The Design Of Buoy Communication Node Of The Active Passive Underwater Acoustic Positioning System

The acoustic positioning technology is a branch of the underwater acoustic science, an utility technology which is used catholically in ocean science domain.This dissertation originates from "The active/passive underwater positioning system" project. The positioning system adopts the long base line positioning technology, which has these advantage of long operating range and high positioning precision and real-time . The positioning system have two methouds to measure underwater target with high speed: the active positioning mode, in other words, needs to install acoustic beacon on the target .The positioning system uses signal, which is emitted by the acoustic beacon, to locate and track target; the other one is the passive positioning mode. This makes use of the noise which is radiated by target with high speed, to position and track target,without need for acoustic beacon.The content of research in this dissertation is to provide stable and reliable radio communication for the positioning system. The positioning system adopts TDMA (Time Division Multiple access) mode. The dissertation include three parts, shown as following:1. Design of communication node. The hardware takes advantage of low power consumption. The DSP(Digital Signal processor) is the main controller. The hardware uses FPGA to connect the DSPs , the spread spectrum communication station and the GPS receiver.2. Accomplish hardware interface and design system synchronous impulse. The FPGA program is modularized. Different module is relative independent in favor of increasing stability of the whole system.3. Realize communication protocol of the positioning system achieving by the DSP.The validity of the above word has been proved by the trials in SongHua lake.