Local Geoid height calculations with GNSS, airborne, and spaceborne Lidar data

Abstract

Determining the exact position of objects on the Earth’s surface is extremely important. The general purpose of this study is to calculate local geoid and orthometric heights of points obtained from ICESat-2/ATLAS, airborne LIDAR, and GNSS/CORS data and to investigate the performance of ICESat-2/ATLAS in predicting ground heights in urban areas. The calculated geoid and orthometric height values from ICESat-2/ATLAS were compared with the height values from the airborne LIDAR and GNSS/CORS data. In this study, a total of 52 points were collected in the field using the GNSS/CORS system. The accuracy of the geoid heights of these points was verified using three different methods: (a) using 12 local C1-C3 degree GPS leveling points, (b) using the new Turkey Geoid 2020 (TG20), and (c) using the improved TG20 dataset by applying interpolation methods. In addition, interpolation methods including weighted arithmetic mean, kriging, multi-quadratic, polynomial, and TIN were applied to our datasets. Statistical analyses including RMSE, MSE, MAE, ME, and R2 were applied to our datasets. As a result, the accuracy values based on polynomial interpolation method between LIDAR-ICESat-2/ATLAS were found to be as RMSE = 2.003 cm, MSE = 4.013 cm, MAE = 1.748 cm, ME = 0.004 cm, and R2 = 1.00. The accuracy values between GNSS/CORS-ICESat-2/ATLAS were found to be as RMSE = 3.091 cm, MSE = 9.558 cm, MAE = 2.723 cm, ME = 1.401 cm, and R2 = 1.00,. According to our results, the relationship between LIDAR-ICESat-2/ATLAS is better than the relationship between GNSS/CORS-ICESat-2/ATLAS.