Discrete noise source suppression in underwater acoustic channel has attracted great attention in recent years. The paper proposes a new principle for dealing with the problem. This new principle is called matched fie...Discrete noise source suppression in underwater acoustic channel has attracted great attention in recent years. The paper proposes a new principle for dealing with the problem. This new principle is called matched field noise suppression (MFNS). Based on a previous work of the authors group, a full understanding about how a discrete noise source shows effects on the performance of a towed hydrophone line array has been obtained. In light of that finding, MFNS is proposed, which explores and utilizes the characteristics of the noise transmission channel to achieve much greater suppression of the noise in comparison with existing approaches. MFNS combines the concept of matched field processing (MFP) and optimal sensor array processing (OSAP) together to suppress the discrete noise source and to maintain an optimal beam for receiving far-field wanted plane wave signals. A MFNS beam-former is deduced in constraint with signal plane-wave response being unit and noise matched field response being zero. A closed-form solution of the weight vector for the beam-former is given. Computer simulation results agree well to the theoretical analysis.展开更多
Two optimal beamforming approaches for sensor arrays with arbitrary shapes and element directivities are proposed. The first one minimizes the sidelobe level while keeping the distortionless response in the direction ...Two optimal beamforming approaches for sensor arrays with arbitrary shapes and element directivities are proposed. The first one minimizes the sidelobe level while keeping the distortionless response in the direction of the desired signal and maintaining the mainlobe width. The second approach maximizes the array gain while keeping the mainlobe direction and controling the sidelobe level which is strictly guaranteed to be below a prescribed value. Array weight norm constraint is used to improve the robustness of the two optimal beamforming approaches against random errors. The first approach provides the optimal tradeoff among the sidelobe level, the beamwidth and robustness; and the second approach provides the optimal tradeoff among the array gain, the sidelobe level and robustness. Both optimal beamforming problems are formulated as the second-order cone programming which can be easily solved using well-developed interior-point methods. Results of computer simulations and lake-experiment for a circular array demonstrate superior performance of the approaches proposed in this paper in comparison to some existing adaptive-based algorithms.展开更多
An approach to designing time domain broadband frequency invariant beamformer via optimal array pattern synthesis and optimal FIR filters design is proposed. First, the working frequency band is decomposed into a numb...An approach to designing time domain broadband frequency invariant beamformer via optimal array pattern synthesis and optimal FIR filters design is proposed. First, the working frequency band is decomposed into a number of narrow band frequency bins.The array weights at each frequency bin are designed via optimal array pattern synthesis methods to insure that the synthesized pattern approximates the desired one within the mainlobe area. Then, a bank of FIR filters corresponding to the input channels are designed to provide the frequency responses that approximate the array weights in the working frequency band for each sensor. Finally, each sensor feeds a FIR filter and the filter outputs are summed to produce the beam output time series. Both array pattern synthesis and FIR filters design problems are formulated as the second-order cone programming (SOCP), which can be easily solved using well-developed interior-point methods. Results of computer simulations and lake-experiment for a twelve-element semicircular array demonstrate satisfactory performance of the proposed approach.展开更多
To quickly obtain the sound speed profile (SSP) in shallow water by inversion methods, an inversion scheme for SSP in shallow water using matched-beam processing (MBI) is developed. The cost function of MBI is based o...To quickly obtain the sound speed profile (SSP) in shallow water by inversion methods, an inversion scheme for SSP in shallow water using matched-beam processing (MBI) is developed. The cost function of MBI is based on matched-beam concept. It is verified experimentally that MBI is feasible and superior in comparison to conventional matched-field inversion (MFI) by using the East China Sea Experiment data. The SSP inverted by MBI using the wide-band explosion signals is in good agreement with the results measured based on conductivity, temperature and depth (CTD) in the experiment. And the root of mean square error of the inverted SSP is less than 2 m/s. Research results have shown that MBI is robust with respect to the sediment parameters mismatch. And SSP in shallow water can be more quickly obtained by MBI than by MFI.展开更多
文摘Discrete noise source suppression in underwater acoustic channel has attracted great attention in recent years. The paper proposes a new principle for dealing with the problem. This new principle is called matched field noise suppression (MFNS). Based on a previous work of the authors group, a full understanding about how a discrete noise source shows effects on the performance of a towed hydrophone line array has been obtained. In light of that finding, MFNS is proposed, which explores and utilizes the characteristics of the noise transmission channel to achieve much greater suppression of the noise in comparison with existing approaches. MFNS combines the concept of matched field processing (MFP) and optimal sensor array processing (OSAP) together to suppress the discrete noise source and to maintain an optimal beam for receiving far-field wanted plane wave signals. A MFNS beam-former is deduced in constraint with signal plane-wave response being unit and noise matched field response being zero. A closed-form solution of the weight vector for the beam-former is given. Computer simulation results agree well to the theoretical analysis.
文摘Two optimal beamforming approaches for sensor arrays with arbitrary shapes and element directivities are proposed. The first one minimizes the sidelobe level while keeping the distortionless response in the direction of the desired signal and maintaining the mainlobe width. The second approach maximizes the array gain while keeping the mainlobe direction and controling the sidelobe level which is strictly guaranteed to be below a prescribed value. Array weight norm constraint is used to improve the robustness of the two optimal beamforming approaches against random errors. The first approach provides the optimal tradeoff among the sidelobe level, the beamwidth and robustness; and the second approach provides the optimal tradeoff among the array gain, the sidelobe level and robustness. Both optimal beamforming problems are formulated as the second-order cone programming which can be easily solved using well-developed interior-point methods. Results of computer simulations and lake-experiment for a circular array demonstrate superior performance of the approaches proposed in this paper in comparison to some existing adaptive-based algorithms.
基金This work was supported by the National Natural Science Foundation of China (60472073) and (10304015).
文摘An approach to designing time domain broadband frequency invariant beamformer via optimal array pattern synthesis and optimal FIR filters design is proposed. First, the working frequency band is decomposed into a number of narrow band frequency bins.The array weights at each frequency bin are designed via optimal array pattern synthesis methods to insure that the synthesized pattern approximates the desired one within the mainlobe area. Then, a bank of FIR filters corresponding to the input channels are designed to provide the frequency responses that approximate the array weights in the working frequency band for each sensor. Finally, each sensor feeds a FIR filter and the filter outputs are summed to produce the beam output time series. Both array pattern synthesis and FIR filters design problems are formulated as the second-order cone programming (SOCP), which can be easily solved using well-developed interior-point methods. Results of computer simulations and lake-experiment for a twelve-element semicircular array demonstrate satisfactory performance of the proposed approach.
文摘To quickly obtain the sound speed profile (SSP) in shallow water by inversion methods, an inversion scheme for SSP in shallow water using matched-beam processing (MBI) is developed. The cost function of MBI is based on matched-beam concept. It is verified experimentally that MBI is feasible and superior in comparison to conventional matched-field inversion (MFI) by using the East China Sea Experiment data. The SSP inverted by MBI using the wide-band explosion signals is in good agreement with the results measured based on conductivity, temperature and depth (CTD) in the experiment. And the root of mean square error of the inverted SSP is less than 2 m/s. Research results have shown that MBI is robust with respect to the sediment parameters mismatch. And SSP in shallow water can be more quickly obtained by MBI than by MFI.
