Research On Key Technologies In Blind Receiving System Of Frequency Hopping Communication

Frequency hopping(FH)communication technology has superior anti-jamming and anti interception performance,which makes it widely used in military communication.Blind receiving system can effectively reconnoitre signals in the absence of prior information,which has become the research focus of communication electronic warfare.However,the received signals by non cooperative parties are in low signal-to-noise ratio and doped with various interference signals,which brings great challenges to blind receiving system of FH communication.In order to solve the problem of low reliability of blind receiving system in complex electromagnetic environment,this paper focuses on key technologies such as signal detection,parameter estimation and modulation recognition in blind receiving system of FH communication.Firstly,the FH communication system is described,and ten modulation modes are discussed.This paper analyzes the key technologies of blind receiving system,and introduces the common interference in FH communication.Secondly,the FH signal detection method is studied.The power spectrum is used to process the signal,and the multi-scale analysis is used to extract the features.In order to remove the redundunt information,the principal component analysis method is discussed.Combined with random forest,this paper proposes the FH signal detection algorithm based on machine learning,and its performance is verified.Then,the FH signal parameter estimation method is studied.In order to suppress the cross terms,the specific kernel function is designed,which can keep the good concentration in time-frequence domain.The target transfer probability function is constructed to extract the FH signal ridge.This paper proposes the parameter estimation method based on time-frequency ridge,and the reliability is verified.Finally,the modulation recognition method is studied.Combined with the mechanism of cyclic spectrum,the modulation signals are transformed into images,and the convolutional neural network model is construted.On this basis,this paper proposes modulation recognition algorithm based on deep learning,and verifies feasibility of the algorithm by simulation.At the same time,combined with the above-mentioned key technologies research,the scheme of FH communication blind receiving system is designed,and the performance of the proposed scheme in this paper is verified.