JPS6239336Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device that uses ultrasonic waves to detect the velocity and direction of tidal currents, schools of fish, and the like.

Conventionally, tide meters were used exclusively for tidal currents, and fish finders were used for detecting schools of fish, but focusing on the fact that both have some common functions from the perspective of underwater exploration, this invention uses common functions. This system makes effective use of the system and uses some additional equipment to serve both functions.

Before explaining the embodiments of the present invention, we briefly touch on the concept of a tidal current meter.

When a ship sends out ultrasonic waves toward the ocean floor, reflected waves return from the ocean floor. When there is a tidal current at a given depth, this tidal current has different acoustic properties from normal seawater, and there is a difference in the so-called acoustic impedance value, so the tidal current becomes a reflective layer for ultrasonic waves.
Ultrasonic waves are reflected from there.

In this case, since the ship is traveling at a certain speed and the current is also flowing at a certain speed, a deviation occurs between the transmitted frequency and the frequency of the reflected wave due to the Doppler effect. Since the deviation value is a function of the flow velocity, the flow velocity can be calculated by detecting the Doppler portion and finding the frequency difference.

Therefore, by detecting ground speed using reflected waves from the seabed and detecting water speed using reflected waves from the tidal layer, the true speed of the tidal current can be obtained from the difference between the two.

In actual measurements, values are obtained in the ship's left-right direction (X-axis direction) and longitudinal direction (Y-axis direction), and then vectors are combined to determine the true speed and heading.
As shown in Figure 1, ultrasonic beam A (or A and B) is transmitted vertically from the ship S in the longitudinal direction, and ultrasonic beam C (or C and D) is transmitted in the horizontal direction. The configuration is such that the waves are transmitted toward the seabed at an appropriately determined angle θ, and reflected waves from the seafloor and the current are extracted.

On the other hand, a fish finder is a device that sends out ultrasonic waves from a boat downwards or in any direction, and detects the presence of a school of fish by mainly obtaining reflected waves from the school of fish.As is well known, it is used in fishing in general. It is.

As you can see above, both the current meter and the fish finder are
All have in common that they use ultrasonic waves underwater and receive reflected waves from a reflector.

This invention utilizes the common features of both, namely the transmission and reception of ultrasonic waves, and by adding recorders and other equipment necessary for displaying fish schools, it can be used as both a current meter and a fish finder, making it effective in fishing. This will be explained below based on an example.

FIG. 2 is a block diagram of the embodiment simplified to the extent that the function can be understood.

In the figure, 1 is an oscillation unit, K is a changeover switch provided in the oscillation unit, 2 is a plurality of transducers, 3 is a front or rear ground amplifier, 30 is a left or right ground amplifier, and 4 is a ground amplifier on the left or right side. a front or rear water booster, 40 a left or right water booster, 5 a calculation and display device;
These constitute a tidal current meter.

Here, the ground amplifier extracts only the reflected waves from the seabed with a high echo signal level, and the water amplifier extracts the reflected waves from the tidal layer and the reflected waves from the sea bed with a low echo signal level. It's getting old.

If you want to measure only the tidal current, turn the switch K to the A side and use the transmission drive generator included in the oscillator 1 to generate the keying pulse P for tidal current measurement that is sent at regular intervals from a pulse generator (not shown). Transducer G and transmitter/receiver 2 through transmitting amplifier A.
When the transducer 2 transmits ultrasonic waves in a predetermined direction at a constant cycle, reflected waves from the seabed and tidal layer return, and the signals are transmitted to the ground amplifiers 3 and 30 and the water amplifier 4. and 40, and then the flow velocity and direction are processed by the calculation and display device 5, and the results are displayed. Here, the oscillator 1 and the transducer transmit and receive ultrasonic waves, and the ultrasonic waves are sent out in multiple directions such as the front, back, left and right of the boat, so if you use this, you can detect schools of fish in multiple directions. The detection range is wider than general-purpose fish detectors that detect only one direction vertically downward.

In the figure, 6 and 7 are fish finder amplifiers used in ordinary fish finders, and the figure shows two amplifiers, but since multiple transducers are used for a current meter, it is necessary to adjust the number accordingly. It should be placed in .

8 is a selector that can select and switch the fish finder amplifiers 6, 7, etc. connected to each transducer individually, or connect a plurality of them at the same time. This allows the school of fish in a desired direction to be detected. However, the means for selection is omitted in the figure. Next, numeral 9 is a commonly used recorder such as a belt drive type.

When used as a tidal current meter, ultrasonic waves for detection may be transmitted at any time without any restrictions; however, for fish detection, waves must be transmitted when the recording pen passes the 0 position on the scale. Therefore, the changeover switch K of the oscillator 1 is set to the (0) side, and the oscillator 1 is driven by a keying pulse Q for the fish finder generated by a keying circuit (not shown) in the recorder.

Thus, the device as a whole is extremely effective because it can be used as a current meter alone, and also has the function of a fish finder, allowing it to detect schools of fish in multiple directions.

The above is a basic example, but since the water amplifier generally has a high gain, it can be used as it is for detecting schools of fish to roughly detect schools of fish.

Figure 3 shows the configuration at that time.In this case, attenuators 10 and 11 are used instead of amplifiers 6 and 7 in Figure 2, and these are connected to the rear stage of the water amplifier. This is what I did.

Water amplifiers are constructed to extract signals with low reverberation levels, so they have high gain.
As it is, it is not suitable for detecting schools of fish where the echo level changes widely, so attenuators 10 and 11 are used to adjust the gain, which is simpler and less expensive than the case shown in Figure 2. However, when it comes to fish detection, the shape of fish schools varies, such as schools of fish being close to the seabed or schools of fish and plankton coming together, so it is necessary to take measures to accurately detect schools of fish. Normally, the amplifier itself has some ingenuity. Therefore, it must be said that simply using the current meter's water intensifier and adjusting the gain is insufficient in terms of faithfully grasping the true nature of the fish school.

As seen above, the present invention has both the functions of a current meter and a fish finder, so it is effective and extremely convenient in practice when used in fishing.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the concept of an ultrasonic current meter. Second
The figure is a block diagram of an embodiment of the present invention. FIG. 3 is a block diagram of another embodiment. 1... Oscillator section, 2... Transducer/receiver, 3, 30...
Ground multiplier, 4, 40... Water multiplier, 5... Calculation and display device, 6, 7... Fish finder multiplier, 8...
...Selector, 9...Recorder, 10, 11...Attenuator.

Claims (1)

[Scope of claim for utility model registration] (1) A transducer that transmits ultrasonic waves in a predetermined direction underwater, an oscillator that drives the transducer, a ground amplifier and water amplifier that receive echo signals, and tidal currents. In a tidal current meter, the oscillator is configured with a calculation and display device that calculates and displays the speed and direction of the tidal current. A switch to be operated is provided, and when measuring the tidal current, operate the switch, drive the oscillator with a keying pulse for tidal current measurement, and send out ultrasonic waves of a constant period from the transducer to measure the tidal current. The receiving side of the transducer of the current meter is equipped with a fish finder amplifier, a selector, and a recorder for displaying fish schools. As a result, when the recording pen of the recorder passes through the O position on the scale, a wave is transmitted in response to a keying pulse for fish finding, and the results of the detection of a school of fish by the transducer selected by the selector are displayed. A device that doubles as an ultrasonic current meter and a fish finder. (2) The device according to item 1, wherein an attenuator is connected to a rear stage of the water amplification device instead of the fish finder amplification device.