Research On The Multiplexing Technology Of Tracking And Communication Based On The Four Quadrant Detector

Space laser communications technology has become one of the most effective methods to solve the bottleneck of the radio frequency communication. With the development of small satellite technology, the miniaturization requirements for the laser communication terminal have been imminently. This paper introduces a space laser communication multiplexing technology based on four quadrant detector for tracking and communications. We use single detector to complete the function of multiple tasks which could effectively reducing the weight and capacity of the system and improve the light energy utilization. This technology have significance meaning for the miniaturization of laser communication terminal.At first, this paper introduces the laser communication technology development,and emphasis on the current situation of the development for the small terminal and the tracking system and communication system principle. Secondly, we analyzed the basic principle of the four quadrant detector for tracking detector and the influence of the spot size, the spot pattern, the background light and the dead area characteristic for centroid detection. The performance parameters and noise components of the four quadrant detector are also analyzed. In the last, we propose the plan and target in tracking and communication multiplexing technology based on the four quadrant detector. We realize the electronic hardware system in this system in final.In the end of this paper, we test the hardware system, the communication rate can reach 10 Mbps by the modulation of Manchester code, the detection limit sensitivity is-33 dBm, the bit error rate is 10-7. For the minimum position resolution of the spot centroid detection is 1.5um, the angular resolution is 0.7?rad. The accuracy of random vibration tracking error is the 2.5?rad(P-P value) ? We preliminarily verified the feasibility of using the four quadrant detector as the tracking and communication multiplexing detector and lay the foundation for small laser communication terminal.