| 摘要 |
PURPOSE:To accurately measure tidal current without hindering a ship sailing the sea by synthesizing tidal current speed components and current direction components based on Doppler deviation frequencies due to respective ultrasonic beams having required shapes of two pairs of ultrasonic transmitter-receivers arranged in parallel with respect to vector. CONSTITUTION:Ultrasonic transmitter-receivers 4 and 5 are arranged in parallel correspondingly to ultrasonic beams which are wide in the horizontal direction but are narrow in the vertical direction, and fine particles at a measurement point 9 which are moved together with the tidal current are measured by transmission and reception ultrasonic waves crossing at the point 9, and the Doppler deviation frequency proportional to the tidal current speed component is detected, and a tidal current speed component 10 and the current direction component are determined by a flowmeter 7. A tidal current speed component 11 and the current direction component are determined in the same manner by another flowmeter 6 provided with ultrasonic transmitter-receivers 4 and 5 having ultrasonic frequencies different from those of the transmitter-receivers, and components 10 and 11 and current direction components are synthesized respectively with respect to vector to accurately measure true tidal current speed 12 and the current direction without hindering many ships sailing the sea. When transmitter-receivers 4 and 5 are turned upward and downward, a depth component of the tidal current is measured. |
