JP2014029663A - Monitoring system and monitoring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monitoring system and a monitoring method capable of suppressing monitoring errors, even when there are many electric waves having frequency bands that are the same as or adjacent to that of an electric wave to be used, in a structure in which human activities are monitored in a predetermined area by using the electric wave.SOLUTION: A monitoring system 201 comprises: a transmitter 151, which is installed in a predetermined area, for transmitting an electric wave; and an invasion detection device 101, which is installed in a predetermined area, for receiving the electric wave transmitted from the transmitter 151 and monitoring human activities in the predetermined area on the basis of the received electric wave. The transmitter 151 repeats a transmission period of an electric wave and a transmission stop period. Then, the invasion detection device 101 calculates a space feature amount in a predetermined area by using an electric wave received within the transmission period of the received electric waves and monitors human activities in the predetermined area on the basis of the calculated space feature amount.

Description

  The present invention relates to a monitoring system and a monitoring method, and more particularly to a monitoring system and a monitoring method for monitoring a human motion using a spatial feature.

  Intrusion detection devices that detect human movements in a predetermined area such as a room have been developed. As an example of an intrusion detection method, for example, “Study on indoor intruder detection by UWB-IR”, Terajaka Junji et al., IEICE Transactions B, Vol. J90-B, No. 1, pp.97-100, 2007 On January 1, 2000 (Non-Patent Document 1), a method using a propagation delay profile, that is, a power delay profile by UWB-IR (Ultra Wide Band-Impulse Radio) is disclosed.

  However, in the method described in Non-Patent Document 1, interference with other wireless services becomes a problem because a wideband signal is used, and because the received signal power is used, it is affected by indoor multipath fading, The detection accuracy may deteriorate.

  As a technique for solving such a problem, for example, Japanese Patent Laid-Open No. 2008-216152 (Patent Document 1) discloses the following configuration. That is, the event detection device calculates an eigenvector, that is, an arrival angle distribution based on the received signal of each array antenna, and calculates an inner product value of the eigenvector and a normal eigenvector as a comparison reference. Then, the event detection device detects an event, that is, an intruder, based on a comparison result between the inner product value and a predetermined threshold value.

"Examination of indoor intruder detection by UWB-IR" Keiji Terasaka et al., IEICE Transactions B, Vol. J90-B, No. 1, pp.97-100, January 1, 2007

JP 2008-216152 A

  When the radio wave used by the event detection device described in Patent Document 1 is, for example, a 2.4 GHz band radio wave, the radio wave output from other electronic devices such as a microwave oven, a Bluetooth (registered trademark) device, and a ZigBee device. A large number of radio waves in the same or close frequency band exist in the detection target area. For this reason, the event detection apparatus performs calculation for intrusion detection using radio waves other than radio waves to be used, and erroneous detection occurs.

  The present invention has been made in order to solve the above-described problems, and has as its object the use of a frequency band that is the same as or close to the radio wave to be used in a configuration for monitoring human actions in a predetermined area using radio waves. To provide a monitoring system and a monitoring method capable of suppressing monitoring errors even when there are a large number of radio waves.

  (1) In order to solve the above-described problem, a monitoring system according to an aspect of the present invention is arranged in a predetermined area and is arranged in a predetermined area, and is arranged in the predetermined area and transmitted from the transmitter. And a receiver for monitoring a human operation in the predetermined area based on the received radio wave, wherein the transmitter includes a transmission period and a transmission stop of the radio wave. The receiver repeats the period, and the receiver calculates a spatial feature amount in the predetermined area using a radio wave received in the transmission period among the received radio waves, and a human in the predetermined area based on the calculated spatial feature amount. Monitor the operation of

  With such a configuration, wireless signals from other devices such as Bluetooth devices and wireless LAN devices during the transmission suspension period can be excluded from the monitoring calculation target. As a result, in an environment where it is unclear which radio signal is to be monitored due to a turbulent radio signal, the timing to be monitored can be clarified and monitoring can be performed satisfactorily. In addition, the above “repeat radio wave transmission period and transmission stop period” means repeating periodically, repeating aperiodically, or a combination thereof. Therefore, it is possible to arbitrarily set the transmission period and the transmission stop period.

  Therefore, in a configuration in which human action in a predetermined area is monitored using radio waves, monitoring errors can be suppressed even when there are many other radio waves in the same or close frequency band as the radio waves to be used.

  (2) Preferably, the transmitter transmits an unmodulated signal as the radio wave, and the receiver includes a radio wave having a frequency component different from that of the unmodulated signal among the radio waves received in the transmission period. The radio wave determined to be excluded is excluded from the spatial feature calculation target.

  With such a configuration, a radio wave having a frequency component different from that of the unmodulated signal can be handled as a jamming wave, so that the jamming wave can be easily identified.

  Then, when a radio wave received during the transmission period includes an interfering wave, the receiver excludes the radio wave from the target for calculating the spatial feature amount, thereby improving the human motion monitoring accuracy in a predetermined area. Can do.

  Further, for example, it is possible to narrow a range in which a band of a wideband interference wave radiated from a Bluetooth device and a wireless LAN device overlaps a band of a desired wave.

  As a result, the probability that the desired wave and the disturbing wave overlap on the frequency axis can be reduced, so that the receiver can reduce the probability of receiving the disturbing wave having the same frequency as the desired wave. it can.

  (3) More preferably, the receiver includes a mixer for frequency-converting the radio wave by multiplying the received radio wave by a frequency conversion signal having substantially the same frequency as the unmodulated signal, and the mixer A filter for attenuating a component having a frequency equal to or lower than a predetermined frequency among the frequency components of the signal frequency-converted by the above, and a detection circuit for detecting the level of the signal that has passed through the filter. Based on the detection result of the detection circuit, it is determined whether or not the radio wave received in the transmission period includes a radio wave having a frequency component different from that of the unmodulated signal.

  In this way, the received radio wave is frequency-converted using a frequency conversion signal having substantially the same frequency as the non-modulated signal, so that the radio wave transmitted by the transmitter can be converted into a DC (Direct Current) or low frequency region in the baseband. Therefore, an interference wave having a frequency component different from the radio wave transmitted by the transmitter can be easily detected by monitoring only the component in the high frequency region in the baseband.

  (4) Preferably, the transmitter repeats the transmission period and the transmission stop period at a timing according to a predetermined pseudorandom pattern, and the receiver transmits a signal indicating a detection result of the received radio wave and the predetermined pseudorandom pattern. A correlation calculation with a signal according to a pattern is performed, and the timings of the transmission period and the transmission stop period are estimated based on the result of the correlation calculation.

  With such a configuration, a signal according to a predetermined pseudo-random pattern synchronized with the timing of the transmission period and the transmission stop period can be generated in the receiver.

  Accordingly, the receiver can appropriately grasp the transmission period during which radio waves should be monitored based on the predetermined pseudo-random pattern without acquiring timing information from the transmitter side.

  In addition, since the timing of the transmission period and the transmission stop period is random, in the time axis, the probability that the transmission period and the timing at which the jamming wave is transmitted can be reduced. The probability of simultaneously receiving radio waves and jamming waves from the transmitter can be reduced.

  (5) More preferably, the transmitter receives a radio wave, and the radio wave received in the transmission period includes a radio wave having a frequency component different from that of the non-modulated signal. Stop signal transmission.

  In this way, the transmission of the unmodulated signal is stopped in a situation where it is expected that it is difficult for the receiver to accurately monitor the human action due to the interference wave having a frequency component different from that of the unmodulated signal. Therefore, unnecessary radio wave radiation can be prevented. Further, power consumption of the transmitter due to unnecessary radio wave radiation can be prevented.

  (6) More preferably, the radio wave having a frequency component different from that of the non-modulated signal is a radio wave having a frequency component whose absolute value of the difference from the frequency of the non-modulated signal is smaller than a predetermined value.

  With such a configuration, when a radio wave that is an interference wave is included in the received radio wave, the radio wave can be excluded from the target for calculating the spatial feature value. Reduction can be suppressed appropriately.

  (7) More preferably, the radio wave having a frequency component different from that of the unmodulated signal is a radio wave including a frequency component receivable by the receiver.

  With such a configuration, it is possible to appropriately identify radio waves that can adversely affect the calculation of spatial feature values used for monitoring human movements and exclude them from the spatial feature value calculation targets.

  (8) Preferably, the receiver detects that there is no or little human action in the predetermined area.

  With such a configuration, it is possible to satisfactorily watch over a person in a predetermined area.

  (9) Preferably, the receiver detects occurrence of human motion in the predetermined area.

  With such a configuration, for example, it is possible to satisfactorily detect a person who has entered a predetermined area and to take effective crime prevention measures.

  (10) Further, a monitoring method according to an aspect of the present invention includes a transmitter arranged in a predetermined area for transmitting radio waves, and a radio wave arranged in the predetermined area and transmitted from the transmitter. A monitoring method in a monitoring system comprising a receiver for monitoring a human operation in the predetermined area based on the received radio wave, wherein the transmitter repeats a transmission period and a transmission stop period of the radio wave And a receiver calculates a spatial feature amount in the predetermined area using a radio wave received during the transmission period among the received radio waves, and based on the calculated spatial feature amount, a human feature in the predetermined area is calculated. Monitoring the operation.

  With such a configuration, wireless signals from other devices such as Bluetooth devices and wireless LAN devices during the transmission suspension period can be excluded from the monitoring calculation target. As a result, in an environment where it is unclear which radio signal is to be monitored due to a turbulent radio signal, the timing to be monitored can be clarified and monitoring can be performed satisfactorily. In addition, the above “repeat radio wave transmission period and transmission stop period” means repeating periodically, repeating aperiodically, or a combination thereof. Therefore, it is possible to arbitrarily set the transmission period and the transmission stop period.

  Therefore, in a configuration in which human action in a predetermined area is monitored using radio waves, monitoring errors can be suppressed even when there are many other radio waves in the same or close frequency band as the radio waves to be used.

  According to the present invention, in a configuration in which a human operation in a predetermined area is monitored using radio waves, monitoring errors are suppressed even when there are many other radio waves in the same or close frequency band as the radio waves to be used. be able to.

It is a figure which shows the usage image of the intrusion detection apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the intrusion detection system which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the transmitting apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the bit string of the predetermined pseudorandom pattern which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of DBM which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the intrusion detection apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the frequency spectrum of the electromagnetic wave processed in the intrusion detection apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the frequency spectrum in the baseband of the electromagnetic wave detected in the intrusion detection apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the received signal synchronizing part in the intrusion detection apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the change of the correlation value with respect to the time gap in the transmission side PN sequence and the reception side PN sequence which concern on the 1st Embodiment of this invention. It is a figure which shows the structure of the control part in the intrusion detection apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the signal which the transmitter and intrusion detection apparatus transmit / receive at each timing which concerns on the 1st Embodiment of this invention. It is a sequence diagram which shows an example of the operation | movement at the time of performing an intrusion detection process based on the electromagnetic wave which the intrusion detection apparatus which concerns on the 1st Embodiment of this invention received from the transmitter. It is a figure which shows the structure of the transmitting apparatus which concerns on the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<First Embodiment>
FIG. 1 is a diagram showing a usage image of the intrusion detection device according to the first embodiment of the present invention.

  Referring to FIG. 1, the intrusion detection device according to the first embodiment of the present invention functions as a moving object detection sensor. At least a pair of transmitters and receivers as intrusion detection devices are installed in a closed space, for example, a house, which is to be used as a warning area. The intrusion detection device receives a radio wave transmitted within a certain interval or continuously from the transmitter at the receiver and performs signal processing based on the received radio wave, thereby opening and closing the person and the door that has entered the room. Etc. are detected.

  For example, the intrusion detection device is an array type radio wave sensor, includes a plurality of receiving antenna elements, and realizes a moving object detection function using a change in radio wave propagation in a closed space. In principle, the radio waves used by the intrusion detection device are not limited in frequency, bandwidth, and the like.

[Basic system]
FIG. 2 is a diagram showing the configuration of the intrusion detection system according to the first embodiment of the present invention.

  Referring to FIG. 2, intrusion detection device (receiver) 101, transmitter 151, wireless LAN access point 161, wireless LAN terminal 162, and electronic device 171 are provided in a predetermined area such as a room. Yes. The intrusion detection apparatus 101 and the transmitter 151 constitute an intrusion detection system (monitoring system) 201.

  The transmitter 151 transmits the radio wave intermittently by repeating a transmission period for transmitting a radio wave based on an unmodulated signal, that is, a signal having a single frequency component, and a transmission stop period for stopping the transmission of the radio wave.

  The “single frequency component” may include a broadening of the line width due to fluctuations in the frequency of radio waves or distortions in the waveform of radio waves. “Repeat” means repeating periodically, repeating aperiodically, or a combination thereof. Therefore, it is possible to arbitrarily set the transmission period and the transmission stop period.

  The intrusion detection device 101 monitors human actions in an area where a plurality of devices such as the wireless LAN access point 161, the wireless LAN terminal 162, and the electronic device 171 transmit wireless signals.

  More specifically, the intrusion detection device 101 monitors human movements in the area based on the spatial feature amount indicating the state of the predetermined area. That is, the intrusion detection apparatus 101 monitors the state in the predetermined area based on the wave propagation properties such as reflection and diffraction. Specifically, the intrusion detection apparatus 101 monitors human movements by monitoring arrival angle distributions calculated based on reception signals of a plurality of antennas.

  In the intrusion detection system 201, the intrusion detection apparatus 101 performs a monitoring operation using 2.4 GHz band radio waves that are transmitted intermittently by the transmitter 151 by repeating the transmission period and the transmission stop period.

  The wireless LAN access point 161 transmits and receives wireless signals to and from the wireless LAN terminal 162 in accordance with a predetermined wireless communication method, for example, a wireless LAN method of the IEEE 802.11 standard. This radio signal is an ISM (Industry Science Medical band) band radio signal in the vicinity of 2.4 GHz, for example.

  The electronic device 171 is, for example, a microwave oven, a Bluetooth device, or a ZigBee device, and outputs a 2.4 GHz band radio wave to the outside during operation.

[Problems caused by receiving jamming waves]
The intrusion detection apparatus 101 receives radio waves transmitted from the transmitter 151 by, for example, a plurality of array antennas, and monitors human actions in a predetermined area by performing the following processing based on the received radio waves.

  That is, the intrusion detection apparatus 101 extracts a spatial feature amount using the arrival angle distribution, for example, in the same manner as the configuration described in Patent Document 1. That is, the intrusion detection apparatus 101 acquires an initial vector, that is, an eigenvector when there is no intruder, vno.

Next, the intrusion detection apparatus 101 enters an operation for detecting an intruder, and acquires vob (t) that is an eigenvector at the observation time t. Then, the intrusion detection apparatus 101 extracts P (t), which is a spatial feature, by calculating the inner product of vno, which is an initial vector, and vob (t). P (t) is represented by the following equation.
P (t) = vno · vob (t)

  P (t) indicates the amount of change from the initial vector serving as a comparison reference. The intrusion detection device 101 can monitor a human action in a predetermined area based on the calculated spatial feature P (t).

  Specifically, the intrusion detection device 101 detects the occurrence of a human motion in a predetermined area based on the spatial feature amount P (t). More specifically, the closer the spatial feature P (t) is to “1”, the closer the state of the predetermined area at the observation time t is to the normal state where no intruder exists in the predetermined area. For this reason, the intrusion detection apparatus 101 determines that a human has entered a predetermined area when the spatial feature P (t) is less than a predetermined threshold, for example, “0.9”.

  However, since the electronic device 171 located around the predetermined area uses a 2.4 GHz band radio signal, for example, it is the same as or very close to the frequency of radio waves transmitted and received between the transmitter 151 and the intrusion detection device 101. There are cases where a radio signal having a frequency, that is, a radio signal having a frequency component that can be detected by the intrusion detection apparatus 101 is output.

  In this case, if the intrusion detection device 101 receives the radio wave from the transmitter 151 and the radio wave from the electronic device 171 at the same time, the intrusion detection device 101 cannot distinguish the radio wave from which device. Cannot be monitored properly.

  That is, the intrusion detection apparatus 101 has a problem in that a human signal in a predetermined area cannot be appropriately monitored based on the radio wave from the transmitter 151 because the radio signal transmitted by the electronic device 171 becomes an interference wave. To do.

  For example, when the frequency of the jamming wave is always constant, the transmitter 151 and the intrusion detection device 101 select a frequency at which no jamming wave exists and perform transmission / reception of radio waves at the selected frequency, thereby causing the above problem. Can be solved. However, the jamming wave is not always a radio wave having the same frequency.

  For example, a wireless LAN access point 161, a wireless LAN terminal 162, a Bluetooth device, and the like may transmit and receive packets using a 2.4 GHz band wireless signal according to a frequency hopping method.

  The frequency hopping method is a method of changing the frequency of a radio signal transmitted / received between the wireless LAN access point 161 and the wireless LAN terminal 162 at predetermined time intervals, for example. In addition, when the transmission / reception of information is not properly performed in the wireless LAN access point 161 and the wireless LAN terminal 162 due to occurrence of an interference wave at a certain frequency, the information is transmitted / received again at another frequency, Select a frequency that generates less interference. As a result, the wireless LAN access point 161 and the wireless LAN terminal 162 can appropriately transmit and receive information.

  The wireless LAN access point 161, the wireless LAN terminal 162, the Bluetooth device, and the like that use the frequency hopping method change the use frequency every very short time. For this reason, when the intrusion detection apparatus 101 receives a radio wave transmitted by the transmitter 151, is an interference wave from the wireless LAN access point 161, the wireless LAN terminal 162, the Bluetooth device, etc. included in the received radio wave? It is difficult to determine whether or not.

  Therefore, intrusion detection system 201 according to the embodiment of the present invention solves the above problem by the following configuration and operation.

[Transmitter configuration]
FIG. 3 is a diagram illustrating a configuration of the transmitter according to the first embodiment of the present invention.

  FIG. 4 is a diagram showing an example of a bit string of a predetermined pseudo-random pattern according to the first embodiment of the present invention.

  FIG. 5 is a diagram illustrating an example of the DBM according to the first embodiment of the present invention.

  Referring to FIG. 3, transmitter 151 includes oscillator 71, DBM (Double Balanced Mixer) 72, pseudorandom signal generator 73, bandpass filter 74, power amplifier 75, antenna 76, and oscillator 85. And an up-converter 86.

  For example, the oscillator 71 generates a local signal having a frequency FIF in an IF (Intermediate Frequency) band, and outputs the generated local signal to the DBM 72. Specifically, the local signal is a sine wave of 300 MHz, for example.

  Referring to FIG. 4, pseudo-random signal generation unit 73 repeatedly generates a bit string of a predetermined pseudo-random pattern shown from time ts to time te in FIG. 4, for example, every Tp that is a predetermined period. . The bit string is pseudo-random noise that takes two values of logic high and logic low almost randomly. The chip period Tc is the reciprocal of the chip rate that is the clock frequency in the bit string.

  The pseudo random signal generation unit 73 generates a PN (Pseudorandom Noise) series signal by generating a voltage having a level corresponding to the logical value of the bit string, and outputs the generated PN series signal to the DBM 72.

  Specifically, the pseudo random signal generation unit 73 generates a PN series signal by generating a voltage Vh and a voltage Vl for a logic high and a logic low in the bit string, respectively. For example, voltage Vh is higher than a threshold voltage of a diode included in DBM 72 described later, and voltage Vl is zero volts.

  Referring to FIG. 5, DBM 72 is a double balanced modulator, which multiplies a local signal from oscillator 71 and a PN sequence signal from pseudorandom signal generator 73, and a signal indicating the multiplication result is bandpassed. Output to the filter 74.

  More specifically, the DBM 72 is represented by an equivalent circuit as shown in FIG. 5A, and includes an input-side transformer T1, an output-side transformer T2, and diodes D1, D2, D3, and D4.

  The primary coil L1 in the transformer T1 has a first end connected to the oscillator 71 via the node I1, and a second end connected to the signal ground G1. The secondary coil L2 coupled to the primary coil L1 by mutual inductance has a first end connected to the anode of the diode D1 and the cathode of the diode D3, and a second end connected to the anode of the diode D4 and the cathode of the diode D2. With ends. An intermediate point of the secondary coil L2 is connected to the pseudo random signal generation unit 73 via the node I2.

  Primary coil L12 in transformer T2 has a first end connected to the cathode of diode D1 and the anode of diode D2, and a second end connected to the cathode of diode D4 and the anode of diode D3. The intermediate point of the primary coil L12 is connected to the signal ground G2. The secondary coil L11 coupled to the primary coil L12 by mutual inductance has a first end connected to the band pass filter 74 via the node O1, and a second end connected to the signal ground G3.

  Specifically, the signal grounds G1, G2, and G3 are reference potentials having a level of zero volts.

  For example, when a zero-volt voltage corresponding to the voltage Vl is output from the pseudo random signal generation unit 73 to the node I2, the DBM 72 does not generate a potential difference between the node I2 and the signal ground G2. D3 and D4 are not in a conductive state. In this case, the DBM 72 is represented by an equivalent circuit as shown in FIG. 5B, and the local signal output from the oscillator 71 to the node I1 is the node because the diodes D1, D2, D3, and D4 are not conductive. Not output from O1.

  On the other hand, for example, when the voltage Vh is output from the pseudo random signal generation unit 73 to the node I2, a potential difference of the voltage Vh is generated between the node I2 and the signal ground G2. Since voltage Vh is higher than the threshold voltage of diodes D1, D2, D3, and D4, forward current flows in diodes D1 and D4. That is, since the diodes D1 and D4 are in a conductive state, the DBM 72 is represented by an equivalent circuit as shown in FIG. The local signal output from the oscillator 71 to the node I1 is output from the node O1 to the bandpass filter 74 because the diodes D1 and D4 are in a conductive state.

  Bandpass filter 74 attenuates components outside a predetermined frequency band in the local signal received from DBM 72. Thereby, the band pass filter 74 outputs a signal of a predetermined frequency band to the up converter 86.

  Upconverter 86 multiplies the signal received from bandpass filter 74 and the local signal of the frequency (FTX-FIF) received from oscillator 85, and outputs a signal indicating the multiplication result to power amplifier 75.

  More specifically, the up-converter 86 is a signal having a frequency FTX that is the sum of the frequency FIF of the signal received from the bandpass filter 74 and the frequency (FTX-FIF) that is the frequency of the local signal, that is, no modulation. Generate a signal. That is, up-converter 86 generates a non-modulated signal with frequency FTX by frequency-converting the signal received from bandpass filter 74. The frequency FTX is, for example, 2.4 GHz.

  Then, up-converter 86 outputs the generated 2.4 GHz band signal to power amplifier 75.

  Power amplifier 75 amplifies the local signal received from up-converter 86 and outputs the amplified signal to antenna 76. For example, as shown in FIG. 2, the signal is transmitted as radio waves from the antenna 76 to the air, and is received by the intrusion detection device 101 via a space in a predetermined area.

  The DBM 72 outputs the local signal received from the oscillator 71 to the bandpass filter 74 during the period when the level of the signal indicates + Vh in the PN sequence signal generated by the pseudo random signal generation unit 73. In other words, the period in which the level of the PN sequence signal indicates + Vh or the period in which the level of the bit string illustrated in FIG. 4 indicates logic high corresponds to a transmission period in which radio waves are transmitted from the transmitter 151.

  Further, the DBM 72 does not output the local signal received from the oscillator 71 to the band pass filter 74 during the period when the level of the PN sequence signal indicates zero volts. In other words, the period in which the level of the PN sequence signal indicates zero volts or the period in which the level of the bit string illustrated in FIG. 4 indicates logic low corresponds to a transmission stop period in which radio waves are not transmitted from the transmitter 151.

  As shown in FIG. 4, since the bit string is repeatedly generated for each period Tp in the pseudo random signal generation unit 73, the transmitter 151 repeats the transmission period and the transmission stop period of the unmodulated radio wave, thereby Transmit radio waves intermittently. That is, the transmitter 151 transmits radio waves that are on-off-keyed.

  It is assumed that the transmission period and the transmission stop period in the on / off modulation are sufficiently longer than the period of the radio wave of the unmodulated signal. In this case, the radio wave transmitted by the transmitter 151 in the transmission period can be approximated to an unmodulated radio wave, and the spread of the radio wave band due to the on / off modulation can be suppressed to be small.

[Configuration of intrusion detection device]
FIG. 6 is a diagram showing the configuration of the intrusion detection device according to the first embodiment of the present invention.

  Referring to FIG. 6, intrusion detection apparatus 101 includes interference wave detection unit 51, array reception unit 52, reception signal synchronization unit 53, control unit 54, and oscillator 55.

  The interference wave detection unit 51 includes an antenna 41, a low noise amplifier 42, a DBM 43, a high pass filter 44, and a comparator (detection circuit) 45.

  Array receiving unit 52 includes array antenna unit 21, receiving unit 22, and branch circuit 35. The array antenna unit 21 includes, for example, four antennas. The receiving unit 22 includes four sets of a band pass filter (BPF) 31, a low noise amplifier 32, a down converter 33 and an A / D converter (ADC) 34 corresponding to the antennas in the array antenna unit 21.

  For example, the oscillator 55 generates a local signal that is a frequency conversion signal having substantially the same frequency as the frequency FTX that is the sum of the frequencies of the local signals generated in the oscillator 71 and the oscillator 85 in the transmitter 151.

  The interference wave detection unit 51 determines whether or not the radio wave received by its own intrusion detection device 101 includes a radio wave having a frequency component different from that of an unmodulated signal that is a radio wave transmitted by the transmitter 151. Interference wave detection information is generated, and the generated interference wave detection information is output to the control unit 54.

  Here, the radio wave having a frequency component different from that of the non-modulated signal is, for example, a radio wave having a frequency component not included in the band of the non-modulated signal.

  FIG. 7 is a diagram illustrating an example of a frequency spectrum of radio waves processed in the intrusion detection device according to the first embodiment of the present invention.

  Referring to FIG. 7, when interference wave detection unit 51 receives only the radio wave transmitted by transmitter 151, the frequency spectrum of the received radio wave is generated by oscillator 55 as shown in FIG. A single spectrum is obtained at or near the frequency FTX, which is the frequency of the local signal to be transmitted.

  On the other hand, when the jamming wave detection unit 51 simultaneously receives the jamming wave in addition to the radio wave transmitted by the transmitter 151, the frequency spectrum of the received radio wave has a frequency FTX as shown in FIG. And a spectrum having a wide band from the frequency FL to the frequency FU.

  This is because a broadband interference wave is output from a microwave oven or the like, or in a wireless LAN access point 161, a wireless LAN terminal 162, a Bluetooth device, a ZigBee device, etc., in order to transmit / receive information at a high speed, This is because is emitted.

  Note that the interference wave in this case is assumed to be a radio wave obtained by modulating, for example, the frequency FTX or a local signal in the vicinity thereof at high speed. The same discussion can be applied to radio waves obtained by modulating a local signal greatly different from the frequency FTX at high speed.

  Referring to FIG. 6 again, the low noise amplifier 42 in the interference wave detection unit 51 amplifies the radio wave received by the antenna 41 and outputs it to the DBM 43.

  The DBM 43 multiplies the signal received from the low noise amplifier 42 and the local signal having the frequency FTX received from the oscillator 55, and outputs a signal indicating the multiplication result to the high pass filter 44.

  More specifically, the DBM 43 generates a signal having a frequency that is the sum and difference of the frequency of the signal received from the low noise amplifier 42 and the frequency FTX that is the frequency of the local signal. That is, the DBM 43 converts the frequency of the signal received from the low noise amplifier 42.

  For example, when the DBM 43 receives a signal having a single spectrum at the frequency FTX as shown in FIG. 7A from the low-noise amplifier 42, the DBM 43 performs a DC component whose frequency is zero by frequency down-conversion and frequency up-conversion. An AC component signal having a frequency of (2 × FTX) is generated.

  Further, for example, when the DBM 43 receives a signal having a wide spectrum as shown in FIG. 7B from the low noise amplifier 42, the DBM 43 generates the following signals. That is, the DBM 43 performs baseband signal having a frequency component from zero to (FU-FTX) as shown in FIG. 7C by frequency down-conversion and frequency up-conversion as shown in FIG. 2 generates a signal having a wide band from the frequency (FL + FTX) to the frequency (FU + FTX) around a frequency (2 × FTX) not shown.

  When the high-pass filter 44 receives the frequency-converted signal from the DBM 43, the high-pass filter 44 attenuates the component below the frequency Fc1 in the received signal and passes the component having a frequency higher than the frequency Fc1 to the comparator 45.

  More specifically, the high-pass filter 44 has a frequency higher than the frequency Fc1 in the frequency-converted signal received from the DBM 43 as shown in FIG. 7D in which FIG. 7C is expanded in the frequency axis direction. , That is, the component indicated by HPF is passed to the comparator 45. As a result, the high pass filter 44 outputs a signal having a frequency spectrum as shown in FIG.

  For example, when the level of the signal received from the high-pass filter 44 exceeds a predetermined threshold voltage Vth4, the comparator 45 outputs a high-level signal indicating that an interference wave has been received to the control unit 54.

  For example, when the level of the signal does not exceed the threshold voltage Vth4, the comparator 45 outputs a low level signal indicating that no interference wave is received to the control unit 54.

  FIG. 8 is a diagram illustrating an example of a frequency spectrum in a baseband of radio waves detected by the intrusion detection device according to the first embodiment of the present invention.

  Referring to FIG. 8, range 1 from zero to frequency Fr <b> 1 indicates a signal band in the baseband after frequency conversion of a radio wave of an unmodulated signal transmitted by transmitter 151. A range 2 from zero to the frequency Fr2 indicates a signal band in the baseband after frequency conversion of radio waves that can be received by the array receiving unit 52 described later.

  Referring to FIG. 8A, the interference wave detector 51 receives, for example, an RF (Radio Frequency) band radio wave JAM1 having a single spectrum, and outputs a signal in the baseband after frequency conversion of the radio wave JAM1. Assume that the signal has a frequency Fj1 having a level exceeding the threshold voltage Vth4.

  Here, it is assumed that the frequency Fj1 is higher than the frequency Fr1 and lower than the frequency Fr2. In addition, the frequency of the radio wave JAM1 may be rephrased as the absolute value of the difference from the frequency of the unmodulated signal transmitted by the transmitter 151 being larger than the frequency Fr1 and smaller than the frequency Fr2.

  The radio wave JAM1 is a radio wave having a frequency component different from that of the non-modulated signal transmitted by the transmitter 151, and the radio wave that the array receiving unit 52 erroneously detects as the radio wave transmitted by the transmitter 151. is there. The frequency Fc1 of the high pass filter 44 is assumed to be higher than the frequency Fr2.

  In this case, since the frequency Fc1 is higher than the frequency Fr2, the interference wave detection unit 51 cannot detect the radio wave JAM1 as an interference wave.

  Therefore, it is preferable that the frequency Fc1 of the high-pass filter 44 is lower in order for the interfering wave detection unit 51 to detect the radio wave JAM1 as an interfering wave. The transmitted radio wave is detected as an interference wave.

  Therefore, as shown in FIG. 8B, the frequency Fc1 of the high-pass filter 44 is set to the same value as the frequency Fr1.

  As a result, the interference wave detection unit 51 can detect the radio wave JAM1 having a frequency component that can adversely affect the array reception unit 52 such as erroneous detection as an interference wave.

  Referring to FIG. 8C, the interference wave detection unit 51 receives, for example, an RF band radio wave JAM2 having a single spectrum, and the signal in the baseband after frequency conversion of the radio wave JAM2 is the threshold voltage Vth4. Assume that the signal has a frequency Fj2 having a level exceeding.

  Here, it is assumed that the frequency Fj2 is higher than the frequency Fr1 and the frequency Fr2. In addition, the frequency of the radio wave JAM2 may be paraphrased as the absolute value of the difference from the frequency of the unmodulated signal transmitted by the transmitter 151 being higher than the frequency Fr1 and the frequency Fr2.

  The radio wave JAM2 is a radio wave having a frequency component different from that of the unmodulated signal transmitted by the transmitter 151 and is not detected by the array receiving unit 52. The frequency Fc1 of the high pass filter 44 is set to the same value as the frequency Fr1.

  In this case, since the frequency Fj2 is higher than the frequency Fc1, the interference wave detection unit 51 detects the radio wave JAM2 as an interference wave. However, since the radio wave JAM2 is a radio wave that is not detected by the array receiving unit 52, if the jamming wave detection unit 51 detects the radio wave JAM2 as a jamming wave, the data used for calculating the spatial feature amount in the intrusion detection device 101 is reduced. This is not preferable.

  Therefore, a low-pass filter that attenuates a component having a frequency higher than the frequency Fc1, for example, a component having a frequency equal to or higher than the frequency Fc2, may be disposed between the high-pass filter 44 and the comparator 45.

  For example, as shown in FIG. 8D, when the frequency Fc2 of the low-pass filter is set to the same value as the frequency Fr2, the interference wave detection unit 51 does not detect the radio wave JAM2 that is not detected by the array reception unit 52 as an interference wave.

  That is, the interference wave detection unit 51 detects a signal having a frequency component whose frequency in the baseband is higher than the frequency Fc1 and lower than the frequency Fc2 and having a level exceeding the threshold voltage Vth4 as an interference wave. .

  With such a configuration, the interfering wave detection unit 51 selectively detects a radio wave having a frequency component whose absolute value of the difference from the frequency of the non-modulated signal is smaller than a predetermined value among radio waves having a frequency component different from the non-modulated signal. can do. Thereby, the reduction | decrease of the data used for calculation of the space feature-value in the intrusion detection apparatus 101 can be suppressed appropriately.

  The above discussion can be applied not only to a single spectrum such as the radio wave JAM1 or the radio wave JAM2, but also to a radio wave having a wide baseband component.

  Since the signal received by the comparator 45 is a component having a frequency higher than the frequency Fc1 and lower than the frequency Fc2, the influence of the component in the vicinity of the frequency (2 × FTX) is eliminated, and a high level signal or a low level signal is removed. A signal can be output to the control unit 54.

  Note that the low-pass filter may be disposed not between the high-pass filter 44 and the comparator 45 but between the DBM 43 and the high-pass filter 44.

  Further, a band pass filter that attenuates frequency components below the frequency Fc1 and attenuates frequency components above the frequency Fc2 may be arranged instead of the high pass filter 44 and the low pass filter.

  Referring to FIG. 6 again, in the receiving unit 22 in the array receiving unit 52, the bandpass filter 31 is a component outside the predetermined frequency band among the frequency components of the signal received by the corresponding antenna in the array antenna unit 21. Is attenuated.

  The low noise amplifier 32 amplifies the signal that has passed through the band pass filter 31 and outputs the amplified signal to the down converter 33.

  The down converter 33 multiplies the signal received from the low noise amplifier 32 by the local signal received from the oscillator 55 via the branch circuit 35, thereby down-converting the signal received from the low noise amplifier 32, for example, in the baseband band. The signal is converted into a signal and output to the A / D converter 34.

  When receiving the timing signal from the control unit 54, the A / D converter 34 converts the signal into a digital signal indicating the level of the signal received from the down converter 33 and outputs the digital signal to the control unit 54. The value of the digital signal corresponds to the radio wave reception level in the intrusion detection apparatus 101.

  FIG. 9 is a diagram illustrating a configuration of a reception signal synchronization unit in the intrusion detection device according to the first embodiment of the present invention.

  Referring to FIG. 9, received signal synchronization unit 53 includes antenna 221, detection unit 222, comparator 223, synchronization acquisition unit 251, synchronization tracking unit 252, PN sequence generation unit 253, and synchronization tracking control unit. 254.

  The synchronization acquisition unit 251 includes a multiplier 224, a band pass filter 225, a comparator 226, and an acquisition completion determination unit 227.

  The synchronization tracking unit 252 includes multipliers 229 and 231, bandpass filters 230 and 232, a subtracting unit 233, and a lowpass filter 234.

  In addition, PN sequence generation section 253 includes pseudo random signal generation section 239 and 1/2 Tc delay sections 240 and 241.

  The reception signal synchronization unit 53 generates a PN sequence signal (hereinafter also referred to as a reception-side PN sequence) and reproduces the phase of the generated reception-side PN sequence based on the radio wave transmitted by the transmitter 151. The phase is matched with the phase of the PN sequence (hereinafter also referred to as a transmission-side PN sequence).

  The reception signal synchronization unit 53 estimates a radio wave transmission period and a transmission stop period that are repeated in the transmitter 151 based on the reception side PN sequence. Then, the reception signal synchronization unit 53 outputs a signal on the reception side PN sequence matched with the phase of the transmission side PN sequence to the control unit 54.

  More specifically, the detection unit 222 is a frequency that is the sum of the frequencies of the local signals generated by the oscillator 71 and the oscillator 85 in the transmitter 151 for the radio waves received by the antenna 221 and transmitted by the transmitter 151. Down-conversion is performed with a local signal having substantially the same frequency as FTX.

  Then, the detection unit 222 acquires the transmission side PN sequence signal by reproducing the PN sequence generated by the transmitter 151, and outputs the acquired transmission side PN sequence signal to the comparator 223.

  The comparator 223 converts the level of the signal on the transmission side PN sequence received from the detection unit 222 into a predetermined binary value based on the predetermined threshold voltage Vth1. Specifically, for example, when the level of the signal on the transmission side PN sequence received from the detector 222 is equal to or higher than the threshold voltage Vth1, the comparator 223 outputs +1 volt, and the comparator 223 outputs the signal on the transmission side PN sequence. When the level is lower than the threshold voltage Vth1, -1 volt is output.

  Then, the comparator 223 multiplies the transmission side PN sequence signal whose signal level is adjusted to +1 volt or -1 volt as the received radio wave detection result by the multiplier 224 in the synchronization acquisition unit 251 and the synchronization tracking unit 252. To the devices 229 and 231.

  The pseudo random signal generation unit 239 in the PN sequence generation unit 253 generates a pseudo random pattern generated by the pseudo random signal generation unit 73 in the transmitter 151, that is, a bit string equivalent to the pseudo random pattern shown in FIG. Then, the pseudo-random signal generation unit 239 generates a PN sequence signal having a level corresponding to the logical value of the bit string.

  Specifically, the pseudo random signal generation unit 239 generates E (Early) -code 242, which is a PN sequence signal, by generating +1 volt and -1 volt, for example, for logic high and logic low in the bit string, respectively. Is generated.

  Then, the pseudo random signal generation unit 239 outputs the generated E-code 242 to the multiplier 229 and the 1/2 Tc delay unit 240 in the synchronization tracking unit 252.

  At this time, the pseudo random signal generation unit 239 outputs the E-code 242 having the phase set by the synchronous tracking control unit 254. That is, the phase of the E-code 242 output from the pseudo random signal generation unit 239 is controlled by the synchronous tracking control unit 254.

  When receiving the E-code 242 from the pseudo-random signal generator 239, the 1/2 Tc delay unit 240 delays the received E-code 242 for a time corresponding to a half period of the chip period Tc, thereby receiving a signal on the receiving side PN sequence. P (Present) -code 243 is generated.

  Then, 1/2 Tc delay unit 240 outputs a signal on the reception side PN sequence to control unit 54, multiplier 224 in synchronization acquisition unit 251, and 1/2 Tc delay unit 241.

  When receiving the reception-side PN sequence signal from the 1 / 2Tc delay unit 240, the 1 / 2Tc delay unit 241 delays the received reception-side PN sequence signal by a time corresponding to a half period of the chip period Tc. (Late) -code 244 is generated. Then, the 1/2 Tc delay unit 241 outputs the generated L-code 244 to the multiplier 231 in the synchronization tracking unit 252.

  That is, the signal on the receiving side PN sequence is P-code 243, which is delayed from E-code 242 by a time corresponding to a half cycle of chip cycle Tc, and corresponds to a half cycle of chip cycle Tc from L-code 244. The time to do is ahead.

  In addition, the synchronization tracking control unit 254 can control the phase of the E-code 242 to control the signal of the receiving PN sequence and the phase of the L-code 244 corresponding to the phase.

  The multiplier 224 in the synchronization acquisition unit 251 performs a correlation operation between the transmission-side PN sequence signal received from the comparator 223 and the reception-side PN sequence signal received from the 1 / 2Tc delay unit 240. Specifically, the multiplier 224 multiplies the signal on the transmission side PN sequence by the signal on the reception side PN sequence.

  When the band-pass filter 225 receives a signal indicating the multiplication result of the signal on the transmission side PN sequence and the signal on the reception side PN sequence from the multiplier 224, the band pass filter 225 attenuates the high frequency component in the received signal so that only the low frequency component is obtained. Pass to comparator 226. That is, the band pass filter 225 functions as an integration circuit.

  More specifically, in the multiplier 224, for example, when the phases of the transmission side PN sequence and the reception side PN sequence completely coincide with each other, when the signal level of the transmission side PN sequence is +1 volt, the reception side PN always When the sequence signal level is +1 volt and the transmission side PN sequence signal level is −1 volt, the reception side PN sequence signal level is always −1 volt. For this reason, since the level of the signal indicating the multiplication result in the multiplier 224 is always a positive voltage, the output voltage of the bandpass filter 225, which is the integration result of the signal, has a large positive value.

  On the other hand, in the multiplier 224, for example, when the phases of the transmission side PN sequence and the reception side PN sequence are shifted, when the signal level of the transmission side PN sequence is +1 volts, the signal level of the reception side PN sequence is −1. In some cases, the level of the signal on the transmission side PN sequence is -1 volts, and the level of the signal on the reception side PN sequence may be +1 volts. Therefore, the output voltage of the bandpass filter 225 does not exceed the output voltage in the case where the phases of the transmission side PN sequence and the reception side PN sequence match.

  FIG. 10 is a diagram illustrating an example of a change in correlation value with respect to a time shift in the transmission-side PN sequence and the reception-side PN sequence according to the first embodiment of the present invention.

  Specifically, the output voltage represents a correlation value between the transmission side PN sequence and the reception side PN sequence. Then, the correlation value changes as shown in FIG. 10A with respect to a phase shift between the transmission side PN sequence and the reception side PN sequence, that is, a time shift. That is, the output voltage of the band-pass filter 225 exhibits a maximum value when the phases of the transmission side PN sequence and the reception side PN sequence match.

  Comparator 226 outputs voltage Von when the integration result received from bandpass filter 225 is equal to or higher than threshold voltage Vth2, and outputs voltage Voff when the integration result is less than threshold voltage Vth2. To do.

  Here, the threshold voltage Vth2 is equal to or lower than the integration result in the case where the phases of the transmission side PN sequence and the reception side PN sequence match, and the phases of the transmission side PN sequence and the reception side PN sequence match. It is set to a value that is greater than or equal to the integration result in the absence.

  Based on the voltage level received from the comparator 226, the acquisition completion determination unit 227 determines whether or not the phases of the transmission-side PN sequence and the reception-side PN sequence match. Specifically, when the acquisition completion determination unit 227 receives the voltage Von from the comparator 226, the acquisition completion determination unit 227 determines that the phases of the transmission side PN sequence and the reception side PN sequence match.

  Further, when receiving the voltage Voff from the comparator 226, the acquisition completion determination unit 227 determines that the phases of the transmission side PN sequence and the reception side PN sequence do not match. Then, the capture completion determination unit 227 outputs the determined result to the synchronous tracking control unit 254.

  When the synchronization tracking control unit 254 receives a determination from the acquisition completion determination unit 227 indicating that the phase of the transmission side PN sequence and the reception side PN sequence are shifted, the synchronization tracking control unit 254 performs the following processing. That is, the synchronization tracking control unit 254 performs a process of shifting the phase of the E-code 242 generated by the pseudo random signal generation unit 239 in either the positive direction or the negative direction by the time Tc, for example, every period Tp.

  The synchronization tracking control unit 254 continues the process until receiving a determination indicating that the phases of the transmission-side PN sequence and the reception-side PN sequence match from the capture completion determination unit 227, whereby the transmission-side PN sequence and reception The phases of the side PN sequences can be matched.

  Even if the reception signal synchronizer 53 performs the above processing to make the phases of the transmission side PN sequence and the reception side PN sequence coincide with each other, the phase may be shifted with time due to external noise and clock frequency fluctuations. is there. In order to deal with this phase shift, the synchronization tracking unit 252 generates an error signal indicating the phase shift between the transmission-side PN sequence and the reception-side PN sequence. Then, the synchronization tracking control unit 254 controls the phase of the E-code 242 generated in the pseudo random signal generation unit 239 based on the generated error signal, thereby changing the phases of the transmission side PN sequence and the reception side PN sequence. Match.

  More specifically, the multiplier 229 in the synchronization tracking unit 252 performs a correlation operation of the transmission side PN sequence signal received from the comparator 223 and the E-code 242 received from the pseudo random signal generation unit 239. Specifically, multiplier 229 multiplies the transmission side PN sequence signal by E-code 242.

  When the band-pass filter 230 receives the output voltage of the multiplier 229, the band-pass filter 230 attenuates the high-frequency component in the received output voltage, and passes the low-frequency component to the subtraction unit 233. The low frequency component indicates a correlation value E that is a correlation between the transmission side PN sequence signal and the E-code 242.

  Correlation value E changes as shown in FIG. 10B with respect to a phase shift between the transmission side PN sequence and the reception side PN sequence, that is, a time shift. The correlation value E shows a maximum value when the time lag is Tc / 2 indicating half of the cycle Tc of one chip.

  Multiplier 231 performs a correlation operation on the transmission-side PN sequence signal received from comparator 223 and L-code 244 received from ½ Tc delay unit 241. Specifically, multiplier 231 multiplies the transmission-side PN sequence signal by L-code 244.

  When the band-pass filter 232 receives the output voltage of the multiplier 231, the band-pass filter 232 attenuates the high-frequency component in the received output voltage to pass the low-frequency component to the subtracting unit 233. The low-frequency component indicates a correlation value L that is a correlation between the transmission-side PN sequence signal and L-code 244.

  Correlation value L changes as shown in FIG. 10C with respect to a phase shift between the transmission side PN sequence and the reception side PN sequence, that is, a time shift. The correlation value L indicates the maximum value when the time lag is (−Tc / 2).

  The subtractor 233 generates an error signal indicating a difference between the correlation value L acquired from the bandpass filter 232 and the correlation value E acquired from the bandpass filter 230, that is, (correlation value L−correlation value E), and the generated error signal Is output to the low-pass filter 234.

  The low pass filter 234 attenuates the high frequency component in the error signal received from the subtracting unit 233 and then outputs the error calculation signal to the synchronous tracking control unit 254.

  As shown in FIG. 10D, the error signal has a phase shift between the transmission-side PN sequence and the reception-side PN sequence, that is, a time shift, in the time range from (−Tc / 2) to Tc / 2. It is proportional to the deviation. Specifically, the error signal indicates zero when the phases match and there is no time lag.

  The error signal shows a positive value when the time lag is negative, that is, when the phase of the receiving PN sequence is advanced with respect to the phase of the transmitting PN sequence. The error signal shows a negative value when the time lag is positive, that is, when the phase of the receiving PN sequence is delayed with respect to the phase of the transmitting PN sequence.

  Therefore, when the error signal shows a positive value, the synchronization tracking control unit 254 delays the phase of the E-code 242 generated by the pseudo random signal generation unit 239 by, for example, a predetermined amount corresponding to the value of the error signal.

  Further, when the error signal shows a negative value, the synchronous tracking control unit 254 advances the phase of the E-code 242 generated in the pseudo random signal generation unit 239 by, for example, a predetermined amount corresponding to the error signal.

  Thus, by adjusting the generation phase of the E-code 242 generated by the pseudo random signal generation unit 239, the phase of the reception side PN sequence can be made to follow the phase of the transmission side PN sequence. That is, the P-code 243 output from the reception signal synchronization unit 53 can be synchronized with the signal of the transmission side PN sequence.

  FIG. 11 is a diagram showing a configuration of a control unit in the intrusion detection device according to the first embodiment of the present invention.

  FIG. 12 is a diagram illustrating an example of signals and jamming wave timings transmitted and received by the transmitter and the intrusion detection device at each timing according to the first embodiment of the present invention.

  Referring to FIG. 11, control unit 54 includes a spatial feature amount calculation unit 11, a detection unit 12, a sampling timing instruction unit 13, and an interference wave determination unit 14.

  The sampling timing instruction unit 13 generates a timing signal based on the P-code 243 received from the reception signal synchronization unit 53.

  Referring to FIG. 12, the horizontal axis from (A) to (F) in FIG. 12 represents the time axis. Based on the PN sequence signal generated by itself, the transmitter 151 transmits a radio wave in “ON” indicating a radio wave transmission period, and sets a radio wave transmission stop period as shown in FIG. In the “OFF” shown, the transmission of radio waves is stopped.

  Further, since the P-code 243 is synchronized with the signal on the transmission side PN sequence, the switching timing of the logic high and logic low of the timing signal generated by the sampling timing instruction unit 13 is shown in FIG. As shown, it coincides with the switching timing of the transmission period and the transmission stop period shown in FIG.

  Strictly speaking, the transmission-side PN sequence is delayed as compared with the PN sequence in the transmitter 151 by a propagation time necessary for radio waves to propagate from the transmitter 151 to the intrusion detection apparatus 101. However, when it is assumed that the one-chip period Tc is sufficiently longer than the propagation time, it may be approximated that the PN sequence and the transmitting PN sequence are synchronized.

  Referring to FIG. 11 again, sampling timing instructing unit 13 outputs the generated timing signal to A / D converter 34 in array receiving unit 52.

  The A / D converter 34 in the array receiver 52 shown in FIG. 6 samples the signal received from the down converter 33 in accordance with the timing signal received from the sampling timing instruction unit 13 and converts it into a digital signal indicating the radio wave reception level. .

  Therefore, the A / D converter 34 operates only while the transmitter 151 is transmitting radio waves, and does not sample the signal received from the down converter 33 while the transmitter 151 stops transmitting radio waves.

  Specifically, the A / D converter 34 receives from the down converter 33 from time ts1 to ts2, from time ts3 to ts4, and from time ts5 to ts6, for example, as shown in FIG. The received signal is sampled and converted into a digital signal indicating the radio wave reception level.

  Thereby, the A / D converter 34 can be operated in synchronization with the timing at which the transmitter 151 transmits radio waves.

  Further, when an interference wave is generated in a predetermined area, the interference wave detection unit 51 detects the level of the interference wave as shown in FIG. For example, the interference wave N2 is generated during a radio wave transmission stop period, but the A / D converter 34 operates only during the radio wave transmission period, and therefore does not sample the interference wave N2.

  As a result, the transmitter 151 repeats the radio wave transmission period and the transmission stop period, and the intrusion detection apparatus 101 performs sampling of the radio wave only during the transmission period, so that in the transmission stop period as in the interference wave N2. It is possible to prevent sampling of the generated interference wave.

  That is, the intrusion detection apparatus 101 receives the radio wave only during the transmission period of the on / off modulated radio wave, thereby reducing the probability of receiving the radio wave and the interfering wave at the same time as compared to the case where the radio wave is always received. Can be made.

  The interference wave determination unit 14 determines whether an interference wave is received based on the interference wave detection information received from the interference wave detection unit 51.

  More specifically, when the interference wave determination unit 14 receives a high level signal from the comparator 45 in the interference wave detection unit 51, the interference wave determination unit 14 determines that the interference wave is received, and the interference wave detection unit 14 receives a low level signal from the comparator 45. When the signal is received, it is determined that the interference wave is not received. Then, the interference wave determination unit 14 outputs the determination result to the spatial feature amount calculation unit 11.

  Specifically, the jamming wave N1 is generated during a radio wave transmission period as shown in FIG. 12C, and the comparator 45 in the jamming wave detection unit 51 is shown in FIG. A high level signal is output to the interference wave determination unit 14 from time tn1 to time tn2.

  Further, as shown in FIG. 12C, the jamming wave N2 is generated during a radio wave transmission stop period, and the comparator 45 in the jamming wave detection unit 51 performs time tn3 as shown in FIG. From time to time tn4, a high level signal is output to the interference wave determination unit 14.

  Further, as shown in FIG. 12C, the jamming wave N3 is generated from the radio wave transmission stop period to the transmission period, and the comparator 45 in the jamming wave detection unit 51 is shown in FIG. As described above, a high-level signal is output to the interference wave determination unit 14 from time tn5 to time tn6.

  As described above, since the disturbing wave N1 and the disturbing wave N3 are generated during the radio wave transmission period, the reception level of the radio wave received by the array receiving unit 52 is, for example, as shown in FIG. 151 is obtained by adding the reception level of the jamming wave to the reception level of the radio wave transmitted by 151.

  While receiving the digital signal indicating the reception level from the A / D converter 34 in the array receiving unit 52 during the radio wave transmission period, the spatial feature amount calculating unit 11 receives the determination received from the digital signal and the interference wave determining unit 14. The following processing is performed based on the result.

  That is, the spatial feature quantity calculation unit 11 receives a digital signal indicating the reception level corresponding to each antenna in the array antenna unit 21 from the array reception unit 52 while the determination result indicates that the interference wave is not received. Based on these digital signals, the level and arrival timing of the radio waves received by the array antenna unit 21 are calculated.

  Then, the spatial feature amount calculation unit 11 calculates a spatial feature amount P (t) in a predetermined area based on the calculation result. That is, the spatial feature quantity calculation unit 11 calculates a spatial feature quantity P (t) indicating the state of the predetermined area for a predetermined area where a human motion is to be detected.

  On the other hand, the spatial feature quantity calculation unit 11 excludes the digital signal received from the array reception unit 52 from the calculation target of the spatial feature quantity P (t) while the determination result indicates that the interference wave is received.

  Specifically, the space feature amount calculation unit 11 performs the following processing from time ts1 to time ts2 that is a radio wave transmission period. That is, the spatial feature quantity calculation unit 11 receives the determination result that the interference wave is not received from the interference wave determination unit 14 from time ts1 to time tn1 and from time tn2 to time ts2, as shown in FIG. As shown in (F), the spatial feature P (t) is calculated based on the digital signal received from the array receiver 52.

  Also, the spatial feature quantity calculation unit 11 receives the determination result indicating that the interference wave is received from the interference wave determination unit 14, and from time tn1 to time tn2, as shown in FIG. The digital signal received from the receiving unit 52 is excluded from the calculation target of the spatial feature value P (t).

  Further, since the spatial feature quantity calculation unit 11 always receives the determination result that the interference wave is not received from the interference wave determination unit 14 from the time ts3 to the time ts4 that is the transmission period of the radio wave, (( As shown in F), the spatial feature P (t) is calculated based on the digital signal indicating the reception level in the transmission period.

  In addition, the spatial feature amount calculation unit 11 performs the following processing from time ts5 to time ts6, which is a radio wave transmission period. That is, the spatial feature quantity calculation unit 11 receives the determination result indicating that the interference wave is received from the interference wave determination unit 14, and from time ts5 to time tn6, as shown in FIG. The digital signal received from the receiving unit 52 is excluded from the calculation target of the spatial feature value P (t).

  In addition, the spatial feature quantity calculation unit 11 receives the determination result indicating that the interference wave is not received from the interference wave determination unit 14, and from time tn6 to time ts6, as shown in FIG. Based on the digital signal received from the receiving unit 52, the spatial feature amount P (t) is calculated.

  Thereby, the space feature amount calculation unit 11 can exclude the reception level when the intrusion detection apparatus 101 simultaneously receives the radio wave and the interference wave transmitted by the transmitter 151 from the calculation target of the space feature amount.

  Then, the spatial feature quantity calculation unit 11 outputs the calculated spatial feature quantity P (t) to the detection unit 12.

  Upon receiving the spatial feature value P (t) from the spatial feature value calculation unit 11, the detection unit 12 monitors the human motion in a predetermined area based on the received spatial feature value P (t).

  FIG. 13 is a sequence diagram illustrating an example of an operation when the intrusion detection device according to the first embodiment of the present invention performs intrusion detection processing based on radio waves received from a transmitter.

  The transmitter 151 and the intrusion detection apparatus 101 read out a program including each step of the sequence from a memory (not shown) and execute it. This program can be installed externally. The installed program is distributed in a state stored in a recording medium, for example.

  Referring to FIG. 13, first, oscillator 71 in transmitter 151 generates a local signal (step S10).

  Next, the local signal is subjected to on / off modulation in the DBM 72 in the transmitter 151 by the PN sequence signal output from the pseudo random signal generation unit 73 (step S12).

  Next, the transmitter 151 up-converts and amplifies the on-off modulated local signal, and then transmits it as a radio wave from the antenna 76 (step S14). The transmitter 151 transmits the radio wave intermittently.

  The radio wave is propagated through a predetermined area and then received by, for example, the intrusion detection device 101 (step S16).

  Next, when the reception signal synchronization unit 53 in the intrusion detection apparatus 101 receives the radio wave transmitted by the transmitter 151, the reception signal synchronization unit 53 reproduces the transmission side PN sequence based on the received radio wave. Then, the reception signal synchronizer 53 generates a signal on the reception side PN sequence synchronized with the reproduced transmission side PN sequence (step S20).

  Next, the reception signal synchronization unit 53 outputs the P-code 243 that is a signal of the reception side PN sequence to the control unit 54 (step S22).

  Next, the control unit 54 generates a timing signal based on the P-code 243 received from the reception signal synchronization unit 53 (step S24), and outputs the generated timing signal to the array reception unit 52 (step S26).

  Next, the array receiver 52 receives radio waves intermittently transmitted by the transmitter 151 in accordance with the timing signal received from the controller 54 (step S28), and down-converts the received radio waves. Next, the array receiving unit 52 converts the down-converted signal into a digital signal indicating a reception level (step S32).

  Next, the array receiver 52 outputs the digital signal to the controller 54 (step S36).

  Further, the interference wave detection unit 51 receives radio waves transmitted intermittently by the transmitter 151 (step S30), and generates a baseband signal by down-converting the received radio waves.

  Next, the interference wave detection unit 51 generates interference wave detection information indicating whether or not an interference wave having a frequency different from the frequency of the radio wave has been received based on the baseband signal (step S34). Then, the interference wave detection unit 51 outputs the generated interference wave detection information to the control unit 54 (step S38).

  Next, when the interference wave detection information received from the interference wave detection unit 51 indicates that the interference wave is not received (NO in step S40), the control unit 54 performs the following processing.

  That is, the control unit 54 calculates a spatial feature amount based on the digital signal received from the array receiving unit 52 (step S42).

  Next, the control unit 54 detects a human motion in a predetermined area based on the calculated spatial feature amount (step S44).

  In the intrusion detection system according to the first embodiment of the present invention, the intrusion detection device 101 is configured to detect a human intrusion into a predetermined area as a human motion occurs in the predetermined area. However, the present invention is not limited to this. The intrusion detection device 101 may be configured to detect the start of a human action in a predetermined area as the occurrence of a human action in the predetermined area. Also in this case, the intrusion detection device 101 can detect the start of human action existing in the predetermined area based on the variation of the spatial feature P (t).

  By the way, when the radio wave used by the event detection device described in Patent Document 1 is, for example, a 2.4 GHz band radio wave, the same radio wave is output from other electronic devices such as a microwave oven Bluetooth device and a ZigBee device, or Many radio waves in adjacent frequency bands exist in the detection target area. For this reason, the event detection apparatus performs calculation for intrusion detection using radio waves other than radio waves to be used, and erroneous detection occurs.

  On the other hand, in the intrusion detection system according to the first embodiment of the present invention, the transmitter 151 repeats the radio wave transmission period and the transmission stop period. Then, the intrusion detection apparatus 101 calculates a spatial feature amount in the predetermined area using the received radio wave during the transmission period, and monitors human movements in the predetermined area based on the calculated spatial feature amount. .

  With such a configuration, wireless signals from other devices such as Bluetooth devices and wireless LAN devices during the transmission suspension period can be excluded from the monitoring calculation target. As a result, in an environment where it is unclear which radio signal is to be monitored due to a turbulent radio signal, the timing to be monitored can be clarified and monitoring can be performed satisfactorily. In addition, the above “repeat radio wave transmission period and transmission stop period” means repeating periodically, repeating aperiodically, or a combination thereof. Therefore, it is possible to arbitrarily set the transmission period and the transmission stop period.

  Therefore, in a configuration in which radio waves are used to monitor human movements in a predetermined area, erroneous detection, that is, monitoring errors can be suppressed even when there are many other radio waves in the same or close frequency band as the radio waves to be used. Can do.

  In the intrusion detection system according to the first embodiment of the present invention, the transmitter 151 transmits an unmodulated signal as a radio wave. Then, the intrusion detection apparatus 101 excludes radio waves that have been determined to contain radio waves having a frequency component different from that of the unmodulated signal from the radio waves received during the transmission period, from the calculation target of the spatial feature.

  With such a configuration, a radio wave having a frequency component different from that of the unmodulated signal can be handled as a jamming wave, so that the jamming wave can be easily identified.

  The intrusion detection apparatus 101, when a radio wave received during the transmission period includes an interference wave, excludes the radio wave from the target for calculating the spatial feature amount, thereby improving the human motion monitoring accuracy in a predetermined area. Can be increased.

  Further, for example, it is possible to narrow a range in which a band of a wideband interference wave radiated from a Bluetooth device and a wireless LAN device overlaps a band of a desired wave.

  Thereby, since the probability that the desired wave and the interference wave overlap on the frequency axis can be reduced, the intrusion detection apparatus 101 reduces the probability of receiving the interference wave having the same frequency as the desired wave. be able to.

  In the intrusion detection system according to the first embodiment of the present invention, the intrusion detection apparatus 101 multiplies the received radio wave by a frequency conversion signal having substantially the same frequency as the non-modulated signal, thereby generating the radio wave. DBM 43 for frequency conversion, high-pass filter 44 for attenuating components below a predetermined frequency among frequency components of the signal frequency-converted by DBM 43, and a level of a signal that has passed through high-pass filter 44 The comparator 45 is provided. Based on the detection result of the comparator 45, the intrusion detection apparatus 101 determines whether the radio wave received during the transmission period includes a radio wave having a frequency component different from that of the unmodulated signal.

  In this way, the received radio wave is frequency-converted using a frequency conversion signal having substantially the same frequency as that of the unmodulated signal, so that the radio wave transmitted by the transmitter 151 is down-converted to a DC or low frequency region in the baseband. Therefore, it is possible to easily detect an interference wave having a frequency component different from the radio wave transmitted by the transmitter 151 by monitoring only the component in the high frequency region in the baseband.

  In the intrusion detection system according to the first embodiment of the present invention, the transmitter 151 repeats the transmission period and the transmission stop period at a timing according to a predetermined pseudo-random pattern. The intrusion detection apparatus 101 performs a correlation operation between the transmission side PN sequence signal indicating the detection result of the received radio wave and the reception side PN sequence signal according to a predetermined pseudo-random pattern, and transmits based on the correlation calculation result. Estimate the timing of the period and the transmission suspension period.

  With such a configuration, the intrusion detection apparatus 101 can generate a signal according to a predetermined pseudo-random pattern synchronized with the timing of the transmission period and the transmission stop period.

  Thereby, the intrusion detection apparatus 101 can appropriately grasp the transmission period during which radio waves should be monitored without acquiring timing information from the transmitter 151 side based on the predetermined pseudo-random pattern.

  In addition, since the timing of the transmission period and the transmission stop period is random, it is possible to reduce the probability that the transmission period overlaps with the timing at which the jamming wave is transmitted on the time axis. Can reduce the probability of receiving radio waves and jamming waves from the transmitter 151 at the same time.

  In addition, in the intrusion detection system according to the first embodiment of the present invention, the intrusion detection device 101 detects the occurrence of a human action in a predetermined area.

  With such a configuration, for example, it is possible to satisfactorily detect a person who has entered a predetermined area and to take effective crime prevention measures.

  In the intrusion detection apparatus according to the first embodiment of the present invention, the eigenvector is used as the spatial feature quantity. However, the present invention is not limited to this. Not only the eigenvector but also a configuration using other spatial features such as a delay profile described in Non-Patent Document 1 may be used.

  In the intrusion detection apparatus according to the first embodiment of the present invention, the one-dimensional feature value is used as the spatial feature value. However, the present invention is not limited to this. A configuration using a multidimensional feature value as the spatial feature value may be used. For example, the eigenvector itself can be used as the feature vector, or a delay profile as described in Non-Patent Document 1 can be used.

  In the intrusion detection system according to the first embodiment of the present invention, the human motion in the predetermined area is detected based on the on / off modulated radio wave. However, the present invention is not limited to this. For example, an intrusion detection system that detects human movement in a predetermined area by using frequency hopping may be used.

  Moreover, although the intrusion detection system according to the first embodiment of the present invention is configured to use unmodulated radio waves, the present invention is not limited to this. For example, an intrusion detection system that detects a human motion in a predetermined area by using a modulated radio wave may be used.

  Further, the intrusion detection device according to the first exemplary embodiment of the present invention is configured to receive radio waves from different antennas in the interference wave detection unit 51, the array reception unit 52, and the reception signal synchronization unit 53, respectively. However, the present invention is not limited to this. The interference wave detection unit 51, the array reception unit 52, and the reception signal synchronization unit 53 may be configured to process received radio waves based on radio waves received from all or partly shared antennas.

  The intrusion detection device according to the first embodiment of the present invention is configured to synchronize with the timing at which the transmitter 151 transmits radio waves based on a predetermined pseudo-random pattern included in the received radio waves. However, the present invention is not limited to this. The transmitter 151 may be configured to transmit some signal as timing information to the intrusion detection apparatus 101 by wire.

  Moreover, although the intrusion detection apparatus according to the first embodiment of the present invention is configured to perform a binary determination of the presence or absence of an intruder, the present invention is not limited to this. The structure which outputs the parameter | index which shows the level of intrusion possibility may be sufficient.

  Moreover, although the intrusion detection device according to the first embodiment of the present invention is an array type radio wave sensor, it may be another type of radio wave sensor.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Second Embodiment>
The present embodiment relates to an intrusion detection system in which an interference wave detection function is added in a transmitter as compared with the intrusion detection system according to the first embodiment. The contents other than those described below are the same as those of the intrusion detection system according to the first embodiment.

  FIG. 14 is a diagram illustrating a configuration of a transmitter according to the second embodiment of the present invention.

  Referring to FIG. 14, transmitter 152 includes power amplifier 84 instead of power amplifier 75 as compared with transmitter 151 according to the first embodiment, and further includes transmission control unit 82 and interference wave detection unit. 83.

  The interference wave detection unit 83 includes an antenna 77, a low noise amplifier 78, a DBM 79, a high pass filter 80, and a comparator 81.

  For example, the oscillator 71 generates a local signal having a frequency FIF in an IF (Intermediate Frequency) band, and outputs the generated local signal to the DBM 72.

  The pseudo-random signal generation unit 73 generates a PN sequence signal and outputs the generated PN sequence signal to the DBM 72 and the transmission control unit 82.

  The DBM 72 multiplies the local signal from the oscillator 71 and the PN sequence signal from the pseudo random signal generator 73 and outputs a signal indicating the multiplication result to the bandpass filter 74.

  Bandpass filter 74 attenuates components outside a predetermined frequency band in the local signal received from DBM 72. Thereby, the band pass filter 74 outputs a signal of a predetermined frequency band to the up converter 86.

  Upconverter 86 multiplies the signal received from bandpass filter 74 and the local signal of the frequency (FTX-FIF) received from oscillator 85, and outputs a signal of frequency FTX indicating the multiplication result to power amplifier 84.

  Power amplifier 84 amplifies the local signal received from up-converter 86 and outputs the amplified signal to antenna 76. The amplification factor of the power amplifier 84 is controlled by the transmission control unit 82.

  The jamming wave detection unit 83 generates jamming wave detection information for determining whether or not the transmitter 152 of the own wave has received the jamming wave by the following process. That is, the low noise amplifier 78 in the interference wave detection unit 83 amplifies the radio wave received by the antenna 77 and outputs it to the DBM 79.

  The oscillator 87 generates a local signal having a frequency FTX in the 2.4 GHz band, for example, and outputs the generated local signal to the DBM 79. Specifically, the local signal is, for example, a 2.4 GHz sine wave. For example, a mixer that generates the sum frequency of the oscillator 71 and the oscillator 85 may be arranged instead of the oscillator 87.

  The DBM 79 multiplies the signal received from the low noise amplifier 78 and the local signal having the frequency FTX received from the oscillator 87, and outputs the signal subjected to frequency conversion to the high pass filter 80 by multiplication.

  When the high-pass filter 80 receives the frequency-converted signal from the DBM 79, the high-pass filter 80 attenuates the component below the frequency Fc3 in the received signal, and passes the component having a frequency higher than the frequency Fc3 to the comparator 81.

  For example, when the level of the signal received from the high-pass filter 80 exceeds a predetermined threshold voltage Vth3, the comparator 81 outputs a high-level signal indicating that an interference wave has been received to the transmission control unit 82.

  For example, when the level of the signal does not exceed the threshold voltage Vth3, the comparator 81 outputs a low-level signal indicating that no interference wave is received to the transmission control unit 82.

  Note that a low-pass filter that attenuates a component having a frequency higher than the frequency Fc3, for example, a component having a frequency equal to or higher than the frequency Fc4, may be disposed between the high-pass filter 80 and the comparator 81. As a result, the signal received by the comparator 81 becomes a frequency component between the frequency Fc3 and the frequency Fc4. Therefore, after eliminating the influence of the component near the frequency (2 × FTX), the high-level signal or the low-level signal The signal can be output to the transmission control unit 82.

  That is, the interference wave detection unit 83 outputs a high-level signal that is interference wave detection information to the transmission control unit 82 when the interference wave is received. Further, the interference wave detection unit 83 outputs a low-level signal that is interference wave detection information to the transmission control unit 82 when no interference wave is received.

  The transmission control unit 82 controls the amplification factor of the power amplifier 84 based on the PN sequence signal received from the pseudo random signal generation unit 73 and the interference wave detection information received from the interference wave detection unit 83.

  Specifically, the transmission control unit 82 receives a signal of a level indicating that a radio wave is transmitted from its own transmitter 152 in the PN sequence signal, and transmits the interference wave in the interference wave detection information. When receiving a high level signal indicating reception, the amplification factor of the power amplifier 84 is made zero. As a result, the transmitter 152 stops transmitting radio waves.

  Thus, when the transmitter 152 detects an interfering wave having a frequency different from that of the radio wave transmitted by itself during the transmission period in which the radio wave is transmitted, the transmitter 152 can stop the transmission of the radio wave.

  Since other configurations and operations are the same as those of the intrusion detection system according to the first embodiment, detailed description thereof will not be repeated here.

  As described above, in the intrusion detection system according to the second embodiment of the present invention, the transmitter 152 receives a radio wave, and the radio wave received in the transmission period includes a radio wave having a frequency component different from that of the unmodulated signal. While included, the transmission of the unmodulated signal in the transmission period is stopped.

  In this way, transmission of the unmodulated signal is stopped in a situation where it is difficult for the intrusion detection device 101 to accurately monitor the human action due to the interference wave having a frequency component different from that of the unmodulated signal. By doing so, unnecessary radio wave radiation can be prevented. Further, power consumption of the transmitter 152 due to unnecessary radio wave radiation can be prevented.

  In the intrusion detection system according to the first and second embodiments of the present invention, the radio wave having a frequency component different from that of the unmodulated signal has an absolute value of a difference from the frequency of the unmodulated signal smaller than a predetermined value. It is a radio wave of the frequency component.

  With such a configuration, when a radio wave that becomes an interference wave is included in the received radio wave, the radio wave can be excluded from the spatial feature amount calculation target. Data reduction can be appropriately suppressed.

  In the intrusion detection system according to the first and second embodiments of the present invention, the radio wave having a frequency component different from that of the unmodulated signal is a radio wave including a frequency component that can be received by the intrusion detection device 101.

  With such a configuration, it is possible to appropriately identify radio waves that can adversely affect the calculation of spatial feature values used for monitoring human movements and exclude them from the spatial feature value calculation targets.

  In the intrusion detection system according to the second embodiment of the present invention, the intrusion detection device 101 is configured to detect a human intrusion into a predetermined area as a human motion occurs in the predetermined area. However, the present invention is not limited to this. The intrusion detection device 101 is configured to detect the start of a human action existing in a predetermined area as the occurrence of a human action in the predetermined area, similar to the intrusion detection system 201 according to the first embodiment of the present invention described above. It may be.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Third Embodiment>
The present embodiment relates to a monitoring system in which the purpose of use is changed as compared with the monitoring system according to the first embodiment and the second embodiment. The contents other than those described below are the same as those of the monitoring system according to the first embodiment, that is, the intrusion detection system 201.

  In the intrusion detection system 201 according to the first exemplary embodiment of the present invention, the detection unit 12 in the intrusion detection apparatus 101 has a predetermined area based on the spatial feature amount P (t) calculated by the spatial feature amount calculation unit 11. As the monitoring of the human motion in, the occurrence of the human motion in the predetermined area, for example, the intrusion of the human into the predetermined area or the start of the human action existing in the predetermined area is detected.

  On the other hand, in the watching system (monitoring system) 301 according to the third embodiment of the present invention, as a monitoring process for monitoring human actions in a predetermined area, a person in the predetermined area, specifically, a person to be watched over A watch-over process is performed to detect no or small movements.

  More specifically, the detection unit 12 of the intrusion detection apparatus 101 in the watching system 301 has no human action in a predetermined area based on the spatial feature P (t) calculated by the spatial feature calculation unit 11 or Detect low. Specifically, for example, the detection unit 12 monitors whether or not there is a person who has not moved for a predetermined time due to occurrence of an abnormality such as a heart attack in a predetermined area. This predetermined area is, for example, an area where one or a plurality of humans are performing an action such as walking during normal times.

  The spatial feature amount calculation unit 11 of the intrusion detection apparatus 101 in the watching system 301 is similar to the spatial feature amount calculation unit 11 in the intrusion detection system 201 according to the first embodiment of the present invention, and the initial vector vno A spatial feature P (t) at the observation time t is calculated using the eigenvector vob (t) at t.

  Here, the initial vector vno used as a reference for comparison in the watching system 301 is an eigenvector when no person is present in a predetermined area, for example.

  Therefore, as the spatial feature P (t) is smaller than “1”, the state of the predetermined area at the observation time t is closer to the normal state where one or more people are moving.

  For this reason, the detection unit 12 determines that there is no or little human action in the predetermined area when the state in which the spatial feature P (t) is equal to or greater than the predetermined threshold continues for a predetermined time or longer.

  Specifically, assuming that the predetermined threshold value is “0.9”, the detection unit 12 determines that the human being in a predetermined area is human if the spatial feature P (t) is smaller than “0.9”. It is determined that the operation is in a normal state. On the other hand, when the state in which the spatial feature P (t) is “0.9” or more continues for a predetermined time or more, the detection unit 12 determines that there is no human action or a small abnormal state in the predetermined area. .

  Since other configurations and operations are the same as those of the intrusion detection system 201 according to the first embodiment of the present invention described above, detailed description will not be repeated here.

  As described above, in the watching system according to the third embodiment of the present invention, the transmitter 151 repeats the radio wave transmission period and the transmission stop period. Then, the intrusion detection apparatus 101 calculates a spatial feature amount in the predetermined area using the received radio wave during the transmission period, and monitors human movements in the predetermined area based on the calculated spatial feature amount. .

  With such a configuration, wireless signals from other devices such as Bluetooth devices and wireless LAN devices during the transmission suspension period can be excluded from the monitoring calculation target. As a result, in an environment where it is unclear which radio signal is to be monitored due to a turbulent radio signal, the timing to be monitored can be clarified and monitoring can be performed satisfactorily. In addition, the above “repeat radio wave transmission period and transmission stop period” means repeating periodically, repeating aperiodically, or a combination thereof. Therefore, it is possible to arbitrarily set the transmission period and the transmission stop period.

  Therefore, in a configuration in which radio waves are used to monitor human movements in a predetermined area, erroneous detection, that is, monitoring errors can be suppressed even when there are many other radio waves in the same or close frequency band as the radio waves to be used. Can do.

  Further, in the watching system according to the third embodiment of the present invention, the intrusion detection device 101 detects that there is no or little human action in a predetermined area.

  With such a configuration, it is possible to satisfactorily watch over a person in a predetermined area.

  In the monitoring system 301 according to the third embodiment of the present invention, it has been described that the contents other than those described above are the same as the intrusion detection system 201 according to the first embodiment of the present invention. It may be the same as the intrusion detection system according to the second embodiment of the present invention.

  For example, the watching system 301 according to the third embodiment of the present invention may include a transmitter 152 as in the intrusion detection system according to the second embodiment of the present invention. In this case, the interference wave detection unit 83 in the transmitter 152 detects an interference wave transmitted from another device.

  Then, when the jamming wave is detected by the jamming wave detection unit 83, the transmitter 152 stops transmission of the on / off modulated radio wave.

  In this way, stop transmission of unmodulated signals in situations where it is expected that it is difficult for the receiver to accurately detect human movements due to interference waves having frequency components different from those of unmodulated signals. Thus, monitoring errors in the receiver can be suppressed, and human watching in a predetermined area can be performed satisfactorily. In addition, since unnecessary radio wave radiation can be prevented, power consumption of the transmitter due to unnecessary radio wave radiation can be prevented.

  In the intrusion detection apparatus according to the third embodiment of the present invention, the eigenvector is used as the spatial feature quantity, but the present invention is not limited to this. Not only the eigenvector but also a configuration using other spatial features such as a delay profile described in Non-Patent Document 1 may be used.

  In the intrusion detection apparatus according to the third embodiment of the present invention, the one-dimensional feature value is used as the spatial feature value. However, the present invention is not limited to this. A configuration using a multidimensional feature value as the spatial feature value may be used. For example, the eigenvector itself can be used as the feature vector, or a delay profile as described in Non-Patent Document 1 can be used.

  In addition, the intrusion detection system according to the third embodiment of the present invention is configured to detect human movements in a predetermined area based on radio waves subjected to on / off modulation. However, the present invention is not limited to this. For example, an intrusion detection system that detects human movement in a predetermined area by using frequency hopping may be used.

  Moreover, although the intrusion detection system according to the third embodiment of the present invention is configured to use unmodulated radio waves, the present invention is not limited to this. For example, an intrusion detection system that detects a human motion in a predetermined area by using a modulated radio wave may be used.

  Further, the intrusion detection device according to the third exemplary embodiment of the present invention is configured to receive radio waves from different antennas in the interference wave detection unit 51, the array reception unit 52, and the reception signal synchronization unit 53, respectively. However, the present invention is not limited to this. The interference wave detection unit 51, the array reception unit 52, and the reception signal synchronization unit 53 may be configured to process received radio waves based on radio waves received from all or partly shared antennas.

  The intrusion detection device according to the third embodiment of the present invention is configured to synchronize with the timing at which the transmitter 151 transmits radio waves based on a predetermined pseudo-random pattern included in the received radio waves. However, the present invention is not limited to this. The transmitter 151 may be configured to transmit some signal as timing information to the intrusion detection apparatus 101 by wire.

  Moreover, although the intrusion detection device according to the third embodiment of the present invention is configured to perform a binary determination of the presence or absence of an intruder, the present invention is not limited to this. It may be configured to output an index indicating the level of possibility of human inactivity or low activity.

  Moreover, although the intrusion detection device according to the third embodiment of the present invention is an array type radio wave sensor, other types of radio wave sensors may be used.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 11 Spatial feature-value calculation part 12 Detection part 13 Sampling timing instruction | indication part 14 Interference wave determination part 21 Array antenna part 22 Reception part 31 Band pass filter 32 Low noise amplifier 33 Down converter 34 A / D converter 35 Branch circuit 41, 77 Antenna 42, 78 Low noise amplifier 43, 79 DBM
44, 80 High-pass filter 45, 81 Comparator (detection circuit)
51, 83 Interference wave detection unit 52 Array reception unit 53 Reception signal synchronization unit 54 Control unit 71, 85, 87 Oscillator 72 DBM
73 Pseudorandom signal generator 74 Bandpass filter 75, 84 Power amplifier 76 Antenna 82 Transmission controller 86 Upconverter 101 Intrusion detection device (receiver)
151 Transmitter 161 Wireless LAN Access Point 162 Wireless LAN Terminal 171 Electronic Equipment 201 Intrusion Detection System (Monitoring System)
221 Antenna 222 Detector 223, 226 Comparator 224, 229, 231 Multiplier 225, 230, 232 Band pass filter 227 Acquisition completion determination unit 233 Subtraction unit 234 Low pass filter 239 Pseudo random signal generation unit 240, 241 1/2 Tc delay unit 251 Synchronization acquisition unit 252 Synchronization tracking unit 253 PN sequence generation unit 254 Synchronization tracking control unit 301 Monitoring system (monitoring system)

Claims (10)

A transmitter arranged in a predetermined area for transmitting radio waves,
A monitoring system including a receiver disposed in the predetermined area, receiving a radio wave transmitted from the transmitter, and monitoring a human operation in the predetermined area based on the received radio wave;
The transmitter repeats the radio wave transmission period and transmission stop period,
The receiver calculates a spatial feature amount in the predetermined area using a radio wave received during the transmission period among the received radio waves, and monitors a human action in the predetermined area based on the calculated spatial feature amount. Monitoring system. The transmitter transmits an unmodulated signal as the radio wave,
The receiver excludes, from the calculation target of the spatial feature quantity, radio waves determined to include radio waves having frequency components different from those of the unmodulated signal among radio waves received during the transmission period. The monitoring system according to 1. The receiver
A mixer for frequency converting the radio wave by multiplying the received radio wave by a frequency conversion signal having substantially the same frequency as the unmodulated signal;
A filter for attenuating components below a predetermined frequency among the frequency components of the signal frequency-converted by the mixer;
A detection circuit for detecting the level of the signal that has passed through the filter,
3. The receiver according to claim 2, wherein the receiver determines whether a radio wave received in the transmission period includes a radio wave component having a frequency component different from that of the unmodulated signal based on a detection result of the detection circuit. The monitoring system described. The transmitter repeats the transmission period and the transmission stop period at a timing according to a predetermined pseudo-random pattern,
The receiver performs a correlation calculation between a signal indicating a detection result of the received radio wave and a signal according to the predetermined pseudo-random pattern, and estimates timings of the transmission period and the transmission stop period based on the correlation calculation result The monitoring system according to any one of claims 1 to 3.   The transmitter receives radio waves and stops transmission of unmodulated signals in the transmission period while radio waves received in the transmission period include radio waves of frequency components different from the unmodulated signals; The monitoring system according to claim 2 or claim 3.   The radio wave having a frequency component different from that of the unmodulated signal is a radio wave having a frequency component whose absolute value of the difference from the frequency of the unmodulated signal is smaller than a predetermined value. Monitoring system.   The monitoring system according to claim 6, wherein the radio wave having a frequency component different from that of the non-modulated signal is a radio wave including a frequency component receivable by the receiver.   The monitoring system according to any one of claims 1 to 7, wherein the receiver detects that there is no or little human action in the predetermined area.   The monitoring system according to any one of claims 1 to 7, wherein the receiver detects occurrence of a human motion in the predetermined area. A transmitter arranged in a predetermined area for transmitting radio waves,
A monitoring method in a monitoring system, comprising: a receiver disposed in the predetermined area, receiving a radio wave transmitted from the transmitter, and monitoring a human operation in the predetermined area based on the received radio wave. And
The transmitter repeats the radio wave transmission period and transmission stop period; and
The receiver calculates a spatial feature amount in the predetermined area using a radio wave received during the transmission period among the received radio waves, and monitors a human action in the predetermined area based on the calculated spatial feature amount. And a monitoring method.

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