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.