Study On The Depth Estimation Of Target Based On Vertical Linear Array

With the development and utilization of the marine environment, sonar is developing towards the array form. Beam-forming technology has become a mature technology. The vertical line array has vertical aperture, the incident pitch angle of the target signal can be got by analyzing the delay and phase.Taking the vertical line array target pitch angle's estimation as a based, two kinds of target depth estimation method which adapt to the environment of the underwater were put forward.Firstly, on the basis of the vertical line array, target pitch angle information is got with the spatial spectrum estimation. In the paper, the CBF and MVDR based on the vertical line array beam-forming technology are introduced and studied. Three-dimensional simulation model was established with phase and azimuth information introduced by the difference between the sound paths. Through the theoretical analysis and simulation, pitch angle measurement of target in multi-path environment was realized.Then, target depth estimation in the condition of multipath was studied in the paper. The multi-path exists because of the border reflection in the environment under water. Based on ray-acoustic model, the relationships between the direct wave?multi-path injection angles and the sound source's depth and distance were analyzed. The location resolving model based onthe vertical linear array was built as well. A time delay image of distance and DO A can be achieved by the beam-forming technology with the received signal. Theoretical analysis indicated that the multi-path impact is related to the target range, depth and DOA. The method of target depth estimation and the simulation results were verified by the processing the data from the lake experiment.Finally, the superposition of direct sound wave and repercussion wave from sea was analyzed on the base of the model of point source near the sea. And a new method for signal separation was suggested based on the depth of the target. In this method, the trace of target and beam-forming output were achieved from the image of distance and DOA with the data of vertical linear array. A generalized Fourier transform was done to the beam-forming output along the trace of target to separate signal of target based on the depth and verified by simulation.