| Space Telemetry,Track and Command(TT&C)is widely used in military field,but Space TT&C links are exposed to space communications and are susceptible to various electromagnetic signals in space,especially hostile interference signals.The communication safety of the Space TT&C links involves the safety of the spacecraft's transponder and the ground space station,and determines whether the strategic information can be transmitted safely and accurately.Therefore,in order to ensure the communication security of the TT&C link,it is necessary to detect the interference signal and make effective protection decisions.Therefore,in this paper,focusing on the complex electromagnetic interference environment in the Space TT&C link,we focus on the study of multi-dimensional interference recognition and decision-making technology.The main work of this article includes the following parts:First,three improved interference detection algorithms based on frequency domain are studied.Aiming at the six common jamming signals in the Space TT&C link,simulation analysis and performance comparison of the three detection algorithms were carried out,and an improved CME detection algorithm with high detection rate of wideband jamming signals and easy FPGA implementation was determined.The relationship between the decision threshold and the false alarm probability in the interference detection algorithm is analyzed in detail.Second,the interference multi-dimensional perception scheme design of the TT&C link is completed.A set of classification feature parameters with obvious classification features,insensitivity to interference signal parameters and no prior information are extracted,including interference energy factor,time-domain peak-to-average ratio,spectral bandwidth factor,and fractional Fourier transform domain energy aggregation degree.The decision threshold was determined through simulation analysis,the interference signal classification rules based on decision tree were established,and the feasibility of interference recognition scheme was verified through simulation analysis.Third,an evaluation system for interference protection performance of Space TT&C system based on fuzzy comprehensive hierarchy method was established.Aiming at the inherent characteristics of the TT&C link and the means of interference protection,an evaluation index set is established,and fuzzy comprehensive hierarchy method is used to comprehensively evaluate each index,and the feasibility of the evaluation method is determined through simulation analysis.Finally,combined with interference recognition and evaluation results,a rule-based interference protection strategy is given.Fourth,the interference multidimensional sensing technology is implemented and verified on the FPGA hardware platform.Detailed design of the interface and implementation method of key modules,including improved CME interference detection,fractional Fourier transform,interference energy factor and other modules.In fact,in the board test,when the JSR is greater than 10 dB,the detection probability of the interference signal is greater than 99%,which verifies the correctness of the implementation scheme.The thesis proposes the interference sensing and decision-making scheme for the Space TT&C link,and implements the interference sensing technology on FPGA,which has certain engineering value. |
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