Multiple Targets Detection of Linear Frequency-Modulated Continuous Wave Active Sonar Using Fractional Fourier Transform

Liu, Dali; Qu, Haoran; Wang, Wei; Deng, Jianxin

doi:10.1080/10584587.2020.1728798

Cited by 4 publications

(6 citation statements)

References 12 publications

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“…In engineering applications, an LFM signal is introduced as a broadband signal for analysis, and the expression of a typical LFM signal can be obtained in the real number domain [35], as shown in Equation ( 28):…”

Section: Echo Integration and Voltage Estimation Under Broadbandmentioning

confidence: 99%

Broadband Scattering Characteristic Quantization Technique for Single Fish Based on a Split-Beam Echosounder

Ai,

Li,

Yao

et al. 2023

Fishes

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The utilization of broadband quantization data increases the possibility of practical applications for fish target recognition based on the acoustic scattering theory. However, the quantification of broadband data is more complex than that of narrowband systems, requiring consideration of the broadband characteristics of split-beam transducers, seawater absorption, and circuits. This paper elucidates the scatterer acoustic field equation, transducer power equation, and signal processing flow in split-beam broadband quantization technology for engineering applications. A broadband calculation model based on transducer parameters is proposed to enhance the generalization ability of broadband quantization technology to different types of sonar. The classical echo integration method is combined with Fourier transform to meet the requirements of target strength (TS) estimation under broadband signals. This paper includes a series of experiments to prove the rationality and effectiveness of the method. The results demonstrate that the provided calculation model can more accurately reflect the backscattering characteristics of the scatterer, but certain errors remain. This article analyzes the sources of errors and validates the effectiveness of the new TS calculation method.

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Section: Echo Integration and Voltage Estimation Under Broadbandmentioning

confidence: 99%

Broadband Scattering Characteristic Quantization Technique for Single Fish Based on a Split-Beam Echosounder

Ai,

Li,

Yao

et al. 2023

Fishes

View full text Add to dashboard Cite

show abstract

“…Linear frequency modulation (LFM) signals are widely used in hydroacoustic communication and detection, and direction of arrival (DOA) estimation is important [ 1 , 2 ]. To estimate received signal DOA, beamforming methods represented by conventional beamforming (CBF) [ 3 ] and minimum variance distortionless response (MVDR) [ 4 ] were proposed.…”

Section: Introductionmentioning

confidence: 99%

Deconvolved Fractional Fourier Domain Beamforming for Linear Frequency Modulation Signals

Liu

Tao

Sun

et al. 2023

Sensors

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To estimate the direction of arrival (DOA) of a linear frequency modulation (LFM) signal in a low signal-to-noise ratio (SNR) hydroacoustic environment by a small aperture array, a novel deconvolved beamforming method based on fractional Fourier domain delay-and-sum beamforming (FrFB) was proposed. Fractional Fourier transform (FrFT) was used to convert the received signal into the fractional Fourier domain, and delay-and-sum beamforming was subsequently performed. Noise resistance was acquired by focusing the energy of the LFM signal distributed in the time–frequency domain. Then, according to the convolution structure of the FrFB complex output, the influence of the fractional Fourier domain complex beam pattern was removed by deconvolution, and the target spatial distribution was restored. Therefore, an improved spatial resolution of DOA estimation was obtained without increasing the array aperture. The simulation and experimental results show that, with a small aperture array at low SNR, the proposed method possesses higher spatial resolution than FrFB and frequency-domain deconvolved conventional beamforming.

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“…However, the strong coupling of the LFM signal in the time–frequency domain makes it difficult to separate the signal from the noise. Fractional Fourier transform (FrFT) has chirp basis decomposition characteristics, suitable for LFM signal filtering [ 28 , 29 , 30 , 31 ]. Some scholars have successfully detected cracks in reinforced concrete using the method of horizontal fusion of CODA waves and multi-ultrasonic sensor signals [ 32 , 33 ].…”

Section: Introductionmentioning

confidence: 99%

A New Method for Erosion Prediction of 90° Elbow Based on Non-Axisymmetric Ultrasonic-Guided Wave and the PSO–LSSVM Algorithm

Wang

Zhou

et al. 2023

Sensors

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The non-axisymmetric exciting guided wave can detect the thinning section of the elbow, and the time domain energy value of the signal collected at the outer arch position of the receiving end displays a downward trend as the remaining thickness of the erosion area decreases. To address the difficulty in detecting the erosion degree of the elbow with high accuracy, this paper uses the linear frequency modulation (LFM) signal to excite a non-axisymmetric guided wave that propagates in the 90° elbow and collects signals through four PZT receivers. To predict the erosion degree, the corresponding relationship between the energy value of the four signals after fractional Fourier filtering and the degree of elbow erosion is established through the particle swarm optimization (PSO)–least squares support vector machine (LSSVM) algorithm. The results show that the method proposed has an average accuracy rate of 98.1864%, 94.7167%, 99.119%, and 99.9593% for predicting the erosion degree of four elbow samples, and 94.0039%. and 81.2976% for two new erosion degrees, which are higher than the nonlinear regression model, LSSVM algorithm, and BP neural network algorithm. This study has guiding significance for real-time monitoring of elbow erosion.

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Multiple Targets Detection of Linear Frequency-Modulated Continuous Wave Active Sonar Using Fractional Fourier Transform

Cited by 4 publications

References 12 publications

Broadband Scattering Characteristic Quantization Technique for Single Fish Based on a Split-Beam Echosounder

Broadband Scattering Characteristic Quantization Technique for Single Fish Based on a Split-Beam Echosounder

Deconvolved Fractional Fourier Domain Beamforming for Linear Frequency Modulation Signals

A New Method for Erosion Prediction of 90° Elbow Based on Non-Axisymmetric Ultrasonic-Guided Wave and the PSO–LSSVM Algorithm

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