Optimization Of LCMV-based Adaptive Beamforming Algorithm With Hydroacoustic Array Signal Processing

As most countries in the world pay attention to the ocean,underwater communication technology has become a key development direction for China.In order to study more reliable underwater communication technology,hydroacoustic array signal processing is indispensable,which can effectively ensure the accuracy of signal reception.As an important part of array signal processing,beamforming(BF)has been developed rapidly in recent years.The essence of beamforming is to achieve the purpose of enhancing the desired signal and suppressing interference by weighting each array element for space domain filtering,which has been widely used in various aspects of military and civil fields.How to improve the beamforming algorithm to make the beamforming more accurate and efficient has become a hot research topic.In this paper,an adaptive beamforming algorithm based on Linearly Constrained Minimum Variance(LCMV)is improved and simulated,and a special matrix optimization beamforming algorithm based on LCMV criterion with PID control optimized Kalman filtering is proposed(Kalman filtering-PID control-Matrix processing based on LCMV,KPM-LCMV).This algorithm uses the PID control algorithm to optimize the Kalman filter to iterate the DOA estimation results accurately,and at the same time,the covariance matrix of the received signal is transformed in the frequency domain and the special matrix is reconstructed in order to reduce the computational effort and the sensitivity to the change of the signal-to-noise ratio.In addition,a DSP-based array signal collector is designed to acquire the measured signals and the optimized algorithm is used to beamform the resulting array signals to obtain the accurate received signals.Therefore,this study has theoretical and practical significance in the study of underwater communication systems.The main research of this paper is divided into two parts:(1)To address the shortcomings of DOA estimation accuracy and beam formation stability in LCMV algorithm and the problem of large computation,this paper proposes the KPM-LCMV algorithm,the specific process is as follows: firstly,the Kalman filter algorithm is applied to the classical Direction of Arrival(DOA)estimation algorithm of multiple iterations and corrected by the resulting error,and then the Kalman filter algorithm is further optimized by Proportion Integration Differentiation(PID)control to obtain the accurately estimated signal direction.This part is based on the PID control technology to eliminate the steady-state error in the Kalman algorithm,while predicting the trend of the error and responding to it in advance,so as to improve the accuracy of DOA estimation.This part is based on the linear constrained minimum variance(LCMV)criterion,the frequency domain transformation method and the generalized inverse matrix processing method to optimize the covariance matrix of the signal,to improve the computational efficiency by reducing the computational volume of the matrix,and to reduce the impact of small eigenvalue perturbations on the beam formation when the signal-to-noise ratio increases.(2)In order to verify the effectiveness of the algorithm,this paper designs a signal transceiver module based on TMS320C6747 Serial Peripheral Interface(SPI)for collecting actual data,which includes a multi-channel Digital to Analog Converter(DAC)module,Analog to Digital Converter(ADC)module,power amplifier module,preamplifier filter module,hydroacoustic transducer module,etc.In this paper,we use Binary Phase Shift Keying(BPSK)modulation and demodulation principle to convert the signal into a frequency band signal using BPSK modulation,and finish the signal transmission underwater through the transducer.The underwater communication system uses Code Composer Studio(CCS)as the software platform,and is a hydroacoustic array communication system based on Digital Signal Processor(DSP)SPI communication interface.In summary,the KPM-LCMV algorithm is proposed in this paper,and the simulation results of the algorithm show that the new algorithm has the advantages of small computation,high accuracy and good stability compared with the classical LCMV beamforming algorithm,while the new algorithm proves the practicability of the algorithm through the actual test of the hydroacoustic array communication system designed in this paper.