The GNSS-Levelling Local Geoid Determination Using the Conditional Adjustment with Unknown Model

Abstract

GNSS-Levelling geoid determination is defined as the mathematical relation between orthometric and ellipsoidal height. The local polynomial surface interpolation method is one of the most widely applied methods for GNSS-Level-ling geoid determination. The basic solution of polynomial surface interpolation is based on the geoid undulation, the difference of orthometric and ellipsoidal height, including some undetectable measurement error. In this study, firstly, the1st, 2nd and 3rd degree polynomial surface were taken as the geoid surface to determine the appropriate polynomial degree for selected study area, Samsun province of Turkey, using ordinary least squares adjustment models. Then, the Conditional Adjustment with Unknown Model adjustment solutions are made for these real work data. At the end of application, the results were then compared to these models and some suggestions were made for future applications. © 2023, Croatian Geodetic Society. All rights reserved.