Bulletin of Surveying and Mapping ›› 2024, Vol. 0 ›› Issue (7): 41-47.doi: 10.13474/j.cnki.11-2246.2024.0708

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High-precision terrain-based on-orbit geometric calibration method for laser altimeter

ZHANG Hao1,2,3, XU Qi4, HUANG Peiqi4, CHEN Gang2,3, XIE Huan4,5   

  1. 1. Institute of Geospatial Information, Information Engineering University, Zhengzhou 450000, China;
    2. State Key Laboratory of Geo-information Engineering, Xi'an 710000, China;
    3. Xi'an Research Institute of Surveying and mapping, Xi'an 710000, China;
    4. College of Surveying and Geo-informatics, Tongji University, Shanghai 200092, China;
    5. Shanghai Key Laboratory for Planetary Mapping and Remote Sensing for Deep Space Exploration, Shanghai 200092, China
  • Received:2023-12-07 Published:2024-08-02

Abstract: The digital calibration method for laser altimeters has attracted increasing attention due to its prominent advantages of high calibration frequency and low consumption of manpower and resources. This paper proposes a “two-step” digital calibration method for laser altimeters, focusing on the geometric positioning model of linear regime laser altimeters. A geometric calibration model concerning roll angle, pitch angle, and range system error is constructed, and calibration tests are conducted using publicly available reference terrain data SRTM and high-precision digital calibration fields. Comparing and analyzing with the actual field detector experimental calibration data of the GF-14. The results show that the geometric calibration method proposed in this paper has an angle difference within 0.5 arcseconds and a ranging difference within 0.2 m compared to the ground detector calibration parameters. By independently validating the elevation accuracy of the calibrated results, both the proposed digital calibration method and detector calibration method exhibit good consistency in footprint elevation bias. The RMSE between the footprint elevations obtained from both methods and the high-precision airborne LiDAR point cloud elevations is less than 0.3 m. The method proposed in this paper is not only ensures accuracy, but also reduces the consumption of human and material resources, providing a new approach and method for on-orbit normalization calibration of spaceborne laser altimeters.

Key words: linear system laser altimeter, in-orbit geometric calibration, digital calibration method

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