Study On Multistatic Sonar Key Technologies

Detecting and positioning disoperative submarines is one of the ocean guard keepingtasks today. With the development of acoustic stealth technologies of submarines, radiatednoise and target echo level are getting lower. The acoustic stealth technologies bring thetraditional active sonar and passive sonar great challenges. Active sonar system can be seeneasily by submarine and passive sonar’s detection ability is limited. However, with theadvantages of active and passive sonar, multistatic sonar will get more in submarine detectingtask. This dissertation is organized with issues on multistatic sonar positioning and tracking.The first task of multistatic sonar system design is choosing the configuration andplatform of sonars. So these questions are discussed firstly. An optimized configuration ofmultistatic sonobuoys bounded with energy is proposed after the basic principles and effectivedetecting zone of bistatic sonar are given, that can cover a given maritime space with anoptimized theorem. Based on the specular echo theory, a specular echo track concept isproposed. The specular echo track of optimized circle cluster configuration mentioned aboveis given. Aiming at the characteristic that the TS of target in specular spot is higher than otherspots, an optimized configuration based on specular echo detecting is proposed. In thisconfiguration, the specular echoes of target can be captured by different receivers in turn. Thetank experiment result of specular echo will be given in the below.When the configuration of multistatic sonar is given, in some special condition, directblast will occur. So it is necessary to research the direct blast problem. Aiming at the problemof direct blast interference in bistatic sonar, several kinds of adaptive algorithms are discussed.Jamming matrix direct blast suppression algorithm and nulls constraint matrix direct blastsuppression algorithm are proposed. Simulation result indicates the validity of the algorithms.The nulls constraint matrix algorithm based on broad band is also presented. Nulls constraintmatrix algorithm based on3dimension column array in integrative sonar of submarine isdiscussed here. With the virtual array transform, column array is transformed into2dimensions rectangle arrays which can be restricted in its side-lobe with Chebyshev weight in2dimensions and the nulls constraint matrix algorithm can be used with a restricted side-lobe.Moreover, the next key work is target positioning and tracking. Based on D-S evidencetheory, a combined logic data association (CLDA) algorithm is proposed.3kinds of typicaltracks that are single target linear track,2targets parellel track and3target crossing track aresimulated with CLDA and kalman filter algorithm. The simulation results indicate the validityof CLDA. At last, the result of bistatic sonar tank experiment is preseted.4items of bistatic sonartank experiment are measure experiment of GDOP in bistatic, specular echo measure inbistatic, experiment of direct blast constraint and target tracking. The results of GDOPmeasure experiment and specular echo measure experiment fit the theoretical results well.Direct blast suppression experiment also proves the validity of jamming matrix algorithm andnulls constraint matrix algorithm. With the high SNR, the side-lobe level gains of pre and postsuppression of the2algorithms are37dB and47dB approximatively. The detectionprobability of jamming matrix algorithm is high than nulls constraint matrix algorithm in thesame SNR. In the target tracking experiment of bistatic sonar, single target linear track,2targets parellel track and single target circular track are completed. Comared with NNDA,CLDA is provided with a higher correct associating probability and tracking precision. Theresult of bistatic sonar tank experiment can support the outfield trial.