Joint Estimation Of Vertical Angle And Time Delay Difference Of Deep-sea Transient Acoustic Signal

The passive positioning technology of transient underwater acoustic signals of deep-sea underwater targets is of great significance in both military and civil fields.Hyperbolic intersection location by measuring the time delay difference between nodes by multi node long baseline positioning system is a common and effective passive target location method..However,due to the measurement error of delay difference between nodes caused by multi-path and sound line bending of deep-sea channel,the positioning accuracy will be affected..Therefore,this paper considers the scheme of first separating multi-path signals by using composite linear array with pitch angle measurement ability for each node and then positioning the baseline,so as to obtain high-precision time delay estimation,The pitch angle of the corresponding signal can also be obtained,so as to improve the positioning accuracy.Based on the analysis of the passive localization of the long baseline transient underwater acoustic signal of the composite array,a passive localization scheme of the transient underwater acoustic signal based on the multi-path separation of the vertical array is proposed,and the specific problems in the multi-path separation of the vertical array are studied,The main contents are as follows:Firstly,the problems of long baseline passive positioning of transient underwater acoustic signal are analyzed to give the long baseline positioning scheme of deep-sea transient underwater acoustic signal.Firstly,by analyzing the characteristics of transient underwater acoustic signal and using ray acoustic model,the propagation characteristics and multi-path law of transient underwater acoustic signal in deep sea are studied.Then,on this basis,the influence of delay difference estimation error caused by multipath effect on long baseline positioning accuracy is simulated and analyzed,and a long baseline positioning scheme of transient underwater acoustic signal based on multipath separation is given.Then,the joint estimation method of pitch angle and time delay of transient underwater acoustic signal based on vertical array is studied,which is the key technology in the long baseline positioning scheme of deep-sea transient underwater acoustic signal based on multi-path separation.For ideal vertical array,a multi-path signal pitch angle estimation method based on signal segmentation and deconvolution beamforming is proposed.On this basis,the multi-path separation of single node received signal can be carried out,so as to improve the estimation accuracy of time delay difference between nodes,Its effectiveness is verified by simulation and experimental data analysis.In addition,the estimated pitch angle of the vertical array can also be used to add constraints to the sound line bending correction.For the tilted non ideal vertical array,the vertical array can still separate multi-path signals,but the pitch angle cannot be estimated directly.To solve this problem,this paper forms a composite array by using the vertical array and vector hydrophone,and uses the horizontal azimuth resolution of vector hydrophone,The multi-path pitch angle estimation of tilted vertical array is realized,and the pitch angle estimation performance of tilted vertical array is analyzed by simulation.Finally,the calibration of vertical array under the condition of flow impulse is studied to ensure the feasibility of multi-path separation of vertical array.The flow impulse will increase the vertical array shape error and the pitch angle estimation error.Based on the analysis of the mathematical model of vertical array under the condition of flow impulse,the basic principles of two vertical array calibration methods based on auxiliary sound source and depth sensor are given,and the array error and pitch angle estimation accuracy of the two methods are analyzed by simulation.After calibration,the pitch angle estimation performance of the vertical array is significantly improved.