Satellite downlink scheduling problem: A case study

TL;DR

This paper addresses the complex downlink scheduling problem for SAR satellites, proposing a fast, abstracted scheduling method and empirically comparing meta-heuristics to improve efficiency over existing approaches.

Contribution

It introduces a fast schedule generation procedure that simplifies constraints and identifies the most effective meta-heuristic for SAR satellite downlink scheduling.

Findings

The proposed method outperforms current scheduling approaches.

Meta-heuristics vary in effectiveness; the best one is identified.

Empirical results demonstrate improved scheduling efficiency.

Abstract

The synthetic aperture radar (SAR) technology enables satellites to efficiently acquire high quality images of the Earth surface. This generates significant communication traffic from the satellite to the ground stations, and, thus, image downlinking often becomes the bottleneck in the efficiency of the whole system. In this paper we address the downlink scheduling problem for Canada's Earth observing SAR satellite, RADARSAT-2. Being an applied problem, downlink scheduling is characterised with a number of constraints that make it difficult not only to optimise the schedule but even to produce a feasible solution. We propose a fast schedule generation procedure that abstracts the problem specific constraints and provides a simple interface to optimisation algorithms. By comparing empirically several standard meta-heuristics applied to the problem, we select the most suitable one and show that it is clearly superior to the approach currently in use.