Technologies and Applications of Block Adjustment Without Control for ZY-3 Images Covering China

The key technologies and applications of the large-scale block adjustment for the ZY-3 three linear array stereo imagery pairs under the condition without using ground control points (GCPs) are introduced, in which the three-linear-array stereo imagery pairs covering whole mainland China are modified together. A series of key techniques including the high-precision steady re-imaging, establishment of the adjustment model based on the virtual control points, errors detecting and eliminating technology (including the images with anomaly geometric accuracy and the gross tie points), and the organization and fast calculation of the large-scale adjustment normal equation are provided. Based on these technologies, 8802 three-linear-array stereo imagery pairs (26406 images) cover whole mainland China were processed together under the condition without using GCPs. The availability and the accuracy of the presented method is verified according to the processed data. The satisfactory experimental results indicate that the presented method could not only ensure the unbiased estimation of the whole block, but also restrain the transfer and accumulation of the internal distortion, thereby ensure the consistency of the geometric accuracy. In addition, the demonstration of the method applied in Germany is also provided in the paper, which further indicates the presented method is available and feasible.