Research And Implementation Of Intelligent Decision Technology For The Downlink Of Telemetry Tracing And Command System

With the continuous advancement of space exploration,aerospace TT&C system,as the lifeline of communication between spacecraft and ground station,is the key to ensure the smooth development of aerospace missions.However,the open TT&C frequency band makes it difficult to achieve reliable communication only depending on the antijamming capability of the TT&C system itself in the face of complex electromagnetic environment with all kinds of interference.Therefore,the TT&C link needs to enhance its adaptability to the environment to ensure efficient data transmission of the system.This thesis combines the idea of cognitive radio,focuses on the research of intelligent decision-making technology for downlink of TT&C system,designs anti-interference intelligent decision-making scheme,and completes FPGA development and verification based on hardware platform.The main research work completed is as follows.First,an intelligent decision-making scheme for the downlink of the TT&C system is designed.After studying the principle of TT&C system,an anti-jamming intelligent decision-making scheme is designed according to the composition of downlink and the parameter characteristics of measurement and telemetry links.At the same time,in order to evaluate the link performance under different parameter configurations reasonably,an anti-jamming performance evaluation index and evaluation function are designed based on the system index and performance requirements.Second,intelligent decision-making algorithms based on rule-based reasoning,genetic algorithm,BP neural network,and DDPG reinforcement learning are studied for the downlink of TT&C systems.Firstly,the principles and processes of the four algorithms are described.Then,based on the background of the TT&C system and the database,the models and parameters are designed for different intelligent decision algorithms.Finally,aiming at single interference,compound interference and intelligent interference scenarios,the simulation performance of decision-free and different decision algorithms is summarized,and the advantages and disadvantages between the decisionmaking modes are compared,and the validity of the intelligent decision scheme is verified.It is verified that the integration of anti-jamming intelligent decision-making technology can improve the adaptability and anti-jamming ability of the TT&C system to complex interference environment,and can make the link achieve higher performance evaluation value.Thirdly,an FPGA implementation scheme for anti-interference intelligent decisionmaking is designed.First,the overall composition and processing flow of the intelligent decision scheme are given.Then,the design method of the key modules is introduced in three parts.The correctness of the code logic design is verified by the simulation results of Modelsim.Finally,the resource usage of different modules is analyzed,which meets the system requirements and is feasible.Fourthly,the intelligent decision-making performance was verified through actual scenario testing.Intelligent decision-making scheme is deployed through hardware platform,and field test environment is set up.Whether anti-jamming intelligent decisionmaking can restore the airspace transmission capability of the downlink of the TT&C system under six kinds of interference scenarios is tested.The results show that the success rate of reliable communication achieved by the TT&C link that loses lock due to interference reaches 95%,which meets the anti-jamming requirements of the overall design,and the average convergence time is 1.07 s.The decision-making scheme is efficient.In summary,this thesis mainly focuses on the intelligent decision-making technology for the downlink of TT&C systems.The research results have reference significance for improving the anti-interference ability of TT&C systems and ensuring reliable transmission in complex interference environments.