A Graph-Theoretic Approach to Optimal Planning of Satellite Downlink Operation

Abstract

A satellite in an elongated elliptical orbit may be operated while switching the configuration for communications according to changes in altitude. Although such operation is generally complicated as compared with a satellite in low Earth orbit, there is still a common desire to maximize the amount of downlink data. To this end, the operation plan for communications configuration needs to be optimized in detail according to momentary changes, so that more data can be downlinked. Conversely, switching the configuration many times leads to an increase in the operational load for satellite operators. We thus want to control the number of configuration changes. This problem of creating such an operation plan is too complex to be dealt with solely by human operators. In particular, as there are more options in configuration, the number of combinations increases exponentially. Therefore, by representing the operation plan graphically, this paper reduces the planning problem to a shortest path problem, and solves it to obtain an operation plan for maximum downlink. We also introduce parameters to adjust configuration changes, and obtain the correlation between the amount of downlink data and the switching frequency.