| Free space optical communication than traditional microwave communication has greater bandwidth capacity,higher data transmission,stronger anti-jamming ability,the stronger the advantages of the confidentiality,its application prospect is very broad.However,because space optical communication is susceptible to atmospheric attenuation,atmospheric turbulence and jitter deviation,the probability of interruption of communication system is greatly increased,which limits the practical application of space.In addition,when the space optical communication system is in normal communication,it is necessary to monitor the operating state of the system in real time and adjust it timely.This not only increases the actual cost of the system,but also very high requirements for operators.This is also an obstacle to the practical application of space optical communication.In this paper,the spatial optical communication system model is introduced,the system SNR under the coherent detection system is given,and the effects of atmospheric attenuation,atmospheric turbulence and tracking error on system performance are discussed in detail,and corresponding numerical simulation analysis is performed.The system probability density function based on the joint effect of the EW channel model is deduced.Then,based on the obtained system probability density expression,the article derives the outage probability of the system,and analyzes its relationship with transmission distance,atmospheric turbulence intensity,normalized jitter deviation,and normalized beamwidth.Corresponding numerical simulation analysis shows that increasing the receiving aperture can improve the outage probability of the system.Increasing the beam width can significantly reduce the outage probability of the system,such as when the normalized SNR is 20 dB and the normalized beam width is 4.The outage probability of the system has been reduced to 0.03.The signal-to-noise ratio of the system can be appropriately reduced to lower the outage probability of the system.The data obtained in the simulation can be used as a reference for the actual design of the system.Finally,this paper gives the design of performance monitoring device and implements the system.The article starts with the APP on the mobile phone side to introduce the technical principles and technical difficulties in detail,and analyzes the key codes.Then it analyzes the design method of the lower computer,introduces in detail the control of the ARM core board to the turntable motor,and initializes and captures the camera.Save and send graphics and drive the SMS transceiver module.Finally,an indoor test was conducted to verify the functional feasibility of the system,the stability of the system and the corresponding delays,and satisfactory results were obtained. |
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