Research On Frequency Hopping Signal Sorting Technology

Frequency hopping(FH)communication technology has been widely used in the field of modern communication due to its superior anti-interference characteristics,multiple access networking capabilities and low probability of interception.The networking capability of FH communication makes it effective to improve the antiinterference,anti-tracking and anti-interception capabilities of a single network,which has very great tactical significance.At the same time,in the actual combat environment,the intercepted signal is often not a single frequency hopping signal,so the useful frequency hopping signal must be sorted out in order to obtain valid information.Under this circumstance,it is an important content in the research of FH communication to study the networking mode of FH communication and the sorting technology of frequency hopping signals to provide technical support for the realization of interference or recovery information.The main contents of this thesis are as follows:(1)Firstly,the FH communication system and its networking theory are studied,including the working theory of FH communication system,frequency hopping sequence and the networking mode of FH communication system.Then,because frequency hopping signal is a non-stationary signal,the signal needs to be pre-processed and analyzed,and the relevant parameter information of signal needs to be extracted before signal sorting.Among them,the basic principles of digital channelization,short-time Fourier transform and Wigner-Ville distribution are mainly studied,and the advantages and disadvantages of each method are analyzed.Finally,the parameter estimation method of frequency hopping signal based on short time Fourier transform is studied.(2)Secondly,the mathematical model of single-channel detection frequency hopping signal is introduced,and the sorting algorithm of synchronous orthogonal network station is studied.The method of sorting is mainly based on the structural characteristics of Lempel-Greenberger(L-G)model,and the theory of the sorting algorithm for odd and even users is derived respectively.The advantage of this sorting method is that it does not need information of hopping time,hopping rate,and the disadvantage is that it can only realize signal sorting under L-G model.Then,based on the mapping method of FH sequences,a method for inversion of FH sequences after random mapping is proposed.Finally,the sorting algorithm of asynchronous non-orthogonal network is studied,which is based on the different starting time.The precise estimation of hopping time and the processing method of frequency collision used in this paper are studied in detail.(3)Thirdly,this paper introduces the mathematical model of multi-channel frequency hopping signal and its sorting algorithm flow,and studies the estimation method of signal source numbers,which is an estimation method based on the theorem of Gershgorin Disks.Then,the theory of classical multiple signal classification algorithm is introduced,the problem of hopping frequency collision is solved through a second estimating of the signal source numbers for the frequency signal.(4)Finally,the design and implementation of frequency hopping signal processing and analysis simulation software are introduced,including software functions,design flow and software design interface,in the end,the software performance is tested and the test results are statistically analyzed.