Strapdown Airborne Gravimetry Based on Aircrafts and UAVs: Postprocessing Algorithms and New Results

The paper describes a new methodology for postprocessing raw data from a strapdown airborne gravimeter based on a navigation-grade inertial measuring unit and global navigation satellite system receivers (one is on board the aircraft and the others are placed on the ground). The key aspects of the methodology’s algorithms are outlined. We also present the numerical results (gravity estimates) from two airborne gravimetry surveys. The surveys were carried out using state-of-the-art strapdown airborne gravimeters on board a fixed-wing aircraft (An-3T) and helicopter-type unmanned aerial vehicle (UAV). In the first survey, the flights were flown in the draped mode with extreme vertical accelerations reaching 2.5 g, which appears to be the first case in airborne gravimetry. In the second survey, the UAV was flying at a constant altitude. The gravity estimation accuracy (RMS) varies from the sub-mGal up to 2-mGal level depending on campaign, with larger values corresponding to the draped flight survey.