Application of Laser Tracking Technology to Absolute Calibration of Space-borne Radar Altimeters

Space-borne radar altimeter can measure a majority of the global sea surface height within an accuracy of few centimeters, but there are various errors in altimetry measurements, so absolute calibration activities must be carried out. Ground laser station has range accuracy better than 1 cm, so it can serve for the independent calibration combined with the space-borne laser reflector array (LRA). In this paper, the general model of the laser calibration for space-borne altimeter was deduced, which was not presented in the relevant publications. Afterwards, simulations and error analysis were executed based on the model, and the calibration precision was estimated quantificationally. In particular, the Grasse laser observations (actual laser echoes from the Jason-2 satellite LRA) in the vicinity of the Corsica calibration site were analyzed, and the results were promising. Finally, the contributions of the laser station in the calibration site were summarized, and the benefits of simultaneously operating laser station and GNSS buoy configuration was emphasized. The construction and performance assessment of China's forthcoming satellite altimeter calibration site would benefit from the study in this paper.