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

Determining the exact position of objects on the Earth's surface is extremely important. The general pur-pose 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 pre-dicting 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 data -set 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.(c) 2022 National Authority of Remote Sensing & Space Science. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).