<abstract xmlns="http://www.w3.org/1999/xhtml"><p>The paper demonstrates the use of frequency reassignment for bearing estimation. For this task, signals derived from a linear equispaced passive array are used. The presented method makes use of Fourier transformation based spatial spectrum estimation. It is further developed through the application of two-dimensional reassignment, which leads to obtaining highly concentrated energy distributions in the joint frequency-angle domain and sharp graphical imaging. The introduced method can be used for analysing, <italic>a priori</italic>, unknown signals of broadband, nonstationary, and/or multicomponent type. For such signals, the direction of arrival is obtained based upon the marginal energy distribution in the angle domain, through searching for arguments of its maxima. In the paper, bearing estimation of three popular types of sonar pulses, including linear and hyperbolic frequency modulated pulses, as well as no frequency modulation at all, is considered. The results of numerical experiments performed in the presence of additive white Gaussian noise are presented and compared to conventional digital sum-delay beamforming performed in the time domain. The root-mean-square error and the peak-to-average power ratio, also known as the crest factor, are introduced in order to estimate, respectively, the accuracy of the methods and the sharpness of the obtained energy distributions in the angle domain.</p></abstract>

The paper demonstrates the use of frequency reassignment for bearing estimation. For this task, signals derived from a linear equispaced passive array are used. The presented method makes use of Fourier transformation based spatial spectrum estimation. It is further developed through the application of two-dimensional reassignment, which leads to obtaining highly concentrated energy distributions in the joint frequency-angle domain and sharp graphical imaging. The introduced method can be used for analysing, a priori, unknown signals of broadband, nonstationary, and/or multicomponent type. For such signals, the direction of arrival is obtained based upon the marginal energy distribution in the angle domain, through searching for arguments of its maxima. In the paper, bearing estimation of three popular types of sonar pulses, including linear and hyperbolic frequency modulated pulses, as well as no frequency modulation at all, is considered. The results of numerical experiments performed in the presence of additive white Gaussian noise are presented and compared to conventional digital sum-delay beamforming performed in the time domain. The root-mean-square error and the peak-to-average power ratio, also known as the crest factor, are introduced in order to estimate, respectively, the accuracy of the methods and the sharpness of the obtained energy distributions in the angle domain.

Bearing Estimation Using Double Frequency Reassignment for a Linear Passive Array

Polish Maritime Research

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

The paper demonstrates the use of frequency reassignment for bearing estimation. For this task, signals derived from a linear equispaced passive array are...

Bearing Estimation Using Double Frequency Reassignment for a Linear Passive Array

Published Online: Oct 11, 2017

Page range: 26 - 35

DOI: https://doi.org/10.1515/pomr-2017-0087

Keywords
Direction of arrival, DOA, instantaneous frequency, short-time Fourier transform, STFT, time-frequency reassignment, intercept and surveillance sonar, crest factor

© 2017 Krzysztof Czarnecki et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Bearing Estimation Using Double Frequency Reassignment for a Linear Passive Array

Published Online: Oct 11, 2017

Page range: 26 - 35

DOI: https://doi.org/10.1515/pomr-2017-0087

KeywordsDirection of arrival, DOA, instantaneous frequency, short-time Fourier transform, STFT, time-frequency reassignment, intercept and surveillance sonar, crest factor

© 2017 Krzysztof Czarnecki et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
Direction of arrival, DOA, instantaneous frequency, short-time Fourier transform, STFT, time-frequency reassignment, intercept and surveillance sonar, crest factor