JPS63135799A - Acoustic homing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in an acoustic homing device for guiding an underwater vehicle to a target.

(Prior art and its problems) Acoustic homing devices for underwater vehicles emit sound waves into the water using a transmitter, capture the reflected sound from the target object using a receiver, and calculate the emission time of the sound wave and the reflected sound. This system guides the underwater vehicle to the target by determining the distance to the target from the difference between the time of reception of the reflected sound and the direction of the target from the angle at which the reflected sound arrives. However, the second
It looks like the graph of sound speed and depth shown in Figure and Figure 3.
The speed of sound in water decreases as the water depth increases, and the sound ray 22, which is the path of the sound wave, is refracted and curved downward. by the way,
Conventional acoustic homing devices do not have a function to correct this curvature of sound rays. In conventional acoustic homing devices, sound waves are treated as traveling straight through water.

In FIG. 2, reflected sound from a target object 20 reaches the underwater vehicle 10 through a sound ray 22. Here, the tangent of the sound ray 22 when the underwater vehicle 10 reaches <31. Target 2
0 and the underwater vehicle 10 is defined as 21, and the angles that the tangent line 31 and the straight line 21 make with the traveling direction of the underwater vehicle 10 are respectively 0. Let ψ be. As mentioned above, in conventional devices where sound waves are considered to travel in a straight line, the target 2 that occurs on the tangent line 31
Since the virtual image 30 of 0 is mistakenly recognized as the target object 20, the underwater vehicle 10 moves at an angle of depression ψ5! /c Where to steer,
By being steered in the direction of the elevation angle θ, the underwater vehicle 10 is erroneously guided in the direction of the virtual image 30. If the underwater vehicle 10 continues straight ahead, it will move to the position of the virtual image 30, but in reality, the underwater vehicle 10 will repeatedly detect the position of the target object 20.
Since the underwater vehicle 10 travels, the distance between the position of the target object 20 and the position of its virtual image 30 gradually becomes smaller each time it is detected, and the underwater vehicle 10 can eventually reach the target object 20. However, in that case, the underwater vehicle 10 does not travel along the straight line 21, but instead travels in a circuitous manner along the longer acoustic ray 22. Also,
As shown in Figure 3, the sound waves reflected from the water surface reach the target 20.
The underwater vehicle 10 is mistakenly recognized as a direct reflection from the water, and guidance is performed based on the sound.If the underwater vehicle 10 continues straight ahead, it will jump to the surface of the water. Also, if the reflection occurs at the bottom of the water, it will collide with the bottom.

SUMMARY OF THE INVENTION An object of the present invention is to provide an acoustic homing device that can guide an underwater vehicle to a target in the shortest distance, and also eliminates the risk of the underwater vehicle jumping to the surface of the water or colliding with the bottom. be.

(Means for solving the problem) As shown in FIG. 1, the acoustic homing device of the present invention has the following features:
An acoustic homing device that is installed on an underwater vehicle and guides the underwater vehicle to a target object based on the difference between the time when a sound wave is emitted into the water and the time when the reflected sound from the target object is received, and the arrival angle of the reflected sound. There is a depth detector that measures the water depth of the underwater vehicle, a sound ray calculator that calculates the curvature of a sound ray, which is the course of a sound wave, from correlation data between water depth and sound speed, and a target object based on the curvature of the sound ray. and a target position calculator for calculating the position of.

(Embodiment) FIG. 1 shows the configuration of an embodiment of the present invention. The functions of this embodiment will be explained based on the examples shown in FIGS. 2 and 3.

The transducer 5 is driven by the transmitter 4 to radiate sound waves into the water, receives reflected sound from the target object 20, and outputs an electrical signal. This signal is transmitted to the target detection section 6 and the horizontal direction detection section 7.
, are sent to the vertical direction detection section 8, respectively. Target detection unit 6
calculates the apparent distance Rf at the target 20t in FIG. 2 from the difference between the emission time of the sound wave and the reception time of the reflected wave and sends it to the sound ray calculator l. The horizontal position detection section 7 detects the horizontal azimuth of the target object 20 from the arrival angle of the reflected sound and sends it to the target position calculator 2. Similarly, the vertical azimuth detection section 8 detects the apparent vertical azimuth angle θ of the target object 20 from the arrival angle of the reflected sound and sends it to the sound ray calculator 1. The depth detector 3 detects the depth of the underwater vehicle 10 and sends it to the sound ray calculator 1. The sound ray calculator l calculates the curvature of the sound ray at that depth from pre-stored correlation data between water depth and sound speed and the depth and azimuth θ of the underwater vehicle lO, and the calculated sound! 22, the position of the target object 20 is calculated and sent to the target position calculator 2. The target position calculator 2 calculates the true distance Rr to the target 20, which is the length of the straight line 21 connecting the position of the target 20 thus obtained and the current position of the underwater vehicle 10, and the depression angle ψ of the straight line 21. know. Furthermore, the horizontal direction angle and depression angle ψ of the target object 20 given from the horizontal direction detection unit 7
The information on the direction in which the underwater vehicle 10 should be guided is sent to the steering calculation device 9 along with the distance Rr.

In this way, the underwater vehicle 10 is guided to the target object 20 through the shortest distance. Further, if the determined position of the target object 20 is above the water surface or below the water bottom, it can be seen that a reflected wave from the water surface or the water bottom has been received, respectively. Therefore, if the position of the target object 20 calculated based on the reflected waves is canceled until the direct reflected sound from the target object 20 is captured, the underwater vehicle 10 that has jumped out to the water surface will not collide with the water bottom. can avoid.

(Effects of the Invention) By using the acoustic homing device of the present invention, it is possible to guide an underwater vehicle to a target in the shortest distance, and it is also possible to prevent the underwater vehicle from jumping out to the water surface or colliding with the bottom of the water. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention. FIG. 2 is a conceptual diagram for explaining an example of how the embodiment shown in FIG. 1 is used. FIG. 3 shows the second example of the embodiment shown in FIG.
FIG. 3 is a conceptual diagram for explaining a usage example different from the one shown in the figure. 1...Sound ray calculator, 2...Target position calculator, 3...
・Depth detector, 4... Transmitter, 5... Transducer/receiver, 6
...Target detection section, 7...Horizontal direction detection section, 8...
Vertical direction detection unit, 9... Steering calculation device, 10... Underwater vehicle, 20... Target, 30... Virtual image of target 0 Agent Patent attorney Shinsuke Honjo (Blue L) (Sound speed) Figure 3

Claims (1)

[Claims] An acoustic homing device that is installed on an underwater vehicle and guides the underwater vehicle to a target object based on the difference between the time when a sound wave is emitted into the water and the time when the reflected sound from the target object is received, and the arrival angle of the reflected sound. A depth detector that measures the water depth of the underwater vehicle, a sound ray calculator that calculates the curvature of a sound ray, which is the course of a sound wave, from correlation data between water depth and sound speed, and a target object based on the curvature of the sound ray. and a target position calculator for calculating the position of the acoustic homing device.