JPS63180882A - Length measuring apparatus for underwater moving object - Google Patents

Abstract

PURPOSE:To enable measurement of length of an underwater moving object with a simple construction, by measuring arrival time of a reflected sound from the front of an underwater moving object and that from the rear thereof and the frequency thereof. CONSTITUTION:This apparatus is basically provided with a transmitter 5, a receiver 6, a time detection circuit 7, a frequency detection circuit 8 and a computing circuit 9. Then, the transmitter 5 transmits an ultrasonic wave with a frequency F0 in the full bearing direction of 360 deg.. The receiver 6 receives a reflected sound from an underwater moving object and converted into an electrical signal to be applied to the circuit 7 and the circuit 8. The circuit 7 determines the arrival time t1 of the reflected sound from the front of the underwater moving object and the arrival time t2 of the reflected sound from the rear to be applied to the circuit 9. The circuit 8 determines the frequency F1 of the reflected sound from the front of the underwater moving object and that F2 of the reflected sound from the rear to be applied to the circuit 9. The circuit 9 calculates the length L of the underwater moving object from the frequencies F0, F1 and F2 and from the arrival times t1 and t2.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a length measuring device that measures the length of an underwater moving object underwater.

(Prior Art) FIG. 4 shows the conventional measurement principle. In FIG. 4, a length measuring device 10 is placed at an appropriate location on the bottom of the water. At the same time, the length L of the underwater moving object 11 is measured according to the following equation (1).

L= L2!3 i n-1-1l sinφ1---
--1 --- (1) Here, the angles φl and φ2 are angles from the perpendicular in the length measuring device 10 to the front and rear parts of the underwater moving object 11 (hereinafter referred to as "azimuth angles").

Moreover, the distance Lr is the distance from the length measuring device 10 to the front part of the underwater moving object 11, and the distance t2 is the distance to the rear part. The distance Ll and t2 are determined from the arrival time of the reflected sound. As shown in FIG. 5, among the reflected sounds from the underwater moving object 11, the reflected sounds from the front and rear parts of the object are denoted by 13. Same 1
4 shows a thick amplitude, so the reflected sound 13. The arrival time of the same 14 is 1. ．． 1. Then, the distance Ll and the same t2 are calculated using the following formula (2
), calculated using (3). Note that C is the speed of sound in water.

1+=stop −・・・−−−(2) t2=
” Part 1 ----1---(3) On the other hand,
The azimuth angle φh and φ2 are also the same as the reflected sound 13. However, since it is necessary to obtain it three-dimensionally, a conventional length measuring device 10 is constructed as shown in FIG. That is, the conventional length measuring device 10 has three systems of receivers 16 . 17 and 18. The receiver 17 is arranged at the origin position of the X-Y coordinate set on the arrangement plane of the length measuring device 10, and the electrical conversion signal of the transmitted and reflected sound is given to the time detection circuit 19, and the phase detection circuit 20 and 21, respectively.

One time detection circuit calculates the arrival time t1+t2 using the above equations (2) and (3) and supplies it to the arithmetic circuit 22.

One of the transfer devices 16 is arranged on the X-axis, and an electrical conversion signal of the reflected sound of the transfer device 16 is given to the other input of the phase detection circuit 20 . As a result, the phase detection circuit 20 determines the phase difference between the received and reflected sounds at the receivers 17 and 16, and calculates the phase difference between the azimuth angles φ1 and φ1. Component of the same φ2 in the X direction (φIX, φ2X)
It is given to the arithmetic circuit 22 as .

The other transfer device 18 is arranged on the Y-axis, and the electrical conversion signal of the transfer reflected sound is given to the other input of the phase detection circuit 21. As a result, the phase detection circuit 21 determines the phase difference between the transmitted and reflected sound at the receivers 17 and 18, and calculates the phase difference between the received and reflected sounds at the azimuth angle φ1. Y-direction component of the same φ2 (φIY, φ2Y)
It is given to the arithmetic circuit 22 as .

In this way, the calculation circuit 22 can calculate the length of the underwater moving object 11 according to the equation (1).

(Problems to be Solved by the Invention) The conventional length measuring device described above measures the arrival time of the reflected sound from the front part of an underwater moving object, the arrival time of the reflected sound from the rear part, and the azimuth angle of each reflected sound. Since the length is measured by doing this, it is necessary to provide three systems of transfer devices for azimuth measurement, which poses a problem that the circuit is complicated and the shape is large.

The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a length measuring device for an underwater moving object that can measure the length of an underwater moving object with a simple configuration.

(Means for Solving the Problems) In order to achieve the above object, a length measuring device for an underwater moving object according to the present invention has the following configuration.

That is, the length measuring device for an underwater moving object of the present invention is a length measuring device for an underwater moving object that measures the length of an underwater moving object by acoustically detected sound reflected from the front and rear parts of the underwater moving object. a time detection circuit that detects the arrival time of the reflected sound; a frequency detection circuit that detects the frequency of the reflected sound; and an arithmetic circuit that calculates the length of the underwater moving object from the detected arrival time and frequency. This is a length measuring device for an underwater moving object, which is characterized by being equipped with;

(Function) Next, the function of the underwater moving object of the present invention having the above configuration will be explained.

FIG. 1 is a diagram showing the principle of measurement according to the present invention. In FIG. 1, reference numeral 1 indicates a length measuring device of the present invention.

This length measuring device 1 is placed at an appropriate location on the bottom of the water, as in the conventional case, and measures frequency F in all directions of 360°.

It transmits ultrasonic waves. The symbols t1 and L2 are the distances from the length measuring device 1 to the front and rear parts of the underwater moving object 2. The underwater moving object 2 is moving at a moving speed of V, and from the front of the underwater moving object 2 there is a frequency of F1,
Ultrasonic waves at frequency F2 are reflected from the rear. The reflected sound at the front of the underwater moving object 2 is at an angle θl from the direction of movement.
Also, it is assumed that the reflected sound is reflected at an angle θ2 from the moving direction at the rear.

FIG. 2 is for explaining the Doppler effect of reflected sound. In FIG. 2, in general, the frequency F from the sound source 3 is
The frequency F' of the reflected sound that is emitted at , hits an object 4 moving at a speed V, is reflected, and returns to the position of the sound source 3 is the distance between the line connecting the sound source 3 and the moving object 4 and the moving object 4. If the angle between the moving direction and the moving direction is θ, it is expressed by the following equation (4).

F′=(1+λ■41dan) F −=−・−−
(4) where Co is the speed of sound in the medium. In addition,
For simplicity, it is assumed that the sound source 3 is stopped.

That is, the frequency F1+F2 shown in FIG. 1 is determined by the following equations (5) and (6), where C is the sound speed in water.

F s −(1+” ” ”) F o
−−−−−−−−(5)F2−(1+ ” ” ”
) Fo---(6) Also, in FIG. 1, it is clear that the length L is expressed by the following equation (7).

L=t2cosθ2−Llcosθ1---
--- (7) Then, equations (2), (3), and (
From 5) to (7), the length can be expressed by the following equation (8).

Here, t□: Arrival time t2 from the front of the underwater moving object
: Arrival time Δfl from the rear of the underwater moving object = pt −
FO: Doppler component of the frequency of the reflected sound from the front of the underwater moving object Δf2=F2 Fo: Doppler component of the frequency of the reflected sound from the rear of the underwater moving object Thus, in the present invention, the arrival time t! ,
t2 and the frequency F1 of the reflected sound. By simply measuring F2, the length of an underwater moving object can be determined. As a result, only one system of delivery device is required.

As explained above, according to the length measuring device for an underwater moving object of the present invention, the arrival time of the reflected sound from the front part and the reflected sound from the rear part of the underwater moving object, and the frequency of these reflected sounds are measured. Since you can find the length of an underwater moving object by simply doing this, you only need one delivery system.
Circuit simplification.

This has the effect of making the device smaller and lighter.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows a length measuring device for an underwater moving object according to an embodiment of the present invention. This length measuring device basically includes a wave transmitter 5, a wave receiver 6, a time detection circuit 7, a frequency detection circuit 8, and an arithmetic circuit 9.

The transmitter 5 transmits ultrasonic waves having a frequency of FO in all directions of 360°.

The delivery device 6 receives reflected sound reflected by an underwater moving object, converts it into an electric signal, and supplies it to a time detection circuit 7 and a frequency detection circuit 8.

The time detection circuit 7 determines the arrival time t1 of the reflected sound from the front of the underwater moving object and the arrival time t2 of the reflected sound from the rear of the underwater moving object.
(Figure 5 and equation (2)).

(see (3)), and feeds it to the arithmetic port 9.

The frequency detection circuit 8 detects the frequency F! of the reflected sound from the front of the underwater moving object! Then, the frequency F2 of the reflected sound from the rear is determined and fed to the arithmetic circuit 9.

The arithmetic circuit 9 has a frequency F. , Fl, F2, and arrival time tI+t2, the length of the underwater moving object is calculated according to the above equation (8).

(Effects of the Invention) As explained above, according to the length measuring device for an underwater moving object of the present invention, the arrival time of the reflected sound from the front part and the reflected sound from the rear part of the underwater moving object, and the arrival time of the reflected sound from the front part and the rear part of the underwater moving object are measured. Since the length of an underwater moving object can be determined simply by measuring the frequency of

This has the effect of making the device smaller and lighter.

[Brief explanation of the drawing]

Fig. 1 is a detailed explanatory diagram of the present invention, Fig. 2 is an explanatory diagram of the Doppler effect, Fig. 3 is a block diagram of the configuration of a length measuring device for an underwater moving object according to an embodiment of the present invention, and Fig. 4 is an explanatory diagram of the Doppler effect. FIG. 5 is a received waveform diagram of a length measuring device, and FIG. 6 is a block diagram of a conventional length measuring device for underwater moving objects. 1...Length measuring device of the present invention, 2...Underwater moving object, 3...Sound source, 4...
・Moving object, 5... Transmitter, 6...
Receiver, 7... Time detection circuit, 8...
...Frequency detection circuit, 9...Arithmetic circuit, 1
0... Conventional length measuring device, 11... Underwater moving object, 15... Transmitter, 16...
...Receiver 1, 17...Receiver 2, 18...
...Receiver 3, 19...Time detection circuit, 20
... Phase detection circuit 1, 21 ... Phase detection circuit 2, 22 ... Arithmetic circuit. Agent Yoshihiro Yahata Patent attorney Ai big @Fo -------
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Claims (1)

[Claims] In a length measuring device for an underwater moving object that measures the length of an underwater moving object by acoustically detected reflected sound from the front and rear parts of the underwater moving object; a time detection circuit that detects the arrival time of the reflected sound; A length measuring device for an underwater moving object, comprising: a frequency detection circuit that detects the frequency of the reflected sound; and a calculation circuit that calculates the length of the underwater moving object from the detected arrival time and frequency. .