Improved method of atmospheric delay correction using China meteorological station data for a laser altimeter

The atmospheric refraction delay caused by the uneven distribution of the refractive index of the atmosphere, is one of the main sources of the ranging error for a space-borne laser altimeter and mainly influenced by the surface pressure. At present, the method of calculating surface pressure is based on NCEP meteorological data and the time-space interpolation method derived by GLAS research team. For the GLAS system, the correction precision is sufficient (1 cm) for its core observing target in the relatively flat ice-sheet region; however, the correction precision is low for a complex land target. Based on the observation data of China domestic meteorological stations, a modified inverse-distance weighted interpolation algorithm was derived to improve the correction precision of the atmospheric refraction delay; then, the correction precision was compared with traditional GLAS method. In the highland and high latitudes area, the correction error was reduced from more than 2 cm to less than 0.5 cm using the new interpolation algorithm with domestic meteorological data, which was equivalent to improve the overall accuracy of 10% compared to the whole 15 cm measurement accuracy of GLAS system. This research will be reference to improve the measurement accuracy for future domestic space-borne laser altimeter.