Airborne Bouguer gravity based on synchronous terrains surveyed using helicopter airborne gravimetry

Large-scale mining activities have been continued in key exploration areas. Consequently, the mined-out areas, waste dumps, and tailings ponds of mines are constantly deforming. As a result, the digital terrain method fails to make the terrain data closely match the airborne gravimetric data, leading to serious correction errors in airborne gravity terrain correction and stone-slab correction. This study calculated the difference between the GNSS geodetic height and the radio terrain clearance altitude of the helicopter gravity and magnetic survey system and then converted the GNSS geodetic height into normal height. Then, the synchronous surveyed terrains were obtained through leveling and fine-scale processing. Moreover, the surveyed terrain data, together with various collected terrain data, were compared with the ICESat-2/ATL08 spaceborne laser elevation. The results show that the surveyed terrains Wxd100 and Wxd400 had elevation precision of 5.33 m and 8.93 m, respectively. After airborne Bouguer gravity correction was conducted using the surveyed terrains, the data quality of the mining area and several typical survey lines was greatly improved.