Surface elevation of Bowdoin Gletscher, Greenland in July 2013

Two sets of dual-frequency GPS (Leica Geosystems System 1200) were used to measure the surface elevation with a kinematic positioning mode. One GPS antenna was fixed on the bedrock at the eastern side of the glacier as a reference station. Another GPS antenna was mounted on a 2 m long pole to serve as a rover station. The survey was carried out along one longitudinal and three transverse profiles. Measurements were performed every ~20 m along the profiles. Three-dimensional coordinates relative to the reference station were computed by post-processing the data with GPS analysis software (Leica GeoOffice). The estimated error of the measurements is less than 5 cm.本研究采用两套双频GPS（dual-frequency GPS，Leica Geosystems System 1200），以动态定位模式开展地表高程测量。其中一套GPS天线固定于冰川东侧的基岩上，作为基准站；另一套GPS天线安装于2米长的杆体上，作为流动站。本次测量沿1条纵剖面与3条横剖面进行，沿剖面每间隔约20米完成一次数据采集。通过GPS分析软件（Leica GeoOffice）对原始数据进行后处理，解算出相对于基准站的三维坐标。本次测量的估算误差小于5厘米。