| The problem of weak target detection under strong interference has always been a hot and difficult problem in hydroacoustic detection.Whether it is a multi-target situation of strong target interference to weak targets,or platform sonar detection in the case of close range platform noise interference to long-range weak target detection,is an important issue that needs to be addressed urgently.In recent years,underwater gliders and other unmanned acoustic detection platforms have developed rapidly.Unmanned platform quiet gliding section is a good carrier of acoustic detection equipment,but its own in order to maintain a smooth attitude and surfacing,diving maneuvers and other heading state needs to be adjusted by a variety of electromechanical equipment,these have brought interference to the platform detection,the paper focuses on the research of interference suppression technology for platform interference in the detection process of small conformal arrays of gliders.Platform self-noise interference can be divided into continuous spectrum interference and line spectrum interference in the frequency domain.This paper conducts interference suppression research from two perspectives: time-frequency domain and spatial domain.The main research content includes:In the time-frequency domain,the interference cancellation algorithm based on Least Mean Square(LMS)in the time domain is used for continuous spectrum interference.The algorithm extracts the reference input of the noise source based on the localization of the noise source,uses the noise source location information,and does the subtraction operation between the estimated signal obtained from the reference signal and the signal contaminated by the interference under the least mean square error criterion for interference suppression.The interference canceling algorithm based on Partitioned Fast Block Least-Mean-Square(PFBLMS)is used for line spectrum interference;under the condition of knowing the prior information of interference frequency,the Notch filtering algorithm with multi-channel parallel connection is used.The Notch filtering algorithm can accurately track line spectrum interference and is a narrowband filter with good filtering effect.In the spatial domain,beam zero trapping is used for continuous spectrum interference suppression,and the zero trapping power formulas of Bartlett beam zero trapping technique and MVDR beam zero trapping technique are derived for near and far field signal mixing conditions.The advantage of the beam zero-trap interference suppression algorithm is that the form of the zero-trap right is only related to the spatial location of the interference,which does not produce a detection blind zone affecting the detection of far-field targets while suppressing the nearfield interference at the specified location.Moreover,the algorithm does not require real-time calculation,the zero trap of the beam generated by the zero trap right can be preformed,not limited by the shape of the array.The overall computational effort is small,suitable for engineering applications.The paper simulates the above various interference suppression algorithms in a conformal array detection scenario,and verifies the effectiveness of the interference suppression algorithms by processing sea trial data. |
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