详细阐述了利用GLAS数据和GPS数据生成Dome-A地区DEM的方法。首先进行GLAS数据转化, 便于与GPS数据结合, 提出一种快速搜索GLAS和其光斑(Footprint)覆盖GPS点的算法, 比较GLAS数据和GPS数据发现, 均值差异最大为1.118 m, 最小为0.997 m, 而标准差稳定为5-6 cm, 在进行椭球变换修正之后, 差值最大为0.405 m, 最小为0.284 m;之后利用改进的角度限差法沿测线对GPS数据进行特征点提取, 得到抽稀之后的数据;再利用抽稀之后的GPS数据和处理后的GLAS数据使用克里金插值方法生成研究区DEM。利用1199个GPS点和53个GLAS检验点对最后生成的DEM进行了精度分析, 残差中误差为5 cm, 最大残差绝对值为12 cm。利用原始GPS数据, 原始GPS数据和GLAS数据, 处理后GPS数据利用克立金插值方法分别生成了研究区的DEM, 通过等高线提取分析以及检验点的误差分析, 处理后的GPS数据生成的DEM要优于原始GPS数据的, 证明GPS处理的必要性。

A method is presented for combining GPS and GLAS data to produce a high-quality DEM. First, the GLAS data was transformed so that it could be combined with GPS data to produce a DEM. An algorithm was selected to locate GLAS points and the GPS points covered by GLAS footprints were highlighted. Comparison of the two types of data indicates that the maximum and minimum mean height differences are 1.118 m and 0.997 m, respectively, with a stable standard of about 5-6 cm. The maximum and minimum values became 0.405 m and 0.284 m after rectification by ellipsoid transformation. Detailed components of the error are also discussed. Next, sparse GPS data were extracted as feature points along the GPS measurement profile using a revised angle limitation method. Finally, a DEM was produced for the Dome-A using processed GPS data and transformed GLAS data. 1199 of the GPS points and 53 of the GLAS footprints were used to validate the DEM, with 5 cm and 12 cm as the mean and absolute maximum, respectively, of residuals. Additionally, three other DEMs were produced using original GPS data, original GPS data and GLAS data, and processed GPS data. The DEM produced with processed GPS data exhibited better accuracy than that produced from original GPS data according to comparison of contours and residuals of check points, confirming the importance of the GPS process.