On-orbit geometric calibration of satellite laser altimeters using infrared detectors and corner-cube retroreflectors

After being launched into orbit, the geometric calibration of a satellite laser altimeter will reduce errors in laser pointing and ranging caused by satellite vibrations during launch, environmental changes, and thermal effects during long-term operation, which guarantees the accuracy of measurement data. In this study, a satellite laser geometric calibration method combining infrared detectors and corner-cube retroreflectors (CCRs) is proposed. First, a CCR-based laser ranging error calibration method was established, and then a laser pointing error calibration model was derived based on a single infrared detector array. Taking GaoFen-7 (GF-7) satellite laser beam 2 as the experimental object, laser geometric calibration was realized using an infrared detector and CCR-measured data. Then, the accuracy of the proposed method was compared with that of other calibration methods, the CMLID and the CMSPR. The results show that the accuracy of the proposed calibration method is equivalent to that of the CMLID and higher than that of the CMSPR. Among them, the accuracy of the laser pointing after calibration using the proposed method is better than 0.8 arcsec, and the elevation accuracy of the laser on flat, sloping, and mountainous terrains is better than 0.11 m, 0.30 m, and 1.80 m, respectively.