tailieunhanh - Improvement of the accuracy of the quasigeoid model VIGAC2017

This scientific article will introduce a first research result for improvement of accuracy of the quasigeoid model VIGAC2017 on the base of it’s fitting to 194 national quasigeoid heights by the least squares collocation. Research results show that accuracy of the quasigeoid model VIGAC2017 will be obtained at level of ±0,058 m and increased to 20,69 % | Vietnam Journal of Earth Sciences, 40(1), 39-46, Doi: Vietnam Academy of Science and Technology Vietnam Journal of Earth Sciences (VAST) Improvement of the accuracy of the quasigeoid model VIGAC2017 Ha Minh Hoa Vietnam Institute of Geodesy and Cartography (VIGAC) Received 14 June 2017; Received in revised form 25 October 2017; Accepted 10 November 2017 ABSTRACT A national spatial reference system will be constructed based on a highly accurate national quasigeoid model with accuracy more than 4 cm. In Vietnam at the present stage there isn’t a detailed gravimetric measurement in mountainous regions and marine area. So with the purpose of improvement of accuracy of the national quasigeoid model VIGAC2017, we only can solve the task of fitting this model to national quasigeoid heights obtained from heights GPS/first, second orders levelling quasigeoid heights through least squares collocation. This scientific article will introduce a first research result for improvement of accuracy of the quasigeoid model VIGAC2017 on the base of it’s fitting to 194 national quasigeoid heights by the least squares collocation. Research results show that accuracy of the quasigeoid model VIGAC2017 will be obtained at level of ±0,058 m and increased to 20,69 %. Keywords: National spatial reference system; national quasigeoid height; least squares collocation; covariance matrix; semivariogram; semivariance function. ©2018 Vietnam Academy of Science and Technology 1. Introduction 1 A wide application of GNSS technology with GNSS data processing in ITRF and a combined usage of detailed gravimetric data and more accurate with every passing day Earth Gravity Model (EGM) for the construction of a highly accurate national quasigeoid model naturely lead to a bulding of a national spatial reference system. Ha Minh Hoa, 2017 had found that the most impotant base for the bulding of the national spatial reference system is the .