Scheduling Running Modes of Satellite Instruments Using Constraint-Based Local Search

Cédric Pralet, Solange Lemai-Chenevier, Jean Jaubert

Abstract: In this paper, we consider a problem involved in the management of Earth observation satellites. The input of the problem is a time-stamped observation plan and the output is a schedule of transitions between running modes of instruments available on board. These transitions must be scheduled so as to effectively realize the acquisitions requested, while satisfying several constraints, including duration constraints, non-overlapping constraints, and resource constraints over the thermal consumption of instruments. Criteria such as the minimization of the number of times instruments are switched off are also considered, for long-term reliability issues. The scheduling problem obtained needs to be solved several times per day, and the requirement is to produce good quality solutions in a few seconds. To produce such solutions, we propose a specific constraint-based local search procedure. Experiments are performed on realistic scenarios involving hundreds of observations, and the approach is compared with other techniques.