Derivation Of Gravity Anomalies From Airborne Gravimeter And Imu Recordings-validation With Regional Analytic Models Using Ground And Satellite Gravity Data

摘要

For testing the performance of the upgraded LaCoste and Romberg airborne gravimeter S124 and evaluating the newly updated software, an airborne gravity test campaign has been carried out in the northern part of Germany by GFZ Potsdam in autumn 2006 using the aircraft Cessna 404 of "Hansa Luftbild" Company, Muenster. We present the results of a profile flown SW-NE in both directions at a nearly constant mean altitude of ～1100 m with a ground speed of ~230 km/h, crossing one of the most pronounced gravity anomalies in Central Europe with peak-to-peak amplitude of about 70mgal. The scalar gravity anomalies along the flight trajectories have been derived from the airborne gravimeter taking into account platform recordings and data from the GPS-controlled Inertial Measurement Unit (IMU) Aerocontrol IIb. All common corrections have been performed on the raw gravity data. Due to problems in GPS recording, we used the IMU data only. To verify the airborne gravity results, ground-based and satellite-derived gravity data have been used to compute local analytical gravity field models in a new methodological approach that allows the calculation of gravity anomalies at flight altitudes. For the most part there is a good agreement between the INS-airborne-derived and the independently modelled gravity anomalies, yielding best results of about 3.5mgal RMS.