Polynomial Model for Determination of Local Geoid

A Case Study of University of Maiduguri, Borno State, Nigeria

Abstract

Conversion of ellipsoidal heights of Global Navigation Satellite System (GNSS) observations to orthometric heights for efficient use requires an accurate determination of the local geoid which is essential for myriad of applications, ranging from precise positioning to other geodetic studies. However, local geoid has not been adequately determined in several locations globally. This thesis presents a comprehensive study on the development and application of a polynomial model for the determination of the local geoid, with a specific focus on the University of Maiduguri, located in Borno State, Nigeria. The research reviewed of existing geodetic methods and models, highlighting the limitations and challenges faced in the local context. Then, an innovative polynomial model is proposed and developed to address the specific geoid determination requirements of the study area. The model integrates ground-based measurements, satellite data, and advanced computational techniques to enhance accuracy and reliability. The methodology employed involves an extensive data collection campaign, incorporating precise leveling data, and GNSS observations. The collected data are processed and analyzed to derive the coefficients of the polynomial model, tailored to the local characteristics of the University of Maiduguri region. The research used rigorous least square technique, to compute eleven coefficients for the model, by Least squares adjustment procedure in Matlab environment. The result from the adjusted geoid models to the survey data at 31 points revealed that the mean accuracy of local geoidal heights at 0.026, and EGM20 - 5.624m level was attainable The study revealed the effectiveness of the proposed polynomial model in accurately determining the local geoid, providing valuable insights into the geodetic landscape of Borno State. The results were validated through comparisons with existing geoid models and ground truth measurements, demonstrating the model's robustness and applicability. This research contributes to the advancement of geodetic techniques in the specific context of Borno State, Nigeria, and lays the groundwork for further studies in geoid modeling and its applications in regional geosciences is hereby recommended.