Comparative Analysis of Ellipsoidal Elevation Surveyed by GNSS System, SRTM and ASTER GDEM
COMPARATIVE ANALYSIS OF ELLIPSOIDAL ELEVATION SURVEYED BY GNSS SYSTEM, SRTM AND ASTER GDEM
R. Noetzold1,2, M.C. Alves1,3, J.A.F. Sobrinho1, R.A. Gallon, M.J.P.A. Oliveira1, H.H.T. Borges1,R.T. Silva1
1.Federal University of Mato Grosso, Cuiabá – MT
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Abstract: The aim of this study was to compare the ellipsoidal height using the GNSS system, SRTM images and Aster GDEM images. The survey was conducted on the campus of Federal University of Mato Grosso, Cuiabá - MT. The static surveying was performed in 27 neighboring points, where a Global Navigation Satellite Systems (GNSS) receiver was installed as a base. Subsequently, we performed the real time kinematic survey supported on adjusted basis to obtain the correct elevation data of 3883 points. Then, the data base were processed and corrected by the Precise Point Positioning Method. The elevation data from SRTM and Aster GDEM models, extracted by the nearest neighbor technique were used for comparation. Subsequently we compared the GNSS data with the data extracted from the images, SRTM and ASTER, by linear regression, and we performed the calculation of Root Mean Square Error (RMSE). The results showed: R² of 0,84 between Aster GDEM and GNSS; 0,86 between GNSS and SRTM and 0,83 between Aster GDEM and SRTM . A similar result was obtained by RMSE, where the biggest error occurred in the comparison between Aster GDEM and SRTM data.
Keywords:Digital elevation model, Accuracy, Global navigation satellite survey.