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Parameter estimation of LFM signals based on time reversal 被引量:2
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作者 MA Xinjie QI Wei +1 位作者 CHE Kaijun WU Gang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2023年第3期674-681,共8页
In this paper,parameter estimation of linear frequency modulation(LFM)signals containing additive white Gaussian noise is studied.Because the center frequency estimation of an LFM signal is affected by the error propa... In this paper,parameter estimation of linear frequency modulation(LFM)signals containing additive white Gaussian noise is studied.Because the center frequency estimation of an LFM signal is affected by the error propagation effect,resulting in a higher signal to noise ratio(SNR)threshold,a parameter estimation method for LFM signals based on time reversal is proposed.The proposed method avoids SNR loss in the process of estimating the frequency,thus reducing the SNR threshold.The simulation results show that the threshold is reduced by 5 dB compared with the discrete polynomial transform(DPT)method,and the root-mean-square error(RMSE)of the proposed estimator is close to the Cramer-Rao lower bound(CRLB). 展开更多
关键词 linear frequency modulation(LFM)signal time reversal Cramer-Rao lower bound(CRLB) parameter estimation
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A high performance waveform and a new ranging method for the proximity detector
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作者 Qi-le Chen Xin-hong Hao +1 位作者 Xiao-peng Yan Ping Li 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2020年第4期834-845,共12页
Signal modulation is an essential design factor for proximity detectors and directly affects the system's potential performance.In order to achieve the advantages of chaotic codes bi-phase modulation(CCBPM)and lin... Signal modulation is an essential design factor for proximity detectors and directly affects the system's potential performance.In order to achieve the advantages of chaotic codes bi-phase modulation(CCBPM)and linear frequency modulation(LFM) simultaneously,this paper designed a waveform which combined chaotic codes bi-phase modulation and linear frequency modulation(CCBPM-LFM) for proximity detectors.The CCBPM-LFM waveform was analyzed in the aspect of time delay resolution(TDR) and Doppler tolerance(DT) based on ambiguity function(AF).Then,a ranging method,which we called instant correlation harmonic demodulation(ICHD),was presented for the detector using the CCBPM-LFM waveform.By combining time domain instant correlation with harmonic demodulation,the ICHD solved the problem caused by combination modulation and made the most of the linear frequency modulation(LFM) harmonics and the correlation of chaotic codes.Finally,a prototype was implemented and ranging experiments were carried out.From the theoretical analysis and experimental results,the proximity detector used the CCBPM-LFM waveform has an outstanding detection performance. 展开更多
关键词 Proximity detectors Detection performance Combination modulation Chaotic codes bi-phase modulation linear frequency modulation
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Mathematic principle of active jamming against wideband LFM radar 被引量:13
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作者 Shixian Gong Xizhang Wei +1 位作者 Xiang Li Yongshun Ling 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第1期50-60,共11页
The inherent mathematic principle of active jamming against the wideband linear frequency modulated(LFM) radar is investigated. According to different generation strategies, the active jamming methods are reclassifi... The inherent mathematic principle of active jamming against the wideband linear frequency modulated(LFM) radar is investigated. According to different generation strategies, the active jamming methods are reclassified into three groups, i.e.,non-coherent jamming(NCJ), convolution jamming(CJ) and multiplying jamming(MJ). Based on the classification, the mathematic principles of different active jamming groups are put forward, which describe the relationships between the modulated signals and the jamming results. The advantages and disadvantages of different groups are further analyzed, which provides a new perspective for the study of jamming/anti-jamming methods and a potential for engineers to integrate similar jamming methods into one jammer platform. The analyses and simulation results of some typical active jamming methods prove the validity of the proposed mathematics principle. 展开更多
关键词 linear frequency modulated(LFM) mathematic principle active jamming
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Multi-component LFM signal detection and parameter estimation based on Radon-HHT 被引量:9
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作者 Chen Wenwu Chen Rushan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第6期1097-1101,共5页
A new method is proposed to analyze multi-component linear frequency modulated (LFM) signals, which eliminates cross terms in conventional Wigner-Ville distribution (WVD). The approach is based on Radon transform ... A new method is proposed to analyze multi-component linear frequency modulated (LFM) signals, which eliminates cross terms in conventional Wigner-Ville distribution (WVD). The approach is based on Radon transform and Hilbert-Huang transform (HHT), which is a recently developed method adaptive to non-linear and non-stationary signals. The complicated signal is decomposed into several intrinsic mode functions (IMF) by the empirical mode decomposition (EMD), which makes the consequent instantaneous frequency meaningful. After the instantaneous frequency and Hilbert spectrum are computed, multi-component LFM signals detection and parameter estimation are obtained using Radon transform on the Hilbert spectrum plane. The simulation results show its feasibility and effectiveness. 展开更多
关键词 linear frequency modulated empirical mode decomposition Hilbert-Huang transform Hilbert spectrum.
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Wigner-Hough transform based on slice's entropy and its application to multi-LFM signal detection 被引量:6
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作者 Hongwei Wang Xiangyu Fan +1 位作者 You Chen Yuanzhi Yang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第4期634-642,共9页
To enhance the capacity of the radar-reconnaissance interception receiver recognizing linear frequency modulated (LFM) at a low signal-noise ratio, this paper presents WignerHough transform (WHT) of the LFM signal and... To enhance the capacity of the radar-reconnaissance interception receiver recognizing linear frequency modulated (LFM) at a low signal-noise ratio, this paper presents WignerHough transform (WHT) of the LFM signal and its corresponding characteristics, derives the probability density functions of the LFM signal and Gaussian white noise within WHT based on entropy (WHTE), dimension under different assumptions and puts forward a WHT algorithm based on entropy of slice to improve the capacity of detecting the LFM signal. Entropy of the WHT domain slice is adopted to assess the information size of polar radius or angle slice, which is converted into the weight factor to weight every slice. Double-deck weight is used to weaken the influences of noise and disturbance terms and WHTE treatment and signal detection procedure are also summarized. The rationality of the algorithm is demonstrated through theoretical analysis and formula derivation, the efficiency of the algorithm is verified by simulation comparison between WHT, fractional Fourier transform and periodic WHT, and it is highlighted that the WHTE algorithm has better detection accuracy and range of application against strong noise background. 展开更多
关键词 low signal-to-noise ratio linear frequency modulated signal probability density function Wigner-Hough transform (WHT) signal detection entropy of slice
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Combining Radon-ambiguity transform with second-order difference to improve detection probability of LFM signals in low SNR 被引量:4
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作者 Tan Xiaogang Wei Ping Li Liping 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第1期13-19,共7页
The Radon-ambiguity transform (RAT), although efficient for detecting the linear frequency modulated signals (LFMs), is troubled by the energy accumulation of noise in low signal-to-noise ratio (SNR). A secondor... The Radon-ambiguity transform (RAT), although efficient for detecting the linear frequency modulated signals (LFMs), is troubled by the energy accumulation of noise in low signal-to-noise ratio (SNR). A secondorder difference (SOD) method is proposed to treat with this problem. In the SOD method, the optimal search step and difference step are derived from the LFM rate resolution formula. The sharpness of the peaks of RAT is measured by curvature, and the sharpness, but not the magnitude of the peaks, is used to detect the LFMs. The SOD method removes the noise energy accumulation and reserves the drastically changing components integrally; thus, it improves the detection probability of LFMs in low SNR. The expected performance of the new method is verified by 100 Monte Carlo simulations. 展开更多
关键词 linear frequency modulated signals Radon-axnbiguity transform detection probability low signal-to-noise ratio.
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Adaptive digital self-interference cancellation based on fractional order LMS in LFMCW radar 被引量:6
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作者 LUO Yongjiang BI Luhao ZHAO Dong 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2021年第3期573-583,共11页
Adaptive digital self-interference cancellation(ADSIC)is a significant method to suppress self-interference and improve the performance of the linear frequency modulated continuous wave(LFMCW)radar.Due to efficient im... Adaptive digital self-interference cancellation(ADSIC)is a significant method to suppress self-interference and improve the performance of the linear frequency modulated continuous wave(LFMCW)radar.Due to efficient implementation structure,the conventional method based on least mean square(LMS)is widely used,but its performance is not sufficient for LFMCW radar.To achieve a better self-interference cancellation(SIC)result and more optimal radar performance,we present an ADSIC method based on fractional order LMS(FOLMS),which utilizes the multi-path cancellation structure and adaptively updates the weight coefficients of the cancellation system.First,we derive the iterative expression of the weight coefficients by using the fractional order derivative and short-term memory principle.Then,to solve the problem that it is difficult to select the parameters of the proposed method due to the non-stationary characteristics of radar transmitted signals,we construct the performance evaluation model of LFMCW radar,and analyze the relationship between the mean square deviation and the parameters of FOLMS.Finally,the theoretical analysis and simulation results show that the proposed method has a better SIC performance than the conventional methods. 展开更多
关键词 adaptive digital self-interference cancellation(ADSIC) linear frequency modulated continuous wave(LFMCW)radar fractional order least mean square(LMS)
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Statistical performance of IF estimation of LFM signals with timevarying amplitude using the peak of WVD 被引量:2
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作者 Chen Guanghua Ma Shiwei Qin Tinghao Wang Jian Li Ming Cao Jialin 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2005年第4期787-791,共5页
The instantaneous frequency (IF) estimation of the linear frequency modulated (LFM) signals with time-varying amplitude using the peak of the Wigner-Ville distribution (WVD) is studied. Theoretical analysis show... The instantaneous frequency (IF) estimation of the linear frequency modulated (LFM) signals with time-varying amplitude using the peak of the Wigner-Ville distribution (WVD) is studied. Theoretical analysis shows that the estimation on LFM signals with time-varying amplitude is unbiased, only if WVD of time-varying amplitude reaches its maximum at frequency zero no matter in which time. The statistical performance in the case of additive white Guassian noise is evaluated and an analytical expression for the variance is provided. The simulations using LFM signals with Gaussian envelope testify that IF can be estimated accurately using the peak of WVD for four models of amplitude variation. Furthermore the statistical result of estimation on the signals with amplitude descending before rising is better than that of the signals with constant amplitude when the amplitude variation rate is moderate. 展开更多
关键词 instantaneous frequency linear frequency modulated signals Wigner-Ville distribution statistical performance variance.
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