Feasibility study of normal height system in Taiwan
Journal
Proceedings - 39th Asian Conference on Remote Sensing: Remote Sensing Enabling Prosperity, ACRS 2018
Journal Volume
5
Pages
3215-3221
Date Issued
2018
Author(s)
Abstract
The normal height system is based on the quasi-geoid, which represents the vertical distance from the quasi-geoid to terrain surface. To make possible an accurate normal height system, the normal gravity should be first determined. This study aims to build the quasi-geoid by using local gravity observations and a global spherical harmonic model in Taiwan. The quasi-geoid undulation was first computed by using the global Earth Gravity Model 2008 (EGM08) with a spherical harmonic model. In addition, the influence of terrain was also considered in the residual terrain model. The hybrid method was then used to construct a high-Accurate quasi-geoid component model in conjunction with the remove-compute-restore method, which includes surface curve fitting method. Finally, the normal heights were transformed by calculating the difference between the GNSS-derived geometric heights and the results of quasi-geoid undulation model. To evaluate its practical feasibility, the estimated normal heights were compared to the orthometric heights as adopted in Taiwan's national datum. Based on the numerical results, the mean relative difference to the orthometric heights is about 1.5cm per kilometer. It reaches the accuracy level that fulfils the needs of most engineering applications, but with less cost than that of the traditional approach for maintaining the orthometric height system. ? 2018 Asian Association on Remote Sensing. All Rights Reserved.
Subjects
Cost engineering; Curve fitting; Global positioning system; Harmonic analysis; Landforms; Earth gravity models; Engineering applications; Global Navigation Satellite Systems; Height datum; Normal height; Orthometric height system; Residual terrain models; Spherical harmonic models; Remote sensing
Type
conference paper