关键词: 全球数字高程模型, 动态精密单点定位, EGM2008, 精度检核

Abstract:

SRTM,ASTER GDEM and AW3D are typical global digital elevation models (DEMs) and they gradually play a critical role in many applications.This paper aimed to assess SRTM,ASTER GDEM and AW3D using GNSS dynamic precise point postioning (PPP) data.Firstly,we collected data by GNSS system fixed on the roof of a car along Guangzhou to Zhaoqing highway and subsequently obtained dynamic measuring data by PPP technology.Secondly,we transformed the ellipsoidal height of dynamic measuring points to orthometric height by earth gravitation model 2008 (EGM2008) and instrument height.Finally,four interpolation methods (Linear,Nearest,Cubic and Spline) are used to validate the orthometric heights of SRTM,ASTER GDEM and AW3D.The results show that the interpolation results of four methods have a good consistency and the standard deviations (STDs) of height of SRTM3 V4.1,ASTER GDEM V2,AW3D30 are better than 3.4,4.1,and 3.3 m respectively.The validating results of three DEMs are better than their target height accuracies of 16,17,and 5 m respectively.The proposed method is quick,efficient,and applicable for assessing DEMs.

Key words: GDEM, dynamic PPP, EGM 2008, accuracy check