Research On Underwater Multi-user Acoustic-electric Joint Localization Technology

Ocean contains a wealth of marine biological resources, energy resources, space andchemical resources. Offshore or deep-sea diving operation is necessary to explore the ocean.Real-time monitoring and recording the position information of diver by underwaterpositioning technology is an effective way to prevent diving accidents. However, there aremany difficulties to be overcome in underwater positioning technology due to the inherentnoise of underwater acoustic channel, serious multi-path effects, long transmission delay andother disadvantages.This paper designed an underwater multi-user electro acoustic positioning system basedon frequency-hopping technology. The underwater positioning system can overcome theproblem of multi-path effects and range ambiguity by the introduction of frequency hoppingcarrier technology. It also improved the accuracy of underwater positioning and achievedunderwater multi-user positioning by code division multiple access technology at the sametime. The main work of this paper are as follows:1.The problems of underwater positioning technology was analyzed according tounderwater acoustic channel characteristics. Frequency-hopping technology was applied tounderwater positioning to solve the problems of underwater multi-path effects and rangeambiguity. Walsh orthogonal coding was used as user address coding to meet the requirementsof the multi-user underwater positioning, a set of multiple target tracking and positioningsystem was built which suitable for offshore fishing and leisure diving. The systemperformanced simulation test and got the desired effect.2.The Zigbee network was presented to as the way to form the network of the surfacebuoy nodes on the water,aim at the application scenarios of recreational diving. So we can usethe Zigbee network function, according to the actual positioning needs, quickly and easily addthe number of buoys nodes, so as to improve the positioning accuracy. It also put forward tolocate the relative positioning of reference node by using Zigbee network positioning enginefor positioning coordinate reference of underwater target. Compared with traditionalunderwater positioning technology using GPS for assisted positioning, this new method improved the positioning accuracy and reduced system cost. Applicable networkcommunication protocol was developed to ensure the reliability of the underwater positioningnode, the surface buoy and communication between the network control terminal. The methodwhich applied to the system clock synchronization was researched to ensure the requirementof each part of the system time synchronization. Finally, the detailed design principle andworkflow of the system components, and the corresponding circuit design were described.The simulation for the design ensured the feasibility of the system.