Research On TDOA Localization Method Based On Underwater Multistatic Sonar

With the increasingly close international exchanges,the competition between big countries is becoming more and more intense,and the exploration and development of the ocean is a very important part of the competition between countries.The country that has the initiative in the ocean will undoubtedly have more advantages in the competition in the future.The construction of the ocean will involve many related fields,and the location of underwater target source is a very important aspect,no matter in the civilian field or in the military field,underwater location plays a pivotal role.At present,acoustic wave is one of the most suitable signals for ocean exploration,and multi-base sonar is the detection equipment made of the corresponding principle of acoustic wave,and positioning with multi-base sonar is a very important way in the current underwater positioning.In view of the current development situation,this paper,based on a military scientific research project,puts forward corresponding positioning methods respectively for three scenarios with practical significance in multi-base sonar positioning.The main work and innovation of this paper are as follows:1.The propagation of acoustic signals in Marine media is different from that of electromagnetic waves in air.Generally,the propagation speed of electromagnetic waves can be regarded as a constant,while the propagation of acoustic waves in Marine media is affected by various factors.Based on this situation,this paper proposes a joint estimation algorithm of sound velocity and target location under unknown sound velocity.A new model with constraint equality is constructed by using Lagrange multiplier method,and the model is solved by using Lagrange multiplier method.The performance of the proposed algorithm can reach the optimal position estimation in theory,and it is verified by experimental simulation.2.In addition to the joint estimation of sound velocity and target position by taking it as a completely unknown quantity,sometimes the prior value of sound velocity can also be obtained by measurement.In this case,if the sound velocity is treated as a completely unknown quantity,the performance of the algorithm will no doubt fail to reach the optimal level.In order to solve this problem,a simple two-step algorithm is proposed in this paper,which takes the time difference of signal arrival as the observation quantity and multi-base sonar as the positioning model.The weighted least squares principle is applied in the first and second steps of the algorithm respectively from different processing angles.Compared with the existing closed algorithm,it is not only simpler,but also has the same localization performance.Meanwhile,the performance is verified and compared from theoretical derivation and experimental simulation.3.For the existing closed solution algorithm,the second-order error term generated in the operation is usually ignored in the process of solving,which may increase the estimated bias of the positioning algorithm.Therefore,it is necessary to reduce the bias of the algorithm.This article in view of the existing base of sonar multistep weighted algorithm,through the analysis to its offset increasing factors,from the first step of cutting existing algorithm of offset and the perspective of reducing algorithm calculation steps,puts forward the corresponding bias cut algorithm,at the same time,through the theoretical derivation and experimental simulation prove that the proposed algorithm can offset of existing weighted algorithm effectively cut,At the same time,it will not affect the estimated mean square error of the existing algorithm.