Research On Improve Resolution Methods Based On Small Scale Array

In recent years, with the strong development of Marine technology, the bearingdetection technology that used for underwater target becomes the focus in the industry.The existing bearing detection technology ignores the consideration of the cost for thepursuit of higher accuracy, although it gets better accuracy but its cost has increasedrapidly, which hindered its application in the actual environment. In order to solve thecompromise of cost and estimation precision, under the condition of fixed array numberand spacing as small as possible, this paper designed the virtual mobile array (VMA)method, which improves the accuracy of target detection on a small scale array.Firstly, the theory of array is briefly introduced. By establishing the receiving modelof underwater array, it compares and analyses four different methods of beamforming,Points out the advantages and disadvantages of each method, and gives the evaluationindexes of array.Secondly, this paper studies deeply virtual array and synthetic aperture technology,and does simulation and analysis for them, which show that technology can both increaseaperture of the array in the virtual sense, improves resolution of the array, and in the scopeof M≤N-K+1, with the increase of the number in virtual array, array has higherresolution on the targets. But for the limit of virtual length, it presents improved virtualarray method, and gets lower lobe and narrower disc than existing methods by simulation.Finally, in order to overcome the limitations of virtual array, this paper proposes anew algorithm of underwater target bearing estimation based on virtual mobile array(VMA). Through the simulation compared with different methods with high resolutionestimation and virtual array beamforming with different SNR. Under the same conditions,it compares with the virtual array of fixed array and synthetic aperture array, VMA methodhas more accurate resolution for underwater target bearing, and close to the distinguishprobability of the same total number in FA array, realized the narrow beam with highdirectivity curve.