Research On Post/starboard Discrimination Algorithm Of Towed Array

In the sonar system,the technology of port/starboard discrimination in beamforming has been widely studied by all over the world and it is one of the key technologies nowadays.In this paper,the port/starboard discrimination algorithms based on towed array are studied.Based on the dual-line array and the vector array,four algorithms are studied respectively.The characteristics,advantages and disadvantages are analyzed from several aspects,which provides a reliable reference for solving the port/starboard discrimination problems.The feasibility and validity of the algorithm are verified by simulation experiments and experimental data.First of all,according to the development history of the towed array,several classic port/starboard discrimination algorithms are listed,their characteristics is briefly described.And the development and the present situation of the port/starboard discrimination algorithm are introduced.This paper analyzed the natural directivity and the port/starboard discrimination ability of the towed array.On this basis,geometric phase shift algorithm and time delay addition/subtraction algorithm are introduced.They have the advantages of small computation and good real-time performance.Under the condition of single-frequency signal,narrowband signal and low SNR,they have strong port/starboard discrimination ability,and they are less affected by array distortion.The geometric phase shift algorithm is very sensitive to the signal bandwidth widening.This paper researched the natural directivity and the port/starboard discrimination ability of the vector array.On the basis of that,the port/starboard discrimination algorithm based on the cross spectrum of pressure,particle velocity and the port/starboard discrimination algorithm based on Bartlett null-beamforming are proposed.The two algorithms applies to wide application environment and they overcome the disadvantages of uneven vector port/starboard discrimination algorithm and improve the target detecting speed.The port/starboard discrimination based on the cross spectrum of pressure,particle velocity is not suit for the situation of multi-targets which in same frequency.The port/starboard discrimination based on Bartlett null-beamforming can solve the problem of detecting multi-targets in same frequency and can also work well in the condition of that the two goals are perfectly symmetrical about the array.It can be verified that both the two algorithms are valid and feasible by experimental data.Finally,four kinds of port/starboard discrimination algorithms are compared and analyzed from the aspects of real-time,robustness,calculation,hardware complexity and manufacturing cost.