JP5554029B2 - Intrusion detection device - Google Patents

Description

  The present invention relates to an intrusion detection apparatus that detects an intruder such as an intruder or an intruder in a monitoring area, and more particularly to an intrusion detection apparatus that detects an intruding object in a monitoring area using a leaky coaxial cable.

  The conventional intrusion detection device is installed in parallel around the site where two leaky coaxial cables are to be monitored, the transmitter outputs a transmission signal to one leaky coaxial cable, and the leaky coaxial cable transmits the transmission signal to the radio wave. Radiates to space. When an intruding object exists around the leaky coaxial cable, the radio wave is reflected by the intruding object. The other leaky coaxial cable receives the direct wave radiated from one leaky coaxial cable and the reflected wave reflected by the object and outputs the received wave as a received signal to the receiver. The receiver analyzes the amplitude and phase of the received signal, determines the amount of time change of the amplitude and phase with a predetermined threshold, and detects an intruding object (see, for example, Patent Document 1).

Japanese Patent No. 3770389

  However, the prior art has the following problems. The conventional intrusion detection device measures the total distance of the distance of the intruding object in the leaky coaxial cable direction and the distance of the leaky coaxial cable in the vertical direction. Therefore, when the reflected wave with a large reflection level is received by a large object far away and when the reflected wave with a small reflection level is received by a small object nearby, the amount of time change in the amplitude and phase of the received signal is almost the same. It becomes. In order to determine these with the same threshold value, there is a problem that a distant object that is not a detection target is erroneously detected.

  Moreover, since the size of the detected object cannot be identified, there has been a problem that environmental changes such as raindrops that are not detection targets and small animals are erroneously detected.

  The present invention has been made to solve the above-described problems, and detects an intruding object near the leaky coaxial cable and identifies the size of the intruding object when the intruding object contacts the leaky coaxial cable. An object of the present invention is to obtain an intrusion detection device that can accurately detect an object to be detected.

An intrusion detection device according to the present invention is installed in a transmission leaky coaxial cable that radiates a transmission signal as a radio wave, and substantially parallel to the transmission leaky coaxial cable, and the radio wave and surface wave mode radiated in a surface wave mode are disrupted. A transmission leaking coaxial cable that receives at least one of the radiated radio waves and outputs it as a reception signal, and generates the transmission signal from an oscillation signal in a frequency band in which the radio wave operates in the surface wave mode. Obtained from the determination signal, a transmission means for outputting to one end of the leaky coaxial cable, a determination signal generation means for generating a determination signal representing a propagation characteristic for each propagation time of the radio wave using the received signal and the oscillation signal. The object is transmitted when the received signal strength for each propagation time of the radio wave exceeds a second threshold and the time variation of the received signal strength exceeds a third threshold. An identification signal output means for detecting contact with at least one of the leaky coaxial cable and the reception leaky coaxial cable, and outputting the received signal intensity and the amount of time change as an identification signal; and a size of the object prepared in advance And the object identification database in which the relationship between the identification signal and the identification signal is compared with the object identification database to identify the size of the object, and the identified size exceeds a preset size. In this case, it is provided with an object identification means for detecting that the object has entered .

  According to the intrusion detection device of the present invention, the leaky coaxial cable is operated in the surface wave mode to emit radio waves, and the intruding object is detected from the amplitude and phase of the received signal that fluctuates due to the collapse of the surface wave mode and the amount of change over time. Since the contact with the leaky coaxial cable is detected, the object can be accurately detected without erroneously detecting a distant object. In addition, since the size of the contacted object is identified from the amplitude and phase of the received signal and the amount of change over time, the object can be accurately detected without erroneously detecting an object that is not a detection target such as raindrops or small animals.

It is a block diagram which shows the structure of the intrusion detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the waveform of the analysis signal of the intrusion detection apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the approach detection and contact detection by the determination device 302 of the intrusion detection apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the contact detection in the determination device 303 of the intrusion detection apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the relationship between the object position of the vertical direction distance of the leaky coaxial cable in a different size object, and received signal strength. It is a block diagram which shows the structure of the intrusion detection apparatus which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structure of the intrusion detection apparatus which concerns on Embodiment 3 of this invention. It is a block diagram which shows the structure of the intrusion detection apparatus which concerns on Embodiment 4 of this invention. It is a block diagram which shows the detailed structure of the delay circuit group and correlator group of the intrusion detection apparatus which concerns on Embodiment 4 of this invention. It is a block diagram which shows the structure of the intrusion detection apparatus which concerns on Embodiment 5 of this invention. It is a block diagram which shows the detailed structure of the oscillator group and detector group of the intrusion detection apparatus which concerns on Embodiment 5 of this invention.

  Hereinafter, preferred embodiments of the intrusion detection device of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
An intrusion detection apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a configuration of an intrusion detection apparatus according to Embodiment 1 of the present invention. In the following, in each figure, the same reference numerals indicate the same or corresponding parts.

  1, an intrusion detection device according to Embodiment 1 of the present invention includes a radio 1, a transmission leakage coaxial cable 2, a reception leakage coaxial cable 3 laid substantially parallel to the transmission leakage coaxial cable 2, and a termination. A device 4 and a terminator 5 are provided.

  The wireless device 1 is provided with a transmission unit 100 connected to one end of the transmission leaky coaxial cable 2, a reception unit 200 connected to one end of the reception leaky coaxial cable 3, a contact detection unit 300, and an identification unit 400. ing.

  The transmission means 100 is provided with a frequency setting device 101, an oscillator 102, and an amplifier 103.

  The receiving means 200 is provided with an amplifier 201, a band pass filter (BPF) 202, a detector 203, and a memory 204.

  The contact detection unit 300 includes an FFT calculator 301, a determiner 302, a determiner 303, a threshold value setter 304, a threshold value setter 305, and an alarm device 306.

  The identification means 400 is provided with an object identifier 401, an object identification database (DB) 402, and an alarm device 403.

  The terminator 4 is connected to the other end of the transmission leakage coaxial cable 2 that is not connected to the transmission means 100. The terminator 5 is connected to the other end of the reception leaky coaxial cable 3 that is not connected to the receiving means 200.

  Next, the operation of the intrusion detection device according to the first embodiment will be described with reference to the drawings.

  In FIG. 1, a transmission means 100 outputs an oscillation signal whose frequency is changed in a time-division manner within a frequency band in which a radio wave radiated from a transmission leaky coaxial cable 2 operates in a surface wave mode to the transmission leaky coaxial cable 2 as a transmission signal. To do.

  The transmission leaking coaxial cable 2 radiates a transmission signal as a radio wave to space. The transmission leaky coaxial cable 2 operates in the surface wave mode when the radiation from the periodically slotted slots is uniform. In the surface wave mode, the radio wave propagates in the direction (longitudinal direction) along the transmission leaky coaxial cable 2 because the electric field energy abruptly attenuates with an exponential function as the vertical propagation distance of the transmission leaky coaxial cable 2 increases. When an object approaches or comes into contact with the transmission leaky coaxial cable 2, the radiation from the slots periodically vacated in the transmission leaky coaxial cable 2 is not uniform and the surface wave mode is lost. Even if the propagation distance in the direction increases, the attenuation of the electric field energy decreases.

  The reception leaky coaxial cable 3 receives a radio wave radiated in the surface wave mode and / or a radio wave radiated from the surface wave mode and outputs the received signal to the receiving means 200 as a received signal. When the surface wave mode is disrupted, the electric field energy attenuation is reduced. Therefore, comparing the received signal level when the surface wave mode is disrupted with the received signal level operated in the surface wave mode, the received signal when the surface wave mode is disrupted. The level gets bigger.

  The receiving unit 200 stores the amplitude and phase of the received signal obtained by detecting the received signal with reference to the oscillation signal of the transmitting unit 100 as an analysis signal. At the same time, the frequency of the oscillation signal when used for detection is also stored as an analysis signal.

  The contact detection unit 300 obtains a propagation characteristic in a frequency region in which a signal transmitted from the transmission unit 100 reaches the reception unit 200 through the transmission leakage coaxial cable 2 and the space and the reception leakage coaxial cable 3. The IFFT calculation (inverse FFT calculation) is performed on the stored analysis signal to calculate the propagation characteristics in the time domain. The calculated amplitude and phase of the propagation characteristics, their time change amount, and the like are compared with a predetermined threshold value, and the approach of the object to the transmission leakage coaxial cable 2 and the contact with the transmission leakage coaxial cable 2 are determined. When the contact of the object with the transmission leaking coaxial cable 2 is detected, the first alarm is sounded.

  When detecting the contact of the intruding object to the transmission leaky coaxial cable 2, the identification unit 400 performs object identification by comparing the amplitude, phase, and time variation thereof with a previously created object identification database 402. When it is determined that an object larger than a predetermined threshold is detected as a result of object identification, the object identification result is displayed and a second alarm is sounded.

  The frequency setting unit 101 in the transmission means 100 presets and sets values of a start frequency, an end frequency, a frequency step, and a frequency switching time within a frequency band in which radio waves operate in the surface wave mode on the transmission leakage coaxial cable 2. The setting signal for instructing the frequency is output to the oscillator 102 and the memory 204 in the receiving means 200. Further, the frequency setting unit 101 outputs a trigger signal such as a timing indicating the start frequency or the end frequency to the FFT calculator 301 in the contact detection unit 300.

  The oscillator 102 outputs a signal having a frequency according to the instruction of the setting signal to the amplifier 103 and the detector 203 in the receiving unit 200 as an oscillation signal. The amplifier 103 amplifies the oscillation signal to a predetermined level and outputs it to the transmission leakage coaxial cable 2 as a transmission signal.

  The transmission leaking coaxial cable 2 radiates a transmission signal as a radio wave to space. The emitted radio wave operates in the surface wave mode. The surface wave mode is determined by the frequency of the signal transmitted to the transmission leaky coaxial cable 2 and the periodic interval of slots periodically (equally spaced) in the longitudinal direction of the surface of the transmission leaky coaxial cable 2. In the case of the transmission leaky coaxial cable 2 having slots opened at the periodic interval P, the maximum frequency fmax operating in the surface wave mode is expressed by the following equation (1).

  fmax = c / (P (√ (εr) +1)) (1)

  Here, c is the velocity of the radio wave, and εr is the relative permittivity of the dielectric in the transmission leakage coaxial cable 2. If the frequency is lower than the maximum frequency fmax, it operates in the surface wave mode. For example, in the case of the transmission leaky coaxial cable 2 with the periodic interval P = 1 m and the relative dielectric constant εr = 1.23, the maximum frequency fmax is about 142 MHz.

  Similarly, in the reception leaky coaxial cable 3, the maximum frequency operating in the surface wave mode can be obtained from the slot interval P and the relative dielectric constant εr in the reception leaky coaxial cable 3. When the transmission leaky coaxial cable 2 and the reception leaky coaxial cable 3 use cables having the same periodic interval and relative dielectric constant, the maximum frequency operating in the surface wave mode is the same. When operating in the surface wave mode, the radio waves uniformly radiated from the slots of the transmission leaky coaxial cable 2 undergo phase interference in the cable vertical direction and propagate in the cable longitudinal direction. Therefore, the electric field energy exponentially decays exponentially as the vertical distance increases.

  When an object approaches or comes into contact with the transmission leaky coaxial cable 2 or the reception leaky coaxial cable 3, the surface wave mode collapses at the approaching point or the contacting point, and the attenuation of the electric field energy is small even if the propagation distance in the vertical direction of the radio wave increases. Become. In addition, the closer the object is to the transmission leaky coaxial cable 2 or the reception leaky coaxial cable 3, the more the surface wave mode collapses at a position where the electric field energy is higher, so the electric field energy is increased even if the propagation distance in the vertical direction of the radio wave increases. The attenuation of becomes smaller.

  The reception leaky coaxial cable 3 receives the radio wave radiated to the space and outputs it to the reception means 200 as a reception signal. The amplifier 201 in the receiving means 200 amplifies the received signal to a predetermined level and outputs it to a bandpass filter (BPF) 202. The pass frequency band of the band pass filter 202 is a start frequency and an end frequency set by the frequency setting unit 101 in the transmission unit 100. The band pass filter 202 outputs the received signal from which the signal in the unnecessary frequency band is removed to the detector 203. The detector 203 performs quadrature detection (IQ detection) on the received signal using the oscillation signal from the oscillator 102 as a reference signal, and outputs the IQ signal to the memory 204. The memory 204 stores an IQ signal at each frequency as an analysis signal.

  Quadrature detection is to obtain a low-frequency baseband signal by multiplying the reference signal by the 0 degree component and the 90 degree component. The IQ signal here is an I signal obtained by the 0 degree component and a 90 degree component. The obtained Q signals are collectively called. The square sum of the I signal and the Q signal corresponds to the intensity of the received signal, the square root of the square sum of the I signal and the Q signal corresponds to the amplitude of the received signal, and the arctangent of the I signal and the Q signal corresponds to the phase.

  FIG. 2 is a diagram for explaining an IQ signal (analysis signal) stored in the memory 204. The propagation characteristic in the frequency domain is obtained from the setting signal and IQ signal stored in the memory 204. As shown in FIG. 2, when the horizontal axis is the frequency and the vertical axis is the received signal intensity, the power spectrum waveform 500 has a high received intensity in the frequency band of the surface wave mode.

  When receiving the trigger signal from the frequency setting unit 101 in the transmission unit 100, the FFT calculation unit 301 in the contact detection unit 300 executes an IFFT (inverse FFT) calculation using the analysis signal read from the memory 204 and performs analysis. The signal is converted from a frequency domain signal to a time domain signal, and the calculation result is output to the determiner 302 and the determiner 303 as a determination signal. The analysis signal stored in the memory 204 stores the characteristics of the received signal in the frequency domain and has a relationship between the frequency and the received signal, whereas the determination signal has the characteristics of the received signal in the time domain and the relationship between time and the received signal. Become. That is, propagation characteristics such as reception intensity for each propagation time of a radio wave required to output a transmission signal and radiate it as a radio wave, receive the radiated radio wave and input it as a reception signal are derived. The length obtained by multiplying the propagation time by the speed of light is based on one end of the transmission leaky coaxial cable 2 to which the transmission signal is input as a reference, the propagation distance in the transmission leaky coaxial cable 2, the propagation distance in space, and the reception leaky coaxial. This corresponds to the sum of propagation distances in the cable 3.

  The determination unit 302 in the contact detection unit 300 compares the determination signal with the first threshold value set in advance by the threshold value setting unit 304, and when the amplitude or phase of the reception signal exceeds the first threshold value, the intruding object is cabled. Detects approaching to. Further, the intruding object touches the cable when the amplitude and phase of the received signal exceed the second threshold by comparing the determination signal with the second threshold (> first threshold) preset by the threshold setter 304. Detecting that

  FIG. 3 is a diagram for explaining approach detection and contact detection by the determiner 302 of the intrusion detection device according to Embodiment 1 of the present invention.

  The arrows around the transmission leaky coaxial cable 2 in FIG. 3 indicate the state of radio wave propagation when operating in the surface wave mode. When the intruding object 600 approaches the transmission leaking coaxial cable 2, the surface wave mode is lost due to reflection, absorption, and transmission of radio waves by the intruding object 600 at the approaching location. When the surface wave mode is broken, the electric wave energy is less attenuated with respect to the increase in the vertical distance of the transmission leaky coaxial cable 2. The received signal intensity of the radio wave whose surface wave mode is broken in the reception leaky coaxial cable 3 is increased, and a peak waveform 601 is obtained. It is assumed that the intruding object 600 approaches the transmission leaking coaxial cable 2 when the received signal strength of the peak waveform 601 is compared with the first threshold and the first threshold is exceeded.

  Next, when the intruding object 602 comes into contact with the transmission leaking coaxial cable 2, the surface wave mode is destroyed due to reflection, absorption, and transmission of the radio wave at the location where the radio wave with the highest electric field energy is propagated. Since the surface wave mode collapses at the place where the electric field energy is highest, the fluctuation of the received signal strength of the radio wave whose surface wave mode of the reception leaky coaxial cable 3 is broken becomes larger than the received signal strength at the time of approach. When the received signal strength of the peak waveform 603 is compared with the second threshold and exceeds the second threshold, it is assumed that the intruding object 602 contacts the transmission leaking coaxial cable 2.

  When the determination unit 302 detects contact of an intruding object, it outputs a contact detection signal to the determination unit 303, and uses the maximum value of the received signal intensity when the contact of the intruding object is detected as an identification signal. Output to 401.

  The determination unit 303 calculates the time change amount of the received signal strength at each cable position with a predetermined time resolution, and when the touch detection signal is input, the time change amount of the past several points and the threshold value setter 305 set in advance. Compared with the threshold value 3, a contact is detected when the third threshold value is exceeded.

  FIG. 4 is a diagram for explaining contact detection in the determiner 303 of the intrusion detection device according to Embodiment 1 of the present invention.

  FIG. 4 shows the relationship between the time before and after the contact of the intruding object with the leaky coaxial cable and the amount of fluctuation in the received signal intensity. When contact is made with the leaky coaxial cable, the collapse of the surface wave mode is greatest, and the received signal intensity is also greatly varied to obtain the waveform 700. When the contact detection signal is input from the determiner 302 and the contact of the intruding object is detected, the determiner 303 outputs an alarm signal to the alarm device 306. Further, the determiner 303 outputs the received signal intensity fluctuation amount at the time of the intruding object contact to the object discriminator 401 in the discriminating means 400 as an identification signal. When the alarm signal is input, the alarm device 306 sounds an alarm indicating that an intruding object has been detected in the monitoring area.

  The object discriminator 401 in the discriminating unit 400 compares and collates the identification signal with data in the object identification database (DB) 402 in which the relationship between the object size and the identification signal created in advance by measurement or the like is recorded. Identify object size.

  FIG. 5 is a diagram for explaining the relationship between the object position at the vertical distance of the leaky coaxial cable (LCX) and the received signal strength in objects of different sizes. For objects of different sizes, the maximum value of the received signal strength when contacting the cable differs from the amount of fluctuation of the received signal strength. Specifically, the received signal strength and the time change width when a person touches the cable are larger than those of a small animal (human reception level fluctuation width 800, small animal reception level fluctuation width 801). In this way, the object size can be identified by the received signal intensity and its time variation width. The object discriminator 401 outputs an alarm signal to the alarm unit 403 when the identified object size exceeds a preset size. When the alarm signal is input, the alarm device 403 sounds an alarm indicating that an intruding object to be detected is detected in the monitoring area.

  In the above description, the determination unit 302 in the contact detection unit 300 determines the approach and contact of an object by determining the received signal intensity with a threshold value. As another specific method, the I signal is represented on the horizontal axis and the Q signal is represented on the vertical axis. An object detection area may be provided on the two-dimensional plane plotted on the axis to determine the inside / outside of the area. Similarly, the object discriminators 401 and DB 402 in the discriminating unit 400 also identify the object size by providing an identification area for each object size on a two-dimensional plane in which the I signal is plotted on the horizontal axis and the Q signal is plotted on the vertical axis. May be.

  As described above, the intrusion detection apparatus according to the first embodiment radiates radio waves by operating the leaky coaxial cable in the surface wave mode, and the amplitude and phase of the received signal that fluctuate due to the collapse of the surface wave mode and the time. Since it is detected from the amount of change that the intruding object has contacted the leaky coaxial cable, it is possible to accurately detect the object without erroneously detecting a distant object.

  In addition, since the size of the contacted object is identified from the amplitude and phase of the received signal and the amount of change over time, the object can be accurately detected without erroneously detecting an object that is not a detection target such as raindrops or small animals.

Embodiment 2. FIG.
An intrusion detection device according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 6 is a block diagram showing a configuration of an intrusion detection apparatus according to Embodiment 2 of the present invention.

  6, an intrusion detection device according to Embodiment 2 of the present invention includes a radio 1, a transmission leaky coaxial cable 2, a reception leaky coaxial cable 3 laid substantially parallel to the transmission leaky coaxial cable 2, and a termination. A device 4 and a terminator 5 are provided.

  The wireless device 1 is provided with a transmission unit 100 connected to one end of the transmission leaky coaxial cable 2, a reception unit 200 connected to one end of the reception leaky coaxial cable 3, a contact detection unit 300, and an identification unit 400. ing.

  The transmission means 100 is provided with a frequency sweeper 104, an oscillator 102, and an amplifier 103.

  The receiving means 200 is provided with an amplifier 201, a band pass filter (BPF) 202, a multiplier 205, and a memory 204.

  The contact detection unit 300 includes an FFT calculator 301, a determiner 302, a determiner 303, a threshold value setter 304, a threshold value setter 305, and an alarm device 306.

  The identification means 400 is provided with an object identifier 401, an object identification database (DB) 402, and an alarm device 403.

  The terminator 4 is connected to the other end of the transmission leakage coaxial cable 2 that is not connected to the transmission means 100. The terminator 5 is connected to the other end of the reception leaky coaxial cable 3 that is not connected to the receiving means 200.

  Next, the operation of the intrusion detection device according to the second embodiment will be described with reference to the drawings.

  In FIG. 6, the transmission means 100 transmits to the transmission leakage coaxial cable 2 an oscillation signal obtained by frequency sweeping (chirping the frequency) within the frequency band in which the radio wave radiated from the transmission leakage coaxial cable 2 operates in the surface wave mode. Output.

  The transmission leaking coaxial cable 2 radiates a transmission signal as a radio wave to space. The transmission leaky coaxial cable 2 operates in the surface wave mode when the radiation from the periodically slotted slots is uniform.

  The reception leaky coaxial cable 3 receives a radio wave radiated in the surface wave mode and / or a radio wave radiated from the surface wave mode and outputs the received signal to the receiving means 200 as a received signal.

  The reception unit 200 stores a signal obtained by multiplying the oscillation signal of the transmission unit 100 and the reception signal as an analysis signal.

  The contact detection unit 300 calculates the amplitude and phase for each frequency by performing an FFT operation on the analysis signal stored in the memory 204. Propagation characteristics in the frequency domain where the signal transmitted from the transmission means 100 reaches the reception means 200 through the transmission leaky coaxial cable 2 and the space and the reception leaky coaxial cable 3 are obtained. At this time, the frequency of the FFT calculation result is converted into a distance from the bandwidth of the chirped signal and the chirping period. The obtained distance coincides with the distance that the signal has propagated through the transmission means 100, the transmission leakage coaxial cable 2, the space, the reception leakage coaxial cable 3, and the reception means 200. Compare the calculated amplitude and phase of the propagation characteristics and a predetermined threshold value to determine the approach of the object to the cable, and calculate the amplitude and phase of the propagation characteristics and their time variation and a predetermined predetermined value. The threshold is compared to determine the contact of the object with the cable. When the contact of the object with the cable is detected, the object identification is performed by comparing the amplitude, the phase, the amount of time change thereof, and the data in the object identification database 402. When it is determined that an object larger than a predetermined threshold is detected as a result of object identification, the object identification result is displayed and an alarm is sounded.

  The frequency sweeper 104 in the transmission means 100 presets and sets the values of the center frequency f, the frequency bandwidth B, and the chirp period T in the frequency band in which the radio wave operates in the surface wave mode in the transmission leaky coaxial cable 2. The setting signal for instructing the frequency is output to the oscillator 102 and the memory 204 in the receiving means 200. Further, the frequency sweeper 104 outputs a trigger signal such as a timing signal synchronized with the chirp cycle to the FFT calculator 301 in the contact detection unit 300.

  The oscillator 102 outputs a signal having a frequency according to the instruction of the setting signal to the amplifier 103 and the multiplier 205 in the receiving unit 200 as an oscillation signal. The amplifier 103 amplifies the oscillation signal to a predetermined level and outputs it to the transmission leakage coaxial cable 2 as a transmission signal.

  The transmission leaking coaxial cable 2 radiates a transmission signal as a radio wave to space. The emitted radio wave operates in the surface wave mode. When an object approaches or comes into contact with the transmission leaky coaxial cable 2 or the reception leaky coaxial cable 3, the surface wave mode collapses at the approaching point or the contacting point, and the attenuation of the electric field energy is small even if the propagation distance in the vertical direction of the radio wave increases. Become. Further, the closer the object is to the transmission leaky coaxial cable 2 or the reception leaky coaxial cable 3, the higher the electric field energy, and the greater the disruption of the surface wave mode.

  The reception leaky coaxial cable 3 receives the radio wave radiated to the space and outputs it to the reception means 200 as a reception signal. The amplifier 201 in the receiving means 200 amplifies the received signal to a predetermined level and inputs it to a band pass filter (BPF) 202. The pass frequency band of the band pass filter 202 is the center frequency f and the frequency bandwidth B set by the frequency sweeper 104 in the transmission means 100. The band pass filter 202 outputs the received signal from which the unnecessary frequency band signal is removed to the multiplier 205. Multiplier 205 outputs a signal obtained by multiplying the oscillation signal from oscillator 102 and the received signal to memory 204 as an analysis signal. The memory 204 stores the analysis signal and the setting signal.

  When receiving the trigger signal from the frequency sweeper 104 in the transmission unit 100, the FFT calculator 301 in the contact detection unit 300 executes the FFT calculation using the analysis signal read from the memory 204 and determines the calculation result. To the determiner 302 and the determiner 303. A power spectrum is obtained as the determination signal. From the frequency bandwidth B, the chirp period T, and each frequency fn on the horizontal axis of the FFT calculation result, the time t is obtained from the following equation (2).

  t = (fn / B) T (2)

  The time t is a propagation time of a radio wave required to output a transmission signal and radiate it as a radio wave, receive the radiated radio wave and input it as a reception signal. The length obtained by multiplying the propagation time by the speed of light is based on one end of the transmission leaky coaxial cable 2 to which the transmission signal is input as a reference, the propagation distance in the transmission leaky coaxial cable 2, the propagation distance in space, and the reception leaky coaxial. This corresponds to the sum of propagation distances in the cable 3.

  The determination unit 302 in the contact detection unit 300 compares the determination signal with the first threshold value set in advance by the threshold value setting unit 304, and the object has approached the cable when the received signal intensity exceeds the first threshold value. Is detected. Further, the determination signal is compared with the second threshold value set in advance by the threshold value setter 304, and when the received signal strength exceeds the second threshold value, it is detected that the object has contacted the cable. When the determination unit 302 detects contact of an object, it outputs a contact detection signal to the determination unit 303, and the maximum value of the received signal intensity when the contact of the object is detected is used as an identification signal. Output to.

  The determination unit 303 in the contact detection unit 300 calculates a time change amount of the received signal intensity at each cable position with a predetermined time resolution, and when a contact detection signal is input, the time change amount of the past several points and a threshold setting device. Compared with a third threshold set in advance in 305, if the third threshold is exceeded, a contact is detected. When the determination unit 303 detects contact of an object, the determination unit 303 outputs an alarm signal to the alarm unit 306. Further, the determiner 303 outputs the received signal intensity fluctuation amount at the time of object contact to the object discriminator 401 in the discriminating means 400 as an identification signal. The alarm device 306 sounds an alarm when an alarm signal is input.

  The object discriminator 401 in the discriminating means 400 discriminates the object size by comparing and collating the identification signal with the data in the DB 402 in which the relationship between the object size created in advance by measurement or the like and the identification signal is recorded. When the identified object size exceeds a preset size, an alarm signal is output to the alarm device 403. The alarm device 403 sounds an alarm when a notification signal is input.

  As described above, the intrusion detection device according to the second embodiment operates the leaky coaxial cable in the surface wave mode to radiate radio waves, and changes the amplitude and phase of the received signal that fluctuates due to the collapse of the surface wave mode and the time. Since it is detected from the amount of change that the intruding object has contacted the leaky coaxial cable, it is possible to accurately detect the object without erroneously detecting a distant object.

  In addition, since the size of the contacted object is identified from the amplitude and phase of the received signal and the amount of change over time, the object can be accurately detected without erroneously detecting an object that is not a detection target such as raindrops or small animals.

Embodiment 3 FIG.
An intrusion detection device according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 7 is a block diagram showing a configuration of an intrusion detection apparatus according to Embodiment 3 of the present invention.

  7, the intrusion detection device according to the third embodiment of the present invention includes a wireless device 1, a transmission leakage coaxial cable 2, a reception leakage coaxial cable 3 laid substantially parallel to the transmission leakage coaxial cable 2, a termination A device 4 and a terminator 5 are provided.

  The wireless device 1 is provided with a transmission unit 100 connected to one end of the transmission leaky coaxial cable 2, a reception unit 200 connected to one end of the reception leaky coaxial cable 3, a contact detection unit 300, and an identification unit 400. ing.

  The transmission means 100 is provided with an oscillator 102, a pulse generator 105, and a timer 106.

  The receiving means 200 is provided with an amplifier 201, a band pass filter (BPF) 202, a detector 203, and a memory 204.

  The contact detection unit 300 includes a determination unit 302, a determination unit 303, a threshold setting unit 304, a threshold setting unit 305, and an alarm unit 306.

  The identification means 400 is provided with an object identifier 401, an object identification database (DB) 402, and an alarm device 403.

  The terminator 4 is connected to the other end of the transmission leakage coaxial cable 2 that is not connected to the transmission means 100. The terminator 5 is connected to the other end of the reception leaky coaxial cable 3 that is not connected to the receiving means 200.

  Next, the operation of the intrusion detection device according to the third embodiment will be described with reference to the drawings.

  In FIG. 7, the transmission means 100 pulsates the carrier wave in the frequency band in which the radio wave radiated from the transmission leaky coaxial cable 2 operates in the surface wave mode, and outputs it to the transmission leaky coaxial cable 2 as a transmission signal.

  The transmission leaking coaxial cable 2 radiates a transmission signal as a radio wave to space. The transmission leaky coaxial cable 2 operates in the surface wave mode when the radiation from the periodically slotted slots is uniform.

  The reception leaky coaxial cable 3 receives a radio wave radiated in the surface wave mode and / or a radio wave radiated from the surface wave mode and outputs the received signal to the receiving means 200 as a received signal.

  The receiving means 200 stores the signal obtained by detecting the received signal using the oscillation signal of the transmitting means 100 as a reference signal and the determination signal together with the time when the transmission signal is transmitted as a reference. The propagation characteristic in the time domain in which the signal transmitted from the transmission means 100 reaches the reception means 200 through the transmission leakage coaxial cable 2 and the space and the reception leakage coaxial cable 3 is obtained. At this time, the distance obtained by multiplying the time by the speed of light coincides with the distance that the signal has propagated through the transmission means 100, the transmission leakage coaxial cable 2, the space, the reception leakage coaxial cable 3, and the reception means 200. The received signal strength of the calculated propagation characteristic is compared with a predetermined threshold value to determine the approach of the object to the cable, and the temporal change amount of the received signal strength of the calculated propagation characteristic and the predetermined threshold value are set in advance. A comparison is made to determine the contact of the object with the cable. When the contact of the object with the cable is detected, the object identification is performed by collating the received signal strength, the time variation of the received signal strength, and a database in which the relationship between the object and the received signal strength is stored in advance. When it is determined that an object larger than a predetermined threshold is detected as a result of object identification, the object identification result is displayed and an alarm is sounded.

  The oscillator 102 in the transmission unit 100 outputs an oscillation signal having an oscillation frequency within a frequency band in which radio waves operate in the surface wave mode with the transmission leaky coaxial cable 2 to the pulse generator 105 and the detector 203 in the reception unit 200. To do. The pulse generator 105 converts the oscillation signal into a pulse shape according to a predetermined pulse width and period set in advance and outputs the oscillation signal to the transmission leaking coaxial cable 2 as a transmission signal. Further, the pulse generator 105 outputs the timing for generating a pulse to the timer 106 as a start signal. When the start signal is input, the timer 106 outputs the time from the input of the start signal to the memory 204 as a timer signal.

  The transmission leaking coaxial cable 2 radiates a transmission signal as a radio wave to space. The emitted radio wave operates in the surface wave mode. When an object approaches or comes into contact with the transmission leaky coaxial cable 2 or the reception leaky coaxial cable 3, the surface wave mode collapses at the approaching point or the contacting point, and the attenuation of the electric field energy is small even if the propagation distance in the vertical direction of the radio wave increases. Become. Further, the closer the object is to the transmission leaky coaxial cable or the reception leaky coaxial cable, the higher the electric field energy, and the greater the disruption of the surface wave mode.

  The reception leaky coaxial cable 3 receives the radio wave radiated to the space and outputs it to the reception means 200 as a reception signal. The amplifier 201 in the receiving means 200 amplifies the received signal to a predetermined level and inputs it to a band pass filter (BPF) 202. The pass frequency band of the band pass filter 202 is a frequency band that operates in the surface wave mode. The bandpass filter 202 outputs the received signal from which the unnecessary frequency band signal has been removed to the detector 203. The detector 203 outputs an IQ signal obtained by detecting the received signal using the oscillation signal from the oscillator 102 as a reference signal to the memory 204 as a determination signal. The memory 204 stores the timer signal and the IQ signal simultaneously as a determination signal. Time is the propagation time of a radio wave required to output a transmission signal and radiate it as a radio wave, receive the radiated radio wave and input it as a reception signal. The length obtained by multiplying the propagation time by the speed of light is based on one end of the transmission leaky coaxial cable 2 to which the transmission signal is input as a reference, the propagation distance in the transmission leaky coaxial cable 2, the propagation distance in space, and the reception leaky coaxial. This corresponds to the sum of propagation distances in the cable 3.

  The determination unit 302 in the contact detection unit 300 compares the determination signal with the first threshold value set in advance by the threshold value setting unit 304, and the object has approached the cable when the received signal intensity exceeds the first threshold value. Is detected. Further, the determination signal is compared with a second threshold value set in advance by the threshold value setting unit 305, and when the received signal strength exceeds the second threshold value, it is detected that the object has touched the cable. When the determination unit 302 detects contact of an object, it outputs a contact detection signal to the determination unit 303, and the maximum value of the received signal intensity when the contact of the object is detected is used as an identification signal. Output to.

  The determination unit 303 in the contact detection unit 300 calculates a time change amount of the received signal intensity at each cable position with a predetermined time resolution, and when a contact detection signal is input, the time change amount of the past several points and a threshold setting device. Compared with a third threshold set in advance in 305, if the third threshold is exceeded, a contact is detected. When the determination unit 303 detects contact of an object, the determination unit 303 outputs a notification signal to the alarm unit 306, and outputs a fluctuation amount of the received signal intensity at the time of object contact to the object identification unit 401 in the identification unit 400 as an identification signal. . The alarm device 306 sounds an alarm when an alarm signal is input.

  The object discriminator 401 in the discriminating means 400 discriminates the object size by comparing and collating the identification signal with data in the DB 402 in which the relationship between the object size and the identification signal created in advance by measurement or the like is recorded. When the identified object size exceeds a preset size, an alarm signal is output to the alarm device 403. The alarm device 403 sounds an alarm when a notification signal is input.

  As described above, the intrusion detection apparatus according to the third embodiment operates the leaky coaxial cable in the surface wave mode to radiate a radio wave, and changes the amplitude and phase of the received signal and its time that vary due to the collapse of the surface wave mode. Since it is detected from the amount of change that the intruding object has contacted the leaky coaxial cable, it is possible to accurately detect the object without erroneously detecting a distant object.

  In addition, since the size of the contacted object is identified from the amplitude and phase of the received signal and the amount of change over time, the object can be accurately detected without erroneously detecting an object that is not a detection target such as raindrops or small animals.

Embodiment 4 FIG.
An intrusion detection apparatus according to Embodiment 4 of the present invention will be described with reference to FIGS. FIG. 8 is a block diagram showing a configuration of an intrusion detection apparatus according to Embodiment 4 of the present invention.

  8, the intrusion detection device according to the fourth embodiment of the present invention includes a radio 1, a transmission leaky coaxial cable 2, a reception leaky coaxial cable 3 laid substantially parallel to the transmission leaky coaxial cable 2, and a termination. A device 4 and a terminator 5 are provided.

  The wireless device 1 is provided with a transmission unit 100 connected to one end of the transmission leaky coaxial cable 2, a reception unit 200 connected to one end of the reception leaky coaxial cable 3, a contact detection unit 300, and an identification unit 400. ing.

  The transmission means 100 is provided with a code generator 107, an oscillator 102, a modulator 108, and an amplifier 103.

  The receiving means 200 includes an amplifier 201, a demodulator 206, a delay circuit group 207, a correlator group 208, and a memory 204.

  The contact detection unit 300 includes a determination unit 302, a determination unit 303, a threshold setting unit 304, a threshold setting unit 305, and an alarm unit 306.

  The identification means 400 is provided with an object identifier 401, an object identification database (DB) 402, and an alarm device 403.

  The terminator 4 is connected to the other end of the transmission leakage coaxial cable 2 that is not connected to the transmission means 100. The terminator 5 is connected to the other end of the reception leaky coaxial cable 3 that is not connected to the receiving means 200.

  Next, the operation of the intrusion detection device according to the fourth embodiment will be described with reference to the drawings.

  In FIG. 8, the transmission means 100 modulates an oscillation signal having a frequency set in advance within a frequency band in which the radio wave radiated from the transmission leaky coaxial cable 2 operates in the surface wave mode, and transmits it as a transmission signal. Output to leaky coaxial cable 2.

  The transmission leaking coaxial cable 2 radiates a transmission signal as a radio wave to space. The transmission leaky coaxial cable 2 operates in the surface wave mode when the radiation from the periodically slotted slots is uniform.

  The reception leaky coaxial cable 3 receives a radio wave radiated in the surface wave mode and / or a radio wave radiated from the surface wave mode and outputs the received signal to the receiving means 200 as a received signal.

  The receiving means 200 calculates the amplitude and phase of the correlation value between the baseband signal obtained by detecting the received signal using the oscillation signal of the transmitting means 100 as a reference signal and the code signal from the transmitting means 100, and stores it as a determination signal. To do. At this time, the code signal is delayed by a predetermined delay time and then subjected to correlation calculation with the baseband signal. The delay time is within the shortest to longest range of propagation time for the signal transmitted from the transmission means 100 to reach the reception means 200 through the transmission leaky coaxial cable 2 and the space and the reception leaky coaxial cable 3. The calculated correlation value amplitude and phase are compared with a predetermined threshold value to determine the approach of the object to the cable, and the correlation value amplitude and phase time variation is compared with a predetermined threshold value. Determine contact with the cable. When the object detects contact with the cable, the object identification is performed by collating the amplitude and phase of the correlation value and the amount of change over time with a database in which the relationship between the object and the received signal level is stored in advance. When it is determined that an object larger than a predetermined threshold is detected as a result of object identification, the object identification result is displayed and an alarm is sounded.

  The code generator 107 in the transmission means 100 outputs a preset code as a code signal. The preset code is composed of an M sequence, a GOLD sequence, or the like. The code signal output from the code generator 107 is output to the modulator 108 and the delay circuit group 207 in the receiving means 200.

  The oscillator 102 in the transmission unit 100 uses the transmission leaky coaxial cable 2 to demodulate the signal in the modulator 108 and the reception unit 200 with a signal having a frequency set in advance within the frequency band in which the radio wave operates in the surface wave mode. Is output to the device 206. The modulator 108 uses the oscillation signal as a carrier wave, performs BPSK modulation with the code signal, and outputs the modulation signal to the amplifier 103. The amplifier 103 amplifies the modulated signal to a predetermined level and outputs it to the transmission leaking coaxial cable 2 as a transmission signal.

  The transmission leaking coaxial cable 2 radiates a transmission signal as a radio wave to space. The emitted radio wave operates in the surface wave mode. When an object approaches or comes into contact with the transmission leaky coaxial cable 2 or the reception leaky coaxial cable 3, the surface wave mode collapses at the approaching point or the contacting point, and the attenuation of the electric field energy is small even if the propagation distance in the vertical direction of the radio wave increases. Become. Further, the closer the object is to the transmission leaky coaxial cable 2 or the reception leaky coaxial cable 3, the higher the electric field energy, and the greater the disruption of the surface wave mode.

  The reception leaky coaxial cable 3 receives the radio wave radiated to the space and outputs it to the reception means 200 as a reception signal. The amplifier 201 in the receiving means 200 amplifies the received signal to a predetermined level and outputs it to the demodulator 206. The demodulator 206 performs IQ detection on the received signal as a baseband signal using the oscillation signal of the oscillator 102 in the transmission means 100 as a reference signal, and outputs the IQ signal to the correlator group 208.

  The delay circuit group 207 in the receiving means 200 has a predetermined time resolution in the range from the shortest time to the longest time from when the code signal generated by the code generator 107 is transmitted from the transmitting means 100 to being received by the receiving means 200. In the circuit that performs the delay for each propagation delay obtained in the above, the code signal generated by the code generator 107 is delayed by the propagation delay and output to the correlator group 208 as a delayed code signal. Correlator group 208 performs a correlation operation between the delayed code signal and the IQ signal. The correlation calculation calculates a correlation for one period of the delayed code signal, and calculates a correlation value I corresponding to the I component and a correlation value Q corresponding to the Q component. The square root of the sum of squares of correlation value I and correlation value Q corresponds to the amplitude of the received signal, and the arc tangent of correlation value I and correlation value Q corresponds to the phase of the received signal. Correlator group 208 outputs calculated correlation value I and correlation value Q to memory 204 as determination signals.

  FIG. 9 is a block diagram showing detailed configurations of the delay circuit group 207 and the correlator group 208.

  The delay circuit group 207 includes n delay circuits 207a, 207b,. In addition, the correlator group 208 includes n correlators 208a, 208b,. The code signal output from the code generator 107 is input to n delay circuits 207a, delay circuit 207b,..., Delay circuit 207n in the delay circuit group 207, and is delayed by different delay times in each delay circuit. The delayed code signal is output to the correlator group 208. The delay time is a propagation time of a radio wave required to output a transmission signal, radiate it as a radio wave, receive the radiated radio wave and input it as a reception signal, and each delay circuit of the delay circuit group 207 at a predetermined time interval. The delay time is set. Correlator 208a, correlator 208b,..., Correlator 208n of correlator group 208 performs correlation calculation between the delayed code signal and IQ signal, and outputs correlation value I and correlation value Q as determination signals to memory 204. The length obtained by multiplying the propagation time by the speed of light is based on one end of the transmission leaky coaxial cable 2 to which the transmission signal is input as a reference, the propagation distance in the transmission leaky coaxial cable 2, the propagation distance in space, and the reception leaky coaxial. This corresponds to the sum of propagation distances in the cable 3.

  The determination unit 302 in the contact detection unit 300 compares the determination signal with the first threshold value set in advance by the threshold value setting unit 304, and the object has approached the cable when the received signal intensity exceeds the first threshold value. Is detected. Further, the determination signal is compared with the second threshold value set in advance by the threshold value setter 304, and when the received signal strength exceeds the second threshold value, it is detected that the object has contacted the cable. When the determination unit 302 detects contact of an object, it outputs a contact detection signal to the determination unit 303, and the maximum value of the received signal intensity when the contact of the object is detected is used as an identification signal. Output to.

  The determination unit 303 in the contact detection unit 300 calculates a time change amount of the received signal intensity at each cable position with a predetermined time resolution, and when a contact detection signal is input, the time change amount of the past several points and a threshold setting device. Compared with a third threshold set in advance in 305, if the third threshold is exceeded, a contact is detected. When the determination unit 303 detects contact of an object, the determination unit 303 outputs a notification signal to the alarm unit 306, and outputs a fluctuation amount of the received signal intensity at the time of object contact to the object identification unit 401 in the identification unit 400 as an identification signal. . The alarm device 306 sounds an alarm when an alarm signal is input.

  The object discriminator 401 in the discriminating means 400 discriminates the object size by comparing and collating the identification signal with data in the DB 402 in which the relationship between the object size and the identification signal created in advance by measurement or the like is recorded. When the identified object size exceeds a preset size, an alarm signal is output to the alarm device 403. The alarm device 403 sounds an alarm when a notification signal is input.

  As described above, the intrusion detection apparatus according to the fourth embodiment operates the leaky coaxial cable in the surface wave mode to radiate radio waves, and changes the amplitude and phase of the received signal and the time thereof that change due to the collapse of the surface wave mode. Since it is detected from the amount of change that the intruding object has contacted the leaky coaxial cable, it is possible to accurately detect the object without erroneously detecting a distant object.

  In addition, since the size of the contacted object is identified from the amplitude and phase of the received signal and the amount of change over time, the object can be accurately detected without erroneously detecting an object that is not a detection target such as raindrops or small animals.

  Further, since the signal subjected to code modulation is transmitted and received, the influence of the interference wave can be removed.

Embodiment 5 FIG.
An intrusion detection device according to Embodiment 5 of the present invention will be described with reference to FIGS. FIG. 10 is a block diagram showing a configuration of an intrusion detection apparatus according to Embodiment 5 of the present invention.

  10, an intrusion detection device according to Embodiment 5 of the present invention includes a radio 1, a transmission leaky coaxial cable 2, a reception leaky coaxial cable 3 laid substantially parallel to the transmission leaky coaxial cable 2, and a termination. A device 4 and a terminator 5 are provided.

  The wireless device 1 is provided with a transmission unit 100 connected to one end of the transmission leaky coaxial cable 2, a reception unit 200 connected to one end of the reception leaky coaxial cable 3, a contact detection unit 300, and an identification unit 400. ing.

  The transmission means 100 is provided with an oscillator group 109 and an amplifier 103.

  The receiving means 200 is provided with an amplifier 201, a BPF 202, a detector group 209, and a memory 204.

  The contact detection unit 300 includes an FFT calculator 301, a determiner 302, a determiner 303, a threshold value setter 304, a threshold value setter 305, and an alarm device 306.

  The identification means 400 is provided with an object identifier 401, an object identification database (DB) 402, and an alarm device 403.

  The terminator 4 is connected to the other end of the transmission leakage coaxial cable 2 that is not connected to the transmission means 100. The terminator 5 is connected to the other end of the reception leaky coaxial cable 3 that is not connected to the receiving means 200.

  Next, the operation of the intrusion detection device according to the fifth embodiment will be described with reference to the drawings.

  In FIG. 10, the transmission means 100 outputs an oscillation signal obtained by multiplexing frequencies within a frequency band in which the radio wave radiated from the transmission leaky coaxial cable 2 operates in the surface wave mode to the transmission leaky coaxial cable 2 as a transmission signal. The transmission leaking coaxial cable 2 radiates a transmission signal as a radio wave to space. The transmission leaky coaxial cable 2 operates in the surface wave mode when the radiation from the periodically slotted slots is uniform. In the surface wave mode, the radio wave propagates in the longitudinal direction along the transmission leaky coaxial cable 2 because the electric field energy is rapidly attenuated by an exponential function as the propagation distance in the vertical direction of the transmission leaky coaxial cable 2 increases. When an object approaches or comes into contact with the transmission leaky coaxial cable 2, the radiation from the slots periodically vacated in the transmission leaky coaxial cable 2 is not uniform and the surface wave mode is lost. Even if the propagation distance in the direction increases, the attenuation of the electric field energy decreases.

  The reception leaky coaxial cable 3 receives a radio wave radiated in the surface wave mode and / or a radio wave radiated from the surface wave mode and outputs the received signal to the receiving means 200 as a received signal. When the surface wave mode is disrupted, the electric field energy attenuation is reduced. Therefore, the received signal level when the surface wave mode is disrupted is compared with the received signal level when the surface wave mode is disrupted and the received signal level operated in the surface wave mode. The level gets bigger.

  The receiving unit 200 stores the amplitude and phase of the received signal obtained by detecting the received signal with reference to the oscillation signal of the transmitting unit 100 as an analysis signal. At the same time, the frequency of the oscillator group 109 when used for detection is also stored as an analysis signal.

  The contact detection unit 300 obtains a propagation characteristic in a frequency region in which a signal transmitted from the transmission unit 100 reaches the reception unit 200 through the transmission leakage coaxial cable 2 and the space and the reception leakage coaxial cable 3. The IFFT calculation (inverse FFT calculation) is performed on the stored analysis signal to calculate the propagation characteristics in the time domain. The calculated amplitude and phase of the propagation characteristics, their amount of change with time, and the like are compared with a predetermined threshold value, and the approach of the object to the cable and the contact with the cable are determined. Sounds an alarm when contact is detected with an object cable.

  When the object 400 detects contact of the object with the cable, the identification means 400 performs object identification by comparing the amplitude, phase, and their temporal variation with data in the object identification database 402 created in advance. When it is determined that an object larger than a predetermined threshold is detected as a result of object identification, the object identification result is displayed and an alarm is sounded.

  The oscillator group 109 in the transmission unit 100 includes an amplifier 103 and a reception unit 200 that use signals obtained by multiplexing signals having different oscillation frequencies in a frequency band in which radio waves operate in the surface wave mode in the transmission leaky coaxial cable 2 as oscillation signals. To the detector group 209. The amplifier 103 amplifies the oscillation signal to a predetermined level and outputs it to the transmission leakage coaxial cable 2 as a transmission signal.

  When an object approaches or comes into contact with the transmission leaky coaxial cable 2 or the reception leaky coaxial cable 3, the surface wave mode collapses at the approaching point or the contacting point, and the attenuation of the electric field energy is small even if the propagation distance in the vertical direction of the radio wave increases. Become. In addition, the closer the object is to the transmission leaky coaxial cable 2 or the reception leaky coaxial cable 3, the more the surface wave mode collapses at a position where the electric field energy is higher, so the electric field energy is increased even if the propagation distance in the vertical direction of the radio wave increases. The attenuation of becomes smaller.

  The reception leaky coaxial cable 3 receives the radio wave radiated to the space and outputs it to the reception means 200 as a reception signal. The amplifier 201 in the receiving means 200 amplifies the received signal to a predetermined level and inputs it to a band pass filter (BPF) 202. The pass frequency band of the band pass filter 202 is a frequency band in which the leaky coaxial cable operates in the surface wave mode. The band pass filter 202 outputs the received signal from which signals in unnecessary frequency bands are removed to the detector group 209. The detector group 209 performs quadrature detection (IQ detection) on the received signal using the oscillation signal from the oscillator group 109 as a reference signal, and outputs the IQ signal to the memory 204. The memory 204 stores an IQ signal at each frequency as an analysis signal.

  FIG. 11 is a block diagram showing a detailed configuration of the oscillator group 109 and the detector group 209.

  The oscillator group 109 includes a plurality of oscillators 109a, 109b, and 109c and a combiner 109d, and the detector group 209 includes a plurality of detectors 209a, 209b, and 209c and a distributor 209d. FIG. 11 shows a specific example in which three oscillators and three detectors are used.

  The oscillator 109a, the oscillator 109b, and the oscillator 109c in the oscillator group 109 output signals having different frequencies to the combiner 109d as a first oscillation signal, a second oscillation signal, and a third oscillation signal, respectively. The combiner 109 d outputs a combined signal obtained by combining the oscillation signals to the amplifier 103.

  The distributor 209d in the detector group 209 distributes the received signal to the detector 209a, the detector 209b, and the detector 209c, and outputs it as a distributed signal.

  The detector 209a outputs the result obtained by performing IQ detection on the basis of the distributed received signal and the first oscillation signal of the oscillator 109a to the memory 204 as a first IQ signal.

  Similarly, the detector 209b outputs the result obtained by performing IQ detection on the basis of the distributed received signal and the second oscillation signal of the oscillator 109b to the memory 204 as a second IQ signal.

  Similarly, the detector 209c outputs a result obtained by performing IQ detection on the basis of the distributed received signal and the third oscillation signal of the oscillator 109c to the memory 204 as a third IQ signal.

  Although the detector group 209 is used, the received signal may be subjected to an FFT operation, and an IQ signal may be calculated from the obtained amplitude and phase of each frequency.

  The FFT calculator 301 in the contact detection means 300 performs IFFT (inverse FFT) calculation using the analysis signal read from the memory 204 to convert the analysis signal from the frequency domain signal to the time domain signal, and the calculation result Is output to the determiner 302 and the determiner 303 as a determination signal. The analysis signal stored in the memory 204 stores the characteristics of the received signal in the frequency domain and has a relationship between the frequency and the received signal, whereas the determination signal has the characteristics of the received signal in the time domain and the relationship between time and the received signal. Become. That is, propagation characteristics such as reception intensity for each propagation time of a radio wave required to output a transmission signal and radiate it as a radio wave, receive the radiated radio wave and input it as a reception signal are derived. The length obtained by multiplying the propagation time by the speed of light is based on one end of the transmission leaky coaxial cable 2 to which the transmission signal is input as a reference, the propagation distance in the transmission leaky coaxial cable 2, the propagation distance in space, and the reception leaky coaxial. This corresponds to the sum of propagation distances in the cable 3.

  The determination unit 302 in the contact detection unit 300 compares the determination signal with the first threshold value set in advance by the threshold value setting unit 304, and the object has approached the cable when the received signal intensity exceeds the first threshold value. Is detected. Further, the determination signal is compared with the second threshold value set in advance by the threshold value setter 304, and when the received signal strength exceeds the second threshold value, it is detected that the object has contacted the cable. When the determination unit 302 detects contact of an object, it outputs a contact detection signal to the determination unit 303, and the maximum value of the received signal intensity when the contact of the object is detected is used as an identification signal. Output to.

  The determination unit 303 in the contact detection unit 300 calculates a time change amount of the received signal intensity at each cable position with a predetermined time resolution, and when a contact detection signal is input, the time change amount of the past several points and a threshold setting device. Compared with a third threshold set in advance in 305, if the third threshold is exceeded, a contact is detected. When the determination unit 303 detects contact of an object, the determination unit 303 outputs a notification signal to the alarm unit 306, and outputs a fluctuation amount of the received signal intensity at the time of object contact to the object identification unit 401 in the identification unit 400 as an identification signal. . The alarm device 306 sounds an alarm when an alarm signal is input.

  The object discriminator 401 in the discriminating means 400 discriminates the object size by comparing and collating the identification signal with data in the DB 402 in which the relationship between the object size and the identification signal created in advance by measurement or the like is recorded. When the identified object size exceeds a preset size, an alarm signal is output to the alarm device 403. The alarm device 403 sounds an alarm when a notification signal is input.

  As described above, the intrusion detection apparatus according to the fifth embodiment operates the leaky coaxial cable in the surface wave mode to radiate a radio wave, and changes the amplitude and phase of the received signal and its time that vary due to the collapse of the surface wave mode. Since it is detected from the amount of change that the intruding object has contacted the leaky coaxial cable, it is possible to accurately detect the object without erroneously detecting a distant object.

  In addition, since the size of the contacted object is identified from the amplitude and phase of the received signal and the amount of change over time, the object can be accurately detected without erroneously detecting an object that is not a detection target such as raindrops or small animals.

  DESCRIPTION OF SYMBOLS 1 Radio | wireless machine, 2 Transmission leaking coaxial cable, 3 Reception leaking coaxial cable, 4 Terminator, 5 Terminator, 100 Transmission means, 101 Frequency setting device, 102 Oscillator, 103 Amplifier, 104 Frequency sweeper, 105 Pulse generator, 106 Timer, 107 Code generator, 108 Modulator, 109 Oscillator group, 200 Receiving means, 201 Amplifier, 202 Band pass filter, 203 Detector, 204 Memory, 205 Multiplier, 206 Demodulator, 207 Delay circuit group, 208 Correlator Group, 209 detector group, 300 contact detection means, 301 FFT computing unit, 302 judgment unit, 303 judgment unit, 304 threshold setting unit, 305 threshold setting unit, 306 alarm unit, 400 identification unit, 401 object discrimination unit, 402 object Identification database, 403 alarm.

Claims (8)

A transmission leaky coaxial cable that radiates a transmission signal as a radio wave;
A reception leaky coaxial cable that is installed substantially in parallel with the transmission leaky coaxial cable and receives at least one of the radio wave radiated in the surface wave mode and the radio wave radiated with the surface wave mode collapsed and outputs it as a received signal. When,
Transmitting means for generating the transmission signal from an oscillation signal in a frequency band in which the radio wave operates in the surface wave mode and outputting the signal to one end of the transmission leakage coaxial cable;
A determination signal generating means for generating a determination signal representing a propagation characteristic for each propagation time of the radio wave using the received signal and the oscillation signal;
When the received signal strength for each propagation time of the radio wave obtained from the determination signal exceeds a second threshold, and the amount of time variation of the received signal strength exceeds a third threshold, the object is the transmission leaky coaxial cable. And an identification signal output means for detecting contact with at least one of the reception leaky coaxial cables, and outputting the received signal strength and the time variation as an identification signal;
A database for object identification that records the relationship between the size of the object created in advance and the identification signal;
An object that identifies the size of the object by comparing and comparing the identification signal with the object identification database, and detects that the object has entered if the identified size exceeds a preset size With identification means
An intrusion detection device comprising: The intrusion detection apparatus according to claim 1, wherein the transmission leakage coaxial cable and the reception leakage coaxial cable have slots that are periodically opened. The transmission means outputs the oscillation signal as the transmission signal,
The determination signal generating means includes
Receiving means for detecting the received signal using the oscillation signal as a reference signal to determine the amplitude and phase of the received signal, and holding it as an analysis signal together with the frequency of the oscillation signal;
Means for calculating a determination signal by performing an operation for converting the analysis signal from a frequency domain signal to a time domain signal;
The intrusion detection apparatus according to claim 1 or 2, further comprising: The intrusion detection device according to claim 3, wherein the oscillation signal has a frequency that changes in a time-sharing manner. The transmission means outputs an oscillation signal subjected to frequency sweep as the transmission signal,
The determination signal generating means includes
Receiving means for holding a signal obtained by multiplying the oscillation signal and the reception signal as an analysis signal;
Means for obtaining a propagation characteristic for each frequency of the radio wave from the analysis signal and obtaining the determination signal by obtaining a propagation time of the radio wave from the frequency of the radio wave;
The intrusion detection apparatus according to claim 1 or 2, further comprising: The transmission means pulse-modulates the oscillation signal and outputs it as the transmission signal,
The determination signal generating means includes
Receiving means for holding a signal obtained by detecting the received signal using the oscillation signal as a reference signal and a time based on the time when the transmission signal is transmitted as a determination signal
The intrusion detection apparatus according to claim 1 or 2, further comprising: The transmission means code-modulates the oscillation signal with a code signal and outputs the signal as the transmission signal,
The determination signal generating means includes
Means for detecting the received signal using the oscillation signal as a reference signal to generate a baseband signal;
Means for delaying the code signal by a predetermined time;
Means for calculating an amplitude and a phase of a correlation value between the baseband signal and the delayed code signal and holding the result as a determination signal;
The intrusion detection apparatus according to claim 1 or 2, further comprising: The transmitting means frequency-multiplexes a plurality of the oscillation signals having different frequencies and outputs the signals as the transmission signals,
The determination signal generating means includes
Receiving means for detecting the received signal using each of the plurality of oscillation signals as a reference signal to determine the amplitude and phase of the received signal, and holding the analysis signal together with the frequency of each of the plurality of oscillation signals;
Means for calculating a determination signal by performing an operation for converting the analysis signal from a frequency domain signal to a time domain signal;
The intrusion detection apparatus according to claim 1 or 2, further comprising:

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