JPH06342060A - Trawl-net-opening information reception apparatus - Google Patents

Abstract

PURPOSE:To increase the S/N ratio of a wave-received signal by a method wherein a net-opening information wave-receiver is not exposed to air bubbles flowing at the bottom of a ship and the directive direction of a wave-received beam is directed automatically to a net-opening information transmitter in a net-opening information reception apparatus in a trawling method. CONSTITUTION:A net-opening information wave-receiver 6 is installed at the lower part inside a wave transmitter-receiver dome for a scanning sonar, a phase difference angle phi between output signals of oscillators which are adjacent in a bearing direction is detected by a phase-difference-angle detector 9, phases of the output signals from indivisual oscillators T1 to Tn are set to the same phase in phase shifted 8-1 to 8-N by a phase control signal generated by a phase control part 10 on the basis of the phase difference angle phi, and they are composed by an addition and compostion device 11 and output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a network capable of receiving an ultrasonic signal from a net mouth information transmitter attached to the net mouth of a trawl fishing net with optimum sensitivity even if the trawl fishing net deviates from the stern direction due to a tidal current. The present invention relates to a mouth information receiving device.

[0002]

2. Description of the Related Art In the conventional trawl fishing method, a net mouth information transmitter 2 is attached to the net mouth of a trawl fishing net 1 as shown in FIG. Operates towing of fishing nets. As shown in FIG. 5, the net mouth information transmitter 2 includes an upward fish finder 2a and a downward fish finder 2b. The fish school information obtained by these fish finder is transmitted to an ultrasonic wave to detect nets. The waves are transmitted to the fishing boat towing.

On the fishing boat side, it is necessary to install a wave receiver for receiving the wave. As a method of installing the wave receiver, the net mouth information wave receiver 3 may be fixed to the bottom of the ship as shown in FIG. 6, or As shown in FIG. 7, the elevating device 4 can be made to project further downward from the bottom of the ship, and the bearing can be changed, and as shown in FIG. 8, an underwater towed vehicle 5 equipped with a net mouth information receiver. The method of towing with a tow line has been adopted.

The signal received by the net mouth information receiver provided in this way is then subjected to amplification and other processing by the receiving device provided in the fishing boat, and the signal is transmitted to the net mouth information transmitter 2. The information captured by the fish finder for each of the downward and downward directions is displayed on the CRT.

[0005]

However, in the above-mentioned conventional system, there are various problems in the way of arranging the net mouth information receiver on the fishing boat side. First, in the fixed-bottom-type net mouth information receiver 3 as shown in FIG. 6, the noise due to the bubbles flowing at the bottom of the ship causes the presence of bubbles to interfere with the propagation of ultrasonic waves, resulting in a low SN ratio and unreceivable reception. There is a problem that it often becomes. Further, since the wave receiver is fixed and the direction of the received beam is fixed in the stern direction, there is a problem that it becomes difficult to receive the wave if the fishing net deviates from the stern direction due to the influence of the tidal current.

Therefore, in order to avoid the influence of bubbles and to adjust the direction of the wave receiver, as shown in FIG. 7, an elevating device 4 is provided and a net mouth information wave receiver 3'is attached to the tip of the elevating shaft. More than below to escape from the effect of bubbles,
There is also a method in which the orientation of the wave receiver can be changed by rotating the elevating shaft, but providing the elevating device 4 penetrating the bottom of the ship raises the problem of increasing the cost. Further, as shown in FIG. 8, the method of towing the underwater towed vehicle 5 lacks stability in that the wave receiving surface is directed toward the net mouth information transmitter 2, and it is difficult to adjust the azimuth. There is also the problem of disconnection.

In view of the above problems in the prior art, an object of the present invention is to provide a net mouth information receiver for receiving a sound wave from the net mouth information transmitter in a dome of a transceiver of a scanning sonar. To provide a trawl net mouth information receiving device that is arranged below the net and controls so that the reception beam of the net mouth information receiver is automatically directed to the arrival direction of sound waves, that is, the direction of the net mouth information transmitter. It is in.

[0008]

The present invention has the following means for achieving the above object. That is, the trawl net mouth information receiving device of the present invention is provided below the scanning sonar transmitter / receiver dome and forms a transducer row in which a plurality of transducers are arranged at equal intervals in the azimuth direction, or A net mouth wave receiver that has a plurality of sub-rows stacked one above the other to form one surface, and the vibrating surface is set in the depression angle direction that catches the trawl fishing net; next to the same vibrator row Phase difference angle φ between the received signals of the _two oscillators T ₁ and T ₂ =
a phase difference angle detector for detecting φ ₁ −φ ₂ (where φ ₁ is the phase of T ₁ and φ ₂ is the phase of T ₂ ); if this phase difference angle φ is received and φ is a positive value, In each row, the phase of the output of each vibrator is cumulatively advanced by one phase angle φ per vibrator from the vibrator on the vibrator T ₁ side to the vibrator on the vibrator T ₂ side. Or the phase of the output of each oscillator is sequentially accumulated from the oscillator on the oscillator T ₂ side to the oscillator on the oscillator T ₁ side by the phase angle φ per oscillator. Phase control is performed so as to delay, and if φ is a negative value, the phase of the output of each vibrator is sequentially passed from the vibrator at the end on the vibrator T ₂ side to the vibrator at the end on the vibrator T ₁ side in each column. Phase control is performed so that the phase angle φ per oscillator is cumulatively advanced, or the output of each oscillator is sequentially performed from the oscillator at the end on the oscillator T ₁ side to the oscillator at the end on the oscillator T ₂ side. Phase of oscillator 1
A phase control combining unit for performing phase control so as to cumulatively delay each individual phase angle φ, and then combining all outputs; display means for displaying an image based on the combined outputs; It is a trawl net mouth information receiving device.

[0009]

The operation of the trawl net mouth information receiving apparatus of the present invention having the above-mentioned construction will be described below. Trawl fishing boats are usually equipped with a scanning sonar, especially a full-circumference scanning sonar, and the transducers of the trawlers are protected and housed in the dome so that they can be projected downward from the storage room at the bottom of the vessel by an elevating device when used. In the present invention, the net mouth information receiver is provided below the transmitter / receiver in the transmitter / receiver dome of this scanning sonar, so that a separate lifting device or dome is not provided, resulting in an increase in cost. It is possible to avoid the net mouth information receiver from the bubbles flowing on the bottom of the ship without any, and it is possible to avoid the deterioration of the SN ratio and the reception obstacle due to the bubbles.

Next, automatic adjustment of the receiving direction will be described. The net mouth information receiver of the present invention is formed by a row of transducers in which a plurality of transducers are arranged at equal intervals in the azimuth direction, the receiving surface is oriented in the stern direction, and the depression angle is attached to the trawl fishing net. It is directed toward the network information transmitter.

FIG. 3 is a diagram showing the case where the net mouth information receiver is viewed from vertically above the depression surface. That is,
N transducers T ₁ , T ₂ , T ₃ , ..., T _n , ..., T _N are oriented in the lateral direction (azimuth direction) at equal intervals d with the receiving surface facing the stern.
Are lined up. Depending on the case, a plurality of such transducer rows may be vertically stacked to sharpen the directivity in the depression angle direction of the received beam. However, since this is an explanation of automatic adjustment in the azimuth direction of the received beam, one row Just to explain.

Now, it is assumed that the towing net is swept by the tidal current from the starboard side and is displaced not by the stern direction but by the angle θ from the stern direction to the port side. Then, the sound wave from the net mouth information transmitter attached to the net also comes from the θ direction as shown in FIG. Then, considering the sound wave reaching the vibrator T ₁ as a reference, the sound wave reaching the vibrator T ₂ propagates a distance longer by the distance r, so that the sound wave is delayed by that amount. Since this distance r is represented by Equation 1 from the figure,

[0013]

[Equation 1] r = d sin θ

When this is converted into the phase angle φ of the sound wave, the following formula 2 is obtained.

[0015]

## EQU2 ## φ = (2πd sin θ) / λ

Where λ is the wavelength of the sound wave in water. That is, the phase of the received signal of the oscillator T ₂ lags that of the oscillator T ₁ by φ, and the phase of the received signal of the oscillator T ₃ lags that of the oscillator T ₂ by φ. T
_n of the received signal of the phase is delayed by φ than that of the transducer T _n-1.

Therefore, the phase of the received signal of the oscillator T ₂ is advanced by φ from that of the oscillator T ₁ , and the phase of the received signal of the oscillator T ₃ is advanced by 2φ from that of the oscillator T _1. The phase of the received signal of the oscillator T _n is advanced from that of the oscillator T ₁ by (n−1) φ, or conversely, the phase of the received signal of the oscillator T _n is set to the phase of the oscillator T _N. By delaying by (N−n) φ, the output signals of all N oscillators are aligned in phase, and the output obtained by adding and combining these is maximized. This means that the signal due to the sound wave arriving from the θ direction is output most strongly, which means that the received beam is directed in the θ direction.

Therefore, when a sound wave is received from a certain direction, the phase difference angle φ is detected from the output signals of two adjacent vibrators in the same vibrator row, and the signal with the most advanced phase is detected. The phase of the output of the adjacent vibrator is advanced by φ based on the output vibrator, and the phase of the output of the adjacent vibrator is advanced by 2φ, and so on. Go, or delay the phase of the output of the adjacent vibrator by φ with respect to the vibrator that outputs the signal with the most delayed phase, and further delay the phase of the output of the adjacent vibrator by 2φ. If the phases are controlled so as to increase (cumulatively) and combine, the direction of the received beam is naturally directed to the arrival direction of the sound wave.

In the present invention, T ₁ and T ₂ 2 pieces of transducers T ₁ and T ₂ which adjacent phase difference angle detector (here limited to T _1, T ₂ of FIG. 1 and FIG. 3 The purpose is to distinguish between the two transducers, and therefore the two transducers may be at the ends of the row or near the center of the row). φ is detected, and the phase control synthesizing unit sequentially accumulates or delays the phases of the outputs of the oscillators according to the arrangement order of the oscillators based on the phase difference angle φ and synthesizes them. Therefore, the direction of the received beam is automatically directed toward the network mouth information transmitter.

The case where there is only one transducer row has been described above. However, when it is desired to sharpen the reception directivity in the depression angle direction, a similar transducer row is vertically stacked in a plurality of stages to perform phase control in the same manner. I'll do it.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 2 shows a state in which the net mouth information receiver 6 is fixed in the dome 12 of the all-round scanning sonar transducer 14 below the all-round scanning sonar transducer 14 with a depression angle. It is a figure. The dome 12 is moved up and down by the elevating device 4, and is housed in a storage room provided at the bottom of the ship when not in use. When used, the dome 12 is projected a predetermined distance from the bottom of the ship and is influenced by bubbles flowing through the bottom. I try not to receive it.

The mesh mouth information receiver 6 of FIG. 2 is a perspective view of a case where two transducers forming one row in the azimuth direction are stacked in four stages vertically. In the description of item 1, generally, a case of one row of N oscillators will be described. In FIG. 1, the outputs of the transducers T _{1 to TN} of the network mouth information receiver 6 are sent to the corresponding amplifiers 7-1 to 7-N, where they are amplified to the required levels, and their outputs correspond to each other. To the phase shifters 8-1 to 8-N, and the output of the amplifier 7-1 and the output of 7-2 are transmitted to the phase difference angle detector 9
And the phase φ ₁ of the output signal of the amplifier 7-1.
The phase difference angle φ = φ ₁ −φ ₂ which is the difference between the phases φ ₂ of the output signals of the amplifiers 7-2 is detected.

A well-known phase difference detection circuit is used for the phase difference angle detector 9 itself. Further, in this embodiment, the two signals sent to the phase difference angle detector 9 are from the amplifiers 7-1 and 7-2, which are, for example, 7-2 and 7-3.
It can be from any amplifier if it is from adjacent amplifiers.

The phase difference angle φ thus obtained is sent to the phase controller 10. On the basis of this φ, the phase control unit 10 outputs a phase control signal for shifting the phase by φ, a phase control signal for shifting by 2φ, and similarly (n-1)
The phase shifter 8-
2 and 8-3 are added to the phase shifter 8-n in the same manner.

Each phase shifter shifts the phase of the input signal from each amplifier by the applied phase control signal. At this time, if φ is a positive value, the phase is advanced, and if φ is a negative value, the phase is delayed. As the phase shifter, the phase of the signal applied to the mixer by the well-known frequency conversion method is φ, 2φ, ..., (N-1) φ, ..., (N-1).
By shifting by φ, the phase of the frequency-converted signal can be shifted by the same amount.

The signals whose phases have been adjusted to the same phase by the phase shifters 8-1 to 8-N in this way are sent to the adder / combiner 11 where they are added and combined and output as a net mouth information signal. After this, the display device receives the same signal processing as the conventional net mouth information receiving device, and the fish school image detected by the upward fish school finder 2a and the downward fish school finder 2b included in the net mouth information transmitter 2. Can be displayed clearly.

[0027]

As described above, in the trawl net mouth information receiving device of the present invention, the net mouth information receiver is provided below the dome for the scanning sonar transducer.
During use, the elevator and the scanning sonar both project downwards from the bottom of the ship, so it is possible to avoid a decrease in the SN ratio and wave interference due to air bubbles flowing through the bottom of the ship, and the signals received are adjacent to each other in the azimuth direction. During towing by detecting the phase difference angle between the outputs of the oscillators, setting this as the step width, and advancing or delaying the phase of the output signal of each oscillator in the same phase Even if the trawl fishing net of is deviated from the stern direction due to the influence of tidal current or due to the change of course of the fishing boat, the direction of the received beam is automatically directed to the net mouth information transmitter attached to the net mouth. Since it is not necessary to mechanically change the direction of the wave receiver to search the direction of the fishing net, the directivity of the received beam can be sharpened, and the SN ratio is further improved and a clear fish There is an advantage that the image can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a device of the present invention.

FIG. 2 is a diagram showing a state of installation of a network mouth information receiver in the embodiment of the device of the present invention.

FIG. 3 is an explanatory diagram showing that a phase difference occurs at regular intervals in each transducer output of the network mouth information receiver.

FIG. 4 is a diagram showing a trawl fishing net being towed and a net mouth information transmitter attached to the net mouth.

FIG. 5 is an explanatory diagram of a net mouth information transmitter.

FIG. 6 is a diagram showing a case where a net mouth information receiver is attached to the bottom of a ship.

FIG. 7 is a diagram showing a case where a net mouth information receiver is provided by being lifted up and down to be separated from the ship bottom and further projected downward.

FIG. 8 is a diagram showing a case where a fishing boat is towing a submersible towed body equipped with a net mouth information receiver by a tow line.

[Explanation of symbols]

1 Trawl fishing net 2 Net mouth information transmitter 2a Upward fish finder 2b Down fish finder 3 Net mouth information receiver 3'Net mouth information receiver 4 Lifting device 5 Underwater towed body 6 Net mouth information receiver 7-1 to 7-N amplifiers 8-1 to 8-N phase shifters 9 phase angle detector 10 the phase controller 11 adds the combiner 12 dome 13 insulating oil 14 full surround scanning sonar transducer T ₁ through T _N oscillator

Claims (1)

[Claims] 1. A scanning sonar transmitter / receiver dome is provided below the dome to form a row of transducers in which a plurality of transducers are arranged at equal intervals in the azimuth direction, or the rows of transducers are vertically stacked. And a net mouth information receiver which is formed into one surface and whose vibrating surface is set in the depression angle direction for catching a trawl fishing net; and two adjacent vibrators T ₁ in the same vibrator row. A phase difference angle detector for detecting a phase difference angle φ = φ ₁ −φ ₂ between the received signals of T ₂ (where φ ₁ is the phase of T ₁ , φ ₂ is the phase of T ₂ ); and this phase difference When the angle φ is received and φ is a positive value, the phase of the output of each oscillator is sequentially oscillated from the oscillator at the end on the oscillator T ₁ side to the oscillator at the end on the oscillator T ₂ side in each column. Phase control is performed so as to cumulatively advance by phase angle φ per child, or sequentially from the vibrator at the end on the vibrator T ₂ side to the vibrator at the end on the vibrator T ₁ side. Phase control is performed so that the phase of the output of each transducer is cumulatively delayed by a phase angle φ per transducer, and if φ is a negative value, the transducer T in each column is
Oscillation is performed by phase control so that the phase of the output of each oscillator is sequentially advanced progressively by the phase angle φ per oscillator from the oscillator on the ₂ side end to the oscillator on the oscillator T ₁ side end. Child T ₁
The phase of the output of each oscillator is sequentially controlled from the oscillator on the side of the oscillator to the oscillator on the side of the oscillator T ₂ so as to cumulatively delay by one phase angle φ for each oscillator, and then the whole phase is controlled. A trawl net mouth information receiving apparatus comprising: a phase control combining unit for combining outputs; and a display unit for displaying an image based on the combined outputs.