Research On Towed Array Shape Estimation Methods Based On Sparse-distributed Sensors

The towed array is the main anti-submarine means for platforms such as submarines,surface ships and unmanned underwater vehicles,and is an important sonar equipment for underwater early warning and detection system.For large platforms,towed arrays develop in the direction of large scale,large aperture and multi-dimensionality.For small platforms,towed arrays develop in the direction of light weight and dense grouping.In the actual towing application,due to the influence of array density,ocean hydrodynam-ics and towing platform movement,the towing array will be distorted by external forces in both vertical and horizontal directions,which will seriously reduce the detection ef-fectiveness of towing line sonar if not compensated.The array estimation method based on non-acoustic auxiliary sensors is a common class of methods in engineering.For the two development directions of towed arrays,the array estimation faces the same problem that the non-acoustic auxiliary sensors are sparsely distributed.Therefore,the develop-ment of the array estimation method based on sparsely distributed sensors has important application value.In this paper,a towed array estimation method based on sparsely distributed sensors is studied for the specific application problem of attitude depth sensor installation limita-tion that exists in high frequency dense towed arrays.Firstly,a two-dimensional in-plane towing array force model is established with a flexible towing array as the research object,and the general hydrodynamic equations of the towing array are obtained.On this basis,reasonable assumptions and equation approximations are made for the actual towing ar-ray parameters,and a simplified nonlinear partial differential equation is obtained,and the analytical solution of the lateral displacement of the array under specific parameters is obtained.Secondly,an array estimation method based on the sparse distributed attitude depth sensor information and the self-estimated information of hydrophone array element depth is proposed.Based on the dynamical model,a framework of Kalman filtered array estimation algorithm based on the model and observation quantities is established,and the simulation of the array estimation algorithm based on different observation quantities and application scenarios is realized,and the influence of sensor measurement errors on the array estimation accuracy is analyzed.Finally,the above algorithm is used to process and analyze the actual sea trial observation data,and the effectiveness of the method is verified,which shows that the method has high practical value.The main innovative points of this paper are as follows.(1)A formation estimation method based on sparse distributed attitude depth sensors and array element depth self-estimation and combined with Kalman filtering is proposed to achieve real-time formation estimation under the condition of a small number of aux-iliary sensors.(2)The hydrodynamic equations of the flexible towed array are established,and the analytical solution of the towed array is obtained.(3)Analysing the influence of sensor measurement error on array estimation,and obtained the minimum number of sensors for array shape estimation.