Accuracy Assessment of ICESAT Laser Altimeter Data Using GPS Measurements

The elevations from ICESAT were compared with that from GPS RTK and static GPS measurements.For points along the satellite ground tracks,linear interpolation was used to get the heights of GPS points and compared to the geodetic heights,a minimum of 0.76 m is found for the GPS RTK points.For GPS points near the satellite ground tracks,the points along the ground track are selected by the longitude and latitude differences,5″,10″ and 20″ are used respectively.The heights of the GPS points were interpolated using different interpolation methods,such as arithmetic average,spline,etc..At the point where path of GPS RTK intersects with the ICESAT ground track,a minimum height difference of 0.381 m was found.Static GPS measurement about 45 minutes were carried out near the ICESAT ground tracks.And the coordinates were solved using the continuous operating reference stations with an accuracy better than 0.08 m.A minimum height difference of 0.103 m was found between GPS and ICESAT.