利用车载动态PPP技术检核SRTM、ASTER GDEM和AW3D模型的高程精度

SRTM、ASTER GDEM和AW3D是比较有代表性的全球数字高程模型。本文探讨了采用车载动态PPP技术对上述3类模型的区域高程精度进行检核，首先沿广州至肇庆公路进行连续数据采集，采用动态精密单点定位（PPP）技术解算动态点的WGS-84坐标；然后利用EGM2008重力场模型和仪器高获得动态点的正常高；最后采用4种不同的插值方法对SRTM、ASTER GDEM和AW3D模型进行高程检验。检核结果显示：不同的插值方法具有较好的一致性，SRTM3 V4.1、ASTER GDEM V2、AW3D30的高程标准差分别优于3.4 m、4.1 m和3.3 m，均优于其全球标称高程精度；本文检核方法快速高效，有较好的适用性。

Elevation Accuracy Assessing of SRTM,ASTER GDEM and AW3D Using GNSS Dynamic Precise Point Positioning( PPP) Data

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.