Fast Intra-pulse Analysis And Parameter Estimation For LFM Signals Based On The Instantaneous Frequency

Intra-pulse analysis and parameter estimation are important parts in radar signal analysis and processing,which focus on using suitable algorithms or effective intra-pulse analysis frameworks to achieve rapid detection and extraction of radar signal parameters,and then effective information of the radiation source signal is obtained.The main task of the paper is to study the algorithm of fast intra-pulse analysis of LFM signal based on the digital receiver platform.In the meantime,the algorithm accuracy and hardware implementation complexity is considered in the research and design of the algorithm,then,the algorithm which is adapt to hardware implementation and has high measurement accuracy is choose.In this paper,fast intra-pulse analysis and parameter estimation for LFM signals based on the instantaneous frequency is studied.The main contents of the paper are as follows:Firstly,on the basis of Rife algorithm and M-Rife algorithm,the amplitude and phase frequency measurement algorithm which uses signal spectrum amplitude and phase simultaneously is proposed.The amplitude and phase frequency measurement algorithm has slightly computation to Rife algorithm,but it can achieve higher frequency estimation accuracy than Rife algorithm.In the meantime,compared with M-Rife algorithm,the amplitude and phase frequency measurement algorithm's measurement accuracy is not much different from the M-Rife algorithm,while it is easier to implement than M-Rife algorithm.Secondly,an intra-pulse parameter analysis framework of "Section + STFT + Instantaneous Frequency Analysis + Least Square Linear Fit + Start Frequency Compensation" is proposed.At the same time,the framework was verified and analyzed based on LFM signal.The paper concentrates on analyzing the RMSE value from two aspects of the LFM signal: the RMSE value of initial frequency and the percentage of frequency modulation slope divided by the true value of the LFM signal.Then,fast Intra-pulse analysis and parameter estimation are implemented within 32?s.Finally,with the help of energy detection algorithm,the pulse width of the LFM signals is obtained quickly and accurately.At first,the paper analyzes the feasibility of energy detection algorithm applying to pulse width detection.Hence,a double threshold simple pulse width detection algorithm is raised.The dual-threshold simple pulse width detection algorithm uses a fixed threshold,which does not guarantee that the signal can achieve high pulse width measurement accuracy over the entire signal-to-noise ratio range.Thus,the double threshold adaptive pulse width detection algorithm is proposed.By setting the partition signal-to-noise ratio,different thresholds are assigned to signals in different signal-to-noise ratio ranges.Therefore,a small pulse width RMSE value is guaranteed over the entire signal-to-noise ratio range,the dynamic range is significantly smaller,and accurate measurement of pulse width of pulse signal is implemented.