A Modified MUSIC Algorithm Based On Enhancement In Spatial Spectrum Of A Single Vector Hydrophone

The acoustic field is both a scalar field and a vector field. The acoustic vector hydrophone can measure both pressure and particle velocity of acoustic field at a point in space. Consequently, a single vector hydrophone can accomplish the estimation of underwater target, and without ambiguous direction. Now, in many installation areas that with limited applications place, Take the single vector hydrophone as the receiver of sonar system, is a very popular and practical way of engineering applications in underwater acoustic field.Under this background, this paper proposes a new algorithm based on MUSIC using single acoustic vector hydrophone by enhanced space spectrum under a low SNR conditions.Firstly, this paper reviews the propaedeutics of spatial spectrum estimation based on single vector hydrophone, such as the directional of the vector hydrophone, and the fundamentals and simulation analysis of Bartlett algorithm, MVDR algorithm, MUSIC algorithm. Then this paper analyses the influence on MVDR algorithm and MUSIC algorithm caused by channel amplitude error. The result of analysis in theory and simulation shows that single vector hydrophone amplitude gain of each channel consistency has serious implications on its spatial spectrum estimation performance. The influence caused by the inconsistency in pressure channel is that the width of peak become wider, what's more, sometimes even a 'fake peak' appeared. The influence caused by the inconsistency in the velocity channel is that the location of the peak has little deviation, and the width of peak become wider too. Moreover,the non-consistency of the two velocity channels inevitably lead to inconsistency between pressure channel and velocity channels, so a 'fake peak' maybe appeared.In the last part, this paper proposes a new algorithm based on MUSIC using single acoustic vector hydrophone by enhanced space spectrum under a low SNR conditions. The basic principle of the algorithm is: When Single sound source incident on a single vector hydrophone, add an auxiliary source, if the direction of the auxiliary source is the same as the signal source, the space spectrum of enhanced space spectrum will be enhanced, if the direction of the auxiliary source is not the same as the signal source, two directions combined into one direction, and the spatial spectrum estimation exhibits poor perfonnance. So when the direction of the auxiliary source is consistent with the signal source, it will be enhanced the peak, and take the maximum of the spatial spectrum, and this direction assuredly is the signal source direction. The result of analysis in simulation and processing test data that actually measured shows that, compared with conventional MUSIC algorithms, this algorithm has sharper peaks and higher estimation accuracy, can be achieved with higher accuracy spatial spectrum estimation.