The Reserch Of Vector Hydrophone Passive Synthetic Aperture Technique In The Measurement Radiated Noise

Measurement of underwater-object's radianted noise,in the early using of sound prepressure hydrophone array period, to obtain considerable space gain, need a very large hydrophone array.And the implementation on the project difficult,costly. Passive synthetic aperture technology is for synthetic processing the receiving signal of small-aperture array along the linear motion recorded,in order to achieve the orientation resolving power effects of the virtual Large Aperture Array at the expense of time gain for the space gain. The directivity of vector hydrophone does not change with frequency.If using in the vector-hydrophone towed array,it can expend a smaller cost to improve the towed line array noise suppression, eliminate of a single orientation in the left and right side of vague, improve the targeting accuracy effectively.This article gives an overview of vector hydrophone, including the classification of vector hydrophone, sensitivity, phase characteristics and co-directional. basic principles of passive synthetic aperture is introduced systematically. Two factors that impact the aperture are researched: the signal temporal coherence and dragging velocity. This paper derivates formula of two synthetic aperture algorithms: FFTSA and ETAM. The two algorithm process is descried and simulated. The basic principle of noise measurement is introduced, and also the method. The constant beamwidth method is used when employing towed array for noise measument, and there is an introduction of the method. It is better using synthetic aperture array with constant beamwidth processing than conventional acoustic pressure array, because it can get virtual array with large aperture covering multiple octaves through an array with relatively less elements. This reduces complexity caused by excessively long array.Finally, the previous chapters on the basis of theoretical studies carried out extensive simulation studies.The application of vector passive synthetic aperture sonar has many advantages of passive synthetic aperture sonar, but also eliminate of a single orientation in the left and right side of vague. This paper proves that in the virtual linear array made by synthetic aperture method, constant beamwidth can be used in processing broadband signal. For the same number of elements in the array, synthetic aperture array can get a higher gain and azimuth resolution. Meanwhile, through making lager array, the array which acquisites and processes multiple octaves is formed.Discuss the advantage passive synthetic aperture deal with broad band signal.