Acquisition Technology Of Optical Telescope For Satellite-to-ship Quantum And Laser Communication

Quantum communication is the only form of communication that has been rigorously proven to be secure.The oceans cover 71% of the earth's surface,and the environment is very different from that of the continents,with no communication infrastructure.It is of great significance to expand the coverage area of quantum/laser communication and construct a quantum/laser communication network covering the whole world.The objects of quantum/laser communication are extended to various mobile platforms,including offshore mobile platforms,so as to realize the quantum cryptography and laser communication between the shore and sea,in and between the marine formation,and improve the security protection level of cryptography communication and the bandwidth of information transmission.In the future,based on the "integration of earth and sky" quantum/laser communication network,a multi-dimensional cross-platform quantum/laser communication network can be formed,which can meet the high level of information security protection needs.Satellite-to-ship laser communication or quantum communication is still a blank at home and abroad.The shipborne telescope is designed to establish and maintain a highly dynamic communications link.Unlike ground-based telescope systems,the complexity of the marine environment greatly increases the difficulty of acquisition and tracking.It is difficult to realize the quantum or laser communication between satellite and ship with long distance and strong disturbance under the condition of random and violent oscillation of wave.The research background of this dissertation is quantum/laser communication,and the key technologies of satellite-to-ship optical axis acquisition are deeply and systematically studied.Aiming at the problem that the shipborne telescope is difficult to acquire the long distance and strong disturbance of the satellite to the ship's Line-of-sight(LOS)under the condition of random and violent swing with the wave,the research on the satellite-to-ship quantum/laser communication system and link establishment is carried out.The components,main functions,performance indexes and working principles of the telescope system are discussed.The specific functions of the quantum laser communication system are given.This dissertation discusses that the shipborne quantum laser communication telescope system is the core unit of the quantum laser communication system and is the prerequisite and necessary condition for the establishment of the communication link.The factors that affect the acquisiton performance are analyzed,including field of Uncertainty(FOU)Area,divergence angle of beacon,initial acquisiton time,loss and reacquisiton time of LOS.The relationship between acquisiton stability and link connectivity is analyzed.The disturbance of ships at sea is also discussed.Aiming at the problem that it is difficult for shipborne telescope to reduce the FOU under the strong disturbance of sea waves,the shipborne telescope's high-precision LOS pointing technology under the condition of strong disturbance of sea is studied.A LOS pointing model of the tracking system is constructed,which considers the influence of various factors.The influence of various errors and the model form are analyzed.A semi-parameter estimation method based on supervised learning is proposed based on the characteristic analysis and modeling of the model.A robust estimation method based on data depth weighting is proposed for the existence of gross error.A measurement system error estimation method is proposed to suppress the influence of gross error.Finally,the effectiveness of the proposed method is verified by simulation experiments.In order to solve the problem of satellite-to-ship quantum/laser communication link interrupt recapture,this dissertation develops a recapture technique based on CKF trajectory prediction for shipborne telescope under strong sea disturbance.The motion measurement model of the shipborne telescope and the dynamics model of the satellite terminal are constructed.Combined with uncertainty of ship roll measurement error and uncertainty of model error of target orbit,a trajectory prediction and reacquisiton technique based on CKF enhanced filtering and adaptive filtering is proposed.To ensure the realization of high precision satellite orbit prediction,so as to reduce the lost reacquisiton time,increase the communication time.The effect of fast reacquisiton method is simulated.The effectiveness of the proposed method is verified by simulation experiments.Field experiments were carried out at sea.This dissertation introduces a series of experiments on improving and verifying the LOS acquisition of shipborne quantum laser communication.The open loop pointing error(RMS)of the several stars the azimuth is 25.88",the pitch is 32.75",and the total open loop pointing error is 41.7".At the same time,it is verified that pointing accuracy has stability and can be applied for a long time.There was no significant change in telescope pointing error during the voyage.The acquisition and tracking experiment of " micius" was completed at sea.Micius was acquired three times on board with a 100% acquisition probability,an initial capture error(RMS)azimuth of 58.8" and a pitch of 36.9"(including orbital prediction errors).The initial acquisition of micius quantum satellite was successfully carried out by a modified shipborne telescope.Acquisition time was less than 3 seconds.