JPH05248798A - Voyage ship hull detector and detecting method for voyage ship hull - Google Patents

Abstract

PURPOSE:To distinctly detect an underwater acoustic signal to be generated from a voyage ship hull and the other underwater acoustic signal. CONSTITUTION:A voyage ship hull detector comprises an underwater acoustic sensor 1 and a level detector 3 for detecting a level of an underwater acoustic signal detected by the sensor 1 to detect a voyage ship hull. The detector further comprises a trough change detector 4 for detecting a trough change of an waveform of the signal based on the waveform of the signal detected by the sensor 1, and an AND circuit 5 for taking an AND operation of outputs of the detectors 4 and the 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a running hull detection device and a running hull used for a mine, which receives an underwater acoustic signal and detects the running hull and noise from the signal waveform by distinguishing them from each other. It relates to a detection method.

[0002]

2. Description of the Related Art A conventional sailing hull detecting device for detecting a running hull utilizing underwater sound generated by a hull sailing on water or underwater (including sea and undersea) is a hydrophone underwater. An underwater acoustic sensor such as is installed, the signal level received by the underwater acoustic sensor is monitored by the level detection circuit, and if it exceeds the predetermined level, it is determined that the underwater acoustic signal is generated by the traveling hull. I was trying to detect.

[0003]

However, the underwater acoustic signal received by the underwater acoustic sensor installed underwater is not only the signal from the traveling hull to be detected, but also the buzz (sea noise) of the water surface and others. Noise, that is, acoustic signals from the minesweeper are mixed.

The conventional method for detecting a traveling hull, which is determined by the signal level, has a drawback that an acoustic signal from a minesweeper is erroneously detected. The present invention is intended to solve the above-mentioned drawbacks, and a pseudo signal from a minesweeper and an acoustic signal from a running hull can be strictly distinguished, and is also strong against sea noise such as buzz on the water surface. An object is to provide a traveling hull detection device and a traveling hull detection method.

[0005]

[Principle] FIG. 11 shows a minesweeping signal waveform in which an acoustic signal output from a minesweeper is received by an underwater acoustic sensor, that is, a noise waveform.

(A) of the figure shows a waveform rising vertically, and (B) of the figure shows a waveform rising linearly.
(C) in the figure is a convex shape and the waveform rises,
From the minesweeper, these three waveforms are arbitrarily emitted into the water as a pseudo-acoustic signal generated by the traveling hull.

In the figure, the horizontal axis represents time and the vertical axis represents sensor output voltage. On the other hand, when the underwater sound generated by the running hull when traveling at a constant speed is received by the underwater acoustic sensor of the detection device, the received signal, that is, the sensor output voltage is theoretically known to be Equation 1.

[0008]

[Equation 1]

Here, V is the sensor output voltage, P is the sound pressure generated by the traveling hull, and R is the distance between the underwater acoustic sensor and the navigation hull. As shown in FIG. 2, assuming that the depth of the underwater acoustic sensor 1 installed in the traveling hull detection device 7 and the horizontal distance from the traveling hull 8 are D and x, respectively, R = √
From (D ² + x ² ), Formula 1 becomes Formula 2, and the sensor output voltage V with respect to the horizontal distance x is shown in FIG.

[0010]

[Equation 2]

As described above, the sensor output voltage of the traveling hull 8 changes in accordance with the equation (2). The above equation 2 is a well-known equation, and as shown in FIG.
In the range from -∞ to -D / √2 and from D / √2 to ∞, V changes concavely (∪), and x changes from -D / √2 to D.
In the range up to / √2, V is a convex (∩) changing curve.

The present invention focuses on the fact that x changes concavely in the range from -∞ to -D / √2 in the waveform of the number 2 detected by the underwater acoustic sensor 1, and the running hull 8 and sea noise , Especially as a means to distinguish from the pseudo acoustic signal from the minesweeper,
The concave change is used.

It should be noted that the conventional navigation ship detection device is of a type that simply detects the level as described above, so that it is sufficient that the minesweeper emits an acoustic signal having a level higher than a predetermined level into the water. For the reason and because it is difficult to output the concave acoustic signal, the concave pseudo-acoustic signal is not used in the acoustic minesweeper, and the signal shown in FIG.
It is presumed that the waveform is similar.

[0014]

In order to achieve the above-mentioned object, a traveling hull detection device and a method for detecting a hull of the present invention include an underwater acoustic sensor and an underwater acoustic signal detected by the underwater acoustic sensor. And a level detection unit for detecting the level of the underwater acoustic signal waveform based on the underwater acoustic signal waveform detected by the underwater acoustic sensor. In addition to providing a concave change detecting unit for detecting the concave change of No. 1, and providing an AND circuit for ANDing the output of the concave change detecting unit and the output of the level detecting unit, it is possible to detect the running hull. It has a feature.

Further, the traveling vessel detecting method includes an underwater acoustic sensor and a concave change detecting section for detecting a concave change of the underwater acoustic signal waveform based on the underwater acoustic signal waveform detected by the underwater acoustic sensor. The feature is that the running hull and the sea noise are distinguished based on the concave change of the underwater acoustic signal waveform.

[0016]

Since the traveling hull has a concave underwater acoustic signal waveform characteristic for a certain period, the traveling hull and the sea noise are distinguished by detecting this concave change.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of an embodiment of the present invention.
In the figure, 1 is an underwater acoustic sensor, 2 is a signal processor, 3 is a level detector, 4 is a concave change detector, and 5 is an AND circuit.

As the underwater acoustic sensor 1, for example, a hydrophone is used, and it is installed in water as shown in FIG. As the running hull 8 approaches the running hull detection device 7, the underwater acoustic signal of the screw or the like generated by the running hull 8 is detected by the underwater acoustic sensor 1.

As explained in the section of the above principle, the underwater acoustic sensor 1 detects the underwater acoustic signal waveform shown in FIG. 4 with the passage of time. The concave change detection unit 4 is adapted to detect the presence or absence of a concave change in the underwater acoustic signal waveform detected by the underwater acoustic sensor 1, and in the case of the waveform shown in FIG. Output level signal.

There is a method of outputting the H level signal when the concave change detecting section 4 outputs the H level signal when the concave change is detected once or a plurality of times. If the H-level signal is output when the concave change is detected a plurality of times, the accuracy of detection of the traveling hull 8 becomes high.

By detecting the concave change in the underwater acoustic signal waveform detected by the underwater acoustic sensor 1 in this manner, it is strictly distinguished from the pseudo acoustic signal emitted from the minesweeper shown in FIG. It can also be distinguished from buzzing sea noise.

The signal processing section 2 is further provided with a level detecting section 3 for checking the level of the underwater acoustic signal detected by the underwater acoustic sensor 1 and outputting an H level signal when a level higher than a predetermined level is detected. It has become. The AND circuit 5 takes the AND of the output of the level detecting unit 3 and the output of the concave change detecting unit 4 to make the detection of the traveling hull 8 more reliable.

The detection signal output from the AND circuit 5 is sent to the output circuit, and an ignition signal is output when the central portion of the hull of the traveling hull 8 is detected by another device. Alternatively, the detection signal output from the AND circuit 5 is sent to the output circuit to activate the detonator circuit at an appropriate timing.

FIG. 5 shows the construction of an embodiment of the concave change detecting portion. In the figure, reference numerals 11, 12, and 13 denote comparators, 14 and 15 denote inverters, 16 and 17 denote AND gates, and 18 denotes a time measuring circuit.

Reference voltages S1, S2, S3 are input to the comparators 11, 12, 13, and the reference voltage S
1, S2, S3 and the underwater acoustic signal detected by the underwater acoustic sensor 1 are compared.

Here, the reference voltages S1, S2, S3 correspond to the levels S1, S2, S3 shown in FIG. 4, and these levels S1, S2, S3 are level differences S2-S1, S.
3-S2 are set to be equal to each other. In FIG. 4, each level S1, S2, S3 is displayed at a high level position with a large interval for easy understanding, but these levels are set at a lower position and the interval is set narrower. It should be done.

The time measuring circuit 18 measures the time difference t1-t2 between the pulse of the time width t1 input from the AND gate 16 and the pulse of the time width t2 input from the AND gate 17, and the time difference t1-t2> 0. At this time, an H level signal for determining the depression is output. That is, the time t1 for reaching the equal level interval S1 to S2 is from S2 to S3.
This is because the underwater acoustic signal waveform exhibits a concave change as is apparent from FIG.

If a plurality of concave change detecting portions shown in FIG. 5 are provided and the signal output from the time measuring circuit 18 is received by an AND circuit or a majority decision circuit, the noise of the water surface wave can be reduced. It is possible to more reliably identify the sailing hull.

FIG. 6 shows the configuration of another embodiment of the concave change detecting portion. In the figure, 21 and 22 are differentiating circuits, and 23
Is a positive / negative discrimination circuit, and 24 is a comparator.

A predetermined reference voltage S is input to the comparator 24, and the reference voltage S and the underwater acoustic signal detected by the underwater acoustic sensor 1 are compared.

Here, the reference voltage S corresponds to the level S shown in FIG. 7, and is set to an arbitrary low level. The underwater acoustic signal detected by the underwater acoustic sensor 1 is a differentiation circuit 2
1, the signal differentiated by the differentiating circuit 21 is further differentiated by the differentiating circuit 22 provided in the next stage and input to the positive / negative discriminating circuit 23. .. The positive / negative discrimination circuit 23 is connected to the comparator 2
4 output, that is, the underwater acoustic sensor 1
When the underwater acoustic signal detected in step S reaches a preset level S, it is determined whether the signal input from the differentiating circuit 22 is positive or negative, and when the signal is positive, an H level signal for concave determination is output. ing.

That is, as shown in FIG. 8, the underwater acoustic signal (A) input to the differentiating circuit 21 is the differentiating circuit 21,
This is because the waveform is differentiated twice at 22 and if the second derivative value is positive, the waveform at that time, that is, at the time T at which the level S is reached is a concave change.

In the figure, (B) is the differentiation circuit 2
The waveform of the first-order differentiation output from 1, (C) is the differentiation circuit 2
The waveforms of the second derivative output from 2 are shown respectively. As in the case of FIG. 5, if a plurality of concave change detecting portions shown in FIG. 6 are provided and the signal output from the positive / negative discrimination circuit 23 is received by the AND circuit or the majority circuit,
It is possible to more reliably determine the sailing hull even with the buzz of water waves.

FIG. 9 shows the configuration of another embodiment of the concave change detecting portion. In the figure, 31 is an A / D converter, 32 is a sampling circuit, 33 is a level calculation circuit, 34 is a clock circuit, and 35 to 37 are gate circuits.

The configuration shown in FIG. 9 is for detecting the level increase / decrease for each constant time, and corresponds to the one for detecting the time increase / decrease for each time to reach the constant level width in FIG. That is, the underwater acoustic signal detected by the underwater acoustic sensor 1 is converted into a digital value corresponding to the level by the A / D converter 31, and as shown in FIG. 10, at equal time intervals (Δt). The digitized level value V of the underwater acoustic signal in the sampling circuit 32 at every t1, t2, and t3.
1, V2 and V3 are input to the level calculation circuit 33.

The level operation circuit 33 is the gate circuit 3
The level values V1, V input from 5, 36, 37
2, V3 based on the level difference ΔV1 = V2-V1, ΔV2
= V3−V2 is calculated, and when ΔV2> ΔV1, an H level signal for concave determination is output. That is, when the level difference ΔV2 after the lapse of a certain time Δt is larger than ΔV1, the underwater acoustic signal waveform shows a concave change, as is apparent from FIG.

If a plurality of concave change detecting portions shown in FIG. 9 are provided and the signal output from the level calculating circuit 33 is received by the AND circuit or the majority circuit, the traveling hull can be more surely brought about in this case as well. Can be determined.

Since the A / D converter 31 and the subsequent parts are digitized, it may be replaced with a microprocessor for processing. In addition, data of waveforms having various concave changes is stored in advance as waveform patterns, and a microprocessor is used to match the underwater acoustic signal detected by the underwater acoustic sensor 1 with the waveform pattern having the concave changes. It is also possible to use a concave change detection unit configured to perform waveform comparison processing in step 1.

As described above, it goes without saying that the concave change detecting section 4 may have any circuit configuration for detecting the concave change of the underwater acoustic signal. When the concave change detection unit 4 detects the concave change, the sound source of the underwater acoustic signal is determined to be that of the running hull 8, as can be seen from the description in the principle section.

[0040]

As described above, according to the present invention, the underwater acoustic signal from the minesweeper and the underwater acoustic signal whose source is the traveling hull can be distinguished, and only the traveling hull can be detected reliably. it can.

Moreover, since the AND of the concave change detecting portion and the level detecting portion is adopted, erroneous detection due to sea noise is reduced.

[Brief description of drawings]

FIG. 1 is a configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of underwater acoustic signal detection.

FIG. 3 is a waveform diagram for explaining the principle of detecting a traveling hull.

FIG. 4 is a waveform explanatory view for explaining detection of a concave change.

FIG. 5 is a configuration of an example of a concave change detection unit.

FIG. 6 is a configuration of another embodiment of the concave change detection unit.

FIG. 7 is an explanatory diagram of a waveform for setting a reference level.

FIG. 8 is an explanatory diagram of a primary differential waveform and a secondary differential waveform.

FIG. 9 is a configuration of another embodiment of the concave change detection unit.

FIG. 10 is a waveform explanatory view for explaining detection of a concave change.

FIG. 11 is a waveform diagram of an underwater acoustic signal from a conventional minesweeper.

[Explanation of symbols]

 1 underwater acoustic sensor 2 signal processing unit 3 level detection unit 4 concave change detection unit 5 AND circuit 7 traveling hull detection device 8 traveling hull 11, 12, 13 comparator 18 time measurement circuit 21, 22 differential circuit 23 positive / negative discrimination circuit 24 Comparator 31 A / D converter 32 Sampling circuit 33 Level arithmetic circuit

Claims (5)

[Claims] 1. A traveling hull detecting device comprising an underwater acoustic sensor and a level detecting section for detecting the level of an underwater acoustic signal detected by the underwater acoustic sensor, the traveling hull detecting device being configured to detect a traveling hull. , Based on the underwater acoustic signal waveform detected by the underwater acoustic sensor,
A concave change detection unit for detecting a concave change in the underwater acoustic signal waveform is provided, and an AND circuit for ANDing the output of the concave change detection unit and the output of the level detection unit is provided to detect a traveling hull. A vessel detecting device for sailing vessels, characterized in that 2. A plurality of comparators for comparing the underwater acoustic signal detected by the underwater acoustic sensor with a plurality of different levels that should be equidistant levels, the concave change detecting section comprising:
Based on the output of the comparator, a time difference t1-t2 is obtained from the logic circuit that outputs the time for each of the equal-interval levels, and the time t1 output from the logic circuit and the time t2 output one time later. A time measurement circuit that outputs when the time difference t1-t2 is positive (not including zero),
2. The navigation vessel detecting device according to claim 1, wherein a concave change in the underwater acoustic signal waveform is detected from a time change amount with respect to the equal interval level. 3. The concave change detection unit includes two differentiating circuits that perform first-order and second-order differentiation of the underwater acoustic signal detected by the underwater acoustic sensor, and the underwater acoustic signal has a level equal to or higher than a preset level. When the output of the comparator is generated, a comparator is provided, and a positive / negative discriminating circuit for discriminating the positive / negative of the secondary differential signal output by the differentiating circuit is provided. The navigation ship detection device according to claim 1, wherein the concave change of the vehicle is detected. 4. The concave change detecting section includes an A / D converter for converting an underwater acoustic signal detected by the underwater acoustic sensor from analog to digital, and t _{n-1 at} every predetermined time interval Δt.
A sampling circuit that samples the output of the A / D converter at t _n and t _{n + 1} , and level values V _n-1 , V _{n of} the underwater acoustic signal sampled by the sampling circuit.
Based on V _{n + 1} , the level difference ΔV _n = V _n −V _n−1 , ΔV _{n + 1}
= With obtaining the V _{n + 1} -V _n, further its variation △ V
_{n + 1} - △ seeking V _n, the variation _{△ V n + 1 - △ V} n positive and a level calculating circuit for outputting time (including not zero), hydroacoustic signals from the level variation for equal time The navigation vessel detecting device according to claim 1, wherein a concave change in the waveform is detected. 5. An underwater acoustic sensor and a concave change detecting unit for detecting a concave change in the underwater acoustic signal detected by the underwater acoustic sensor are provided, and the sailing hull is discriminated from the concave change in the underwater acoustic signal waveform. A method for detecting a traveling hull characterized by being performed.