COMPARISON AMONG DIFFERENT TECHNIQUES OF PREDICTING GEOID UNDULATION | ||||
The International Conference on Civil and Architecture Engineering | ||||
Article 34, Volume 7, 7th International Conference on Civil and Architecture Engineering, May 2008, Page 348-373 PDF (423.16 K) | ||||
Document Type: Original Article | ||||
DOI: 10.21608/iccae.2008.45518 | ||||
View on SCiNiTO | ||||
Authors | ||||
Ghazal, G. N.1; Fathalla, T. F.2; Ibrahim, S. H.3; EL-DESOKY, A.M. I.4; Mossa, O. M.4 | ||||
1Lt col. Officer, research student for M.sc. degree M.T.C. | ||||
2Assistant professor, Ain Shams faculty of engineering, Ain Shams University, Cairo, Egypt. | ||||
3Assistant professor, Shoubra faculty of engineering, Cairo, Egypt. | ||||
4Military technical college, Cairo, Egypt. | ||||
Abstract | ||||
The height measurements by Global Positioning System ,GPS, which measures the heights with respect to the reference ellipsoid make confusion with the height of Mean Sea Level (MSL) which determined with respect to geoid. The datum that defines the MSL (also called the geoid) is a complex surface that requires dense and accurate data to define its shape. In this study, ellipsoidal heights of data points were determined from GPS measurements, with respect to WGS84 reference ellipsoid, and we know accurately the undulation of these points at specific locations inside the cairo city. The objective of this research is to predict the undulation of unknown points by using different prediction techniques. Four different prediction methods were used to determine geoid undulation. These methods are: inverse distance weighting method, triangulation method, radius search method, and nearest neighbor method. Comparison among different techniques were applied. Distance as a common variable for all different techniques is used to compare the accuracy for the different resulted values of Geoid undulation. Most results show that the triangulation prediction method is the best for prediction of Geoid undulation. | ||||
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