Graph Based Task Scheduling Algorithm for Earth Observation Satellites

Task planning plays a vital role in the application of the earth observation satellites (EOS) as it can effectively reduce the task execution delay and the system energy consumption. However, it is a classic NP-hard problem. In this paper, we propose a graph-based scheduling algorithm to match the to-be-observed tasks with the sensor resources for the multi-satellite multi-task scenario. Specially, we construct a collision avoidance clustering graph (CACG) to model the relationship between tasks and resources, where the concept of collision set is creatively constructed to characterize the conflict relationships among tasks. Through analyzing which nodes can be a clique in the graph, we can get the aggregated tasks. As such a CACG-based algorithm is proposed to achieve satellite task scheduling, where three criteria,i.e.,the N-priority criterion, the T-priority criterion and the collision avoidance rule, are proposed to enhance the percentage of the completed task and decrease the delays. Finally, we demonstrate the effectiveness of the proposed schemes through simulations.