JPH0434704B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to an underwater detection device that can three-dimensionally display the time course of returning detection signals using a scanning sonar or the like that detects a wide range of directions.

(b) Conventional technology and its disadvantages Since general underwater detection devices only display the ultrasonic reflection signals detected by scanning sonar moment by moment, the time course of the detected object can be directly displayed on the display screen. I can't figure it out. Therefore, in order to solve this problem, the present applicant has
In 198775 and 198776, we proposed a device that three-dimensionally displays the time course of detection signals obtained by scanning sonar. However, since the detection signals displayed by these devices are completely unrelated to the speed and direction of the ship, they have the disadvantage that the true underwater state cannot be accurately grasped from the display screen.

(c) Purpose of the Invention The purpose of the present invention is to display the true underwater conditions three-dimensionally, taking into account the speed and direction of the ship, and to quickly and accurately grasp the conditions of fish schools, seabed, etc., and to improve fishing, navigation, The purpose of the present invention is to provide an underwater detection device useful for seafloor surveying, etc.

(d) Summary of the invention A scanning sonar is used as a sonar that emits ultrasonic waves in a wide range of directions and receives the reflected signals. Here, the specifications of the sonar are set as follows.

(1) The beam shape shall be fan-shaped.

(2) The beam direction shall be directly below the ship and perpendicular to the bow direction. In addition, horizontal and vertical gyroscopes and servo systems shall be used to prevent the beam from wandering due to rolling and pitching of the ship.

FIG. 2 is a diagram showing the above beam. In the figure, 1 is a ship, and 2 is a group of oscillators. The beam is formed into a fan shape directly below the ship, and is composed of k+1 small beams having a beam width of Δθ _v in the direction of travel and Δθ _H in the direction perpendicular to the direction of travel. Here, if the width of the fan-shaped beam is 2θ _H , then 2θ _H = (k+1)×Δθ _H. Therefore, by one transmission, it is possible to detect the underwater situation in a narrow range in the direction of travel within the range of ±θ _H perpendicular to the direction of travel below the ship. The detected signal is displayed as shown in FIG. In this figure, the area near the ocean floor is enlarged, and the detection signals based on the past eight transmissions are shown in the wake (●
(indicated by a symbol) on the CRT.

Next, a method of displaying FIG. 3 will be explained.

Now, as shown in FIG. 4, X-Y-Z coordinates are used to express the underwater position. The current transducer position is the origin, the vertical direction is X, the traveling direction is Z, and the direction perpendicular to Z is Y. Place your eyes at a certain position on the X-Z plane (Y=0, X≧0, Z≧0),
In other words, Figure 3 shows the underwater situation when looking from the top of the ship in the front and rear directions of the ship. 8 in Figure 3
Of the three submarine lines, the bottom line is the one based on the latest transmissions. From the track mark on this display, it can be seen that the ship is currently turning to the left.

In the display screen shown in Fig. 3, when the vertical direction of the screen is x and the horizontal direction is y, the Y direction is the y direction.
The X and Z directions are shown in the x direction, and the seabed position directly below the ship based on the latest transmission is x=M ₀ , y=N/
This is what is displayed in 2. In other words, the display content focuses on the vicinity of the ocean floor. The underwater range displayed on this display screen is ΔX, Y in the X direction.
ΔY in the direction and ΔZ in the Z direction.

The number of pixels on the display screen is (M+1)×(N+1), with M+1 in the x direction and N+1 in the y direction. At this time, the relationship between x, y and X, Y, Z is as follows: a ₁ = M/ΔX ……(1) a ₂ = M/ΔZ ……(2) a ₃ = N/ΔY ……(3) , is shown by the following equations (4) and (5).

x=a ₁ (X-X _B0 )+a ₂・Z+M ₀ ……(4) y=a ₃・Y+N/2 ……(5) Here, X _B0 is the seabed directly below the ship according to the latest (current) transmission. Indicates depth.

In Figure 4, the detection range based on the latest transmission is shown in a fan shape of 0.
In this case, the detection range due to the i-th previous transmission is indicated by a sector i. The apex position of sector i, which is the detection range i times before, is expressed as (0, Y _i , Z _i ). Further, the angle of the ship's traveling direction with respect to the Z-axis at that time is defined as φ _i .

To indicate the position on the fan, polar drift (r, θ)
Use. At this time, the relationship between the fan-shaped position (r, θ) and the display position (x, y) on the display screen is as follows.
It is expressed by equations (9) and (10). Note that θ is positive on the starboard side from directly below.

X=rcosθ...(6) Y=rsinθ・cosφ _i +Y _i ...(7) Z=rsinθ・sinφ _i +Z _i ...(8) (4), (5) equations (6), (7) , Substituting equation (8), x=a ₁・r・cosθ−a ₁・X _B0 +a ₂・r・sinθ・sinφ _i +a ₂・Z _i +M ₀ ...(9) y=a ₃・r・sinθ・cosφ _i +a ₃・Y _i +N/2
...(10) Next, we will discuss how to obtain Y _i , Z _i , and φ _i in equations (9) and (10) above.

These values Y _i , Z _i , and φ _i are the relative positional changes of the past position with respect to the reference position (for example, the current position or the previous position) as the ship moves. In order to determine each type of ship, a positioning device to measure the ship's position and a compass to determine the course are required. Ship position measuring instruments include NNSS, Loran, Omega, and ground speed meters (used in conjunction with compasses), and compasses include gyrocompasses and magnetic compasses. Here we use Doppler sonar, which is a ground speed indicator, and a gyro compass. Now, as shown in FIG. 5, (s, u) coordinates are used to represent the ship's position. Let the north direction be u and the east direction be s. The ship speed is v, the direction of travel is ω, and the point o' in Figure 5 is s-
With the origin of the u coordinate as the origin, and the time when the ship passes point o' as the reference, the ship position (s, u) after T time is as follows (11),
It is shown by equation (12).

s=β ₁・∫ ^T _O v(t)・cosω(t)dt ……(11) u=β ₂・∫ ^T _O v(t)・sinω(t)dt ……(12) In addition, ω is It is the angle with respect to north and is determined by a gyroscope. β ₁ and β ₂ are constants.

Let s, u, ω at the time of transmission of sector i be s _i , u _i , ω _i ,
Let s ₀ , u ₀ , and ω ₀ be the values when sector 0 is transmitted. 6th
The figure shows the relationship between su coordinates and Y-Z coordinates and the positions of sectors i and 0. The ▲ mark indicates the position of sector i, and the ● mark indicates the position of sector 0.

The coordinate obtained by translating the s-u coordinate to the ● mark is s'-
When the u′ coordinate is used, the positions of the ● and ▲ marks on the s′−u′ coordinate are ●mark (0, 0) ▲mark (s _i −s ₀ , u _i −u ₀ ). The coordinate obtained by rotating this s′−u′ coordinate by ω ₀ is Y
Since it is a −Z coordinate, Y=s′cosω ₀ +u′sinω ₀ …(13) Z=−s′sinω ₀ +u′cosω ₀ …(14) In equations (13) and (14), s′= Substituting s _i −s ₀ , u′=u _i −u ₀ , Y _i =(s _i −s ₀ )・cosω ₀ +(u _i −u ₀ )・sinω ₀ ……(1
5) Z _i =−(s _i −s ₀ )・sinω ₀ +(u _i −u ₀ )・cosω ₀
...(16) From this, the relationship between s _i , u _i and Y _i , Z _i was determined.
On the other hand, since φ _i is the difference between ω ₀ and ω _i , φ _i = ω _i −ω ₀ (17).

From the above, calculate the relative position changes Y _i , Z _i , φ _i of each past position with respect to the current position (the reference position is the current position) from equations (15) to (17), and calculate these values. Substitute into equations (9) and (10) to obtain the coordinates x, y of the display screen
By determining this, it is possible to display the underwater conditions as the ship moves three-dimensionally on the display screen. The "coordinate transformation means" according to the present invention corresponds to means for determining the coordinates x and y. In the above example, X _B0 is plotted on the display screen as the seabed depth directly below, so the track can be determined from changes in the plot position. This plot position does not necessarily have to be at the seabed depth directly below the ship, but can be at any _depth
But that's fine.

(e) Structure of the invention FIG. 1 is a block diagram of the present invention.

A transducer group 2 attached to the bottom of the ship receives a transmission pulse from a transmitter 3 and emits a fan-shaped ultrasonic pulse shown in FIG. lead to, A/
The D-converted data is sent to the memory 6 via the switch 5.
guided by. The memory 6 stores A/D converted values of ultrasonic reflection signals at the current position and past positions including the previous position as the ship moves. That is, the received data for the first ultrasonic pulse is stored in the memory 6a, the received data for the second ultrasonic pulse is stored in the memory 6b, and the received data for the third ultrasonic pulse is stored in the memory 6b. 6c. In this way, each received data for n ultrasonic pulses is stored in each memory.

Each memory has a capacity that can store all the detection data for one transmission, and can further divide the detection signal strength into multiple stages and store them. The data stored in memory 6 is stored in color conversion ROM 7.
Displayed on CRT8 via . The color conversion ROM 7 converts the received data stored in each memory into predetermined color data according to the strength of the detection signal.

A CP (clock pulse) circuit 9 supplies a clock pulse to a frequency divider circuit 10. The frequency dividing circuit 10 supplies a transmission synchronization pulse to the transmitter 3, and also supplies n
A transmission synchronization pulse is supplied to the advance counter 11. The value n of the n-ary counter 11 matches the number of memories in the memory circuit 6, and the write memory is switched every time the count increases. Further, an R/W signal (read/write signal) is formed from the output of the counter 11 and is supplied to the memory circuit 6. By this R/W signal, only one of the plurality of memories is set to write mode, and the other memories are set to read mode. The memory circuit 6 further includes a frequency dividing circuit 10.
The r signal and the θ' signal are supplied from . As shown in FIG. 7, each memory is R+1 in the r (distance) direction,
(R+1)×(k+1)×k+1 in the θ′ (angle) direction
It has a capacity of I (bit). Therefore,
The memory is scanned by the r signal and the θ' signal supplied from the frequency dividing circuit 10.
Incidentally, the relationship between θ and θ' is as follows (see FIG. 4).

θ=θ'-k/2 The outputs of the Doppler sonar 12 and the gyro 13 are led to the position and course determining circuit 14, where the position and course of (s, u) stranding are determined.
The position and course data are led to a relative position change calculation circuit 15. In the relative position change calculation circuit 15, the output of the counter 11, r
The signal and signal B from the seabed discriminator 16 are taken in as input data. This relative position change calculation circuit 15 includes n latch circuits, and each latch circuit latches past position and course data including the current and previous times, and seabed depth data directly below the ship at each time. From these data, the amount of relative position change at each past position with respect to the reference position is determined and output to the coordinate conversion circuit 17. The coordinate conversion circuit 17 converts the relative position change amount obtained from the relative position change amount circuit 15 and x, which indicates the display position on the display screen of the CRT 8.
y data and constants ΔX, ΔY, ΔZ (see formulas (1) to (3)), display screen coordinates (x, y) are converted to memory coordinates (r, θ'), and then stored in the memory circuit 6. In contrast, r _o and θ _o signals are output as read address signals. Note that the relative position change calculation circuit 15 uses the previous position as the reference position for calculating the relative position change. That is, the previous ultrasonic pulse emission position is used as a reference position, and the amount of relative position change of each past position with respect to this position is determined.

Next, the operation of the underwater detection device having the above configuration will be explained.

First, when the first ultrasonic pulse is emitted from the transducer group 2, the switching device 5 receives the θ' signal and switches the transducers. Also, since this is the first transmission pulse, the counter 11 counts 1 and the memory circuit 6
The memory 6a is set to write mode. As a result, the received signals from the transducer group 2 consisting of k transducers are sequentially stored in the memory 6a after A/D conversion. The data is stored by scanning in the θ' direction in the r direction in FIG. As described above, each memory has a capacity capable of storing all the detection signals for one transmission, and also has a number of memories capable of storing the intensity I of each received data. During one ultrasonic reception signal, when k/2 transducers, that is, the transducer at the center of the transducer group, receives a reflected signal from the ocean floor, the ocean floor discriminator 16 identifies the ocean floor and The seabed discrimination pulse B is supplied to the relative position change calculation circuit 15. Also, by a circuit not shown,
When this seabed discrimination pulse B is output, the memory 6
The received data directly below the ship (seafloor depth data) stored in a is set to a constant strength.

When all writing to the memory 6a is completed, a second transmission synchronization pulse is supplied to the transmitter 3, and the transducer group 2 emits a second ultrasonic pulse. Further, the counter 11 is counted up, and the memory 6b in the memory circuit 6 is set to the write mode. Furthermore, the memory 6a to which data was previously written is set to read mode.

In the same way, the second received data is stored in the memory 6b. Furthermore, the seabed depth data immediately below the ship at the second location is also set to a constant strength. On the other hand, the relative position change calculation circuit 15 calculates the previous position, that is, the position s ₁ , u ₁ and course ω ₁ at the position where the first ultrasonic pulse was emitted, and the seabed depth X _B1 directly under the ship from the first time. The seabed discrimination pulse B is latched at ₁ . That is, when the memory 6b is set to the write mode, the relative position change amount calculation circuit 15 calculates the seabed depth data _XB1 immediately below the ship at the previous position, its position _s1 , _u1 , and the course _ω1 at the previous position. is latched.

Writing to the memory 6b is completed, and the transmitter 3
When the third transmission synchronization pulse is applied to
b is set to read mode. In addition, in the relative position change amount calculation circuit 15, the already latched data becomes the data from the previous time, and new seabed depth data directly below the ship M _B0 at the previous position, and its position s ₀ , u ₀
And the course ω ₀ at that position is latched. That is, when the received data is stored in the memory 6c, each data corresponding to the previous position and each data corresponding to the position before the previous time are latched in the relative position change amount calculation circuit 15.

In the relative position change amount calculation circuit 15, when at least each data for the previous position and each data for the position before the previous time are latched by the above operation, the previous position is set as the base position and the past position with respect to the reference position is determined. The amount of relative position change is calculated. When there are three types of data to be latched, the previous position is used as a reference position, and the position before the previous time and the amount of relative position change between the previous position and the previous position are calculated. The amount of relative position change is determined by equations (15) to (17). When the coordinate conversion circuit 17 receives this amount of change in relative position, it converts the display screen coordinates (x, y) into memory coordinates (r, θ') based on the amount of change. Address signal r _o obtained by coordinate transformation,
Since θ _o is supplied to the memory circuit 6, this signal is supplied to the memory set to read mode, and the stored data is read out and sent to the color conversion ROM.
7 will be output. For example, memory 6c
is set to the write mode and the memories 6a and 6b are set to the read mode, the address signals r _a , θ _a from the coordinate conversion circuit 17
is supplied to the memory 6a, and address signals r _b and θ _b are supplied to the memory 6b. Address signals r _a and θ _a are output when the input relative position change amount is the change amount from the previous time with respect to the reference position. Further, the address signals r _b and θ _b are output when the input relative position change amount is the relative position change amount of the previous position with respect to the reference position. Therefore, the data stored in the memory 6a and the data stored in the memory 6b are displayed on the display screen of the CRT 8 with a difference between them.

Through the above operations, changes in the seabed and the depth of the seabed directly beneath the ship are displayed three-dimensionally on the display screen as shown in FIG.

(f) Effects of the Invention As described above, according to the present invention, the time course of the detection signal is displayed three-dimensionally, taking into consideration the ship speed and direction of travel, so the state of the fish school, the seabed, etc. can be quickly and accurately determined. can be grasped.

(g) Embodiment FIG. 8 shows a specific example of the above underwater detection device. This example is constructed under the following conditions.

(1) The display screen shall display the past two detection signals.

(2) Set Δθ _H = 1°.

(3) Detection signals are loaded into the memory every 1m.

(4) Each small beam (Δθ _H ×Δθ _V ) is formed by one oscillator. (Actually, it is formed using a delay circuit etc. using a plurality of vibrators, but here it is assumed that it is formed by one vibrator.) The k+1 vibrators of the vibrator group 2 are each predetermined. The transmitter 3 simultaneously emits ultrasonic pulses into the water in the direction indicated by the transmitter. The emitted ultrasonic pulses are reflected by objects such as schools of fish or the seabed, and are received as detection signals by k+1 transducers, each of which has a predetermined pointing direction.

The detection signal received by each vibrator is amplified by k+1 preamplifier groups 20, and then sequentially sent to the A/D converter 4 by the switch 5 according to the count value of the θ' counter 22.

The θ' counter 22 is a k+1 up counter that counts the output pulses of the frequency divider 23. The frequency divider 23 counts the clocks of the CP 100, and its output pulse frequency is C/2×(k+1) [Hz] (C is the speed of sound [m/sec]). Further, the output pulse of the θ' counter 22 is supplied to the r counter 21. The r counter 21 is an R+1 up counter. still,
The θ' counter 22 and the r counter 21 designate a memory write address as shown in FIG.
Also, the relationship between θ (see Figure 4) and θ' is θ=θ'-
It is k/2.

The detection signals digitized by the A/D converter 4 are sent to memories 6a, 6b, and 6c. The memories 6a to 6c each have r
It has a capacity of (R+1) x (k+1) x I (bit) of R+1 in the (distance) direction and k+1 in the θ' (angle) direction,
All detection signals for one transmission can be stored. Note that I indicates that the detection signal strength is divided into 2 ^I stages and stored.

The ternary counter 11 counts the transmission synchronization pulses output from the r counter 21 and outputs the count output to the switch 40. The switch 40 switches the memory set to write mode according to the count value of the ternary counter 11. For example, when the count value is 0, the memory 6a is set to the write mode, and when the count value is 1, the memory 6b is set to the write mode. Memories other than those set to write mode will be set to read mode. The reason why the memory circuit is made up of three memories is because the detection signals displayed on the display screen are from the past two detections, and the memory content of the memory set to read mode is the detection signal from the past two detections. Displayed as a signal. Since there are three memories, a ternary counter 11 is also used. In the diagram, 3
The case where the count value of the decimal counter 11 is 2 is shown. That is, the memories 6a and 6b are set to read mode, and the memory 6c is set to write mode. In this case, the detection signals are being stored in the memory 6c, and the detection signals stored in the memories 6a and 6b are displayed on the CRT 110.

A flip-flop 24 and a switch 25, which are set by the output pulses of the seabed discriminator 16, are circuits for writing a wake on the seabed. The flip-flop 24 is set with a seabed discrimination pulse, and while this is set, the switch 25 connects V _a to the k/2 terminal of the switch 5 instead of the detection signal of the k/2 oscillator. As a result, when the count value of the θ' counter 22 reaches k/2, the voltage of V _a is stored in the memory through the A/D converter 4. Since the voltage value of V _a is set larger than the highest voltage value of the detection signal, the track is displayed on the CRT 110 through the color conversion ROM 7 in a color different from that of the detection signal. Note that the comparator 26 detects that the count value of the θ' counter 22 is k/2+1.
This is for resetting the flip-flop 24 when this occurs.

Each element indicated by reference numerals 41 to 82 constitutes the relative position change calculation circuit 15 shown in FIG. Also code 33
The elements indicated by 38 constitute the position and course determining circuit 14 shown in FIG. The position and course determination circuit 14 includes integration circuits 35 and 36, multipliers 37 and 38, and ROM 3.
It consists of 3,34. Of these, the integration circuit 35,
Each of 36 is composed of two latch circuits, one adder, and one frequency divider, and divides the frequency of the pulse output from CP 100, and repeats the addition for each pulse period output from the frequency divider. Also, the ROM33 calculates cosω from ω, which is the output of the gyro 13, and the ROM33
finds sinω. The Doppler sonar 12 outputs the ship speed v to multipliers 37 and 38. With the above configuration, the integration circuit 35 outputs the position data s shown in equation (11), and the integration circuit 36 outputs the position data u shown in equation (12).
Output.

The relative position change calculation circuit 15 is connected to the switches 41 to 4.
5, latches 50-61, subtractors 70-78,
It is composed of ROMs 80 to 82. Switch 41 forms the latch pulses for latches 50-61. The latch pulse uses a seabed discrimination pulse. 3
When the advance counter 11 is 0, latch pulses are sent to the upper latch group, ie, 50, 53, 56, and 59. When the count value of the counter 11 is 1, a latch pulse is sent to the middle group of latches, that is, latches 51, 54, 57, and 60. Also, when the count value of the counter 11 is 2, the lower latch group, that is, the latch 5
Latch pulses are sent to 2, 55, 58, and 61. Incidentally, since the latch pulse is a seabed discrimination pulse as described above, each data will be latched when the seabed directly under the ship is detected.

Of the latches described above, latches 50-52 are supplied with the seabed depth. In this example, since the detection signal is loaded into the memory every 1 m, the seabed depth is given by the r counter count value when the seabed discrimination pulse is output. Therefore, Latch 50-52
The count value of the r counter is connected to.

The output value s of the integration circuit 35 is led to the latches 53-55. The output value u of the integration circuit 36 is led to the latches 56-58. Further, ω, which is the output value of the gyro 13, is introduced to the latches 59-61. With the above configuration, each value of X _B , s, u, and ω is stored when a seabed discrimination pulse is output to any of the upper, middle, and lower latch groups. For example, as shown in the figure, when the count value of the ternary counter 11 is 2, the latch 52 is
X _B is stored in 55, s is stored in 58, u is stored in 58, and ω is stored in 61.

The switching devices 43 to 45 and the subtractors 70 to 78
are s _i −s ₀ , u _i −u ₀ , ω _i − necessary for equations (15), (16), and (17).
ω ₀
This is a circuit for finding. Now, consider a case where the count value of the ternary counter 11 is 2 as shown in the figure.
In this case, the latches 50, 53, 56, and 59 each contain data of the position before the previous time, X _B1 , s ₁ , u ₁ ,
ω ₁ is memorized. Also, latches 51, 54, 57,
60 is the data of the previous position.
X _B0 , s ₀ , u ₀ , and ω ₀ are stored. At this time,
Since the count value of the ternary counter 11 is subtracted by 1 by the adder 46, the switchers 42 to 45 are set to 2-1.
= 1, indicating 1. Therefore, the outputs of the subtracters 70, 73, and 76 have s ₁ −s ₀ and
u ₁ −u ₀ , ω ₁ −ω ₀ are output. Also, the subtractor 71,
The outputs of 74 and 77 are respectively 0.

ROMs 80 to 82 are circuits for outputting Y _i and Z _i from equations (15) and (16). When the count value of the ternary counter 11 is 2, the outputs of the ROM 80 are Y ₁ and Z ₁ . Also, the output of ROM81 will be Y ₀ and Z ₀ , but
These values are 0.

In addition, in the above relative position change calculation circuit,
If the count value of the ternary counter 11 is 2, the ROM8
The output of 1 corresponds to the reference position.

The coordinate conversion circuit 17 includes three coordinate converters 90.
It consists of ~92. Each coordinate converter is a circuit for determining positions r and θ on the sector with respect to positions x and y on the display screen. Equations (9) and (10) show the relationships of x and y with respect to r and θ, but if we calculate r and θ with respect to x and y from these equations, we get Equations (20) and (21).
becomes.

θ＝tan ^-1 {a ₁ −y′／a ₅・x′−a ₄ y′} ……(20) r＝y′／［a ₅・sin｛tan ^-1
(a ₁・y′/a ₅・x′−a ₄・y′)}] …(21) However, x′=x+a ₁・X _B0 −a ₂・Z _i −M ₀ y′=y− a ₃・Y _i −N/2 a ₄ = a ₂ sinφ _i a ₅ = a ₃ cosφ.

FIG. 9 is a block diagram of a coordinate converter for determining r and θ from the above equations (20) and (21).

As shown in the figure, this coordinate converter is ROM12
0 and a plurality of multipliers and adders 121 to 127. Of course, this coordinate converter can also be constructed from one ROM. By using the coordinate converter with the above configuration, based on the relative position changes Y _i , Z _i , φ _i output from the ROMs 80 to 82, in this example, the seabed _depth at the reference position
It is also possible to convert memory coordinates (r, θ) to display screen coordinates (x, y) based on Coordinate transformed r _o ( _ra , r _b , r _c ) and θ _o (θ _a , θ _b , θ _c )
are supplied to the read address terminals of the memories 6a, 6b, and 6c, respectively. Adders 62 to 64 connected to the read address terminals are for adjusting the relationship between θ and θ' (θ-k/2).

The read data of the memories 6a to 6c is
Output to ROM7. The ROM 7 is a circuit that performs signal strength and color conversion to display the output signals from each memory in color on the CRT. At the same time, the ROM 7 also determines the display priority of the signals in the memories 6a to 6c, so that the count value of the ternary counter 11 is 2.
At this time, the signal from the memory 6b is displayed with priority over the signal from the memory 6a, and the signal from the memory 6c is not displayed at all. Also, 10
5 and 106 are a y deflection coil and an x deflection coil of the CRT 110, 103 and 104 are respective deflection amplifiers, and 102 and 101 are a y counter and an x counter. This y counter 102, x counter 1
01 defines the coordinates (x, y) on the display screen.

In the above embodiment, the seabed is used as a reference and the wake is displayed on the seabed, but instead of using the seafloor as a reference, an arbitrary depth X _p is used as a reference, and
The track may be displayed at _XP .
In this case, instead of the seabed discriminator 16 in FIG. 8, a display depth setting device 200 as shown in FIG.
The comparator 201 may be used.

Furthermore, instead of ROM120 in Figure 9,
RAM and CPU may be used. As shown in Figure 9, since the ROM 120 has a large number of inputs,
This circuit configuration has a very large storage capacity.
Therefore, using RAM and CPU, the inputs are only x′, y′, and φ _i that change moment by moment, and when ΔX, ΔY, and ΔZ change, the CPU calculates using ΔX, ΔY, and ΔZ, and the input. By this, ΔX, ΔY,
Since the input of ΔZ is eliminated, the RAM capacity can be reduced. Of course, this results in ΔX, ΔY,
When changing ΔZ, time is required for calculation. Furthermore, the relative position change calculation circuit 15 is
The circuit configuration can be made very simple by configuring it with a CPU, RAM, and ROM.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an underwater detection device according to the present invention. 2 to 6 are diagrams for explaining the principle of the present invention, in which FIG. 2 is a diagram showing a beam emitted from the transducer group 2, FIG. 3 is a diagram showing an example of a display screen, Figure 4 is a diagram showing the movement state of the beam at the current position and any previous position, Figure 5 is a diagram showing the position of the ship at coordinates (s, u), and Figure 6 is X-
FIG. 3 is a diagram showing the relationship between YZ coordinates and su coordinates. FIG. 7 is a block diagram of the memory. Figure 8A,
B shows a specific example of the above-mentioned underwater detection device, FIG. 9 shows a specific circuit diagram of a coordinate converter, and FIG. 10 shows an example of a circuit for forming an arbitrary depth pulse instead of a seabed discrimination pulse. It is a diagram.

Claims (1)

[Scope of Claims] 1. An underwater detection device that receives and displays ultrasonic reflected signals from a wide range of directions, with the ship as the center, extending to both sides of the ship, and distributed in the distance direction and angular direction. a memory for storing underwater detection information in a fan-shaped area for a plurality of times of detection; a displacement detection means for detecting a change in position with respect to a reference position and a change in course with respect to a reference course due to movement of the ship; and a polar coordinate format stored in the memory. The detected information is converted into a rectangular coordinate format on the display screen, and the displayed position in the rectangular coordinates of the data stored in the memory is parallelized in proportion to the amount of change in the position of the ship with respect to the reference position detected by the displacement detecting means. coordinate converting means for rotating the display position in rectangular coordinates of the data stored in the memory by the amount of change in course with respect to the reference course detected by the displacement detecting means; An underwater detection device characterized by comprising: means for displaying the images in an overlapping manner.