Research On Key Technologies Of Underwater Multi-target Localization

Multi-target localization is the urgent requirement of exploration system in underwater weapon, which is the basis of anti-counterwork, target recognization, and accurate attack. The techniques of multi-target localization can be disassembled into bearing estimation, time-delay estimation, and parameter pairing. The novel improvements of relational topic are summarized in this dissertation.In view of special requirements of homing system, we propose two kinds of multi-target localization methods. The first one is based on the algorithm of parameter pairing. Having resolved multiple targets both in bearing and time-delay domain, the method induct a intensity estimation to accomplish the pairing. In case of appearing different number of targets in bearing and time-delay domain, we introduce corresponding policy of pairing. The second localization method, called ESPRIT-Corr needs no pairing, which is based on the joint estimation of bearing and time-delay. By construct a correlation matrix different from conventional ESPRIT, the method estimates bearings using the general eigenvalues, estimates time-delays using corresponding general eigenvectors, and the parameters in two dimensions are paired automatically. In case of targets with different intensities, we proposed a modified algorithm. We also extend ESPRIT-Corr method to estimate 3-dimension parameter jointly. This two kind of localization methods were validated by plentiful computer simulation.We establish a suit of water tank experiment system for multi-target localization, and then carry out a series of experiment research on multi-target localization and 3-dimension parameter estimation. The abilities of some robust bearing estimation to restrain the errors of sensor array are analyzed in theory and validated by experiments. The results of multi-target localization show that: The method based on pairing can locate two targets successfully. The method based on joint parameter estimation shows preferable performance almost at all times, in cases of various number of targets and various type of signal envelope. 3-dimension parameters of 2-4 targets can be jointly estimated as long as the direction intervals are greater than half beam width.