A Pipelined Synchronization Approach for Satellite-based Automatic Identification System

Because of the wide field of view (FOV) to monitor vessel movements, satellite-based automatic identification system (S-AIS) has been promoted in recent years. However, synchronization is a tough work in S-AIS receiver because of the large Doppler shift and serious signal collision resulting from simultaneous transmission in the FOV of a satellite. In this paper, we propose a pipelined synchronization approach with good performance and low complexity. It consists of three parts, i.e., packet detection, windowing and timing recovery, and frequency and timing offset estimation, which can be implemented in feedforward structure with low complexity. Simulation results show that the proposed synchronization approach has significant performance gain compared with existing algorithms and provides an acceptable estimation range to cope with large Doppler shift and message collision.