Research On Time-frequency Analysis And Parameters Estimation For Multi-component PPS Signal

Polynomial phase signals are widely used in radar,communications,biomedical fields,seismic surveys,and sonar systems.Therefore,the time-frequency analysis and parameter estimation of polynomial phase signals in the background of noise have become one of the important topics in the field of signal processing.The main research object of this paper is the detection and parameter estimation of multi-component PPS signals based on time-frequency distribution nonparametric method and parameterized method.The main contents are as follows:First,the effects of adaptive filtering algorithm and nonlinear mode decomposition algorithm on white gaussian noise and ocean ambient noise suppression are studied.Then,the time-frequency analysis method of single component and multi-component PPS signals is studied.The quality of time-frequency distribution is qualitatively evaluated by the readability of timefrequency image,time-frequency resolution,noise suppression and cross-term suppression,and through the evaluation index of time-frequency distribution,the performance of time-frequency distribution is evaluated quantitatively.The advantages and disadvantages of each time-frequency distribution are verified by the analysis of simulation signals and measured signals,and the optimal time-frequency distribution for a specific situation is judged by synthesizing the qualitative and quantitative evaluation results.Next,the HAF class(HAF,PHAF)and CPF class(CPF,MCPF,PCPF,ICPF,GCPF,PGCPF)algorithms in the method of parametric detection and estimation of PPS signals are studied.Their principles,advantages and disadvantages and improvements are introduced.They are verified by simulation signal analysis.Finally,the time-frequency signal separation method of multi-component signals is studied.Based on the introduction of the existing methods,an improved signal separation method based on timefrequency distribution is proposed for multi-components whose components not only overlapped in time-frequency domain but also have different duration.This method computes the time-frequency representation(TFR)of signal,and extracts the instantaneous frequency(IF)of components by twodimension peak search in a limited area which normalized energy is bigger than the set threshold value.If there is more than one peak from a TFR,IFs of components can be determined and linked by method of minimum slop difference.On this basis,the weighted least squares method is used for parameter estimation.The effectiveness of the improved method is verified by analysis of multiple simulated signals.