The Design Of Cooperative Target Positioning System Based On Underwater Acoustic Network Node

The continuous development of human in the field of marine engineering has increased the demand of underwater acoustic positioning technology. In many occasions, it is necessary to guarantee the concealment of the targets, such as the self-positioning of the submarine. This paper designed a set of underwater acoustic cooperative target positioning system. The node of the underwater acoustic network provides parameter information for the localization process, and three network nodes of this system which have the function of the time delay measurement and the position signal synchronous transmitting are used as the fixed nodes.The positioned node does not take the initiative to transmit the signal, and under the condition of known coordinate, communication mode and communication parameters of each fixed node, receives positioning signal passively and completes the positioning self calculation. We named this kind of positioned node as cooperative target.Position calculation uses Fang algorithm to solve the hyperbolic intersection model .In this paper, the positioning accuracy is simulated in the pool environment and the marine environment, and the error sources are analyzed. In the system, the underwater acoustic spread spectrum communication technology is adopted to realize the transfer of the positioning parameters of each node. The system does not need a unified time standard and does not use high precision, high stability clock source.The hardware platform of the system includes: transducer, signal processing module, ARM module, power amplifying module and power management module. Modules are connected by the bottom plate. The main parameters of signal processing module and the power amplifier module are determined by the communication distance. ARM module is the running platform of the positioning software. The software design of the system includes the fixed node positioning process programming, the positioned node hyperbolic convergence solution programming, GPIO driver programming and the realization of the function of program self -starting and program updating.The positioning system is tested in the water tank, the function of time delay measurement,positioning signal transmitting synchronously and coordinate calculation are verified.Through the statistical analysis of the test data, it is proved that the system is reliable, the performance is stable, and the expected positioning effect is achieved.