Research On Time-Frequency Analysis And Parameter Estimation Algorithms For Frequency Hopping Signal

Frequency hopping(FH) communication has been widely used in militaryfrequency hopping radio, because of its LPI/LPD(Low probability ofinterception/detection) and good anti-jamming features, which increase the difficultyof FH signal detection and interception for the third communication innon-cooperative communication. There, researching effective interception andparameter estimation algorithms for FH signal have significant military meaning.Frequency hopping signal is a typical kind of non-stationary signal, whosespectrum is a function of time. Since it is not enough to get the information of timedomain and frequency domain respectively, therefore, the traditional Fouriertransform parameter estimation has been unable to meet the needs. Time-frequencyanalysis as a new signal processing method, it is more and more widely appreciated inrecent years. The basic idea of time-frequency analysis is to design joint function oftime and frequency and to describe energy density of signal at time and frequencydomain.Firstly, the article introduce the commonly used time-frequency analysisalgorithms(STFT,WVD,SPWVD,ST), and these methods are applied to the frequencyhopping signal. Their respective characteristics are analyzed by the time-frequencyspectrum. Then, on the basis of higher resolution in wavelet transform and SPWVD,discuss the three parameter estimation of frequency hopping signal. Meanwhile, thealgorithms combining time-frequency ridge of SPWVD with WT and differentialmethod based on SPWVD. The simulation results showed that differential methodbased on SPWVD has the higher accuracy in the estimation of hopping time, whichcan be the preferred algorithm to estimate the hopping time.Finally, focus on the parameter estimation algorithms based on Hilbert-Huang transform (HHT),which is the latest time-frequency methods,which has been provedto be suitable for processing non-stationary signals. According to the HHTtime-frequency spectrum has high resolution, and the study on frequency hoppingsignal parameter estimation based on HHT is basically blank. In this paper, the HHTis introduced into the hopping signal parameter estimation, and the estimationalgorithm is given. Focus on jump cycle estimates of hopping signals based on HHTspectrum. The simulation results show that parameter estimation based on HHT hashigher precision than the previous time-frequency method. It illustrates that it iseffective about frequency hopping parameter estimation based on HHT.