JPH07209403A - Submerged direction finder and range finder - Google Patents

Abstract

PURPOSE:To surely confirm at least the two-dimensional direction from a slave machine side (diving worker) to a master machine side (transmitting source) by a simple means. CONSTITUTION:Three microphones 10, 11, 12, three wave detectors 20, 21, 22, and three zero cross position detectors 30, 31, 32 are connected to one arithmetic part 40. The sound wave inputted from the microphone 10 is detected by the detector 20, and the zero cross position is detected by the zero cross position detector 30. The arrival time difference of the sound waves inputted to the three microphone systems are represented by the zero cross positions, and the coming direction of the sound wave is arithmetically operated from them by the arithmetic part 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direction indicator and a range finder for knowing the relative position between the own position and the mother ship position during diving work.

[0002]

2. Description of the Related Art Conventionally, as a directional meter in water, in addition to a compass utilizing geomagnetism, means for transmitting ultrasonic signals from a mother machine and converting two systems of ultrasonic signals to audible sound signals An underwater detection information transmission system (Japanese Patent Laid-Open No. 2-284084) has been proposed which includes a speaker and a speaker and uses the phase difference discrimination ability of both ears of a human to know the direction of the mother machine.

Further, conventionally, as a distance measuring device in water, a time required for a sound wave emitted from its own position to return from a measurement object is measured, and a half of the distance obtained by multiplying the time is obtained. Underwater telephone (Japanese Patent Laid-Open No. 4-36)
No. 0429) has been proposed.

Further, when light can be expected to reach a certain degree, light and sound waves are simultaneously emitted from the mother machine at a constant cycle, and how much time the sound wave arrives behind the light is measured on the slave machine side. However, a technique for multiplying the time by the speed of sound to determine the distance has also been proposed (published on July 20, 1978 by Nikkan Kogyo Shimbun, "Ultrasonic Technical Handbook (new edition)" supervised by Junichi Mitsuyoshi and two others. Pp. 615-719).

[0005]

First, in the conventional underwater direction indicator, even if the direction is known by the geomagnetic compass, it cannot be said that the direction is important for diving work.

Further, in the underwater detection information transmission system, since the two ears are used for phase difference detection for knowing the direction, the wearing is troublesome, and moreover, when it is often desired to know the direction,
It has the drawback of neglecting attention to the surrounding sounds.

Furthermore, the speed of sound in water is about 4 times the speed of sound in air.
Since it is double, the phase difference becomes small, so it is only possible to discriminate with zero phase difference, that is, the direction of the sound source can be specified (if the front or rear is separated) without moving the head normally, but underwater Since the phase difference becomes about 1/4, the sound image is shifted to the center, and there is a complexity that it cannot be accurately identified unless the head is directed toward the sound source and the phase is zero.

Next, in the conventional underwater distance measuring device, the above-mentioned underwater communication device has a drawback that when a plurality of diving workers (divers) want to know their own positions, pulses are interfered on the mother ship side. In addition, since transmission and reception are required, there is a disadvantage that the device becomes complicated and expensive.

Further, the technique described in the above "Handbook of Ultrasonic Techniques" has a drawback in that the attenuation of light in water largely depends on the transparency of water and lacks reliability.

Therefore, the present invention solves the above-mentioned drawbacks of the prior art, and provides an underwater directional indicator capable of reliably knowing at least a two-dimensional direction from the diving operator to the transmission source by a simple means, and a simple It is intended to realize an underwater range finder capable of obtaining sufficient accuracy by means.

[0011]

In order to solve the above-mentioned problems, the underwater direction indicator and the underwater distance meter of the present invention employ the following means.

(1) A plurality of microphones spatially separated from each other, a time difference detector, and a calculator are provided, and the spatial arrival direction of sound waves is calculated from the time difference between the microphone outputs. Underwater direction indicator.

(2) The mother machine has a mother machine timer, a sound wave generator and a speaker, and the slave machine has a microphone, a detector, a slave machine timer and a time difference detector, and has a cycle corresponding to the cycle of the mother machine timer. A sound wave is generated by the sound wave generator, emitted into water by the speaker, received by the microphone, a burst of the sound wave is detected by the detector, and the slave unit is detected by the time difference detector. An underwater distance meter configured to detect a time difference between a timer output and the detector output.

(3) Underwater having a timer, a sound wave generator, and a speaker, and configured so that a sound wave having a cycle corresponding to the cycle of the timer is output by the sound wave generator and emitted into the water by the speaker. Rangefinder mother machine.

(4) A microphone, a detector, a timer, and a time difference detector are provided, and the time difference between the result of detecting the sound wave entering the microphone in water by the detector and the pulse output by the timer is the time difference. An underwater rangefinder slave unit configured to calculate with a detector.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of an underwater directional meter and an underwater distance meter of the present invention will be described with reference to the drawings.

First, FIG. 1 shows the underwater direction of the first embodiment of the present invention. Three microphones 10, 11, 12 and
The three detectors 20, 21, and 22, the three zero-crossing position detectors 30, 31, and 32, and the one arithmetic unit 40 are connected. The sound wave entering from the microphone 10 is detected by the wave detector 20, and the zero crossing position detector 30 detects the zero crossing position. The zero-crossing position represents the arrival time difference of the sound waves that have entered the three microphone systems, and from this, the arrival direction of the sound waves is calculated by the calculation unit 40. The calculation contents of the calculation unit 40 will be described below.

The three microphones 10, 11, 12 are
It is assumed that the zero crossing positions are as shown in FIG. 2 assuming that the points are symmetrically arranged at the points A, B, and C about the point O in FIG. It is found that the sound wave first arrived at the point A, and then the points B and C in this order.
The time difference between points A and B at this time is a, and points A and C
3 is defined as a point D that internally divides the line segment AC at a ratio of a: b in FIG. 3, and a perpendicular line is set on the line segment BD in the direction of A, which is the arrival direction of the sound wave. is there.

Further, in the case of calculation, if the direction of the point A is 0 °, C is 120 ° clockwise, and B is 240 °, the direction of arrival from ABC is 240 ° to 36 °.
It was found to be in the range of 0 °, and the space between them was divided by a: b, so that 240 ° + 120 ° × a / b is the desired direction.

The distance between points A, B and C is, for example, 5 cm.
Then, the maximum arrival time difference is 5 cm ÷ 1500 m / s (sound velocity) = 33 μs. Therefore, assuming that the directional resolution is ± 1 °, a sampling accuracy of 270 ns is set as approximately 1/120. .

Further, since 33 μs needs to be sufficiently shorter than the measurement period, the modulation frequency of the sound wave is 1/3 μs = 3.
It is necessary to select 3 kHz or less, which is one digit lower than 0 kHz.
In practice, it is sufficient to update about 100 times per second, so about 100 Hz is more convenient.

Further, as shown in FIG. 4, the arithmetic unit 40 is driven at a clock of 3.6 MHz and resets at 100 Hz. The values of three counters 1, 2, and 3 are used every 1/100 second. It is configured to determine the minimum value and obtain the differences a and b of the three points.

Next, FIG. 5 shows an underwater rangefinder according to a second embodiment of the present invention. A transmitting unit including a mother machine timer 51, a sound wave generator 52, and a speaker 53 is provided on the mother machine 50 side, and a sound wave burst is transmitted from the speaker 53 at a constant cycle controlled by the mother machine timer 51.

On the slave unit 60 side, the sound wave sent from the mother unit 50 side is received by the microphone 61, and the burst envelope waveform is obtained by the detector 62. In addition, the time difference calculation unit 64 calculates a time difference from a pulse of a constant cycle generated from the child device timer 63 independent of the mother device 50. The distance calculation unit 65 multiplies the time difference by the sound speed to obtain the distance between the mother device 50 and the child device 60.

The phase difference between the mother machine timer 51 and the slave machine timer 63 directly affects the distance accuracy. The accuracy and feasibility will be described below. In the present embodiment, it is assumed that the timer period is 10 seconds and the sound velocity is 1500 m / s and the maximum range is 15 km. If both timers are reset at the start of diving (this is normally done from the mother ship, the operation is easy). If the dive time is 1 hour (3600 seconds), the distance accuracy error between them will be ± 20 m. To maintain it, an accuracy of ± 20 / (1500 × 3600) = ± 3.7 × 10 ⁻⁶ is required. This accuracy is almost the same as the accuracy 10 / (3600 × 24 × 30) = 3.8 × 10 ^{−6 of} an ordinary quartz crystal wristwatch with a monthly difference of 10 seconds, which is sufficiently realizable.

The resetting method is realized by the operator pressing a button near the mother machine 50 at the start of diving to give an offset to the time difference calculation unit 64 so that the display becomes 0 m. In practice, it is often impossible to approach the speaker to 0 m, so it is more realistic to give an initial value of 10 m or 20 m to the eyes.

According to this reset method, if the power source of the slave unit is charged by the charger connected to the mother unit, it is always 0 during charging.
It is possible to automate to initialize to m,
If the charging itself is done by electromagnetic coupling with electromagnetic waves synchronized with the sound wave burst, no special connector is required, which is a great advantage. Further, it may be linked with the reset of the timer for measuring the dive time.

In addition, the sound wave bursts, even at audio frequencies,
It is obvious that the same effect can be obtained even if the ultrasonic wave is amplitude-modulated or frequency-modulated.

Furthermore, it is also useful to use the time signal of the medium and short wave broadcasting and the time signal of the standard telegram (JJY) to reset the timers of the mother device and the child device.

[0030]

As described above, according to the underwater direction indicator of the present invention, at least two-dimensional transmission to the transmission source is achieved by the processing system having at least three spatially separated microphones. Can indicate the direction of. Although it is possible to indicate the three-dimensional direction by using four microphones by the same principle, in practice, the three-dimensional direction can be known by moving the measurement surface using the three microphones.

In the first embodiment, an ultrasonic wave modulated at about 100 Hz is assumed, but it can be realized in principle even if an audible frequency of about 1 kHz is used. In this case, the detectors 20 to 22 of the embodiment are unnecessary.

The zero-crossing position detector is used for phase detection to detect a time difference. However, the same is true if the three signals are cross-correlated so that the phase time difference can be identified. Needless to say, the effect of can be obtained. By taking the correlation, it is not necessary to limit the signal source to a sine wave type, and the direction can be known even with the screw sound of a ship, so it can be applied to avoiding danger.

Next, the underwater rangefinder of the present invention is a very simple one-way transmission system that does not use bidirectional transmission such as sonar, and can obtain sufficient practical distance accuracy. Also,
Since it is one-way transmission, there is no problem even if a large number of slave units are used at the same time.

Further, when the distance between the mother machine and the child machine exceeds a predetermined value, an alarm is generated and the function of notifying the child machine holder can be realized, and the phase of the mother machine is intentionally shifted in an emergency. It can also be used as an emergency return instruction.

Further, when the mother machine breaks down and the sound wave burst is stopped, if the distance calculating section is provided with a measure for maximizing the distance between the mother machine and the child machines, the failure of the mother machine can be immediately detected. It is safe to do so.

Further, in the embodiment, the distance between the mother ship and the diving operator is assumed to be measured. However, if the identification code is attached to the sonic burst to enable selection, a plurality of transmitters are possible.
It is also possible for each diving person to know the distance to the partner or instructor using the transceiver.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a timing diagram of the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of the first embodiment of the present invention.

FIG. 4 is a detailed diagram of an arithmetic unit according to the first embodiment of the present invention.

FIG. 5 is a block diagram of a second embodiment of the present invention.

[Explanation of symbols]

 10-12 Microphone 20-22 Detector 30-32 Zero-crossing position detector 40 Calculation part 50 Mother machine 51 Mother machine timer 52 Sound wave generator 53 Speaker 60 Handset 61 Microphone 62 Detector 63 Handset timer 64 Time difference calculation section 65 Distance calculation Department

Claims (4)

[Claims] 1. A structure having a plurality of microphones spatially separated from each other, a time difference detector, and a calculator, and calculating a spatial arrival direction of a sound wave from a time difference between the microphone outputs. Underwater directional indicator. 2. A mother machine timer, a sound wave generator, and a speaker are provided on the mother machine side, and a microphone, a detector, a child machine timer, and a time difference detector are provided on the child machine side, and a cycle corresponding to the cycle of the mother machine timer is provided. A sound wave is generated by the sound wave generator, emitted into water by the speaker, received by the microphone, a burst of the sound wave is detected by the detector, and the slave unit is detected by the time difference detector. An underwater rangefinder, which is configured to detect a time difference between a timer output and the detector output. 3. A timer, a sound wave generator and a speaker,
An underwater distance measuring mother machine, wherein the sound wave generator outputs a sound wave having a cycle corresponding to the cycle of the timer, and the speaker emits the sound wave into the water. 4. A microphone, a detector, a timer, and a time difference detector are provided, and the time difference is detected by detecting the time difference between the result of detecting the sound wave entering the microphone in water by the detector and the pulse output by the timer. Underwater distance measuring sub-unit, characterized in that it is configured to calculate with a vessel.