Research on APT coarse tracking in free-space laser communication

Acquisition,pointing,and tracking(APT) systems in free-space laser communication are mainly composed of coarse tracking system and fine tracking system.The acquisition of target signal is specifically completed by coarse tracking system to make sure beacon light lie in the dynamic range of fine tracking control system.In this paper,the application of the particle filter in coarse tracking system of APT was presented.Considering the existing problems on the particle filter introduced into the track algorithm,the likelihood model including color and outline dual information fusion was designed.In order to improve the effectivity of the track algorithm under abnormal circumstances,the anomalous detection and recover strategy were adopted.And then simulative system was implemented for tracking facula object.Experimental results show that the likelihood model of multiple information fusion can ensure object tracking even in background interference,posture variety,scale variety and partial occlusion environment.The stability of atmosphere laser communication link can be further improved.