Parameter Estimation Method of Biphase Encoded Signal Based on Smooth Pseudo-Wigner Distribution

Abstract

The invention relates to a two-phase coded signal parameter estimation method based on smoothing pseudo-Wigner-Ville distribution, and mainly solves the problem that the existing method cannot consider both low signal-to-noise ratio and low computational burden. The method comprises the implementation steps that 1) two-phase coded signals of 13-bit barker code sequence coding are generated; 2) FFT transformation is performed on the two-phase coded signals so that the power spectrum is solved; 3) smoothing is performed on the power spectrum and the signal carrier frequency is estimated according to 3dB bandwidth power spectrum centroid of the smoothed power spectrum; 4) smoothing pseudo-Wigner-Ville distribution transformation is performed on the two-phase coded signals so that the amplitude sequence of the carrier frequency can be obtained; 5) the signal code element width is obtained by searching amplitude sequence minimum negative peak spacing, and the number of sub-codes included in the adjacent negative peaks is computed; and 6) estimation of the code element sequence is obtained according to the position of the negative peaks and the number of the sub-codes. The estimate precision for the parameters of the two-phase coded signals can be enhanced under the condition of low signal-to-noise ratio so that the computational burden can be reduced and the method can be used for accurate detection of the target.

Description

technical field [0001] The invention belongs to the technical field of data processing, and in particular relates to a method for estimating parameters of bi-phase coded BPSK signals with smooth pseudo-Wigner distribution SPWVD, which can be used for accurate reconnaissance of targets in radars with low intercept probability. Background technique [0002] In order to reduce the average transmission power and reduce the probability of signal interception, low probability of interception radars usually use pulse compression signals with a large time-bandwidth product. Phase-encoded signal has become a commonly used pulse compression signal because of its high distance resolution and strong anti-reconnaissance and anti-jamming capabilities. Since the echo signal received by the radar is often submerged in a large noise background, it is of great practical significance how to quickly estimate the relevant parameters of the phase-encoded signal under low signal-to-noise ratio whe...

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Problems solved by technology

[0003] Aiming at the parameter estimation problem of BPSK signal, Wu Jiangbiao, Wan Fang and Yu Chunlai proposed "Intrapulse Feature Extraction of Phase Encoded Signal Based on Wavelet Transform Method", see Aerospace Electronic Countermeasures, 2005(3):38-40, in which wavelet transform is used The method of extracting wavelet ridges to identify phase-encoded signals, under the condition of low signal-to-noise ratio, the extraction of wavelet ridges is greatly affected by noise, which affects the estimation accuracy of signal parameters, and this method has a large amount of calculation, which is not suitable for engineering applications; Yin Jihao, Wang Ling, and Chen Tianqi proposed "a method for estimating the carrier frequency, code rate and code sequence of multiple biphase coded signals" see Signal Processing, 2006, 22(5): 639-543, in which time-frequency analysis method- The short-time Fourier transform (STFT) estimates the symbol information and coding sequence of BPSK signals, but the anti-noise performance of STFT is poor, and the estimation accuracy of signal parameters is low in the environment of low signal-to-noise ratio; Lu Mingjiu, Zhou Ming, Han Jun and Deng Jing proposed "A Time-Frequency Analysis Method for Two-phase Coded Signals with Low SNR", see Radar Science and Technology, 2010(6):549-552. In this paper, it is proposed to perform double-thresholding on the result of STFT transformation of the signal Disruption point detection, although this method realizes the parameter estimation of BPSK signal under the condition of low signal-to-noise ratio, but the estimation accuracy is low, and the pulses need to be accumulated during the estimation process, which requires a long processing time and a large amount of calculation

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