71) significant other two roughness, slope. provide a reference GCPs, reasonable selection images, optimization TPs, strategy partition processing large-area imagery.