Consider the problems of frequency-invariant beampattern optimization and robustness in broadband beamforming.Firstly,a global optimization algorithm,which is based on phase compensation of the array manifolds,is used...Consider the problems of frequency-invariant beampattern optimization and robustness in broadband beamforming.Firstly,a global optimization algorithm,which is based on phase compensation of the array manifolds,is used to construct the frequency-invariant beampattern.Compared with some methods presented recently,the proposed algorithm is not only available to get the global optimal solution,but also simple for physical realization.Meanwhile,a robust adaptive broadband beamforming algorithm is also derived by reconstructing the covariance matrix.The essence of the proposed algorithm is to estimate the space-frequency spectrum using Capon estimator firstly,then integrate over a region separated from the desired signal direction to reconstruct the interference-plus-noise covariance matrix,and finally caleulate the adaptive beamformer weights with the reconstructed matrix.The design of beamformer is formulated as a convex optimization problem to be solved.Simulation results show that the performance of the proposed algorithm is almost always close to the optimal value across a wide range of signal to noise ratios.展开更多
The optimum detector for a determined signal in the stationary white noise background In ideal channels is a matched filter．But its performance degenerates seriously in a practical underwater acoustic system for the ...The optimum detector for a determined signal in the stationary white noise background In ideal channels is a matched filter．But its performance degenerates seriously in a practical underwater acoustic system for the complexityof underwater acoustic channels．Based on the estimation of instantaneous frequency sequence and its statistical characteristics，a new type ofrobust detector，Varlance－of-Instantaneous-Frequency Detector（VIFD for short），is presented for the detection of CW pulse according to the features of underwater acousticchannels and operating environment of active sonars． It is proved through theoretical analysis，simulation and experiments that VIFD is promising for its robustness in nonstatlonary interference background and channels and that it is alsorobust for the fluctuations and decny of signal or mlsmatch caused by Doppler－frequency shift．展开更多
In order to ease the pass-band response distortion of the matrix pre-filter,a simple approach for designing matrix spatial filter is proposed,which minimizes the sum of the k maximal distortion norm（k is the number o...In order to ease the pass-band response distortion of the matrix pre-filter,a simple approach for designing matrix spatial filter is proposed,which minimizes the sum of the k maximal distortion norm（k is the number of the constraint points）within the pass-band,while constraining the filter response within the stop-band.Considering the costly amount of calculation of the high-resolution methods,an algorithm with small amount of calculation based on matrix pre-filtering and subspace fitting using acoustic vector array（MF-VSSF）is proposed.Through joint processing of signal subspace of both pressure and particle velocity,the pre-filtering matrix and the signal subspace is decreased to M-dimensional（M is the number of array-element）,hence reduces the time-consumption of the matrix pre-filter design and DOA searching.Simulation results show that,the method offers the same performance as MUSIC with pre-filtering,but has much lesser amount of calculation.Moreover,the designed prefilter can efficiently suppress the interference in the stop-band and improve the estimation and resolution performance of successive DOA estimators.展开更多
A signal analyzing method, named pseudo bearing sequence analysis (PBSA), is proposed. The theoretical foundation and basic ideas of the method, as well as its practical applications in the area of underwater acoustic...A signal analyzing method, named pseudo bearing sequence analysis (PBSA), is proposed. The theoretical foundation and basic ideas of the method, as well as its practical applications in the area of underwater acoustic signal processing, are introduced. A signal detector named variance-of-pseudo-bearing detector (VPBD) is presented as well, which is superior to variance-of-instantaneous frequency detector (VIFD ) in t he reverberation background. The validity of the proposed method bas been confirmed by means of both simulations in computer and the practical processing of trial data.展开更多
基金supported by the National Natural Science Foundation of China(51279043,61201411)the Fundamental Research Funds for the Central Universities(HEUCF120502)the National Key Laboratory on Underwater Acoustic Technology Foundation of China(9140C200203110C2001)
文摘Consider the problems of frequency-invariant beampattern optimization and robustness in broadband beamforming.Firstly,a global optimization algorithm,which is based on phase compensation of the array manifolds,is used to construct the frequency-invariant beampattern.Compared with some methods presented recently,the proposed algorithm is not only available to get the global optimal solution,but also simple for physical realization.Meanwhile,a robust adaptive broadband beamforming algorithm is also derived by reconstructing the covariance matrix.The essence of the proposed algorithm is to estimate the space-frequency spectrum using Capon estimator firstly,then integrate over a region separated from the desired signal direction to reconstruct the interference-plus-noise covariance matrix,and finally caleulate the adaptive beamformer weights with the reconstructed matrix.The design of beamformer is formulated as a convex optimization problem to be solved.Simulation results show that the performance of the proposed algorithm is almost always close to the optimal value across a wide range of signal to noise ratios.
文摘The optimum detector for a determined signal in the stationary white noise background In ideal channels is a matched filter．But its performance degenerates seriously in a practical underwater acoustic system for the complexityof underwater acoustic channels．Based on the estimation of instantaneous frequency sequence and its statistical characteristics，a new type ofrobust detector，Varlance－of-Instantaneous-Frequency Detector（VIFD for short），is presented for the detection of CW pulse according to the features of underwater acousticchannels and operating environment of active sonars． It is proved through theoretical analysis，simulation and experiments that VIFD is promising for its robustness in nonstatlonary interference background and channels and that it is alsorobust for the fluctuations and decny of signal or mlsmatch caused by Doppler－frequency shift．
基金supported by the National Natural Science Foundation of China(61201411)
文摘In order to ease the pass-band response distortion of the matrix pre-filter,a simple approach for designing matrix spatial filter is proposed,which minimizes the sum of the k maximal distortion norm（k is the number of the constraint points）within the pass-band,while constraining the filter response within the stop-band.Considering the costly amount of calculation of the high-resolution methods,an algorithm with small amount of calculation based on matrix pre-filtering and subspace fitting using acoustic vector array（MF-VSSF）is proposed.Through joint processing of signal subspace of both pressure and particle velocity,the pre-filtering matrix and the signal subspace is decreased to M-dimensional（M is the number of array-element）,hence reduces the time-consumption of the matrix pre-filter design and DOA searching.Simulation results show that,the method offers the same performance as MUSIC with pre-filtering,but has much lesser amount of calculation.Moreover,the designed prefilter can efficiently suppress the interference in the stop-band and improve the estimation and resolution performance of successive DOA estimators.
文摘A signal analyzing method, named pseudo bearing sequence analysis (PBSA), is proposed. The theoretical foundation and basic ideas of the method, as well as its practical applications in the area of underwater acoustic signal processing, are introduced. A signal detector named variance-of-pseudo-bearing detector (VPBD) is presented as well, which is superior to variance-of-instantaneous frequency detector (VIFD ) in t he reverberation background. The validity of the proposed method bas been confirmed by means of both simulations in computer and the practical processing of trial data.
