利用境内气象站观测数据的激光测高仪大气延迟改进算法

由大气层折射率分布不均匀引起的大气折射延迟是星载激光测高仪测距误差的主要来源之一，其主要受地表气压的影响。目前计算地表气压方法仅有美国GLAS系统使用的基于NCEP气象数据和时间空间的内插方法，GLAS系统观测相对平坦的南北极冰盖区域的精度足够，但观测地表起伏复杂的陆地目标的精度较低。文中利用国内气象站的观测数据，基于改进的反距离加权内插算法对大气折射延迟修正方法进行改进，并与传统GLAS方法的修正结果进行精度对比。在高原地区以及高纬度地区，采用国内气象数据和新的内插算法可以将修正残差由超过2 cm降低至小于0.5 cm，相对GLAS系统整体15 cm的测量精度，相当于整体精度提高10%，对于未来国产卫星激光测高仪测量精度的提高将有一定参考价值。

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.