수중 통신이 가능한 USBL 위치추적 알고리듬 연구

Abstract

We are developing a USBL system which is capable of two-way underwater acoustic communication for homing and docking of an AUV as well as for exchanging commands and sensor data remotely. The system being developed has to give not only sufficient positioning accuracy but also reliable communication performance. For that purpose, we suggest a USBL algorithm which transmits a minimum peak sidelobe (MPS) sequence or m-sequence by QPSK for positioning and communication. The suggested algorithm measures distances between the transmitter and the receivers of USBL transceiver by exploiting the pseudo-random noise like autocorrelation property of the proposed sequences and measures azimuth and elevation using the phase of cross spectrum between receiver sensors confronting each other. In addition, it adopts a linear minimum mean-square error(LMMSE) equalizer to overcome channel distortion caused by multipath propagation and uses the transmitted sequence as the training sequence required for equalization. In order to verify its performance, we conducted an experiment in the underwater anechoic basin of MOERI/KORDI which has two main signal propagation paths and confirmed that the suggested algorithm works successfully and the equalizer improves the positioning performance by removing multipath interference