System functions estimates for airborne gravimetry

Abstract

One major challenge in airborne gravimetry is increasing not only accuracy but also spatial resolution of both necessary observations for gravity g=a-b, total acceleration (a) and kinematic acceleration (b). To this end, it is necessary to study system characteristics of all components involved. This enables to avoid subsystems mismatch resulting in information loss and to tune hardware and model parameters. The main observation subsystems in our approach are GPS (L1 or L1L2 50/s) receivers (Javad & Novatel) and QFlex_QA3000 accelerometers which are mass/spring systems indicating the specific force; but also ancillary components such as dampers, the aircrafts body itself etc. play a major role. The investigations are based on data from flights as also from experiments such as stroke tests and observations on a kinematic test stand for aircraft-like kinematic height variations. The system characteristics of various components were determined and represented by means of transfer functions or parametric models. Some of these were in agreement with prior information, others were not. This shows that such own tests can make a significant contribution to the improvement of air-borne gravimetry. Also, the various test approaches proved to be useful and complementary.