수중 플랫폼 이동 속도 계측을 위한 위상 배열 센서 설계

Abstract

In order to measure platform movement speed, a DVL (Doppler Velocity Log) is widely used not only for surface ships but also, especially, for submerged platforms such as AUVs (Autonomous Underwater Vehicles) and ROVs (Remotely Operated Vehicles). Typically, a DVL measures ground speed by utilizing the Doppler effect of acoustic waves reflected from the seabed, but it can also measure water-relative speed by using waves scattered by particles in the water column. A traditional DVL has a Janus configuration to transmit and receive acoustic waves in four directions, but recently, DVLs using planar phased-array sensors, which experience less resistance from water flow, have also been used. By varying the phase of each element in the phased array sensor, the steering angle of the beam can be controlled. This allows Doppler measurements to be taken alternately in the forward, backward, left, and right directions, from which the platform velocity can be estimated. As the number of elements increases, the beamwidth decreases. In this paper, assuming a circular element geometry, the beam pattern and beamwidth were estimated while accounting for the effect of the single-element beam pattern.