JP4888275B2 - Intrusion detection device - Google Patents

Description

  The present invention relates to an intrusion detection device that detects an intruder such as an intruder or an intruder in a monitoring area.

  A conventional intrusion detection apparatus uses a leakage cable that is a cable capable of transmitting and receiving radio waves, and embeds a transmission leakage cable and a reception leakage cable in parallel underground. The transmitter outputs a transmission signal to the transmission leakage cable. The transmission signal is radiated as a radio wave from the transmission leakage cable to the space, and the radio wave is received as a reception signal by the reception leakage cable. The received signal is input to the receiver, and the receiver analyzes the amplitude level and phase of the received signal.

  When the intruding object approaches or passes through the leaking cable, the radio wave is reflected by the intruding object, and the amplitude level and phase of the received signal slightly change. The receiver determines a change in the amplitude level or phase of the received signal with a predetermined threshold, and detects the intrusion of the intruding object.

Japanese Patent Laid-Open No. 5-2690 (stages 0002 to 0003, FIG. 8)

  However, in the conventional method, even if it is not desired to detect a large distant object, there is no choice but to adjust with a threshold value for determining a change. Even if the object is far away, when a large object approaches the leaky cable, the amount of change in the received signal becomes large. Therefore, the amount of change in the received signal is about the same as that of an intruder slightly away from the leaky cable. This is because the radio wave attenuates according to the distance away from the leaky cable, but if the target size is large, the received signal becomes a certain size even if it is far from the leaky cable. Therefore, in the conventional method, it is impossible to determine the approach distance between the intruding object and the leaking cable with a threshold value, and there is a problem in that a distant large object is erroneously detected.

  The present invention has been made to solve the above-described problems. An intrusion detection device capable of detecting an approach distance of an intruding object from a leaking cable and performing an accurate intrusion detection based on the approach distance. The purpose is to obtain.

  An intrusion detection apparatus according to the present invention includes a transmission unit that supplies a transmission signal to a leakage transmission unit, a reception unit that detects a reception signal received by the leakage reception unit, and a phase amplitude signal output from the reception unit And a detection unit for detecting an intruding object. The reception unit separates the first transmission / reception mode signal from the reception signal and outputs a first phase amplitude signal, and separates a second transmission / reception mode signal different from the first transmission / reception mode signal from the reception signal. A second phase amplitude signal is output. The detection unit calculates a first variation amount from the first phase amplitude signal, calculates a second variation amount from the second phase amplitude signal, and determines a difference between the first variation amount and the second variation amount. Based on this, the approach distance between the predetermined reference line and the intruding object in the extending direction of the leak transmitting means and the leak receiving means is calculated. Then, an intruding object is detected by determining the approach distance with a predetermined threshold.

  The intrusion detection device according to the present invention detects the approach distance of the intruding object from the leak transmitting means and the leak receiving means on the basis of the difference between the respective fluctuation amounts in the two transmission / reception mode signals, so Intrusion detection.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of an intrusion detection device according to Embodiment 1 of the present invention, and FIG. 2 is a diagram for explaining intrusion detection according to Embodiment 1. In FIG. The wireless device 1 includes a transmission unit 11 that transmits a transmission signal to a transmission leakage cable 2 that is a leakage transmission unit, and a reception unit that detects a reception signal received by the reception leakage cable 3 that is a leakage reception unit. 12 and a detection unit 13 that detects the intruding object 6 by analyzing the phase amplitude signal detected by the reception unit 12 and output from the reception unit 12.

  The transmission unit 11 includes an oscillator 101 that generates a first transmission / reception mode signal and an oscillator 102 that generates a second transmission / reception mode signal. The first transmission / reception mode signal and the second transmission / reception mode signal are combined by the combiner 103, amplified to an appropriate signal level by the amplifier 104, and output to the transmission leakage cable 2 as a transmission signal.

  Here, the transmission / reception mode signal is a signal having a frequency at which the transmission leakage cable 2 operates in a predetermined operation mode and the reception leakage cable 3 operates in a predetermined operation mode. Specifically, the first transmission / reception mode signal is a signal having a frequency at which the transmission leakage cable 2 and the reception leakage cable 3 operate in a radiation mode to be described later, and the second transmission / reception mode signal is a transmission leakage cable. 2 and the reception leaking cable 3 are signals having a frequency at which they operate in a surface wave mode to be described later.

  The wireless device 1 is connected to the transmission leakage cable 2 and the reception leakage cable 3, and the transmission signal generated by the wireless device 1 is radiated from the transmission leakage cable 2 as a radio wave. The transmission signal remaining without being radiated by the transmission leakage cable 2 is absorbed by the terminator 4. The radio wave radiated from the transmission leakage cable 2 is reflected by the intruding object 6 and received by the reception leakage cable 3, and the received reception signal is input to the wireless device 1. A terminator 5 is also connected to the reception leakage cable 3 to prevent reflection at the end.

  The received signal input to the receiving unit 12 is amplified to an appropriate signal level by the amplifier 105, distributed by the distributor 106, and then input to the band pass filter 107 and the band pass filter 108, respectively. The band pass filter 107 is used to separate the first transmission / reception mode signal from the reception signal, and the separated first transmission / reception mode signal is input to the detector 109. The band-pass filter 108 is used to separate the second transmission / reception mode signal from the reception signal, and the separated second transmission / reception mode signal is input to the detector 110.

  The detector 109 and the detector 110 detect an input signal and output the amplitude and phase of the signal, and output a first amplitude phase signal and a second amplitude phase signal, respectively. The first amplitude phase signal and the second amplitude phase signal are input to the detection unit 13. The determination circuit 111 of the detection unit 13 performs analysis and determination using a reference signal and a determination level stored in the memory 112 in advance. When the determination circuit 111 detects the intruding object 6, the alarm device 113 issues an alarm.

  Next, a radiation mode signal and a surface wave mode signal will be described. The difference between the signal in the radiation mode and the signal in the surface wave mode is in the frequency of the signal transmitted or received by the leakage cable. The leaky cable has a structure in which slots or holes are periodically formed on the surface, and radio waves are radiated therefrom. The operation mode of transmission with respect to the oscillation frequency is determined by this periodic interval. Further, the reception operation mode with respect to the reception frequency is determined by the periodic interval of the slots or holes in the leaky cable that receives the signal.

In the case of a leaky cable having slots opened at intervals of the basic period P, the frequency f that becomes the boundary between the radiation mode and the surface wave mode is expressed by equation (1).
f = 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 leakage cable.

  If the frequency is higher than the frequency f expressed by the equation (1), it operates in the radiation mode, and if it is lower than the frequency f, it operates in the surface wave mode. However, some leaky cables have a structure in which subslots are opened during the basic period. This is opened to suppress higher-order radiation modes, and the boundary frequency can be calculated with the fundamental period P. For example, in the case of a leaky cable having a basic period of 1 m, a subslot opened at a position of 1/6 m, 1/2 m, and 2/3 m in the basic period and a relative permittivity εr of 1.23, the boundary frequency Is about 142 MHz.

  When the leakage cable having the above characteristics is used for the transmission leakage cable 2 and the reception leakage cable 3, for example, if the oscillator 101 oscillates at 200 MHz, the leakage cable operates in a radiation mode, and the oscillator 102 operates at 80 MHz. When oscillated, the leaky cable operates in surface wave mode.

  Therefore, when a leakage cable having the same characteristics is used as the transmission leakage cable 2 and the reception leakage cable 3, a 200 MHz signal is used as the first transmission / reception mode signal, so that the transmission leakage cable 2 and the reception leakage cable are used. The cable 3 operates in the radiation mode. Further, by using an 80 MHz signal as the second transmission / reception mode signal, the transmission leakage cable 2 and the reception leakage cable 3 operate in the surface wave mode.

  In FIG. 2, a path 7 represents a signal path from which the transmission signal supplied from the wireless device 1 reaches the reception end of the reception leakage cable 3 through the intruding object 6 from the transmission end of the transmission leakage cable 2. . The transmission signal radiated from the transmission leakage cable 2 is reflected by the intruding object 6 and received as a reception signal by the reception leakage cable 3. The approach distance R at which the intruding object 6 approaches the transmitting leakage cable 2 and the receiving leakage cable 3 is a distance between the reference line 8 and the intruding object 6 in the extending direction of the transmitting leakage cable 2 and the receiving leakage cable 3. For example, the reference line 8 may be the center line of the transmission leakage cable 2 and the reception leakage cable 3.

  The cable distance Z in the extending direction of the leaking cable of the intruding object 6 is a distance from the transmitting end of the transmitting leaking cable 2 to the intruding object 6 along the transmitting leaking cable 2. Since the line segment defining the approach distance R is perpendicular to the reference line 8, the cable distance Z is an approach distance from the reference line 8 from the midpoint of the transmission end of the transmission leakage cable 2 and the reception end of the reception leakage cable 3. The distance to the intersection with the line segment defining R can also be used.

  When an appropriate frequency band is selected from the frequencies operating in the radiation mode, radio waves are radiated from the leaky cable in the direction of 90 degrees, so that the path length L of the path 7 is 2 × Z + 2 × R. The radiation direction of the radio wave from the leaky cable is caused by the structure of the leaky cable, and its characteristics are widely known. Even when a frequency band having a radiation angle other than 90 degrees is used, the cable distance Z can be calculated by geometric calculation.

  Next, the determination operation in the detection unit 13 will be described. FIG. 3 is a diagram illustrating a configuration of the determination circuit 111. The first fluctuation amount calculation means 201 is the absolute value of the complex difference between the first amplitude phase signal Sig-a1 that is the output of the detector 109 and the first reference amplitude phase signal Sig-ra stored in the memory 112. Is calculated as the fluctuation amount of the electric field, and the first fluctuation amount Sig-a2 is output. The second fluctuation amount calculation means 202 is the absolute value of the complex difference between the second amplitude phase signal Sig-b1 that is the output of the detector 110 and the second reference amplitude phase signal Sig-rb stored in the memory 112. Is calculated as the fluctuation amount of the electric field, and the second fluctuation amount Sig-b2 is output. Here, the complex difference is a difference between complex quantities represented by amplitude and phase.

  The reference amplitude phase signal is an amplitude phase signal that serves as a reference when there is no intrusion. For the reference when there is no intrusion, for example, an amplitude phase signal when the intrusion of the intruding object 6 is not detected for a predetermined time or an average value of the amplitude phase signal may be used. The first reference amplitude phase signal Sig-ra is a reference in the first transmission / reception mode signal of 200 MHz, and the second reference amplitude phase signal Sig-rb is a reference in the second transmission / reception mode signal of 80 MHz.

  The approach distance calculation means 203 calculates the approach distance R based on the difference between the first variation amount Sig-a2 and the second variation amount Sig-b2. The determination unit 204 determines that the approach distance R is equal to or less than a predetermined threshold value, and outputs a determination signal Sig-out. The alarm device 113 receives the determination signal Sig-out after the determination means 204 detects that the intruding object 6 has entered the approaching distance R that is equal to or less than a predetermined threshold. The alarm device 113 issues an alarm based on the determination signal Sig-out.

FIG. 4 is a diagram for explaining the operation of the fluctuation amount calculation means. The horizontal axis X is a real axis, and the vertical axis Y is an imaginary axis. For example, when the current amplitude phase signal A2 is C2exp (jθ2) and the reference amplitude phase signal A1 is C1exp (jθ1), the respective signals are represented by X2 + jY2 and X1 + jY1. The amplitude ΔC of the amplitude phase signal A3, which is the difference between the amplitude phase signal A2 and the reference amplitude phase signal A1, is a fluctuation amount, and this fluctuation amount ΔC is expressed by the equation (2).
ΔC = √ ((X2−X1) ² + (Y2−Y1) ² ) (2)
Here, j is an imaginary unit. If the amplitude phase signal obtained by detecting the electric field component of the received signal is used, the fluctuation amount ΔC is the fluctuation amount of the electric field. Hereinafter, the description will be made as the amount of fluctuation of the electric field.

  FIG. 5 is a diagram showing the relationship between the electric field variation ΔC and the approach distance R in the first embodiment. The horizontal axis is the logarithm of the approach distance R, and the vertical axis is the logarithm of the electric field fluctuation amount ΔC. A characteristic line 301 is a variation characteristic of the electric field in the signal received in the radiation mode when the signal transmitted in the radiation mode is reflected by the intruding object 6. The characteristic line 302 is a variation characteristic of the electric field in the signal received in the surface wave mode when the signal transmitted in the surface wave mode is reflected by the intruding object 6. The difference D is a difference value between the logarithmic value of the characteristic line 301 and the logarithmic value of the characteristic line 302 at a certain distance R. In FIG. 5, when the approach distance R is R1, the difference D is D1. Since the attenuation due to radio wave propagation is small in the radiation mode, the degree of decrease in the electric field fluctuation amount ΔC with respect to the approach distance R is smaller than that in the surface wave mode, and the surface wave mode rapidly decreases as the approach distance R increases.

  FIG. 6 is a diagram illustrating the relationship between the difference D and the approach distance R in FIG. The horizontal axis is the logarithm of the approach distance R, and the vertical axis is the difference D. A characteristic line 304 represents the characteristic of the approach distance R of the difference D. Since the difference characteristic shown in FIG. 6 is a logarithmic difference, at each approach distance R, the variation amount ΔC1 of the radiation mode electric field and the variation amount ΔC2 of the surface wave mode electric field increase and decrease at substantially the same rate, and By taking the logarithmic difference of each, the increase or decrease of almost the same rate is offset. Therefore, the characteristic line 304 has a feature that does not depend on the electric field fluctuation amount ΔC, that is, does not depend on the size of the intruding object 6. Accordingly, regardless of the size of the intruding object 6, the approach distance R of the intruding object 6 that approaches the transmitting leakage cable 2 and the receiving leakage cable 3 can be calculated from the characteristic line 304 of the difference characteristic. When the difference D is D1, it can be seen that the approach distance R is R1 using the characteristic line 304. As described above, the approach distance R of the intruding object 6 can be obtained regardless of the size of the intruding object 6.

  As described above, the intrusion detection device according to the first exemplary embodiment approaches the approaching distance of the intruding object 6 from the transmission leakage cable 2 and the reception leakage cable 3 based on the difference between the fluctuation amounts ΔC of the two transmission / reception mode signals. By detecting R, it is conventionally impossible to determine the approach distance R of the intruding object 6 as a threshold, and unlike the case of detecting a large distant object, an accurate intrusion is based on the approach distance R. Detection can be performed. Thereby, a distant large object is not erroneously detected.

  Further, by determining the approach distance R as a threshold, for example, the range of the approach distance R from the transmission leak cable 2 and the reception leak cable 3 such that an alarm is sounded when intruding into 1 m or more and 3 m or less. It is possible to determine a threshold value as a determination criterion. As a result, it is possible to perform an operation such as turning off an alarm when the transmission leakage cable 2 and the reception leakage cable 3 are approached to a set distance or less. Even if the security guard does not manually turn off the alarm and rushes to confirm the intruding object 6, the alarm does not remain sounding and the warning sound is annoying to others. The advantage is that you don't have to worry about unnecessary things.

  Note that, as the two transmission / reception mode signals, the signal operating in the radiation mode and the surface wave mode has been described, but a signal operating in the quasi-surface wave mode can be used instead of the surface wave mode. Even in the frequency band in which the radiation mode is represented by equation (1), the radiation direction of the radio wave radiated from the transmission leakage cable 2 is the direction along the transmission leakage cable 2 at a frequency close to the boundary represented by equation (1). Therefore, the physical characteristics are the same as in the surface wave mode. Even in the quasi-surface wave mode, the electric field variation ΔC rapidly decreases as the distance increases. When the quasi-surface wave mode radio wave is used, the electric field fluctuation amount ΔC is larger as a whole than the pure surface wave mode radio wave. That is, the electric field fluctuation amount characteristic in the quasi-surface wave mode generally rises upward, that is, the reception intensity increases, so that the reception sensitivity is improved at the same approach distance R. Therefore, when the quasi-surface wave mode radio wave is used, the approach distance R can be detected even if the approach distance R is longer than that in the surface wave mode. Further, even if the transmission power of the radio wave in the quasi-surface wave mode is made smaller than that in the surface wave mode, the approach distance R can be detected to the limit of the approach distance R equivalent to that in the surface wave mode. .

Embodiment 2. FIG.
FIG. 7 is a diagram showing a configuration of a determination circuit of the intrusion detection device according to Embodiment 2 of the present invention. The difference from the first embodiment is that the intrusion detection of the intruding object 6 is performed using the cable distance Z calculated by the cable distance calculating means 205.

  The determination unit 206 determines that the approach distance R is equal to or smaller than a predetermined threshold value and that the cable distance Z is within a predetermined threshold value range, and outputs a determination signal Sig-out. Since the intrusion detection of the intruding object 6 is performed based on the approach distance R and the cable distance Z, it can be detected that the intrusion has entered the specific range of the transmission leakage cable 2 and the reception leakage cable 3.

  In order to calculate the cable distance Z, the path length L of the path 7 is first obtained. FIG. 8 is a diagram for explaining a method for calculating a path length in which a transmission signal returns through the intruding object 6. The path length L of the path 7 can be calculated based on the propagation delay time between transmission and reception of radio waves in the same way as a general radar. The radio wave propagation time can be measured by a pulse modulation signal, a code modulation signal, the FM-CW method, or the like. However, while a general radar measures the propagation time from transmission to reception of a received signal, the propagation time of the electric field fluctuation amount ΔC is measured here.

  As shown in FIG. 8A, when the intruding object 6 approaches the transmission leakage cable 2 and the reception leakage cable 3, the intensity of the reception signal varies as indicated by the characteristic line 311 in FIG. 8B. A characteristic line 311 is a propagation time characteristic at the reception intensity of the current amplitude phase signal A2 shown in FIG. A characteristic line 310 is a propagation time characteristic at the reception intensity of the reference amplitude phase signal A1 shown in FIG. A characteristic line 312 is a difference between the characteristic line 311 and the characteristic line 310. By detecting the peak time of the characteristic line 312 as a variation amount of the electric field that is the difference between the characteristic line 310 that is the reference when no intrusion and the characteristic line 311 that is the current reception intensity, the path length L of the path 7 is illustrated. It can be obtained as L1 shown in FIG.

  Specifically, by inputting the first amplitude phase signal Sig-a1 and the first reference amplitude phase signal Sig-ra for the transmission signal for a predetermined time in the first fluctuation amount calculation unit 201 in FIG. The characteristic 312 can be detected as the first fluctuation amount Sig-a2.

  When the frequency band in which the radio wave is radiated in the 90-degree direction from the transmitting leakage cable 2 is selected, the path length L is 2 × Z + 2 × R, and therefore the cable distance Z can be calculated from the path length L and the approach distance R. . Even when a frequency band having a radiation angle other than 90 degrees is used, since the approach distance R can be calculated by geometric calculation, the cable distance Z can also be calculated. This calculation is performed by the cable distance calculation means 205.

  As described above, since the intrusion detection apparatus according to the second embodiment performs intrusion detection of the intruding object 6 based on the approach distance R and the cable distance Z, the specific ranges of the transmission leak cable 2 and the reception leak cable 3 are determined. It is possible to detect the intrusion. Therefore, since the intrusion position of the intruding object 6 can be specified by the cable distance Z, it is possible to promptly respond to the guards thereafter. For example, individual operations such as other monitoring means (camera) and prevention means for the intruding object 6 (sounding a warning sound, turning on a flash) can be executed. In this case, the cable distance Z may be output. In addition, since it can be detected that an intrusion has occurred within a specific range, a difference in alert level in the monitoring area can be added, and many monitoring modes can be set.

  In addition, although the approach distance R and the cable distance Z are input to the determination means 206, it can also be determined only by the approach distance R. Further, the determination range of the approach distance R and the cable distance Z can be arbitrarily set. Depending on the combination of the determination range of the approach distance R and the cable distance Z, other monitoring modes can be realized.

  The approach distance R and the cable distance Z may be determined serially one by one or may be determined simultaneously, that is, by AND operation. By performing the AND operation, the circuit scale can be reduced and the time for outputting the determination result can be shortened as compared with the case where serial determination is performed.

Embodiment 3 FIG.
FIG. 9 is a diagram showing the configuration of the determination circuit of the intrusion detection device according to Embodiment 3 of the present invention. The second embodiment is different from the second embodiment in that the intrusion detection of the intruding object 6 is performed using the object reflection coefficient Γ of the intruding object 6 calculated by the reflection coefficient calculating means 207.

  The determination unit 208 determines that the approach distance R is equal to or smaller than a predetermined threshold, the cable distance Z is within a predetermined threshold range, and the object reflection coefficient Γ is equal to or larger than the predetermined threshold, and the determination signal Sig -Out is output. Since the intrusion detection of the intruding object 6 is performed based on the approach distance R, the cable distance Z, and the object reflection coefficient Γ, it is possible to detect that the intruding object 6 having a predetermined size has intruded.

Next, a method for calculating the reflection coefficient Γ of the intruding object 6 will be described. The variation ΔC of the electric field in the radiation mode is expressed by the following equation.
ΔC = CaΓexp (−2αZ) * (1 / 2R) (3)
Here, Ca is a constant such as the radiation gain of the leaking cable, Γ is the object reflection coefficient, and α is the attenuation of the radio wave per unit length of the leaking cable.

  If the electric field variation ΔC, the cable distance Z, and the approach distance R are known from the equation (3), the constant Ca and the attenuation α can be known in advance, and the object reflection coefficient Γ is obtained. If the relationship between the object reflection coefficient Γ and the object size is experimentally measured in advance, the approximate size of the intruding object 6 can be estimated. That is, according to the installation environment of the intrusion detection device, the object reflection coefficient Γ of a person, a car, a small animal, or the like that may be caught by the intrusion detection device is examined in advance. If the object reflection coefficient Γ is known, the approximate size of the intruding object 6 can be estimated by comparing with the object reflection coefficient Γ examined in advance. However, since the object reflection coefficient Γ varies depending on the material of the intruding object 6 even if it is the same size, the size estimated here is a kind of guide.

  As described above, since the intrusion detection apparatus according to the third embodiment detects the intrusion object 6 based on the approach distance R, the cable distance Z, and the object reflection coefficient Γ, the intrusion object 6 having a predetermined size enters. Can be detected.

  Unlike Embodiment 3, in the conventional method, there is no choice but to adjust with a threshold value for determining the electric field fluctuation amount ΔC. Conventionally, when a small animal is very close to the leaking cable, the fluctuation amount ΔC becomes large, so that the fluctuation amount ΔC is about the same as an intruder slightly away from the leaking cable. This is because radio waves are attenuated according to the distance away from the leaky cable, so that if it is close to the leaky cable, the electric field variation ΔC increases even if the target size is small. Therefore, in the conventional method, determination with the target size of the intruding object 6 is not possible, and there is a problem that small animals are detected.

  As described above, since the intrusion detection device according to the third embodiment detects the intrusion of the intruding object 6 based on the object reflection coefficient Γ, the intrusion detecting device has a predetermined size unlike the conventional detection of small animals. Therefore, it is possible to prevent the detection of the intruding object 6 below. Therefore, it is possible to determine the target size of the intruding object 6 that should be monitored.

  Note that the approaching distance R, the cable distance Z, and the object reflection coefficient Γ are input to the determining unit 208, but it is also possible to determine only by the approaching distance R or only by the approaching distance R and the cable distance Z. Further, the determination range of the approach distance R, the cable distance Z, and the object reflection coefficient Γ can be arbitrarily set. By combining the approach distance R, the cable distance Z, and the determination range of the object reflection coefficient Γ, a different monitoring form than that of the second embodiment can be realized.

  The approach distance R, the cable distance Z, and the object reflection coefficient Γ may be determined serially one by one or may be determined simultaneously, that is, by AND operation. By performing the AND operation, the circuit scale can be reduced and the time for outputting the determination result can be shortened as compared with the case where serial determination is performed.

Embodiment 4 FIG.
FIG. 10 is a diagram showing the configuration of the determination circuit of the intrusion detection device according to Embodiment 4 of the present invention. The third embodiment is different from the third embodiment in that intrusion detection of the intruding object 6 is performed using the object size S of the intruding object 6 calculated by the object size estimating unit 209.

  The object size estimation unit 209 receives the object reflection coefficient Γ output from the reflection coefficient calculation unit 207 and calculates the object size S of the intruding object 6. As in the third embodiment, the relationship between the object reflection coefficient Γ and the object size S may be experimentally measured in advance and calculated based on the relationship. That is, according to the installation environment of the intrusion detection device, the object reflection coefficient Γ and the object size S of a person, a car, a small animal, or the like that may be caught by the intrusion detection device are checked in advance. If the object size S is known, it is possible to detect that the intruding object 6 having a predetermined size has entered by comparing with the object size S that has been examined in advance.

  The determination unit 210 determines that the approach distance R is equal to or smaller than a predetermined threshold, the cable distance Z is within a predetermined threshold range, and the object size S is equal to or larger than the predetermined threshold, and the determination signal Sig− out is output. Since the intrusion detection of the intruding object 6 is performed based on the approach distance R, the cable distance Z, and the object size S, it can be detected that the intruding object 6 having a predetermined size has intruded. Further, since the direct object size S is used as the threshold setting parameter, the setting can be facilitated. Furthermore, since the direct object size S is used, the possibility of erroneous setting can be minimized.

  As described above, since the intrusion detection apparatus according to the fourth embodiment detects the intrusion object 6 based on the approach distance R, the cable distance Z, and the object size S, the intrusion object 6 having a predetermined size has entered. Can be detected.

  Note that the approaching distance R, the cable distance Z, and the object size S are input to the determination unit 210, but it is also possible to determine only by the approaching distance R or by the approaching distance R and the cable distance Z alone. Further, the determination range of the approach distance R, the cable distance Z, and the object size S can be arbitrarily set. By combining the approach distance R, the cable distance Z, and the object size S determination range, it is possible to realize a monitoring mode other than that in the second embodiment as in the third embodiment.

  Further, the approach distance R, the cable distance Z, and the object size S may be determined in series one by one, or three at the same time, that is, by AND calculation. By performing the AND operation, the circuit scale can be reduced and the time for outputting the determination result can be shortened as compared with the case where serial determination is performed.

Embodiment 5 FIG.
In the first to fourth embodiments, the example in which the leakage cables having the same characteristics are used for both the transmission leakage cable 2 and the reception leakage cable 3 has been described. In the fifth embodiment, an example in which a leakage cable having different characteristics is used for the transmission leakage cable 2 and the reception leakage cable 3 will be described.

  In the fifth embodiment, three transmission / reception mode signals are used. Specifically, the first transmission / reception mode signal is a signal having a frequency at which the transmission leakage cable 2 and the reception leakage cable 3 operate in the radiation mode. The second transmission / reception mode signal is a signal having a frequency at which the transmission leakage cable 2 and the reception leakage cable 3 operate in the surface wave mode. The third transmission / reception mode signal is a signal having a frequency at which the transmission leakage cable 2 operates in the surface wave mode and the reception leakage cable 3 operates in the radiation mode.

  The relationship between the frequency f and the operation mode of the leakage cable has already been described in the first embodiment. If the basic period P of the leakage cable is, for example, 1 m for the transmission leakage cable 2 and 1.2 m for the reception leakage cable 3, and the relative dielectric constant εr is 1.23, the transmission leakage from the equation (1) The frequency of the boundary between the cable 2 and the reception leaking cable 3 is as follows. In the transmission leakage cable 2, a frequency lower than about 142 MHz is a surface wave mode, and a frequency higher than about 142 MHz is a radiation mode. In the receiving leakage cable 3, a frequency lower than about 119 MHz is a surface wave mode, and a frequency higher than about 119 MHz is a radiation mode.

  That is, about 119 MHz or less may be assigned to the first transmission / reception mode signal frequency, about 119 MHz to about 142 MHz to the third transmission / reception mode signal frequency, and about 142 MHz or more to the second transmission / reception mode signal frequency.

  FIG. 11 is a diagram showing the relationship between the electric field fluctuation amount ΔC and the approach distance R in the fifth embodiment. The horizontal axis is the logarithm of the approach distance R, and the vertical axis is the logarithm of the electric field fluctuation amount ΔC. A characteristic line 301 is a variation characteristic of the electric field in the signal received in the radiation mode when the signal transmitted in the radiation mode is reflected by the intruding object 6. The characteristic line 302 is a variation characteristic of the electric field in the signal received in the surface wave mode when the signal transmitted in the surface wave mode is reflected by the intruding object 6. A characteristic line 401 is a variation characteristic of the electric field in the signal received in the radiation mode when the signal transmitted in the surface wave mode is reflected by the intruding object 6.

  When the above-described third transmission / reception mode signal is used, the characteristic line 401 becomes a characteristic between the characteristic line 301 and the characteristic line 302 as shown in FIG. In the second transmission / reception mode signal using the surface wave mode for both transmission and reception, the electric field variation ΔC rapidly decreases as the approach distance R increases as indicated by the characteristic line 302. Since the measurement cannot be performed when the reception sensitivity of the wireless device 1 is lower than the reception sensitivity, the first transmission / reception mode signal (characteristic line 301) is used to measure a middle distance region where the second transmission / reception mode signal is lower than the reception sensitivity of the wireless device 1. ) And the third transmission / reception mode signal (characteristic line 401) are effective. If it is not desired to radiate radio waves far away, a signal having a frequency that operates in the surface wave mode may be used in transmission, that is, a second transmission / reception mode signal (characteristic line 302) and a third transmission / reception mode signal (characteristics). Use of the line 401) is effective.

  The method for detecting intruding object 6 is the same as in Embodiments 1 to 4, and description thereof will not be repeated.

  As described above, since the intrusion detection apparatus according to the fifth embodiment uses the leakage cables having different characteristics from the transmission leakage cable 2 and the reception leakage cable 3, the intrusion detection apparatuses according to the first to fourth embodiments receive sensitivity. It is possible to detect that the intruding object 6 has entered even at a distance that cannot be observed.

  Note that, as the third transmission / reception mode signal, the transmission leakage cable 2 operates in the surface wave mode and the reception leakage cable 3 is a signal having a frequency that operates in the radiation mode. A signal having a frequency that operates in the radiation mode and the reception leakage cable 3 operates in the surface wave mode may be used. Also in this case, the characteristic line 401 is a characteristic between the characteristic line 301 and the characteristic line 302 as shown in FIG.

  Further, although the signal operating in the surface wave mode has been described, a signal operating in the quasi-surface wave mode can be used instead of the surface wave mode. By using radio waves in the quasi-surface wave mode, it is possible to detect the intruding object 6 at an approach distance R that is longer than that in the surface wave mode.

Embodiment 6 FIG.
FIG. 12 is a diagram showing a configuration of an intrusion detection device according to Embodiment 6 of the present invention. In the first to fourth embodiments, a signal of one frequency is transmitted from the transmission leakage cable 501, and two reception leakage cables, that is, a first reception leakage cable 502 and a second reception leakage cable 503 are used. They differ in that they receive different transmission / reception mode signals and detect the intrusion of the intruding object 6.

  In FIG. 12, 500 is an oscillator, 504 to 506 are terminators, 507 and 508 are amplifiers, and 509 and 510 are band-pass filters.

  In the sixth embodiment, the transmission leakage cable 501 is operated in the radiation mode, the first reception leakage cable 502 is operated in the surface wave mode, and the second reception leakage cable 503 is operated in the radiation mode. As described above, since the surface wave mode or the radiation mode is determined depending on the slot interval and the use frequency, the first reception leakage cable 502 and the second reception leakage cable 503 have different characteristics. Is used.

  The oscillator 500 generates a transmission signal having a frequency at which the transmission leakage cable 501 operates in the radiation mode. The generated transmission signal is amplified by the amplifier 104 and radiated from the transmission leakage cable 501 as a radio wave. The emitted radio wave is reflected by the intruding object 6 and is received by both the first reception leakage cable 502 and the second reception leakage cable 503. The reception signal received by the first reception leakage cable 502 is amplified to a predetermined level by the amplifier 507, and the first transmission / reception mode signal from which the signal of the unnecessary frequency is removed is separated by the band pass filter 509. The detector 109 detects the first transmission / reception mode signal and outputs amplitude and phase information from the signal as a first amplitude phase signal. In the sixth embodiment, the first transmission / reception mode signal is a signal having a frequency at which the transmission leakage cable 501 operates in the radiation mode and the reception leakage cable 502 operates in the surface wave mode.

  On the other hand, the received signal received by the second receiving leakage cable 503 is amplified to a predetermined level by the amplifier 508, and the second transmission / reception mode signal from which the signal of the unnecessary frequency is removed is separated by the band pass filter 510. . The detector 110 detects the second transmission / reception mode signal and outputs amplitude and phase information from the signal as a second amplitude phase signal. In the sixth embodiment, the second transmission / reception mode signal is a signal having a frequency at which the transmission leakage cable 501 operates in the radiation mode and the reception leakage cable 503 operates in the radiation mode.

  As described above, the first amplitude / phase signal has a characteristic that combines transmission in the radiation mode and reception in the surface wave mode. The second amplitude / phase signal has a combination of radiation mode transmission and radiation mode reception.

  The method for detecting intruding object 6 is the same as in Embodiments 1 to 4, and description thereof will not be repeated.

  As described above, the intrusion detection device according to the sixth embodiment transmits a radiation mode signal from the transmission leakage cable 501 at one frequency, and the first reception leakage cable 502 and the second reception leakage cable 503. Since the transmission / reception mode signals which are different from each other are received, the intrusion detection apparatus according to the first to fourth embodiments can detect that the intruding object 6 has entered even at a distance that cannot be observed because the reception sensitivity is lower than the receiving sensitivity. Further, since transmission is performed with only one oscillator, the circuit scale of the transmission unit 11 can be simplified as compared with the first to fourth embodiments.

  In addition, although there is a leakage cable that operates only in the surface wave mode in principle, such as an open coaxial cable, this may be used as the first reception leakage cable 502.

  The first transmission / reception mode signal has been described in the case of a signal having a frequency at which the transmission leakage cable 501 operates in the radiation mode. However, even if the transmission leakage cable 501 has a frequency at which the transmission leakage cable 501 operates in the surface wave mode. I do not care. This is effective when it is not desired to radiate radio waves far away.

  Further, although the signal operating in the surface wave mode has been described, a signal operating in the quasi-surface wave mode can be used instead of the surface wave mode. By using radio waves in the quasi-surface wave mode, it is possible to detect the intruding object 6 at an approach distance R that is longer than that in the surface wave mode.

  Although the first to fifth embodiments have been described using two oscillators, the frequency of one oscillator is switched, and the frequency signal of the radiation mode and the surface wave mode or the quasi-surface wave mode is switched and output. Also good. A control signal indicating which signal is being output is input to the determination circuit 111, and the determination circuit reads the outputs of the detector 109 and the detector 110 based on the control signal, and then uses the method described above. The intruding object 6 may be detected. With this configuration, the circuit scale of the transmission unit 11 can be simplified.

  Note that the determination circuit 111 of the first to sixth embodiments may be realized by software. It can be changed to other monitoring modes simply by replacing the software. As a result, detailed corrections and function additions are possible, and maintenance and version upgrade of the intrusion detection device can be facilitated.

It is a figure which shows the structure of the intrusion detection apparatus in Embodiment 1 of this invention. 5 is a diagram for explaining intrusion detection according to Embodiment 1. FIG. It is a figure which shows the structure of the determination circuit of FIG. It is a figure explaining the effect | action of the fluctuation amount calculating means of FIG. 6 is a diagram showing a relationship between an electric field fluctuation amount ΔC and an approach distance R in the first embodiment. FIG. It is a figure which shows the relationship between the difference D of FIG. It is a figure which shows the structure of the determination circuit of the intrusion detection apparatus in Embodiment 2 of this invention. FIG. 10 is a diagram for explaining a method for calculating a path length L in the second embodiment. It is a figure which shows the structure of the determination circuit of the intrusion detection apparatus in Embodiment 3 of this invention. It is a figure which shows the structure of the determination circuit of the intrusion detection apparatus in Embodiment 4 of this invention. FIG. 10 is a diagram showing a relationship between electric field fluctuation amount ΔC and approach distance R in the fifth embodiment. It is a figure which shows the structure of the intrusion detection apparatus in Embodiment 6 of this invention.

Explanation of symbols

  2 Leakage cable for transmission, 3 Leakage cable for reception, 6 Intruding object, 8 Reference line, 11 Transmitter, 12 Receiver, 13 Detector, 201 First variation calculation means, 202 Second variation calculation means, 203 proximity distance calculation means, 205 cable distance calculation means, 207 reflection coefficient calculation means, 209 object size estimation means, 501 transmission leakage cable, 502 first reception leakage cable, 503 second reception leakage cable, L path Long, R approach distance, Z cable distance.

Claims (11)

A transmission unit for supplying a transmission signal to the leakage transmission unit; and a reception unit for detecting the reception signal received by the leakage reception unit arranged in parallel with the leakage transmission unit for the transmission signal radiated from the leakage transmission unit; , An intrusion detection device including a detection unit for detecting an intruding object by analyzing the phase amplitude signal output from the reception unit,
The reception unit separates a first transmission / reception mode signal from the reception signal and outputs a first phase amplitude signal, and a second transmission / reception mode signal different from the first transmission / reception mode signal from the reception signal To output a second phase amplitude signal,
The detection unit includes a first fluctuation amount calculating unit that calculates a first fluctuation amount from the first phase amplitude signal, and a second fluctuation that calculates a second fluctuation amount from the second phase amplitude signal. Based on the difference between the amount calculation means and the first variation amount and the second variation amount, the approach distance between the predetermined reference line and the intruding object in the extending direction of the leak transmitting means and the leak receiving means is calculated. An intrusion detection apparatus having an approach distance calculating means for calculating, and detecting the intruding object by determining the approach distance with a predetermined threshold. The first transmission / reception mode signal is a first frequency signal having a frequency at which the leaky transmission unit and the leaky reception unit operate in a radiation mode;
The second transmission / reception mode signal is a second frequency signal having a frequency at which the leakage transmission unit and the leakage reception unit operate in a surface wave mode or a quasi-surface wave mode,
The intrusion detection apparatus according to claim 1, wherein the transmission unit supplies the first frequency signal to the leaky transmission unit and supplies the second frequency signal to the leaky transmission unit. The first transmission / reception mode signal is a first frequency signal having a frequency at which the leaky transmission unit and the leaky reception unit operate in a radiation mode;
The second transmission / reception mode signal is a third frequency signal having a frequency at which the leakage transmission unit operates in a surface wave mode or a quasi-surface wave mode and the leakage reception unit operates in a radiation mode.
The intrusion detection apparatus according to claim 1, wherein the transmission unit supplies the first frequency signal to the leaky transmission unit and supplies the third frequency signal to the leaky transmission unit. The first transmission / reception mode signal is a first frequency signal having a frequency at which the leaky transmission unit and the leaky reception unit operate in a radiation mode;
The second transmission / reception mode signal is a fourth frequency signal having a frequency at which the leakage transmission unit operates in a radiation mode and the leakage reception unit operates in a surface wave mode or a quasi-surface wave mode,
The intrusion detection apparatus according to claim 1, wherein the transmission unit supplies the first frequency signal to the leaky transmission unit and supplies the fourth frequency signal to the leaky transmission unit. The first transmission / reception mode signal is a second frequency signal having a frequency at which the leakage transmission unit and the leakage reception unit operate in a surface wave mode or a quasi-surface wave mode,
The second transmission / reception mode signal is a third frequency signal having a frequency at which the leakage transmission unit operates in a surface wave mode or a quasi-surface wave mode and the leakage reception unit operates in a radiation mode.
The intrusion detection apparatus according to claim 1, wherein the transmission unit supplies the second frequency signal to the leaky transmission unit and supplies the third frequency signal to the leaky transmission unit. The first transmission / reception mode signal is a second frequency signal having a frequency at which the leakage transmission unit and the leakage reception unit operate in a surface wave mode or a quasi-surface wave mode,
The second transmission / reception mode signal is a fourth frequency signal having a frequency at which the leakage transmission unit operates in a radiation mode and the leakage reception unit operates in a surface wave mode or a quasi-surface wave mode,
The intrusion detection apparatus according to claim 1, wherein the transmission unit supplies the second frequency signal to the leaky transmission unit and supplies the fourth frequency signal to the leaky transmission unit. The leakage receiving means includes a first leakage receiving means, a second leakage receiving means having a reception mode different from that of the first leakage receiving means,
The first transmission / reception mode signal is a fifth frequency of the frequency at which the leak transmitting means operates in the surface wave mode or the quasi-surface wave mode and the first leak receiving means operates in the surface wave mode or the quasi-surface wave mode. Signal,
The second transmission / reception mode signal is the fifth frequency signal having a frequency at which the leakage transmission unit operates in a surface wave mode or a quasi-surface wave mode and the second leakage reception unit operates in a radiation mode.
The intrusion detection apparatus according to claim 1, wherein the transmission unit supplies the fifth frequency signal to the leakage transmission unit. The leakage receiving means includes a first leakage receiving means, a second leakage receiving means having a reception mode different from that of the first leakage receiving means,
The first transmission / reception mode signal is a sixth frequency signal having a frequency at which the leakage transmission unit operates in a radiation mode and the first leakage reception unit operates in a surface wave mode or a quasi-surface wave mode;
The second transmission / reception mode signal is the sixth frequency signal at a frequency at which the leaky transmission means operates in the radiation mode and the second leaky reception means operates in the radiation mode,
The intrusion detection apparatus according to claim 1, wherein the transmission unit supplies the sixth frequency signal to the leakage transmission unit. The detection unit detects that the transmission signal supplied from the transmission unit detects the intruding object from a transmission end of the leaky transmission unit based on a state detection time when the state of the first variation amount becomes a predetermined state. A cable distance for calculating the cable length of the intruding object along the leaky transmission means from the transmission end based on the path length and the approach distance based on the path length and the approach distance The intrusion detection device according to claim 1, further comprising an arithmetic unit, wherein the intruding object is detected by determining the cable distance with a predetermined threshold. The detection unit includes reflection coefficient calculation means for calculating an object reflection coefficient of the intruding object based on the first variation amount, the approach distance, and the cable distance, and determines the object reflection coefficient with a predetermined threshold value. The intrusion detection apparatus according to claim 9, wherein the intrusion object is detected. The detection unit includes a reflection coefficient calculation unit that calculates an object reflection coefficient of the intruding object based on the first fluctuation amount, the approach distance, and the cable distance, and the object reflection coefficient calculated by the reflection coefficient calculation unit The intrusion detection apparatus according to claim 9, further comprising: an object size estimation unit configured to estimate an object size based on the object size, and detecting the intrusion object by determining the object size with a predetermined threshold.

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