JPH0439973B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a net formation display device useful for use during net casting work in which a net for catching schools of fish is put into the water. Hereinafter, the case where this invention is used in purse seine fishing will be explained.

In purse seine fishing, a net boat encircles a school of fish by encircling it with a belt-shaped fishing net, and when the bottom of the net reaches a predetermined depth, the bottom is squeezed to capture the school of fish.

When casting a net, if the direction and speed of the current differ between the surface, middle, and lower layers, the net may become twisted or settle in unexpected positions. For this purpose, it would be very effective if the tidal current distribution around the fish school could be measured in advance.

An ultrasonic current meter is a conventional measuring device of this type. Ultrasonic tidal current meters simply detect the Doppler shift component of ultrasonic waves reflected from the measurement target depth, so they are convenient because they can instantaneously measure tidal currents at a desired point. The display usually displays the direction and speed of the current as a vector or as a digital number.

However, this device was only able to grasp the current situation, and changes in the shape of the purse seine had to be inferred using the thinking power of the observer.

Also, the shape of the underwater fishing net and the shape of the net above the water are
A device for displaying information on a CRT display was developed in 1983.
Seen in Publication No. 149073. This device uses radar to detect the position of multiple floats installed on the top of the net to display the net structure at the top of the net, and uses sonar and net depth meter to detect the position of multiple floats attached to the top of the net. The underwater net formation is displayed by receiving the signal transmitted from the net depth meter using sonar. Therefore, radar, sonar, and multiple net depth gauges are required to display net formations on and under water. Furthermore, it is necessary to attach a plurality of net depth gauges to the net for each operation, which makes the work complicated. Furthermore, this conventional device can only know the state of the net in the area where the net depth meter is attached, and cannot accurately detect and display the shape of the entire net. In order to accurately display the overall shape and structure of the net with this conventional device, it is necessary to
It is necessary to attach a large number of net depth gauges to the net at equal intervals in the horizontal direction. Therefore, there is a drawback that the configuration of the entire device is complicated.

The present invention measures the shape of the net on the water using a navigation system installed on a ship, without installing a float that reflects radar signals on the net and multiple net depth gauges, and uses a tidal current meter to measure the shape of the net at a certain depth. A device is provided that indirectly measures the cross-sectional shape of a net and displays the shape of these nets on a display.

The present invention will be explained below based on examples.

In FIG. 1, reference numeral 1 denotes a display device that three-dimensionally displays the ship's track and the magnitude and direction of the current, such as a cathode ray tube display.

FIG. 2 shows an example of the display, where S is the own ship's wake, which can be seen as indicating the shape of the top end of the net. Further, N1 indicates the planar shape of the mesh in the middle layer, and this line is shown in yellow, for example, and the surface layer shape line S is shown in red to distinguish them from each other. Further, N2 indicates the shape of the bottom edge of the net, which is identified in green.

This has the advantage that the network status can be grasped at a glance.

The display contents displayed on the display 1 are stored in the display memory 2, and the stored contents are repeatedly read out and displayed.

In the display memory 2, storage elements are arranged corresponding to each pixel of the display 1, and the storage contents of each storage element are sequentially read out by a horizontal scanning counter 3 and a vertical scanning counter 4.

Horizontal scan counter 3 counts clock pulses from clock pulse source 5. An output pulse is sent to the vertical scanning counter 4 every time the same number of clock pulses as the number of pixels in the horizontal direction of the display 1 is counted. The vertical scanning counter 4 counts the output pulses of the horizontal scanning counter 3 and sends out an output pulse every time it counts the same number of pulses as the number of pixels in the vertical direction of the display 1.

The respective output pulses of the horizontal scanning counter 3 and the vertical scanning counter 4 are sent to the horizontal/vertical scanning circuit 6. The horizontal/vertical scanning circuit 6 scans the pixels of the display 1. For example, when a cathode ray tube display is used, the electron beam scans the pixel positions corresponding to the count values of the horizontal scanning counter 3 and the vertical scanning counter 4. Further, each count value of the horizontal scanning counter 3 and vertical scanning counter 4 is sent to the display memory 2, and the storage contents of the storage element corresponding to each count value are read out. The read stored information is sent to the display 1 and displayed. By that,
The contents of the memory elements corresponding to each pixel of the display 1 are displayed.

The information stored in the display memory 2 is displayed on the display 1 as described above, while the writing of the stored information is performed by the microprocessor 7 (hereinafter referred to as CPU).
It is carried out by.

First, the own ship position is written based on position data measured by the navigation device 8.

As the navigation device 8, for example, a Loran receiver, an Omega receiver, an NNSS receiver, a dead reckoning device, etc. are used,
It measures the navigational position of its own ship and sends out the measured position as, for example, latitude and longitude data. Navigation device 8
The latitude and longitude data sent by is sent to the CPU 7 via the interface 9.

The CPU 7 receives the latitude sent from the navigation device 8;
The display screen of display unit 1 (second
Perform coordinate transformation to the corresponding position on the figure). In this coordinate transformation, for example, a position on the display screen is made to correspond to a specific latitude L1 and longitude L2 position, and a position on the display screen corresponding to the measured latitude and longitude position is calculated using that position as a reference position.

The own ship position on the display screen calculated as described above is written into the corresponding storage element of the display memory 2. Further, at the same time as writing the own ship's position in the display memory 2, the CPU 7 calculates the latitude and longitude lines within a certain range including the own ship's track, and stores the latitude and longitude lines in the corresponding storage element of the display memory 2. Write.

As described above, the own ship's track S is displayed in the memory 2.
Meanwhile, the CPU 7 sends the own ship's position data measured by the navigation device 8 to the first memory 10 and stores it therein. The No. 1 memory 10 stores position data sent by the navigation device 8 at regular intervals, and after the stored content is exceeded, the oldest position data is updated with new position data while being stored.

The own ship's position data stored in the first memory 10 is read by the CPU 7 when writing the own ship's track S in the display memory 2.

Next, writing of tidal flow data will be explained.
The speed of the current in each underwater layer and the direction relative to the ship are obtained by an ultrasonic ship speed current meter 11. This ship speed current meter emits ultrasonic pulses at a constant frequency toward the depth at which the current is measured, and takes advantage of the Doppler effect that corresponds to the moving speed of the ocean floor and water masses. In other words, it is possible to know the speed of the water mass and the speed of the ship from the Doppler frequency, and the direction of the tidal current relative to the ship from the direction in which the sound waves are emitted. However, the orientation obtained here is a relative orientation to the ship's hull, not an absolute orientation.
For this purpose, a direction sensor 12 such as a gyro compass or a magnetic compass is provided, and its output is supplied to the CPU 7 through an interface 13 along with the aforementioned ship speed information and tidal current information.

14 is a material constant setting device that sets data such as the weight, material, shape, etc. of the winding net, and calculates water flow resistance per unit cross-sectional area from these data. is supplied to

The CPU 7 stores this information in the memory 10 in a timely manner.
On the other hand, based on the ship's position signal sent by the navigation device 8, the ship speed information and tidal current information at the ship's position sent by the tidal current meter 11, the output signal of the direction sensor, and the output signal of the material constant setting device 14. Then, calculate the direction and degree of drift of the purse seine in the middle and lower layers, and use the direction and degree of drift of the purse seine obtained in this way to calculate the direction of drift of the purse seine in each middle and lower layer based on the ship position. The position is calculated and the coordinate point on the display memory 2 is determined.

In this way, on the cathode ray tube screen, the network conditions of the surface layer, middle layer, and lower layer are shown as solid lines and in Figure 2, respectively.
They are displayed in an overlapping manner as shown by the dashed line and dotted line. Of course, if a color cathode ray tube display is used to display the top layer, middle layer, and bottom layer in different colors, an even more easily viewable display can be obtained. Note that 16 is a read-only memory in which fixed symbols such as the orientation mark M on the screen are stored.

As described above, the present invention displays the upper end of the cast net based on the output signal of the navigation device, and uses the output signal of the navigation device and the output signal of the tidal current gauge to determine the position of the net in the middle and lower layers. Since the measurement is displayed indirectly, there is no need for the complicated work of installing multiple floats that reflect radar signals on the net and multiple net depth gauges for each operation, and the cross-sectional shape of the entire net can be measured continuously without omission. A device capable of displaying the information can be provided.

In addition, in the embodiment, the upper end length of the purse seine is determined by the navigation device 8.
However, if you manually set the settings, you can display a simulated image similar to the actual operation on the screen. Therefore, it is possible to determine the propriety of the operation before starting the operation, predict the final attitude of the net, and determine the trajectory of the net cast.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing an example of a cathode ray tube display screen.

Claims (1)

[Scope of Claims] 1. A first device that measures the position of the own ship moving while putting the net to be carried in the water and indicates the latitude and longitude of the own ship position.
and ship position measuring means for transmitting a second signal; track signal generating means for generating a signal representing the ship's track based on the first and second signals; a direction sensor; and a direction sensor connected to the direction sensor. tidal current measuring means that emits an ultrasonic pulse signal into the water, receives the reflected wave, and measures the direction and speed of the tidal current at at least one depth using the Doppler effect; net shape signal generating means for generating a signal representing the cross-sectional shape of the net at the depth based on the first and second signals transmitted by the tidal current measuring means and the direction and speed of the tidal current sent out by the tidal current measuring means; A network system consisting of a memory device that stores the signal sent by the network shape signal generation means, and a display device that displays the track and the network shape on its display surface in a manner that allows them to be distinguished from each other based on the output signal of the memory device. Display device. 2. While putting the net to be carried in the water, go around the school of fish and hold the starting and ending ends of the net.Measure the changing position of the own ship and indicate the latitude and longitude of the own ship's position.
a ship position measuring means for transmitting a signal; a track signal generating means for generating a signal representing the own ship's track based on the first and second signals; a direction sensor; A tidal current measuring means for emitting a sonic pulse signal into the water and receiving the reflected wave, and measuring the direction and speed of the tidal current at at least one depth using the Doppler effect; and a setting device for setting constants related to the flow of the net. and representing the cross-sectional shape of the net at the depth based on the first and second signals sent out by the ship position measuring means, the direction and speed of the tidal current sent out by the tidal current measuring means, and the signal sent out by the setting device. a network shape signal generation means for generating a signal; a memory device for storing the signals sent by the wake signal generation means and the network shape signal generation means; A network display device consisting of a display device that displays shapes so that they can be distinguished from each other.