Application Of Acoustic Communication In Underwater Positioning

Now, source is indigent in land. Researching, exploiting and utilizing of marine source are very important. This paper bases on"Integrate technology of detection for gas-hydrate"research of National"863"Project in resources and environmental technology fields. To get the high precision position underwater, we built an integrative underwater position system. It will be useful in marine survey.Satellite position is a simple way for position, but the electronic signal could be absorbed by the water, so it was very hard to use satellite to position the target underwater. In this case, we used the acoustic communication and measure to solve this problem. This page started with the basic theory of echo sounder measure and communication in the water. We compared the equipments in this field, and picked out some equipment as the element of the integrative under water position system.This system is made up by Surface Position Unit, Attitude Measure Unit, Sound Velocity Measure Unit, Underwater Measure Unit and the Compute and Monitor Unit. They will supply absolute position of vessel, attitude value of vessel, waster sound velocity value of working area, range and direction of target, and absolute position of the target and the status of the system. Also we analyze factory which will affect position accuracy, and know that the error of SVP, the accuracy of GPS, error of attitude and bearing, the SNR, and the design of baseline and frequency can put the system position accuracy down.At the last section are twice sea trials. In the first sea trial, the system work correctly under USBL mode. In the second, the USBL function worked correctly, but because of limited time and the bad weather, we just finished some tests of the LBL. Whatever, the system worked correctly and could be used in marine oil, gas-hydrate survey.Finally, the article summarizes the results in the study:1. Building a set of integrative underwater position system suited USBL and LBL position. That will be useful for the object position underwater.2. Analyzing key technology and affecting factors could enhance accuracy in the system.3. Twice sea trials proved the system work correctly, it matched the requirement of the study and could be supplied the high precision position for gas-hydrate survey.