采用南加州地区294个连续GPS观测站的高程资料,本文对该地区的SRTM高程精度进行了评估和验证。结果显示,经过大地水准面差距补偿后(GPS和SRTM分别采用参考椭球面和EGM96大地水准面作为高程基准),SRTM和GPS高程的差异非常小,基本上在0附近波动。高程差异小于10m、20m、30m的点的比例分别达82.7%、93.9%和98.3%。差异的均值为-4.28m,差异的标准偏差为±8.63m。因此该地区的SRTM高程精度优于标称的±16m。
Based on the height data of 294 continuously operated GPS stations in South California, USA, this paper evaluates and validates the height accuracy of SRTM data of that area. The results show that, after considering the Geodi-spheroid separation (the reference ellipsoid and the EGM96 Geoid are used as vertical datum for GPS and SRTM respectively), the height differences between SRTM and GPS are very small. The ratios of the stations which height difference are less than 10m, 20m and 30m should reach 82.7%, 93.9% and 98.3 %, respectively. The mean of the overall difference is - 4.28m and the standard deviation of the difference is ±8.63m, indicating that the accuracy of the SRTM height in this area is better than the nominal ±16m.