수조에서의 수중 초음파 위치추적 및 통신을 위한 모의실험 기법 개발

Abstract

Currently KORDI is developing a USBL system with the two-way digital communication function to cope with increasing demand for underwater wireless communication. Especially the USBL system under development aims at being used for homing and docking test of AUV in water tank facility. Because of its strongly reverberant sound field which causes intersymbol interference, the water tank facility can be regarded as severely frequency-selective communication channel and requires proper consideration of the multipath effect. In order to estimate the performance of the USBL system in water tank environment as well as in open sea environment, we suggest a computer simulation method for it. The suggested method calculates the amplitudes and the time delays of possible multipaths using geometric image source method and adopts the baseband equivalent channel model to allow all simulation procedures to be done with the baseband representation. Using the suggested simulation method, we examine the performance of the USBL positioning scheme which uses QPSK modulation and pseudo-noise sequence with varying signal-to-noise ratios.