Research On Target Localization Based On Underwater Wireless Sensor Network

Underwater passive target localization technology is one of the significant researchissues in the underwater acoustic engineering field and has been widely used practically.With the development of wireless sensor networks technique, the underwater wirelesssensor network, charactered by the distributed data processing and the information fusiontechnology, has been made a focus of underwater acoustic research and provides a newapproach for underwater target positioning system. The dissertation mainly carries on thedeep research on the target localization based on the underwater wireless sensor networks.First of all, the history and research situation of underwater target localization havebeen went back in details and the application background of underwater wireless sensornetwork was introduced. Besides, three measuring methods for target positioning estimationwere summarized thoroughly.Secondly, aiming at the structure of UWSN system consisting of sensors withmicrophone arrays, which function with direction of arrival (DOA) of the target signal, thepaper deduced the errors for DOA measurements taken at each sensor array via MUSICalgorithm basis of the characteristics of underwater acoustic signal transmission. Then, themodel based on underwater wireless sensor network the DOA estimation of targetlocalization was demonstrated. In addition, the maximum likelihood estimation for targetlocalization and the distributed iterative Gauss---Newton algorithm with threshold valuedetection through least-square algorithm estimation for iterative calculation initial results,has been proposed to expedite the computation of target localization. Furthermore,compared to the different noises environment and different target sound power levels, theresults achieve some promising conclusion.Afterwards, based on target energy propagation model derived from the principle ofunderwater acoustic transmission, a novel source estimator combined with detected acousticenergy by threshold value has been presented. The method uses source energymeasurements taken at each sensor of underwater wireless sensors network and presents theweighted centered location and maximum likelihood algorithm for target location, which isfused by the binary detection forehand. Very promising simulations have been conducted,and the effect of different network nodes position and density on localization results hasbeen concluded.Last but not the least, a software LabVIEW platform for underwater acousticcommunication system has been carried on, and the signal sending module, the signalcollecting module, the signal comprehensive processing module and the target localizationsimulation module all have been integrated into the platform. The remote signal waveformssent by a computer are transmitted between underwater acoustic transducers, and the othercomputer with LabVIEW platform has analyzed the collected signals in the time domain、frequency domain and time-frequency domain. Moreover, the platform has taken theadvantages of MathScript function to display the simulation of the target direction ofarrival(DOA) measurement and the two methods of UWSN collaborative passive targetlocalization discussed above.Determined by the two configurations of underwater wireless sensor networks, two localization models for underwater target have been proposed and some feasible simulationhas been conducted. Furthermore, a LabVIEW platform for underwater signalcommunication and target localization simulation module has been designed. All that makesthe solid foundation for the further research tasks.