Resrarch On Performance Charateristics Of Sodium Guide Star Light Space Communication System

The sodium guide has become a hotspot in adaptive optics because it can correct the wavefront distortion.Space optical communication is also important because of its strong anti-interference ability.However,the space optical communication link is difficult to build and can not efficiently implement one to many communication,so based on the combination of two technologies of sodium guide star and space optical communication,the idea of one-to-many space optical communication based on the light of sodium guide star is proposed,and the system characteristic of the communication method is modeled and simulated.The intensity distribution of the cross section of the Gauss beam when it is transmitted to the height of the sodium layer with a certain transmitting angle is simulated.According to the characteristics of the interaction between sodium atom and 589 nm laser,the density matrix is used to describe the influence of differ ent pulse signal laser emission parameters on the photon number of sodium atom.The trend of the number of received photon at the ground receiving end varies with different transmit and receive parameters is analyzed.Based on the height of the atomic layer in the mesosphere,the maximum data transmission rate of the sodium guide star optical space communication is analyzed,the influence of different transmit and receive parameters settings on the maximum transmission rate is researched.The receiving terminal power of sodium guide star light space communication system is analyzed,and the changing trend of the received power with different communication parameters is simulated.Considering the influence of atmospheric turbulence for the laser transmission,the Zernike polynomial is used to establish the numerical simulation of the multi unequal phase screen,and the intensity distribution of the laser which is transmitted to the 90 km layer is simulated and the number of photons produced by a randomly excited sodium atom and the average received power at receiver are calculated.The received photon number at the receiver and the change of the instantaneous power with the emission time are simulated.The received signal is compared with the transmitted signal to prove the reliability transitivity of the sodium guide star light information.In this paper,the optimal parameters selection of the communication link of sodium guide star light are studied when the communication distance is fixed.When the given communication distance is chosen,a communication scheme satisfying the communication data transmission rate or power is selected.The sodium guide star light space communication between one to many is studied.The influence of the elevation,azimuth and azimuth of the transmitter on each receiver is simulated when multiple receivers are not in the same line.The use of sodium guide star can innovate one-to-many space optical communication.The communication method has the advantages of a higher communication efficiency,the covert receiving end and the simple link construction,Which has a strong practical significance.The research of this paper has laid a theoretical foundation for the application of sodium guide light communication.