Prototype development of multi-target tracking system for space multi-node laser communication network

Abstract

Laser communication network is the future trend, but the disadvantage of a traditional laser communication system is that it can only transmit with a single node. To solve this problem, we propose a multi-target tracking technology to simultaneously establish multiple laser communication links. This study also develops a multi-target detection method based on beacon modulation and code division multiple access, proposes an optical antenna central stabilization method, and enhances the controller of the fast steering mirror (FSM) to improve the tracking performance. To verify the feasibility of our proposed method, we build a prototype system for multi-target laser communication and conduct the corresponding experiment. The experiment simulates the multi-target tracking situation by three beam emitting subsystems, and the dynamic tracking performance of the prototype system is verified by applying perturbations through a shaking table. Results show that the proposed method can effectively extract the position of the target in the mixed beam, with an average detection deviation of 2.95 μrad compared with when only a single beam is incident. The introduction of central stabilization enhances the dynamic tracking performance of the optical antenna. Tracking accuracy of the optical antenna is 24.63 μrad when attitude disturbance is applied. The improved controller enhances the performance of FSM, composite tracking accuracy is 5.69 μrad, and tracking error is reduced by 22.16% compared with the traditional PI controller. Performance also improved by 45.42% compared with when there was no improvement. Experimental results verify the effectiveness of the multi-target tracking system. On the basis of the proposed method, we achieve simultaneous tracking of multiple targets in different directions and significantly improve the dynamic tracking performance.