JP3413677B2 - Flow velocity measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow velocity measuring device,
More specifically, the present invention relates to a flow velocity measuring device that corrects the flow velocity data of a velocity meter by positioning data of a buoy to obtain an accurate flow velocity.

[0002]

2. Description of the Related Art As a document disclosing a sea-bottom-type buoy for measuring ocean currents, there is, for example, "Ocean Foundation" (pages 51 to 52) published by the Industrial Research Council. In this conventional example,
An anchor is provided at the bottom, an acoustic disconnecting device and a velocity meter are provided at the top, and a buoy is provided at the top, and these are connected by a rope. Then, in order to measure the flow velocity in the sea, one or a plurality of sea current measuring buoys are installed on the seabed by anchors, and the flow velocity is measured and recorded by a recording device installed inside the anemometer. After a lapse of a certain period of time, a command is sent from the wave transmitter provided on the mother ship to the acoustic disconnection device, the anchor is disconnected, the buoy is levitated, and the anemometer is collected. Then, the inside of the anemometer is taken out so that the measured value can be known.

[0003]

In the ocean current measuring buoy configured as described above, the position of the flowmeter or the buoy moves due to the influence of the ocean current. Therefore, even if the current velocity is measured, its relative velocity is not measured. Not too much. Therefore, it is difficult to accurately measure the flow velocity, and there is a problem that the error appears largely when the flow velocity is large.

The present invention has been made in order to solve the above problems, and it is possible to measure an accurate flow velocity even if the position of the anemometer or buoy moves due to the influence of the ocean current. The purpose is to obtain the device.

[0005]

SUMMARY OF THE INVENTION A flow velocity measuring device according to the present invention is a buoy for velocity measurement, in which an anchor is installed on the bottom of the water, a buoy is attached to the upper end, and a velocity meter or the like is provided between the buoy and the anchor. In the flow velocity measuring device equipped with, the buoy is provided with an acoustic measuring device and a wave transmitter / receiver that transmits a signal at fixed time intervals, and receives a signal transmitted from the wave transmitter / receiver near the water velocity measuring buoy. A plurality of transponders that emit response signals of different frequencies are installed.

[0006]

The position of the buoy is measured at regular time intervals with reference to the transponder. Then, the velocity meter and the acoustic positioning device are collected, or the velocity data and the positioning data are put into the arithmetic device online, the moving velocity of the buoy is calculated from the temporal change amount, and the velocity measured by the velocity meter is measured by the buoy. Compensate according to the moving speed and perform compensation calculation.

[0007]

1 is an explanatory view of an embodiment of the present invention, in which a flow velocity measuring device is constituted by a flow velocity measuring buoy and a transponder. 1 is an anchor provided at the bottom of the flow velocity measuring buoy 2 and is installed at the bottom of the water (seabed, riverbed, etc.), 3 is an acoustic decoupling device provided at the top, and 4 is further provided at the upper part of the One or more anemometers with a recording device, 5 is a buoy with buoyancy provided on the top,
Each of these components is connected by a rope 6 and is arranged in an upright state in the water 7. 8 is an acoustic positioning device installed in a watertight manner inside the buoy 5, 9 is an acoustic positioning device 8
A transducer which is electrically connected to the acoustic positioning device 8 in the lower part of the acoustic positioning device 8 to measure the position of the buoy 5 accurately from the transceiver 9 to the transponder (described later). Issue a question signal to.

A plurality of transponders 10a, 10b, 10c are installed on the water bottom around the buoy 5 (three in the embodiment) in order to find the position of the buoy 5 of the buoy 2 for measuring the flow velocity. A response signal is generated in response to the interrogation signal transmitted from the wave transmitter / receiver 9 and is sent to the wave transmitter / receiver 9 of the acoustic positioning device 8. 11 is a wave transmitter provided on the mother ship 12,
A command is sent to the acoustic disconnecting device 3 to disconnect the anchor 1 and float the buoy. Reference numeral 13 is an arithmetic unit installed on the mother ship 12 and used for correction calculation.

The operation of this embodiment configured as described above will be described. To measure the flow velocity in water, the flow velocity measuring buoy 2 is installed on the bottom of the water with the anchor 1 at the bottom, and the flow velocity is measured and recorded by a recording device installed inside the flow velocity meter 4. However, the measured values thus measured are the velocity meter 4 and the buoy 5 of the velocity measuring buoy 2.
Is a relative speed because of the movement. Therefore, in order to obtain an accurate flow velocity, the position of the buoy 5 is accurately measured, the moving velocity of the buoy 5 is obtained by this measurement value, and the relative velocity measurement value including the error previously measured by the velocity meter 4 is calculated. Buoy 5
It is necessary to obtain an accurate flow velocity by correcting with the measured value of. The procedure is as follows.

As shown in the figure, the acoustic positioning device 8 installed inside the buoy 5 issues an inquiry signal from the wave transmitter / receiver 9 to the transponders 10a-10c at regular intervals.
In response to this interrogation signal, the transponders 10a to 10c
Respond to each other with different frequencies, the transmitter / receiver 9 receives this signal and sends it to the acoustic positioning device 8. Based on the difference between the inquiry signal transmission time and the reception time, the propagation time t (se
Find c). Here, if the sound velocity in water is c (m / s), the direct distance r between the transducer 9 and the transponders 10a to 10c can be obtained by r = 1 / 2ct (m).

Now, the transponders 10a, 10b, 1
0c position, P ₁ (x ₁ , y ₁ , z ₁ ), P ₂ (x ₂ ,
y ₂ , z ₂ ), P ₃ (x ₃ , y ₃ , z ₃ ) are confirmed by calibration work, the position P ₀ (x ₀ , y ₀ , z ₀ ) of the buoy 5 is acoustically positioned. It can be calculated from the direct distance measured by the device 8. The relationship is as shown below. ^{_{(R 11) 2 = (x}} 0 -x 1) 2 + (y 0 -y 1) 2 +
^{_{(Z 0 -z 1) 2 (}} r 12) 2 = (x 0 -x 2) 2 + (y 0 -y 2) 2 +
^{_{(Z 0 -z 2) 2 (}} r 13) 2 = (x 0 -x 3) 2 + (y 0 -y 3) 2 +
(Z ₀ -z ₃₎ ²

In the flow velocity measuring device having the above-described structure, when the intersection point of the direct distances r _{11 to} r ₁₃ is calculated from the positions of the transponders 10a to 10c, the transponders 10a to 10c are calculated.
The solution of the positions of the two buoys above and below the plane connecting the two is obtained.
Of these, the solution existing on the bottom of the water is selected. With this configuration, the position of the buoy can be detected by the coordinate value calculation, and the accurate flow velocity can be measured even if the position of the flowmeter or the buoy moves due to the influence of water flow or the like.

In this way, the position is measured at regular time intervals,
The moving speed of the buoy 5 is obtained from the change in position over time. After a certain time has passed, the wave transmitter 11 provided on the mother ship 12
Sends a command to the acoustic disconnecting device 3, disconnects the anchor 1 and floats the buoy 5, and collects the velocity meter 4. Then, the record inside the velocity meter 4 is taken out and the measured value is known.
Further, a record inside the acoustic positioning device 8 is taken out and the measured value is known. These two data are put into the arithmetic unit 13 and the velocity of the buoy 5 is vector subtracted from the measured value of the velocity meter 4 and correction calculation is performed to obtain the true velocity. When a plurality of anemometers 4 are installed, the catenary of the buoy 5 and the anchor 1 is calculated, and the movement amount for each depth is calculated and corrected.

When the measured flow velocity is V ₁ and the moving velocity of the buoy 5 is V ₂ , the true flow velocity V is calculated by V = V ₁ -V ₂ . In the present embodiment, the case where the correction calculation is performed after the buoy 5 is collected has been described.
If the arithmetic unit 13 is installed inside the and the flow velocity data and the positioning data are input, the correction calculation can be performed online, so that the collection work of the velocity meter and the acoustic positioning device is unnecessary, and the time required for the collection can be omitted. Therefore, even if the position of the flow meter or buoy moves due to the influence of the ocean current, the accurate flow velocity can be efficiently measured. Therefore, according to the present embodiment, even if the flowmeter 4 and the buoy 5 are moved due to the influence of water flow or the like, the accurate flow velocity can be quickly measured.

[0015]

As described above in detail, the flow velocity measuring device according to the present invention is provided with an acoustic positioning device and a wave transmitter / receiver for transmitting a signal at a fixed time on the buoy, and at the bottom of the water near the flow velocity measuring buoy. A plurality of transponders that receive the signals transmitted from the transmitter / receiver and emit response signals of different frequencies are installed, and the buoy positions are measured at regular intervals with reference to these transponders, and the buoys are measured based on the temporal change. Since the moving speed of the buoy is calculated and the flow speed measured by the current meter is corrected by the moving speed of the buoy, accurate flow speed can be measured even if the position of the flow meter or buoy moves due to the influence of water flow etc. can do.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

[Explanation of symbols]

1 anchor 2 Buoy for velocity measurement 4 Anemometer 5 buoys 8 Acoustic positioning device 9 Transceiver 10a, 10b, 10c transponder 12 mother ship 13 Arithmetic device

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01P 5/00

Claims (3)

(57) [Claims] 1. A flow velocity measuring device having a flow velocity measuring buoy, wherein an anchor is installed on the bottom of the water, a buoy is attached to the upper end, and a velocity meter or the like is provided between the buoy and the anchor. An acoustic measuring device and a transmitter / receiver for transmitting a signal at fixed intervals are provided, and a signal transmitted from the transmitter / receiver is received on the bottom of the water near the flow velocity measuring buoy to transmit a response signal of a different frequency. A flow velocity measuring device having a plurality of transponders installed therein. 2. The flow velocity measuring device according to claim 1, wherein an acoustic positioning device is installed inside the buoy. 3. The flow velocity measuring device according to claim 1, wherein an arithmetic unit is installed inside the buoy.