JP3070584B2 - Ship detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ship detection device, and more particularly to a ship detection device which can be installed on the seabed to detect the length of a target ship, and distinguishes between a ship towing a simulated sound source and a normally sailing ship target. The present invention relates to a ship detecting device capable of performing the following.

[0002]

2. Description of the Related Art In a conventional ship detecting apparatus using sound, approach of a ship is detected only by the volume of the radiated noise of the ship, and a simulated sound source that generates the same kind of sound as the radiated noise of the ship is erroneously detected as a target. I will judge. FIG. 12 shows an example of the related art. In FIG. 12, radiation noise 2 due to propeller cavitation of a ship is received by acoustic sensor 4. Acoustic sensor 4
Converts the radiation noise of the ship into a reception signal 402, performs band limitation and detection by the detection circuit 12, and outputs a target detection signal 1001 when the detection signal level exceeds the threshold value 102. In this method, there is a problem in that when the towed simulated sound source 11 used as a disturbance measure of the ship detection device is operated, the simulated radiated noise 21 causes the detection signal level to exceed the threshold value, thereby erroneously detecting the target.

[0003]

A first problem of the prior art is that the conventional method can detect a target, but does not have a function of detecting a target hull length. That was not possible.

[0004] The second problem is that since sound is used, if there is a simulated sound source that simulates radiated noise of a ship, it is erroneously determined that the ship is a navigating ship. That is, in the related art, there is a problem that it cannot be determined whether the sound source is from a ship or a towed simulated sound source.

It is an object of the present invention to provide a ship detecting apparatus capable of distinguishing a false target such as a tow-type pseudo sound source from an actual navigating ship.

Another object of the present invention is to provide position information and
An object of the present invention is to provide a ship detection device capable of detecting a target ship size from speed information / water pressure change time.

[0007]

SUMMARY OF THE INVENTION A ship detecting apparatus according to the present invention detects the time of a change in water pressure at the bow and stern due to drainage of a hull when passing through a ship. More specifically, it has a change width calculation circuit (7 in FIG. 1). The target speed is calculated from the angle and the depth data from directly above. Specifically, it has a target speed calculation circuit (8 in FIG. 1). The target hull length is calculated from the target speed data and the change time of the water pressure. Specifically, it has a hull length calculation circuit (9 in FIG. 1).

Another feature is that it is determined that the direction of the ship is within a certain angle from immediately above when the water pressure changes after passing through the ship. Specifically, a target detection circuit (FIG. 1)
10).

In the present invention, the position and speed of the ship are calculated from the radiation noise due to propeller cavitation of the ship, and the time width of the change in the water pressure at the bow and stern due to the drainage of the hull when passing through the hull is captured.
The hull length can be calculated from the water pressure change time width.

In a normal navigating ship, radiation noise comes from directly above at the time when the water pressure change ends, but a towing type simulated sound source emits a simulated sound at a volume much larger than the radiation noise level of the towing ship. Therefore, at the time when the change in the water pressure of the towed vessel ends, the simulated sound comes not from the upward direction but from the direction of the simulated sound source towed. For this reason, it can be determined whether or not the towing-type simulated sound source is used by determining whether the arrival direction of the radiation noise at the end of the water pressure change is the upward direction.

[0011]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the configuration of the embodiment of the present invention, and the operation will be described below with reference to FIGS. 2, 3, and 5.

The water pressure sensor 3 shown in FIG. 1 averages and converts the water pressure value at the depth where the ship detecting device is laid, to obtain depth data 301. This averaging is performed for a time longer than the cycle of wind waves and swells, and with a time constant that can detect the ebb and flow of tide. Further, as shown in FIG. 2, the water pressure sensor 3 processes the detected water pressure value 303 with a time constant that is long enough to respond to the ebb and flow of the tide to obtain a water pressure time constant processing value 304. Next, the change in water pressure due to the passage of the ship is calculated as follows:
03-304), the water pressure level 302 is output. (AB
In FIG. 1, the water pressure level 302 is input to the water pressure detection circuit 5 and compared with a threshold value. When the water pressure level exceeds the threshold value, a water pressure detection signal 501 is output.
Is set to “1”, and if the threshold is not exceeded, “0” is output.
When passing through the ship, the water pressure detection signal 501 becomes “1” when a change in the water pressure occurs when passing through the stern of the bow. The change width calculating circuit 7 measures a time interval between the water pressure detection signal 501 generated at the time of passing through the bow and 501 generated at the time of passing through the stern, and sets the time interval as a water pressure change time 701.

The acoustic sensor 4 receives the radiated noise 2 from the ship and converts it into an electric signal. As shown in FIG. 3, the acoustic sensor 4 has three receivers 41, 42, and 43 installed on orthogonal axes, and the azimuth detecting circuit 6 uses the time difference of the receiver output between 42 and 41 in the xz plane. Of the angle ４３x
The angle Θy on the yz plane is calculated from the phase difference between the receiver outputs 41. Next, {x, Δy are vector-combined to calculate the zenith angle Θ from directly above to the target.

Next, the operation of the target speed calculation circuit 8 will be described with reference to FIG. Depth data 3 from water pressure sensor 3
01 (FIG. D 5), the movement distance r just above than the zenith angle theta ₁ distance R 'and R' = D × tan (Θ 1) r = R'-
The moving speed V801 of the ship is calculated by V = r / T.

As shown in FIG. 1, a water pressure detection signal 501 and a zenith angle 601 are input to the target detection circuit 10. Inside the target detection circuit 10, the zenith angle Θ 601 is compared with the angle threshold, and when the zenith angle Θ 601 is equal to or smaller than the angle threshold, the angle detection signal 1000 is set to “1”, and when the zenith angle Θ 601 is equal to or larger than the angle threshold, it is set to “0”. Then, a logical product of the angle detection signal 1000 and the water pressure detection signal 701 is obtained, and a target detection signal 1001 is output.

As described above, the water pressure detection signal 501 is "1".
If the angle detection signal 1000 is "1", that is, if the incoming sound is within a certain angle from immediately above, the target detection signal 1001 is output as "1" and determined to be the ship target.

The hull length calculation circuit 9 generates a target detection signal 1001
Only when “1” is “1”, the hull length 901 (L) is calculated from the water pressure change time 701 (Δt) and the moving speed 801 (V) by L = Δ
It is calculated by t × V and output.

The manner in which the azimuth detecting circuit 6 of FIG. 1 detects an angle will be described in detail with reference to FIG. 3 and FIG. First, FIG.
The calculation method of the zenith angle Θ will be described with reference to FIG. As shown in FIG. 3, the receivers 41, 42, 43 are arranged on orthogonal XY axes. At this time, the target sound arrives at an angle of the zenith angle Θ 601 from the Z axis directly above. The azimuth detection circuit 6 uses the receivers 41 and 42 to determine the target azimuth Θx and the receivers 41 and 4
3 to detect the target direction Θy, the zenith angle Θ6
01 is calculated as Θ = {x + {y}}. here,
{} Indicates vector composition.

Next, an example of detection of Δx will be described with reference to FIG. In the receivers 41 and 42 arranged at the acoustic center distance D, the sound wave arriving from the Θx direction is delayed by a distance Δr in the 41 receivers with respect to the 42 receivers. In this case, the delay time of the signal of the receiver 41 is t = Δr / c. The azimuth detecting circuit 6 measures the delay time t, and calculates the target azimuth Θx from 音 x = ARCSIN (t × c / D) from the sound speed c and the acoustic center distance D which are grasped in advance. Also, Δy is calculated using the receivers 41 and 43 in the same manner.

Next, the target detection signal 1 will be described with reference to FIGS.
An example of the output process 001 will be described in detail. FIG. 6 shows a state in which the target of a ship during navigation is detected. In this state, the water pressure level 302 shown in FIG. The water pressure detection circuit 5 compares the input water pressure level 302 with a threshold value, and as shown in FIG. 7B, sets the water pressure detection signal 501 to "1" when the threshold value is exceeded and "0" when the threshold value is not exceeded. Is output. When the water pressure detection signal 501 becomes “1”, it is generated as 501α at the bow and 501β at the stern. The change width calculation circuit 7 measures the time interval Δt between 501α and 501β, and calculates the hydraulic pressure change time 701 (Δt in FIG. 7).
t). Next, the azimuth detecting circuit 6 outputs the zenith angle Θ601 shown in FIG. The target detection circuit 10 compares the zenith angle Θ 601 with the angle threshold value, and when the zenith angle Θ 601 falls below the angle threshold value, as shown in FIG. The angle detection signal 1000 outputs "1". Also, zenith angle 頂 6
When “01” exceeds the angle threshold value, that is, when a sound comes from outside the area of a fixed angle immediately above, the angle detection signal 1000 outputs “0”. 7E, the target detection signal 1001 is obtained by the logical product of the water pressure detection signal 501 and the angle detection signal 1000.
Becomes "1", the water pressure is detected, and the sound comes from a region within a certain angle immediately above the target sound. Therefore, it is determined that the ship is a ship, and the target detection signal 1001 is output as "1".

Next, the operation of the present invention, which is determined to be a false target when a ship is towing a tow-type simulated sound source, will be described with reference to FIG.

A water pressure level 302 is input from a water pressure sensor. In FIG. 9B as in FIG. 7, the water pressure detection signals 501α and 501β are generated at the stern of the bow. Next, FIG.
In −c, the azimuth detecting circuit 6 outputs the zenith angle Θ601, but when the water pressure detection signal 501β is generated because the acoustic signal from the towed simulated sound source is received, the sound is out of a certain angle from immediately above. Coming from the territory. Therefore, as shown in FIG. 9C, the zenith angle Θ 601 exceeds the angle threshold at the time when the water pressure detection signal 501β becomes “1”, and the angle detection signal 1000 in FIG. 9D remains “0”. is there.
Therefore, when the logical product of the water pressure detection signal 501 and the angle detection signal 1000 is obtained as shown in FIG. 9-e, the target detection signal remains “0”, and the sound coming from the region immediately above the fixed angle and outside the predetermined angle is left. Therefore, it is determined to be a false target, and no target is detected.

In FIG. 3, orthogonally arranged receivers are used for azimuth measurement of radiation noise, and azimuth detection is performed using the phase difference. As another embodiment, as shown in FIG. 10, a plurality of receivers are widely arranged to form a sharp receiving directivity and swing the main pole direction of the receiving directivity.形態 is possible.

Further, the water pressure sensor of FIG. 1 outputs a water pressure level 302 by time constant processing. On the other hand, as shown in FIG. 11, a method of mechanically changing the diameter and length of the seawater introduction pipe and detecting the differential pressure from the difference in response speed to a change in water pressure to obtain a water pressure level is also conceivable.

[0025]

A first effect of the present invention is that the size (hull length) of a ship can be detected. The reason is that the target speed V is detected by the acoustic sensor, the hydraulic pressure change time Δt is detected by the hydraulic pressure sensor, and the hull length L = L × Δt can be calculated.

The second effect is that a tow-type simulated sound source can be eliminated. The reason is that it is possible to detect the arrival direction of the sound when the water pressure change due to the passage of the ship occurs, and determine whether the sound source is a simulated sound source.

[Brief description of the drawings]

FIG. 1 is a block diagram of a ship detection device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a water pressure detection process in the embodiment of FIG.

FIG. 3 is a diagram showing position detection by the acoustic sensor according to the embodiment of FIG. 1;

FIG. 4 is a view showing the principle of azimuth detection by the acoustic sensor of FIG. 1;

FIG. 5 is a view for explaining the operation of the target speed calculation circuit of FIG. 1;

FIG. 6 is a diagram showing a state example of ship detection according to the present invention.

FIG. 7 is a diagram showing outputs of main components of FIG. 1 in detecting a ship in the state of FIG. 6;

FIG. 8 is a diagram showing an example of a state of ship detection when a simulated sound source according to the present invention is present.

FIG. 9 is a diagram showing outputs of main components of FIG. 1 in detecting a ship in the state of FIG. 8;

FIG. 10 is a diagram showing another configuration example of the acoustic sensor of FIG. 1;

FIG. 11 is a diagram showing another configuration example of the water pressure sensor of FIG. 1;

FIG. 12 is a diagram showing a conventional ship detection device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Water pressure 2 Ship radiation noise (propeller cavitation noise) 3 Water pressure sensor 4 Acoustic sensor 5 Water pressure detection circuit 6 Azimuth detection circuit 7 Change width calculation circuit 8 Target speed calculation circuit 9 Hull length calculation circuit 10 Target detection circuit 11 Towing simulated sound source 21 Simulated radiation noise 301 Depth data 302 Water pressure level 401 Received signal 501 Water pressure detection signal 601 Zenith angle 701 Water pressure change time 801 Moving speed 901 Hull length

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01S 3/80-3/86 G01S 5/18-5/30 G01S 7/52-7/64 G01S 15 / 00-15/96

Claims (7)

(57) [Claims] 1. A water pressure detecting means for detecting a change in water pressure accompanying passage of a ship, a speed detecting means for detecting a speed of a target ship, and a ship length for calculating a hull length of the target ship from a change time and speed of the water pressure. A ship detection device having calculation means. 2. The ship detecting apparatus according to claim 1, further comprising a target detecting circuit for calculating that a sound source position of the target ship is within a predetermined angle from immediately above when a water pressure changes after passing through the ship. 3. A water pressure sensor, a change width calculation circuit that receives an output of the water pressure sensor and detects a time interval of a water pressure change corresponding to a bow and a stern accompanying passage of a ship, and an acoustic sensor that detects ship radiation noise. An azimuth detection circuit for detecting the azimuth by receiving the output of the acoustic sensor; a speed calculation circuit for calculating the speed of the detection target based on the output of the azimuth detection circuit and the depth data from the water pressure sensor; an output of the change width calculation circuit and the speed calculation circuit And a hull length calculation circuit for calculating a hull length from the output of the hull. 4. A water pressure sensor, a water pressure detection circuit that receives an output of the water pressure sensor and detects a change in water pressure accompanying passage of a tip and an end of a detection target, an acoustic sensor that detects radiation noise from the detection target, and an acoustic sensor And a target detection circuit that receives the output of the sensor and detects the azimuth of the detection target, and receives the output of the water pressure detection circuit and the output of the azimuth detection circuit and determines whether the detection target is a ship. 5. The ship detecting apparatus according to claim 4, wherein the target detecting circuit makes a determination based on an azimuth direction of an output of the azimuth detecting circuit at the time of a change in water pressure when the detection target passes. 6. The ship detection device according to claim 5, wherein the target detection circuit determines that the detection target is a ship when the azimuth direction at the time of a change in water pressure at the time of passing the end of the detection target is equal to or smaller than a predetermined angle. 7. A target detecting circuit according to claim 3, further comprising a target detecting circuit which receives the output of the water pressure sensor and determines whether or not the ship is a ship from the direction detected by the direction detecting power circuit when the water pressure changes due to the passage of the stern of the ship. Ship detection device.