Line-of-sight-pointing for satellites in high altitude inclined elliptic orbits

Abstract

With a growing demand for space communications and resulting overcrowding of geostationary orbit (GEO), the importance of high altitude inclined elliptic orbits is gaining impetus. However, the satellites in these orbits suffer from a severe problem of apparent periodic angular drift around their line-of-sight. This paper addresses this problem and proposes a cost effective method based on tether to continually tilt the satellites in order to compensate for longitudinal and lateral drifts relative to the ground station. The proposed system comprises satellites connected by a flexible tether at a point on each satellite with offsets. A control strategy, is developed for tether offset variations, that ensures judiciously controlled changes in the satellite orientations. The numerical simulation of the governing nonlinear equations of motion establishes the feasibility of the concept. A high degree of line-of-sight pointing of dual satellites as well as the simplicity of the proposed control mechanism make the concept particularly attractive for future space applications.