The Grid Optimization of The Terrestrial Gravity Survey (Case Study: Central Part of Java Island)

BIG has conducted gravity data by using several methods, namely terrestrial gravity and airborne gravity to produce high accuracy of the geoid. The terrestrial gravity survey was carried out using the grid method, and BIG does not have any guidance on the size of the used grid interval size. We try to divide the grid interval into four different sizes of grids, those are km, 10 km, 15 km, and 20 km. A case study in the central part of Java Island, at Semarang and Yogyakarta in 2019, using Scintrex CG-5 relative terrestrial gravimeter equipment. By using the integral stokes and Least Square Collocation (LSC) approaches, the gravimetric geoid is obtained from each grid interval. We compared gravimetric geoid with geometric geoid on 179 vertical benchmarks and obtained the results of the 5 km grid interval having the smallest average value of 0.273 meters ± 0.310 with the most appropriate conformity test.