Topology design algorithm for optical inter-satellite links in future navigation satellite networks

At present, deployment of optical inter-satellite link (OISL) payloads on future navigation satellites are planned for each global navigation satellite system (GNSS). The communication mechanism of an OISL is quite different from that of a radio link, so the existing topology optimization algorithms for radio links is difficult to adapt to the constraints of OISLs. We propose a topological optimization algorithm called multi-objective discrete binary particle swarm optimization (MODBPSO) to optimize the topology of OISLs for future navigation satellites. The emphasis is on minimizing the position dilution of precision (PDOP), point-to-point link delay and terminal idle rate costs. In our simulation test, the multiple complex constraints of OISL, such as maximum link distance, earth occlusion, terminal viewing field, number of terminals and fixed links, are fully considered. The simulation results show that in static topology optimization, MODBPSO can obtain 1-7 network topologies with lower PDOP, link delay, and link idleness rate than the multi-objective simulated annealing (MOSA) simultaneously in a single simulation test with different auxiliary parameters. Besides, it is convenient to select the appropriate solution from a non-dominated solution set for different priority requirements in dynamic topology optimization. In the simulation, we get a solution that can obtain lower average PDOP and link delay, but the terminal idle rate is relatively higher due to the influence of the link switching optimization strategy.