JPS6136189B2 - - Google Patents

Description

[Detailed description of the invention]

[Objective of the Invention] (Field of Application of the Invention) The present invention relates to a scanning sonar detection and display method that performs PPI display, and in particular, to a detection and display method of a scanning sonar that performs PPI display, and in particular, to a detection display method that provides horizontal conversion distance information of the distance to a detected object, such as a school of fish, and an object in a vertical cross section underwater. This invention relates to a scanning sonar detection display method that greatly improves detection ability by allowing the simultaneous display of the positions of fish on the same cathode ray tube surface, making it possible to accurately track schools of fish and judge when it is time to cast a net. be. (Prior art and its problems) In scanning sonar, the transducer is usually made up of a number of oscillators O 1 , O ₂ , O 2 , O 1 , O ₂ , O A group of oscillators formed by arranging _N oscillators in a ring is formed into M stages OS ₁ , OS ₂ ,...
...Using a stack of OS _M , and using a cathode ray tube that is swept in a spiral pattern as shown in Figure 1b as a display device, schools of fish, etc. are detected in the following manner. That is, after simultaneously emitting sound waves T from each transducer of the transducer TR in an umbrella shape corresponding to the depth of the school of fish F as shown in FIG. 2a, each transducer group O ₁ , O ₂ , . . . By sequentially switching the oscillators OS ₁ , OS ₂ , ...OS _M in one row in the vertical direction of the O _N as a group in a fixed direction, the reception of the transducer TR can be adjusted as shown in Fig. 2b. A wave reception posture is created in each direction so that the wave directivity is equivalently scanned, and the detection signal of the fish school F obtained thereby is swept in a spiral shape in synchronization with the switching of the transducer. In addition to the display cathode ray tube in Figure 1b, fish school F
The position of is displayed by the direction φ and the distance L _D. By the way, in fishing methods such as purse seine fishing, in order to track a school of fish and get into a good position for casting a net, the shape of the net to be laid is determined regardless of the depth of the school of fish F located in front of the boat, as shown in Figure 3. In order to
It is necessary to know the horizontal distance L _H from the boat to the school of fish. However, when a scanning sonar as described above is used for tracking, the distance shown on the display cathode ray tube is indicated by the distance L _D to the school of fish. Therefore, the school of fish is F ₁ as shown in Figure 3.
There is no problem when they exist close to the sea surface, such as tuna, bonito, etc., but for active fish schools such as tuna and bonito, for example, from deep to shallow depths like F and F ₁ in Figure 3, there is no problem. It often moves up and down in between. Therefore, the display position of the school of fish on the CRT surface changes according to the movement of the school of fish.
If you rely on this to cast your net, it is difficult to determine the course of your net, and this is one of the major obstacles to purse seine fishing. However, this difficulty can be avoided by converting the display distance into a horizontal distance using the angle of depression of the transducer. However, it is extremely troublesome for each person to make the conversion in response to the frequent movement of schools of fish, and the fishing commander who monitors the CRT display has no time to spare as he is busy communicating with fellow ships and directing his subordinates. Usually there is no. For this reason, conversion work is difficult in practice. Therefore, automatic horizontal distance conversion display is extremely advantageous and necessary for ship maneuvering. However, even if the display is performed using horizontal distances in this way, it is still not sufficient. In other words, in order to catch fish efficiently through purse seine fishing, when preparing to cast the net, the fishing director should be well aware of the relative position of the school of fish F and the net NF, as shown in Figure 4, and move the net in a vertical direction. It is necessary to be able to lay the net while measuring the settling time of the net so that a school of moving fish does not escape from the lower part of the net, for example. However, it is clear that this requirement cannot be met by the conventional display of information based on direction and distance, and it is desirable to realize information in the depth direction, that is, a display that shows the position of a school of fish in a vertical section of the ocean. Moreover, the horizontal distance conversion display as shown above,
If a display showing the position of a school of fish in a vertical cross-section of the ocean could be displayed on the same display screen on a CRT screen, it would have a great effect on increasing the amount of fish caught.Currently, there is nothing that can satisfy this request. has not appeared. The present invention provides a scanning sonar detection and display method that satisfies the above-mentioned requirements, eliminates all the obstacles to fishing operations as described above, and greatly contributes to improving fishing catches. Next, it will be explained in detail using the drawings. [Structure of the Invention] (Means and Effects for Solving the Problems) The present invention has been made based on the idea described below. As shown in Figure 3, when the angle of depression of the emitted sound wave is θ, the distance to the school of fish at that time is L _D , and the horizontal distance is L _H , the distance L _D to the school of fish is calculated horizontally by the following equation (1). It is converted into distance _LH . In the present invention, the sweep speed when the angle of depression θ=0° (the speed that spreads in a spiral shape in the circumferential direction, hereinafter referred to as the sweep speed) is V ₀ , and when the angle of depression is θ°, the sweep speed of the display cathode ray tube V 〓 is converted into a horizontal distance and displayed by slowing down as the depression angle θ increases based on the following equation (2). L _H = L _D cosθ ………(1) V = V ₀ cosθ ………(2) The full scale d ₀ sweep time of the cathode ray tube is T ₀ when the angle of depression is θ = 0°, and T when the angle of depression is θ By controlling the sweep voltage generation circuit of the display cathode ray tube so that the sweep time changes as shown in the following equation (3), the distance to the school of fish is automatically adjusted horizontally as T = T ₀ / cos θ ......(3) The first idea was that it could be converted into a directional distance and displayed using the azimuth φ and the horizontal distance L _H as shown in the A display section of Fig. 5. Also, this idea is B in Figure 5.
Although it is used to display echo images in the direction of depression angle like the display section, since the horizontal distance is already displayed as described above, the sweep speed of the display cathode ray tube is adjusted according to the depression angle θ by V==V ₀ It is changed to cosθ.
Therefore, if we apply the distance information to the fish school to the display cathode ray tube at a speed that removes (or compensates for) the change in sweep time according to the depression angle, that is, a speed that is 1/cosθ times the above V〓 = V ₀ . , the horizontal distance L _H can be returned to the distance L _D to the school of fish. Therefore, in order to display a vertical cross-section underwater, the information added to the compensated cathode ray tube must be accumulated and held over time to a position corresponding to the depression angle within the desired angle range of the display cathode ray tube. If you add it to the cathode ray tube, the horizontal distance L _H
This was done based on the idea that the display and the position and distance L _D of the school of fish F relative to the vertical section of the sea can be shown together on the same scale. Generally speaking, when using omnidirectional scanning sonar, when the depression angle is close to 90°, the scanning range (radius) in the circumferential direction increases.
The angle of depression that is used in practice is 45° to
It is about 60° and never exceeds 80°. Therefore, if the practical range of the depression angle is 0° to 60°, the sweep time ratio is T/T ₀ =1 to 2, which is 1 cos θ0.5. Next, the present invention will be explained with reference to examples. (Embodiment) FIG. 6 is a block circuit diagram of one embodiment of the present invention, and FIGS. 7 and 8 are operation explanatory diagrams. In FIG. 6, reference numeral 1 denotes a receiving rotation signal generating circuit, which continuously sends out an output P ₁ having a cycle T ₁ necessary for switching and rotating the transducer/receiver during one spiral sweep period. Reference numeral 2 denotes a sweeping signal generating circuit for a display cathode ray tube, such as a frequency divider, which divides the frequency of the output _P1 of the receiving rotation signal generating circuit 1. Then, it sends out an output P ₂ with a period T ₂ necessary for the spiral sweep. 3 is a transmission trigger signal generation circuit, which uses the output P ₂ of the sweep signal generation circuit 2 to generate 1 signal every detection period T ₀₀ of the maximum detection distance.
The transmission control pulse P ₀ is sent out. 4 is a transmitter, 5 is a transmission depression angle control circuit, 6 is a depression angle control voltage generation circuit, 7 is a transmission/reception switching circuit, and 8 is a transducer having the structure shown in FIG. 1A. The transmission circuit 4 outputs a transmission output to the transmission depression angle control circuit 5 every time the signal P ₀ is input from the transmission trigger signal generation circuit 3. Further, the depression angle control voltage generating circuit 6 generates a voltage E〓(E
Sends 〓∽θ). The transmission depression angle control circuit 5 includes a transducer group of the transducer 8 having the structure shown in FIG.
OS ₁ , OS ₂ , ......When the number of stacked OS _M is M, it consists of (M-1) delay elements. Then, depending on the magnitude of the voltage E from the depression angle control voltage generating circuit 6, the transmission power from the transmitter 4 is changed at different times t _d0 =0, t _d1 , . . . as shown in FIG. 7a.
…With a delay of t _d(M-1) , each of N sets of transducers
OS ₁ , OS ₂ , . . . is added as an excitation pulse P ₃₁ to OS _M , and based on the overall phase relationship of each emitted wave, the transducer 8 emits sound waves all at once in a 360° direction with a depression angle. 9 is a receiving depression angle control circuit, 10 is a receiving rotation scanning circuit, 11 is a receiving detection signal amplification circuit, 12 is a display cathode ray tube, and the receiving depression angle control circuit 9 is composed of the same number of delay elements as the transmitting depression angle control circuit 5. . The output P 4 of the M×N transducers in M stages×N rows of the transducer 8 is controlled by the control voltage E from the depression angle control voltage generating circuit 6 and input via the transmitting/receiving switching circuit ₇ . is divided into M stages in an arrangement of O ₁ and O _N , and the output of each stage is delayed by the same amount as in the case of transmission and then applied to the reception rotation scanning circuit 10 . The reception rotation scanning circuit 10 is controlled by the output P ₁ of the reception rotation signal generation circuit 1, and opens the gate every time the signal P ₁ is input to allow the output from the reception depression angle control circuit 9 to pass through. That is, within the transmission period T ₀₀ , the display cathode ray tube 12
In synchronization with the spiral sweep period T ₂ of OS ₁ ~
Oscillators O ₁ , O ₂ , ... each formed by OS _M
...N groups of _N are repeatedly switched in a fixed direction at 360 degrees, and each output is sequentially extracted to equivalently scan the receiving directivity of the transducer 8 as shown in FIG. 2b. I do. And the signal obtained from this
_P5 is applied to the display cathode ray tube 12 as a luminance signal via a received signal amplification circuit 11 and a video signal switching circuit 27 to be described later. The above circuit configuration is the same as a conventional scanning sonar except for the video signal switching circuit 27, and the sweep voltage generation circuit has a constant maximum voltage constant cycle required to sweep the full scale of the cathode ray tube when the depression angle θ = 0°. The sawtooth wave voltage of T ₂ causes the output P ₂ of the sweep signal generation circuit 2 to
By sweeping the display cathode ray tube 12 using a sweep signal created by amplitude modulating the phase-shifted signal by 90 degrees, the same display as before, that is, the direction and distance L _D to the school of fish, can be obtained. will be held. Next, circuits 13 and 14 are sweep voltage generation circuits provided to convert and display the distance to the school of fish in the horizontal direction corresponding to the depression angle θ.
3 is a functional voltage generation circuit, and 14 is a variable sweep voltage generation circuit, which will be explained in detail next. First, FIG. 7b is an example of the circuit configuration of the functional voltage generating circuit 13, and FIG. 7c is an explanatory diagram of its operation. 7th
In FIG. b, 131 is a sawtooth wave generating circuit, 132 is a comparator, 133 is a frequency dividing circuit, 134 is a shaping circuit, 135 is a gate, and 136 is a hold circuit. The sawtooth wave generation circuit 131 receives the pulse P ₂ (a in FIG. 7c) from the sweep signal generation circuit 2, and sets the period to T ₂ , the time width to T ₂ /2, and the rise time to c in FIG. 7.
t ₃₁ of b of , the sawtooth wave voltage whose maximum value is the value of E at an depression angle of 90° [E ₉₀ at b of Fig. 7 c]
Create and output _P30 as shown in Figure b. The comparator 132 outputs a pulse P ₃₂ when the sawtooth wave voltage P ₃₁ and the voltage E from the depression angle control voltage circuit 6 become equal, as shown in FIG. 7c (b). Note that the time from t ₃₁ of this pulse P ₃₂ is defined as T〓 _p . Here, the maximum value of T〓 _p is when θ=90°, T〓 _p = T ₂ /2
, and the minimum value is T〓 _p = when θ=0°
It is 0. Also, since E〓∽θ (proportional), T〓 _p
is proportional to θ. Next, the frequency dividing circuit 133 divides the frequency of the pulse P ₂ from the sweep signal generating circuit 2 to create and output a voltage P ₃₃ having a period of 2T ₂ as shown in d of FIG. 7c. This output P ₃₃
is received by the shaping circuit 134, which creates and outputs a cosine wave voltage e ₃₄ having a start time t ₃₁ , a period 2T ₂ and a maximum value E ₀ as shown in e in FIG. 7C. The gate 135 uses the output pulse P ₃₂ from the comparator 132 to extract and output the voltage P ₃₅ at time _Tp of the cosine wave voltage e ₃₄ as shown in e of FIG. 7c. Since the amplitude of this voltage P ₃₅ is T〓 _p ∽θ, it is E ₀ cosθ. The hold circuit 136 holds the output P ₃₅ from the gate 135 and outputs the voltage e ₃₆ with the amplitude E ₀ cos θ of f in FIG. 7c.
Output as Ee. As described above, the function voltage generation circuit 13 receives the voltage E from the depression angle control voltage circuit 6.
〓Receives ∽θ and converts the function voltage E ₀ cosθ=Ee into circuit 14
Output to. Next, _the variable sweep voltage circuit ₁₄ in FIG _.
θ, rises with a pulse of P ₀ at the depression angle θ,
As shown in Figure 7d, the period is T ₀₀ and the maximum value is Ee =
Sawtooth wave voltage e _f 〓= _{E 0 cosθ}
Create t/T ₀₀ . Note that the sawtooth wave voltage of e _f 〓 in the case of depression angle θ = 0° (in the case of E ₀ cos θ = E ₀ ) is defined as e _f0 , and its value at time T ₀ is E _f0 , that is, E _f
0 =E ₀ T ₀ /T ₀₀ . Note that E _f0 is the maximum value that sweeps the full scale d ₀ of the cathode ray tube. Then the depression angle θ
If the time width in which e _f 〓 reaches E _r0 after rising is t〓, then E ₀ cosθt〓/T ₀₀ = E _f0 = E ₀ T ₀ /T ₀₀ From t〓=T ₀ /cosθ Here, T ₀ Since cosθ is T〓 as shown in equation (3), t〓=T〓. Note that e _f0 and e _f 〓 are created by limiting their respective maximum values to E _f0 . Also e _f0
~e _f 〓 is collectively called E _f . In this way, the variable sweep voltage circuit 14 generates the output P ₀ (period T ₀₀ ) from the transmission trigger signal generation circuit 3 and the output Ee=E ₀ cos from the function voltage generation circuit 13.
In response to θ, a sawtooth wave voltage E _f having a maximum value E _f0 and a pulse width T ₀ to T〓 is generated at a period T ₀₀ corresponding to the depression angle 0° to θ° as shown in FIG. 7d. Then, with this sawtooth wave voltage E _f, the sweep signal generating circuit 2 of FIG.
_After amplitude modulating _the output _{P 2 of}
Create the voltage e _a = E ₂ sinωt (ω = 2πf ₂ ) of E ₂ ,
In addition, a sweep signal e _b =E ₂ ·cos ωt is created in the same manner as above using P ₂ with a phase shift of 90°, and this is applied to the horizontal and vertical axes of the display cathode ray tube 12, as well as a known spiral sweep. have them do it. In this way, corresponding to any depression angle θ, the full scale d ₀ sweep time of the display cathode ray tube is T =
It is swept by T ₀ /cosθ. Next, the video signal switching circuit 27 shown in FIG. 6, which will be described later, switches the detection signal amplification circuit 11 shown in FIG.
By inputting the output P ₆ directly to the display cathode ray tube 12 in real time and modulating the brightness,
In display section A of FIG. 5, a school of fish HF is displayed at a position at a horizontal distance L _H corresponding to the distance L _D to the school of fish. For example, in Figures 3 and 5, if the full scale d ₀ of the display cathode ray tube is 100 m and the distance L _D to the school of fish is 75 m, the speed of sound is 1500 m, so if the angle of depression θ is 0°, the full scale The sweep time T ₀ of the scale d ₀ (both A and B display sections) is 133 mS, and the time from the start of the sweep until the fish school HF on the A display section is displayed is 100 mS. Note that the B display section will be described later. Next, if the distance to the school of fish remains the same at 75 m, but only the depression angle θ changes to 60°, the full scale d ₀ is 100 m, but the sweep time is T =
2T ₀ =266mS (both A and B display parts). However, the time it takes for the fish school HF to be displayed on the A display section from the start of the sweep is based on the real-time output _P6 from the amplifier circuit 11, so it is the same as 100 mS.
The fish school HF is displayed at a position of 37.5 m above the full scale d ₀ =100 m. Note that, as described later, the video signal switching circuit 27
Since the output _P6 of the amplifier circuit 11 is passed through in real time only during the period when the bright spot of the display cathode ray tube passes through the A display section, echoes that enter the A display section within the sweep time T are not reflected. All the points are displayed except for the time period when the point passes through the B display section. Next, the circuits 15 to 27 are part of the cathode ray tube surface (B
This is a circuit provided to display positional information of schools of fish corresponding to a vertical section in the sea on the display (display section). In the general purse seine fishing method, the boat is maneuvered so that the school of fish is always located on the right hand side of the boat. Therefore, here, as shown in the B section of Fig. 5, the CRT surface is
An example is shown in which a vertical section of the sea is displayed within the range of 180° to 270° so that it does not interfere with the horizontal distance display. 15 is an azimuth signal generation circuit for selecting and transmitting the azimuth of the target fish school image; 16 is a writing pulse generation circuit for receiving detection signals;
17 is a write circuit, and 18 is a memory circuit. The azimuth signal generating circuit 15 generates a voltage E which is proportional to the azimuth angle φ of the received detection signal HF shown in FIG. This is a known method in which a variable resistor is manually operated in accordance with the display orientation, but its explanation will be omitted here. The write pulse generation circuit 16 uses the output P ₂ of the sweep signal generation circuit 2.
and the output P ₀ of the transmission trigger signal generation circuit 3 as a synchronization signal, and the azimuth signal voltage E from the azimuth signal generation circuit 15 as a control input.
As shown in b and b', within the transmission period T ₀₀ , the sawtooth wave voltage E _SW is created by rising every period T ₂ of the sweep voltage P ₂ and has a maximum value of E360°, and the direction signal voltage E〓. By comparison, a pulse P 7 delayed by a time T 〓 corresponding to the value of the azimuth signal voltage E 〓 from the rise time _of the sweep signal P ₂ is created and outputted as a write pulse P ₇ . In other words, the azimuth angle φ is determined from the rise time of the sweep voltage _P2 .
A pulse P7 delayed by a time T〓 corresponding to the pulse _P7 is output for each sweep. FIG. 8 shows an example of a case where the image of a school of fish is displayed after repeating the spiral sweep of the image display m times, that is, after a time mT ₂ has elapsed. The write circuit 17 has a number of contacts C _{1 ,} C ₂ , . _W
and one slider B, and the memory circuit 18 has the same number of capacitor memory elements as the number of contacts of the input switch.
It is formed by ME ₁ , ME ₂ , ...ME _W.
The input switch of the write circuit 17 switches the slider step by step every time the write pulse _P7 is input from the write pulse generating circuit 16 as shown in FIG. 8b' from the start of the sweep. , writes _the echoes P _{61 ,} P ₆₂ , P ₆₃ , . E _W1 , E _W2 , E _W3 in Figure c...
From the start of the sweep, they are sequentially added to the corresponding memory elements ME ₁ , ME ₂ , ... _{ME W} in FIG.
Write as _W2 , E _W3 , ...... Therefore, in the memory circuit 18, all the received signals of the school of fish in the azimuth φ direction obtained for each spiral sweep are sequentially written into one of the w memory elements. Note that E' _W1 , E' _W2 , E' _W3 . . . in Fig. 8f are the received signals at the previous detection. Next, 19 in FIG. 6 is a read voltage generation circuit, 20 is a read pulse generation circuit, and 21 is a read circuit. The read voltage generation circuit 19 is the transmission trigger signal generation circuit 3
In response to the output P ₀ ( _period T ₀₀ ) of
It rises with a pulse of P ₀ , the period is T ₀₀ , and the maximum value is
Sawtooth wave voltage e _g 〓=E ₀ cosθ with Ee=E ₀ cosθ
Create t/T ₀₀ . Note that e _g 〓 in the case of depression angle θ = 0° (when Ee = E ₀ cos θ = E ₀ ) is the sawtooth wave voltage e _g0 , and the value of the rise time T ₀ is E _g0 , that is, E _g0 = E ₀
Let T ₀ /T ₀₀ . Next, if t is the time when e _g becomes E _g0 after rising at the angle of depression θ°, then E ₀ cosθ・t/T ₀₀ = E _g0 = E ₀ T ₀ /T ₀₀ From this, t = T ₀ cosθ where T ₀ /cosθ is as shown in equation (3) above,
Since T ₀ /cosθ=T〓, t〓=t〓. Note that the maximum values of e _g0 and e _g0 are output as E _g0 . In this way, the read voltage generation circuit 19 outputs the output P ₀ (period T ₀₀ ) from the transmission trigger signal generation circuit 13.
and the output voltage Ee from the function voltage generation circuit 13
= E ₀ cos θ, the angle of depression is 0°~ as shown in Figure 8d.
Corresponding to θ゜, a sawtooth wave voltage E _g (e g0 ~ _{e g} 〓) with a maximum value E _g0 , a period T ₀₀ , and a pulse width T ₀ ~ T〓
Create and output. The read pulse generating circuit 20 generates the read pulse _P8 of FIG. 8 e every time the output voltage Eg of the read voltage generating circuit 19 increases by a certain amount, as shown in steps in FIG. 8 d. The number of pulses within one cycle of the voltage Eg is selected to be the same as the number of memory elements of the memory circuit 18. The read circuit 21 has the same number of contacts as the input switch of the write circuit 17.
It is formed by an output switch having C ₁ , C ₂ , . . . _CW and one slider B. Then, as with writing, every time a read pulse _P8 is input from the start of the sweep, the slider B
is switched, and the memory element ME ₁ of the memory circuit is switched.
ME ₂ , ... Read the write voltage E _W of ME _W. Note that the total readout time is T ₀ -T=T ₀ /cos θ, corresponding to the depression angle of 0° to θ°, respectively. Therefore, the readout voltage E _R of the readout circuit 21 is used as a luminance signal to be applied to the display cathode ray tube 1 in synchronization with an appropriate sweep time to be described later.
In addition to 2, the displayed image will indicate the distance to the school of fish, apart from the direction. As described above, the received signal from the amplifier circuit 11 is written to the memory 18 during the sweep period in which the display A (fish school HF) on the display cathode ray tube shown in FIG. This is done in real time at the time of crossing and is not related to the depression angle θ.
The readout from the memory 18 is performed at appropriate proportional intervals (T/W) within the time period T=T ₀ /cos θ corresponding to the depression angle θ. Prior to the detailed explanation that follows, the gist will be explained.
The readout output E _R is temporarily stored in the hold circuit 22, and then the gate circuit 25 and the video switching circuit are opened at the time when the bright spot is within the sweep time T and passes in the direction of the depression angle θ in the B display section. 27 to the display cathode ray tube 12 to display the fish school RF. Next, the display means of the B display section in FIG. 5 will be explained. Note that the time difference (delay) between the writing time and reading time to the memory circuit is as follows when the depression angle θ=0°.
Although it is within one sweep time T ₂ , when the depression angle is θ°, as shown in _FIG . 22 is a hold circuit, 23 is a 270° voltage generation circuit, 24 is a depression angle display signal generation circuit, 25 is a gate circuit, 26 is a switching pulse generation circuit, and 27 is a video signal switching circuit. The hold circuit 22 holds the voltage E _R read out from the readout circuit 21 at the eighth voltage until the next readout voltage is applied.
As shown in Figure f, the operation is performed to hold E _W1 , E _W2 , E _W3 . That is, the 270° voltage generation circuit 23 and the depression angle display signal generation circuit 24 receive the output P ₂ (period T ₂ ) from the sweep signal generation circuit 2 and the output voltage E from the depression angle control voltage circuit 6, and generate the fifth The angle of depression θ is shown in the B display section of the figure, with the direction of 270° as the reference line (water surface).
In order to display a marker voltage indicating the direction of , and a school of fish RF on the marker line, the gate circuit 25 is controlled from the hold circuit 22 to extract the held signal voltage, and the signal voltage is output to the video signal switching circuit 2 described later.
This circuit controls the output to the cathode ray tube 12 via 7. The 270° voltage generating circuit 23 is a circuit that generates and outputs a voltage three times the voltage value E ₉₀ when the depression angle θ is 90° (a voltage corresponding to 270°). Next, the depression angle display signal generation circuit 24 starts at each rising edge of the P ₂ pulse as shown in FIG. 8i, and has a pulse width of 3T ₂ /
4 (note: time width for sweeping from 0° to 270°), a sawtooth wave voltage e ₂₇₀ whose maximum value increases to E ₂₇₀ is created, and the amplitude of this voltage e ₂₇₀ is also created separately. At the time when the voltage becomes equal to E ₂₇₀ −E=Eh (4), a marker pulse P _9A as shown in FIG. 8g is created. The time width from the rise time of the pulse _P2 to the creation time of the marker pulse _P9A is T _S in FIG. Furthermore, the depression angle display signal generation circuit 24 receives the hold voltage E _W from the hold circuit 22 and generates the next voltage as shown in FIG.

Create a [table]. _{Next ,} as _shown in FIG _. 8 j and _{FIG . 9B} is created as a control signal for displaying a time width (ie, image width) proportional to the echo strength E _W of the fish school RF in the B display section of FIG. 5. Next, the depression angle display signal generation circuit 24 outputs the pulse P _9A and the pulse P _9B to the gate circuit 25. Note that when the voltage E _W from the hold circuit 22 to the depression angle display signal generation circuit 24 is 0, the pulse P _9B is not generated and only the pulse P _9A is output.
_{When the gate circuit 25 inputs the pulses P 9A and P 9B , the hold} circuit 2
The hold voltage E _W of No. 2 is also added and output as a pulse P ₁₀ . Therefore, the pulse P ₁₀ in this case outputs the voltage E _W as a signal voltage between T _E and T _A before and after the display time T _S of the fish school RF. However, if the hold voltage E _W of the hold circuit 22 is 0, P ₉
Only the pulse _A is output for marker use. In this way, the signal of the fish school RF is outputted to display section B in FIG. 5 so as to be displayed with a brightness and a bright line length proportional to the signal intensity. Next, the switching pulse generation circuit 26 uses the output P ₂ of the sweep signal generation circuit 2 to generate a rectangular pulse P ₁₁ that rises at a time corresponding to an azimuth of 180° and falls at a time corresponding to an azimuth of 270°. The video signal switching circuit 27 is switched by the pulse P ₁₁ to change the azimuth from 0° to 180° and from 270° to 0.
At the time corresponding to 180°, the output P ₆ of the receiving detection signal amplification circuit 11 is applied directly to the cathode ray tube 12 in real time, and at the time corresponding to 180° → 270°, the gate is applied not in real time but at the time T = T ₀ / cos θ. circuit 2
5's output P ₁₀ is applied to the cathode ray tube 12. In this way, the readout time for the B display section in Figure 5 is changed so that it is the same as the change in the sweep time of the cathode ray tube due to T ₀ /cos θ, and the once stored reception detection signal is delayed and read out and applied to the cathode ray tube. Ba,
The displayed RF is the distance L _D to the school of fish as shown in Figure 5.
will be shown. In addition, the position of the school of fish with respect to the vertical cross section of the sea can be displayed by using this read signal with the angle of depression at that time with the azimuth angle of 270° of the cathode ray tube as a reference (water surface). As in the display section, information on the horizontal distance of a school of fish based on polar coordinates and information on the position of a school of fish relative to a vertical section in the sea based on rectangular coordinates can be displayed together on the same cathode ray tube surface. In order to make the explanation easier to understand, a switch is used as the write/read circuit and a capacitor is used as the memory circuit in the above description, but other known circuits having the same function may also be used. Furthermore, in the above, a vertical section of the sea was displayed within a 90° angle range of 180° to 270°, but the video signal switching circuit 27
By changing the switching time and switching position, it is possible to display in any direction with any angular width.
In this case, it goes without saying that the voltage of the 270° voltage generating circuit 23 changes in accordance with the above-mentioned arbitrary direction. (Effects) As is clear from the above explanation, according to the present invention, the horizontal distance to an underwater object and the vertical cross-section of the sea can be displayed on the same cathode ray tube screen. This system greatly facilitates the detection of schools of fish and the selection of timing for casting nets, thereby improving the detection ability and has a significant practical effect.

[Brief explanation of the drawing]

Figure 1 a and b are explanatory diagrams of the sweeping conditions of the transducer and display cathode ray tube used in scanning sonar, Figure 2 a and b are explanatory diagrams of the transmission and reception procedures, and Figure 3 is an underwater vertical cross section. Modal diagram of, 4th
Fig. 5 is a diagram of the relationship between a purse seine and a school of fish, Fig. 5 is a display example according to the present invention, Fig. 6 is a block diagram of a configuration example of a display circuit embodying the present invention, and Figs. 7a and 8 are its operation. FIG. 7B is a diagram illustrating an example of the circuit configuration of the function voltage generation circuit, FIG. 7C is a waveform diagram of each part of FIG. 7B, and FIG.

Claims (1)

[Claims] 1 A display cathode ray tube that performs sweep display at a constant speed has a full scale d ₀ sweep time of T==
2d ₀ / (C・cosθ) where C is the speed of sound, and θ is a means of sweeping so that the angle of depression is less than 80°, and the receiver detection No. 1 is input in real time to one of the divided display sections of the display cathode ray tube. A means for displaying the position of the detected object by direction and horizontal distance, and a means for storing the received detection signal of the appropriately selected direction on the display section as a time-series signal in real time, and displaying this stored signal differently from the divided display section. When a bright spot passes in the angular direction corresponding to the depression angle during surface sweeping, it is read out and displayed in a time Te that is 1/cosθ times the writing time so that the full scale of the display section can be displayed as the above d ₀ . 1. A method for detecting and displaying a scanning sonar, characterized in that a direction and a horizontal distance are displayed on the same display cathode ray tube surface, and a position is displayed in a vertical cross section of the water.