Design of an Open-Loop gust alleviation control system for airborne gravimetry

Aircraft operation at low altitude is affected by turbulence producing additional aerodynamic forces and moments. This results in aircraft acceleration and reduces the performance of an airborne gravimeter substantially. To reduce this effect, a gust alleviation control system is necessary. In this paper the control performance of an Open-Loop Control System is examined in the frequency and time domain. The analysis is made by computation of the power density spectra of the vertical and the horizontal acceleration in geodetic co-ordinates. The design objective for the gust alleviation system is a considerable improvement of the gravity measurement accuracy, in particular in the frequency range between 0 Hz and 1 Hz. The requirements of the gravity measurement are at 1 km anomaly wavelength and 1 mGal of accuracy.