关键词: 线性体制激光测高仪, 在轨几何标定, 数字化标定方法

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