JP2007286886A - Vessel traffic monitoring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately monitor traffic in a port with increased acoustic environmental noise due to a plurality of congested vessels. <P>SOLUTION: Magnetic sensors (2-1 to 2-n) and field sensors (3-1 to 3-n) are disposed on a sea bottom 1, and detection signals of the magnetic sensors and the field sensors are captured to a CPU 6 of a control tower 5. Each of the detection signals of the magnetic sensors and the field sensors is divided to a DC component and an AC component, the magnetic DC component and AC component and the field DC component and AC component are analyzed, and compared with a signal pattern for each type of vessels stored in the CPU 6, whereby monitoring a passing vessel and the type of the vessel. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a marine traffic monitoring system used for harbor entry monitoring and the like in the field of crisis management and security, particularly in the security of cooling water intake in nuclear power plants, thermal power plants and large plant facilities.

  As a conventional ship traffic monitoring system, an acousto-magnetic sensor group consisting of multiple acousto-magnetic composite sensors installed on the sea floor is provided, and the magnetic signal and acoustic signal from this acousto-magnetic composite sensor group are simultaneously transmitted to the signal processing unit of the control tower. However, an apparatus is disclosed in which the passage of a ship is detected with a magnetic signal and the type of the ship is identified with an acoustic signal (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 8-220221

  In a conventional method of monitoring the passage of a ship by combining a sound signal and a magnetic signal, in a port or the like, when the environmental noise is large with respect to the sound signal of the ship and a plurality of ships are congested, the sound signal is a propagation distance. However, it was difficult to analyze the acoustic signal because the signals from other ships were mixed. In addition, it is difficult to detect a wooden ship because the magnetic signal is small, and the combined acoustic and magnetic ship traffic monitoring system does not provide a sufficient effect to monitor all ships that pass through it. There was a problem.

  The present invention has been made paying attention to the above-mentioned problems, and it is an object of the present invention to provide a ship traffic monitoring system capable of accurately monitoring traffic even in harbors where a plurality of ships are congested and acoustic environmental noise is large. And

  In the ship traffic monitoring system of the present invention, one or a plurality of magnetic sensors and one or a plurality of electric field sensors are installed in the sea, and the magnetic detection signal of the magnetic sensor and the electric field detection signal of the electric field sensor It is characterized by monitoring the passage of ships.

  In the ship traffic monitoring system according to the present invention, the magnetic detection signal of the magnetic sensor and the electric field detection signal of the electric field sensor are separated into a direct current component and an alternating current component, and the signal of the direct current component and the alternating current component of the magnetic field and the electric field is used. It is good to perform presence / absence determination.

  In the ship traffic monitoring system according to the present invention, the ship classification determination may be performed together with the ship traffic presence / absence determination.

  According to the present invention, the magnetic sensor and the electric field sensor are installed in the sea, and the passage of the ship is monitored by the magnetic detection signal of the magnetic sensor and the electric field detection signal of the electric field sensor. Since a magnetic signal or electric field (potential difference) signal has a short propagation distance relative to an acoustic signal, the signal from other ships is rarely mixed, the environmental noise for the magnetic signal and electric field signal is small, and a wooden ship with a corrosion protection device attached. Since the detection of signals using electric field signals is possible, the magnetic signals and electric fields generated by ships are often used in ship traffic monitoring in harbors and the like where multiple ships, which have been difficult to monitor in the past, are congested and have large acoustic environmental noise. By detecting the (potential difference) signal, traffic monitoring can be performed with high accuracy.

  Hereinafter, the present invention will be described in more detail with reference to embodiments. FIG. 1 is a schematic diagram showing a ship traffic monitoring system according to an embodiment of the present invention. In FIG. 1, a plurality of magnetic sensors 2-1, 2-2..., 2-n and a plurality of electric field (UEP: Underwater Electric Potential) sensors 3-1, 3-2 ... 3-n is arranged. These magnetic sensors 2-1, 2-2... 2 -n and the electric field sensors 3-1, 3-2. Thus, the data is taken into the CPU 6 provided in the onshore management tower 5. In the system shown in FIG. 1, magnetic sensors 2-1, 2-2,..., 2-n and electric field sensors 3-1, 3-2,. As an example system of the embodiment, as shown in FIG. 2, the magnetic sensors 2-1, 2-2,..., 2-n and the electric field sensors 3-1, 3-2,. The cables 4-1 and 4-2 may be separately arranged. The CPU 6 of the management tower 5 receives the detection signals of the magnetic sensors 2-1, 2-2, ..., 2-n and the electric field sensors 3-1, 3-2, ..., 3-n for each sensor. A detection data storage unit is provided. In addition, the detection data storage unit is configured so that the detection signals of the magnetic sensors 2-1, 2-2,..., 2-n and the electric field sensors 3-1, 3-2,. Since it is separated into alternating current components, an area for separating and storing the direct current components and alternating current components of each sensor is provided.

  The processing procedure of the ship traffic monitoring system of the above embodiment will be described with reference to flowcharts shown in FIGS. 5 and 6 and detection signal examples shown in FIGS. In the system shown in FIG. 1, detection signal processing is performed for each of the magnetic sensors 2-1, 2-2,..., 2-n and the electric field sensors 3-1, 3-2,. However, in FIG. 5, FIG. 6, and FIG. 3, one magnetic sensor and electric field sensor are described for convenience.

  When the processing operation is started, the detection signal flag FLG is turned OFF in step ST1. As the detection signal flag FLG, a magnetic signal DC component detection flag, a magnetic signal AC component detection flag, an electric field (potential difference) signal DC component detection flag, and an electric field (potential difference) signal AC component detection flag are provided in the storage unit of the CPU 6. These are all turned off (logic “0”) at the start of the processing operation. Next, the process proceeds to step ST2.

  In step ST2, the magnetic detection signals obtained by the magnetic sensors 2-1, 2-2,..., 2-n are taken in every predetermined sampling time. Subsequently, the process proceeds to step ST3. In step ST3, the captured magnetic detection signal is separated into a DC component (DC to 0.5 Hz) and an AC component (0.5 Hz to several Hz) using a digital filter. As an example, the result of separating the magnetic detection signal and the direct current component and the alternating current component when the ship has passed near the magnetic sensors 2-1, 2-2,..., 2-n is shown in FIGS. ) And (c). These captured magnetic detection signals and the separated DC and AC components are all stored in the detection data storage unit of the CPU 6. Next, the process proceeds to step ST4.

  In step ST4, it is determined whether or not the DC component of the separated and extracted magnetic signal is equal to or higher than the detection level (see (a) of FIG. 4). If the DC component of the magnetic signal is greater than or equal to the detection level, the process proceeds to step ST5. On the other hand, if it is not higher than the detection level, step ST5 is skipped and the process proceeds to step ST6. In step ST5, the magnetic signal DC component detection flag of the detection flag FLG is turned ON (logic “1”). Then, the process proceeds to step ST6.

  In step ST6, the AC component of the separated and extracted magnetic signal is subjected to frequency (FFT) conversion, and then the process proceeds to step ST7. In step ST7, it is determined whether or not the AC component of the separated and extracted magnetic signal is equal to or higher than the detection level (see FIG. 4B). As shown in FIG. 4B, when the AC component of the magnetic signal is frequency-converted, the time axis becomes a level corresponding to the frequency, and when concentrated on a specific frequency, the level exceeds the threshold value. If the AC component of the magnetic signal is greater than or equal to the detection level, the process proceeds to step ST8. On the other hand, if it is not higher than the detection level, step ST8 is skipped and the process proceeds to step ST9. In step ST8, the magnetic signal AC component detection flag in the detection flag FLG is turned ON. Then, the process proceeds to step ST9. In step ST9, the electric field (potential difference) detection signal obtained by the electric field sensors 3-1, 3-2,..., 3-n is taken into the system at every predetermined sampling time. Subsequently, the process proceeds to step ST10. In step ST10, the captured electric field (potential difference) detection signal is separated into a DC component (DC to 0.5 Hz) and an AC component (0.5 Hz to several Hz) using a digital filter. As an example, the electric field (potential difference) detection signal and the result of separation into a DC component and an AC component are shown in FIG. d) As shown in (e) and (f). Next, the process proceeds to step ST11.

  In step ST11, it is determined whether or not the DC component of the separated and extracted electric field (potential difference) signal is equal to or higher than the detection level (see FIG. 4A). If the DC component of the electric field signal is equal to or higher than the detection level, the process proceeds to step ST12. On the other hand, if not higher than the detection level, step ST12 is skipped and the process proceeds to step ST13. In step ST12, the electric field (potential difference) signal DC component detection flag of the detection flag FLG is turned ON. Then, the process proceeds to step ST13.

  In step ST13, the AC component of the separated electric field (potential difference) signal is subjected to frequency (FFT) conversion, and then the process proceeds to step ST14. The frequency conversion in this case is the same as the frequency conversion of the AC component of the magnetic signal described in step ST6. In step ST14, it is determined whether or not the AC component of the separated and extracted electric field (potential difference) signal is equal to or higher than the detection level (see FIG. 4B). If the AC component of the electric field signal is equal to or higher than the detection level, the process proceeds to step ST15. On the other hand, if not higher than the detection level, step ST15 is skipped and the process proceeds to step ST16. In step ST15, the electric field (potential difference) signal AC component detection flag in the detection flag FLG is turned ON. Then, the process proceeds to step ST16.

  In step ST16, signal analysis is performed. With reference to the detection signal flag FLG, a signal that exceeds the detection level is determined to be present, signal analysis is performed, and a signal that does not exceed the detection level is determined to be no signal. For a signal determined to have a signal, a waveform analysis is performed for the DC component, and a fundamental frequency and a harmonic are analyzed for the AC component. Next, the process proceeds to step ST17.

  In step ST17, the presence / absence of vessel traffic is determined using the result of the signal analysis performed in step ST16. Here, the presence / absence of vessel traffic is determined by the combination of ON / OFF of the four detection signal flags. If it is determined that there is a ship traffic, the process proceeds to step ST18. On the other hand, if it is determined that there is no traffic, the process returns to step ST1.

  In step ST18, the ratio analysis of the direct current component and the alternating current component in the magnetic and electric field signals and the ratio analysis of the magnetic and electric field (potential difference) signals are performed, and the vessel analysis is performed using each ratio analysis result and the signal analysis result performed in step ST16. Classification of. Here, the ON / OFF pattern of each detection signal flag for each classification of the ship, the ratio analysis value of the DC component and the AC component of the magnetic signal, the ratio analysis of the DC component and the AC component of the electric field signal are stored in the storage unit of the CPU 6 in advance. Value, magnetic signal and electric field signal ratio analysis value data is stored, and the signal data detected during monitoring is compared with the stored content, and ships that match or close to match are classified.

  In the system of the above embodiment, even when only the magnetic signal or electric field (potential difference) signal of the ship is detected, only the DC component or AC component of the magnetic signal or electric field (potential difference) signal is detected. Even in this case, ship traffic monitoring can be performed.

  In the illustration of FIG. 3, the number of magnetic sensors and electric field sensors is not taken into consideration. However, when a plurality of magnetic sensors and a plurality of electric field sensors are provided as shown in FIGS. The same processing may be performed for each sensor and electric field sensor. In the above embodiment, the ship is classified according to the signal mode of the DC component and the AC component of the ship. However, when the ship goes through the port, the ship actively generates a signal having a determined frequency. A ship key may be used.

It is the schematic which shows the ship traffic monitoring system of one Embodiment of this invention. It is the schematic which shows the ship traffic monitoring system of other embodiment of this invention. It is a wave form diagram explaining the detection signal of the magnetic sensor and electric field sensor of the ship traffic monitoring system of the said embodiment. It is a figure explaining the case where the presence or absence of the direct-current component and alternating current component in the detection signal of the magnetic sensor and an electric field sensor is discriminated. It is a flowchart explaining the ship passage processing procedure of the said embodiment ship passage monitoring system. FIG. 6 is a flowchart for explaining a ship passage processing procedure of the ship passage monitoring system according to the embodiment together with FIG. 5.

Explanation of symbols

1 Seabed 2-1, 2-2, ... 2-n Magnetic sensor 3-1, 3-2, ... 3-n Electric field sensor 4, 4-1, 4-2 Cable 5 Management tower 6 CPU
7 Ship

Claims (3)

  One or a plurality of magnetic sensors and one or a plurality of electric field sensors are installed in the sea, and the passage of the ship is monitored by the magnetic detection signal of the magnetic sensor and the electric field detection signal of the electric field sensor. Ship traffic monitoring system.   The ship according to claim 1, wherein the vessel detects whether or not the vessel is voyage by separating the magnetic detection signal of the magnetic sensor and the direct current component and the alternating current component of the electric field detection signal of the electric field sensor, and determining the DC and AC components of the magnetic and electric fields. Traffic monitoring system. 3. The ship traffic monitoring system according to claim 2, wherein the ship classification determination is performed together with the ship traffic presence / absence determination.

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