On Mean Visibility Time of Non-repeating Satellite Orbits

Abstract

Depending on orbit altitude and orbit inclination a non-geostationary satellite offers different visibility times to fixed ground terminals. One can imagine that the moving sub-satellite point defines a ground track which crosses a small circle around a fixed ground station. This small circle itself is defined by the minimum elevation angle of the ground terminal. In this work we are interested in the mean visibility time of a non-geostationary satellite as seen by a fixed ground station. The paper provides a mathematical analysis and an approximation for the calculation of the mean visibility time. The former shows a good match with the simulation results at all latitudes, the latter provides a good approximation at low latitudes. The mathematical analysis is foreseen to be also useful for analyzing and designing complete satellite constellations.