Space-based AIS multi-user separation based on the improved complex value FastICA

The coverage of the space-based automatic identification system (AIS) is wide and it can be used to monitor the global ships effectively. It also brings a new challenge that the collision of AIS signals from different cells results in loss of all collided message. In order to solve this problem, this paper proposes a multi-user separation scheme based on improved complex value FastICA. In this paper, we give full consideration to the communication mode and signal characteristics of the system. Meanwhile, a step factor is introduced to the complex value FastICA to reduce the algorithm´s sensitivity to initial value. In order to reduce the amount of calculation, the introduced step factor searched based on Wolfe-Powell. Simulation results show that the proposed scheme can separate the collided signals effectively.