Attitude dynamics and control of a vertical interferometric radar tethered altimeter

This paper investigates the attitude dynamics and control of a vertical interferometric synthetic aperture radar tethered altimeter: a system based on two space platforms of comparable mass connected by 1-km tether. Two vertically spaced physical antennas on these platforms supply the terrain height measurement data by making use of radar interferometry. Since the height accuracy is strongly affected by the combined dynamics of the two platforms, this paper will focus on the analysis and control of high-frequency attitude oscillations. The results show that the proposed control system can limit the attitude angle differences and rates to 10 ~ 3 and 10 ~ deg/s, respectively, as required by the proposed application.