Acta Geodaetica et Cartographica Sinica ›› 2023, Vol. 52 ›› Issue (11): 1929-1940.doi: 10.11947/j.AGCS.2023.20220512

• Photogrammetry and Remote Sensing • Previous Articles     Next Articles

Geometric positioning accuracy improvement method without ground control points for global orthorectification of GF-3

LI Xin1, JIANG Boyang1, WANG Taoyang2, ZHANG Guo1, CUI Hao1, CHENG Qian2   

  1. 1. State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China;
    2. School of Remote Sensing and Information Engineering, Wuhan University, Wuhan 430079, China
  • Received:2022-08-26 Revised:2023-04-30 Published:2023-12-15
  • Supported by:
    The Major Project of High-Resolution Earth Observation System (No. GFZX0404130302)

Abstract: The GF-3 satellite is the first C-band multi-polarization high-resolution synthetic aperture radar (SAR) satellite. However, the initial positioning accuracy of GF-3 satellite images is unsatisfaction, it is difficult to directly meet the application requirements of large-area mapping. This paper proposes a large-area SAR orthoimage production method without ground control points (GCP), which significantly improves the geometric positioning accuracy and processing efficiency for SAR image processing. Firstly, the initial positioning accuracy of single-scene SAR images is improved by geometric recalibration. Secondly, the SAR-SGFM matching algorithm is used combined with the multi-node parallel matching strategy to automatically extract the tie points. The image geometric model is refined by the large-area adaptive block adjustment method and the radiometric equalization of adjacent images is realized by using the radiometric consistency processing algorithm. Based on the production and experimental verification of global SAR orthoimages based on the method in this paper, the absolute positioning accuracy of SAR orthoimage is better than 10 meters (1 pixel), the relative positioning accuracy is better than 1 pixel and the radiation of adjacent images is excessively smooth. The results show that the proposed method is effective and feasible in the production of large-scale SAR orthorectification image.

Key words: spaceborne SAR, GF-3, geometric calibration, SAR image matching, block adjustment

CLC Number: