JP2015041332A - Intruder detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intruder detection system capable of securing the detecting accuracy of illegal intrusion.SOLUTION: When an intruder detection system 5 is turned on, a transmitter 6 periodically transmits a super-wideband radio wave Suwb to a receiver 7. An intruder presence/absence determination part 8 calculates a propagation distance from the propagation time of the super-wideband radio wave Suwb received by the receiver 7, and compares the propagation distance with a threshold. When the propagation distance is coincident with or approximate to the threshold, the super-wideband radio wave Suwb of the transmitter 6 is transmitted as a direct wave to the receiver 7 so that the absence of a person between the transmitter 6 and the receiver 7 is determined. On the other hand, when the propagation distance is not coincident with the threshold, the super-wideband radio wave Suwb is interrupted by a person, and transmitted as an indirect wave to the receiver 7 so that the presence of an intruder in a room is determined.

Description

  The present invention relates to an intruder detection system for monitoring unauthorized intrusion.

  2. Description of the Related Art Conventionally, an intruder detection system that detects unauthorized intruders in a vehicle is well known (see Patent Document 1). The intruder detection system is a kind of vehicle anti-theft device. The intruder detection system sounds an alarm with a horn, a buzzer, or the like when a sensor or the like detects intrusion of a person into the vehicle, for example, in a state where the vehicle door is not normally unlocked.

JP 2010-210500 A

  By the way, the sensor of the intruder detection system generally uses a radio wave sensor, a vibration sensor, an infrared sensor, a Hall IC, or the like. However, this type of sensor has a problem that the frequency of false alarms increases because there is a current situation in which unauthorized intrusion into the vehicle cannot be accurately detected.

  The objective of this invention is providing the intruder detection system which can ensure the detection precision of an unauthorized intrusion.

  An intruder detection system that solves the above-mentioned problems has a transmitter with an ultra-wide bandwidth and can transmit an ultra-wide wave in the microwave band (for example, 1 GHz or more), and can receive the ultra-wide bandwidth. And an intruder presence / absence judgment unit that judges whether or not there is an intruder by checking whether the ultra-wideband radio wave received by the receiver is a direct wave or a non-direct wave.

  According to this configuration, attention is paid to the fact that the ultra-wideband radio waves have the characteristics that the attenuation to the human body is large, the straightness is high, and the wraparound is small. The presence or absence of an intruder is determined by checking whether the wave reaches the receiver by waves or indirect waves. That is, when there is no person between the transmitter and the receiver, the ultra-wideband radio wave transmitted from the transmitter reaches the receiver by direct waves, and when there is a person between the transmitter and the receiver, the transmitter Since the ultra-wideband radio wave transmitted from the non-direct wave reaches the receiver, the presence of an intruder is determined. When monitoring the presence or absence of intruders, it is possible to judge the presence or absence of intruders more accurately than when using various sensors by adopting a system that uses ultra-wideband radio waves like this configuration. It becomes. Therefore, it is possible to ensure the detection accuracy of unauthorized intrusion.

  In the intruder detection system, the intruder presence / absence determination unit includes a propagation distance calculation unit that calculates a propagation distance required for the ultra wideband radio wave of the transmitter to reach the receiver, and the propagation distance is a direct wave. Alternatively, it is preferable to include a propagation distance validity determining unit that determines whether or not there is an intruder by confirming which value corresponds to a non-direct wave. According to this configuration, it is possible to accurately detect an intruder using the propagation distance measurement principle.

  In the intruder detection system, when there is no person in the room, the intruder detection system includes a threshold setting unit configured to set a threshold necessary for direct wave or indirect wave identification, and the intruder presence determination unit is received by the receiver Preferably, when the ultra-wideband radio wave satisfies the threshold, the radio wave is identified as a direct wave, and when the ultra-wideband radio wave does not satisfy the threshold, the radio wave is preferably identified as an indirect wave. According to this configuration, an appropriate threshold value is set, which is further advantageous in ensuring the accuracy of detecting unauthorized intrusion.

  In the intruder detection system, it is preferable that the threshold setting unit sets the threshold when a door that opens and closes the room is locked. According to this configuration, since the threshold value is set when the door is locked with a high possibility that there is no person in the room, it is more advantageous for setting the optimum threshold value. Therefore, it becomes more advantageous for ensuring the detection accuracy of unauthorized intrusion.

  In the intruder detection system, the ultra-wide band radio wave is preferably an impulse. According to this configuration, since the impulse is a radio wave having a short pulse width, there are advantages in that the distance resolution is high and the distance measurement accuracy is good. Therefore, it becomes more advantageous for ensuring the detection accuracy of unauthorized intrusion.

  In the intruder detection system, the intruder presence / absence determination unit uses the first wave of the impulse to check whether the ultra-wideband radio wave received by the receiver is a direct wave or a non-direct wave. Is preferably performed. According to this configuration, if an intruder is detected with the first pulse, for example, the presence or absence of the intruder is determined by the second and subsequent pulses that reach the receiver by reflecting off an outdoor obstacle, for example. You do n’t have to. Therefore, even if there is a person's movement outside the room, there is no effect on the determination of intruder detection, which is further advantageous in ensuring the accuracy of detecting unauthorized intrusion.

  In the intruder detection system, when receiving the first transmitter / receiver in which the transmitter and the receiver are integrated, and the ultra-wideband radio wave transmitted from the transmitter, it returns the response to the first transmitter / receiver. A second transceiver, wherein the intruder presence / absence determining unit determines the presence / absence of an intruder using the ultra-wideband radio wave transmitted from the first transceiver and returning through the second transceiver. Is preferred. According to this configuration, it is not necessary to synchronize the first transceiver and the second transceiver, which is advantageous for simplifying the operation control.

  ADVANTAGE OF THE INVENTION According to this invention, intruder detection system can ensure the detection precision of an unauthorized intrusion.

The block diagram of the intruder detection system of 1st Embodiment. Frequency spectrum diagram of ultra-wideband radio waves. The operation | movement figure when setting the threshold value used for confirmation of the correctness of propagation distance. Explanatory drawing of the calculation method of propagation distance. The operation | movement figure when an intruder is not indoors. The operation | movement figure when an intruder exists in a room. (A)-(c) is a communication sequence diagram of the intruder detection system of 2nd Embodiment. The block diagram of the intruder detection system of another example.

(First embodiment)
Hereinafter, a first embodiment of an intruder detection system will be described with reference to FIGS.
As shown in FIG. 1, an intruder detection monitoring target (hereinafter referred to as a vehicle 1) includes a security ECU (Electronic Control Unit) 2 that controls various functions against vehicle theft. The security ECU 2 is connected to a door locking / unlocking detection unit 3 that detects a locking / unlocking state of the vehicle door and a notification unit 4 that can notify an alarm sound. The door locking / unlocking detection unit 3 may be either a switch or a sensor. For example, the notification unit 4 is preferably a horn or a buzzer.

  The vehicle 1 includes an intruder detection system 5 that detects the presence or absence of unauthorized intruders in a room (for example, in a vehicle). The intruder detection system 5 is one function of the vehicle anti-theft function managed by the security ECU 2. The intruder detection system 5 includes a transmitter 6 capable of transmitting an ultra-wideband radio wave Suwb indoors, a receiver 7 capable of receiving an ultra-wideband radio wave Suwb transmitted from the transmitter 6, and an ultra-wideband received by the receiver 7. An intruder presence / absence determination unit 8 that determines whether there is an unauthorized intruder in the room by checking whether the radio wave Suwb is a direct wave or a non-direct wave. The transmitter 6 transmits, for example, one impulse I as the ultra-wideband radio wave Suwb. The transmitter 6 and the receiver 7 are preferably arranged at a position where they can communicate by direct waves and through which an intruder passes. The intruder presence / absence determination unit 8 is preferably provided, for example, in the security ECU 2.

  The direct wave refers to a radio wave that reaches the receiver 7 directly without being blocked by an obstacle, for example, the ultra wideband radio wave Suwb transmitted from the transmitter 6. The indirect wave refers to a radio wave that reaches the receiver 7 after the super wide band radio wave Suwb transmitted from the transmitter 6 is blocked by an obstacle, and includes, for example, a reflected wave, a refracted wave, a diffracted wave, and the like. .

  The transmitter 6 preferably includes a timer 9, for example. The transmitter 6 can recognize the transmission time of the ultra-wideband radio wave Sub by this timer 9. The receiver 7 preferably includes a timer 10, for example. The receiver 7 can recognize the reception time of the ultra-wideband radio wave Suwb by the timer 10. The transmitter 6 and the receiver 7 are time synchronized by setting the timers 9 and 10 at the same time, for example.

  As shown in FIG. 2, the ultra-wideband radio wave Suwb is, for example, a radio wave having a bandwidth of 500 MHz or more and a frequency in the microwave band (1 GHz or more). For example, the frequency of the ultra-wideband radio wave Suwb is preferably 3 GHz to 11 GHz. The frequency of the ultra-wideband radio wave Suwb may be 3 GHz to 5 GHz, or 7 GHz to 11 GHz. In any case, it is preferable to set the frequency of the ultra-wideband radio wave Suwb to a value that satisfies the law.

  As shown in FIG. 1, the intruder presence / absence determination unit 8 includes a propagation distance calculation unit 11 that calculates a propagation distance D required until the ultra wideband radio wave Suwb of the transmitter 6 reaches the receiver 7, and a propagation distance D A propagation distance validity determination unit 12 is provided for determining whether there is an intruder in the room by checking whether the value conforms to a direct wave or a non-direct wave. The propagation distance calculation unit 11 calculates a propagation time t required for the ultra wideband radio wave Suwb from the transmitter 6 to the receiver 7, and calculates the propagation distance D of the ultrawideband radio wave Suwb based on the propagation time t. When the propagation distance D satisfies the threshold Dk, the propagation distance validity determination unit 12 determines that the ultra-wideband radio wave Suwb received by the receiver 7 is a direct wave, and when the propagation distance D does not satisfy the threshold Dk, It is determined that the ultra-wideband radio wave Suwb received by the receiver 7 is a non-direct wave.

  The intruder detection system 5 includes a threshold setting unit 13 that sets a threshold Dk for identifying a direct wave or an indirect wave when there is no person in the room. The threshold setting unit 13 is preferably provided in the security ECU 2, for example. When the threshold setting unit 13 detects that the vehicle door is locked based on the detection signal of the door locking / unlocking detection unit 3, for example, the threshold setting unit 13 measures the distance of the ultra-wideband radio wave Suwb and calculates the propagation distance D calculated at this time. Is set as the threshold value Dk.

Next, the operation of the intruder detection system 5 will be described with reference to FIGS.
[Operation when vehicle door is locked]
As shown in FIG. 3, it is assumed that the authorized user gets off the vehicle 1 and locks the vehicle door. When detecting that the vehicle door is locked, the door locking / unlocking detection unit 3 outputs a vehicle door locking signal to the security ECU 2. When the threshold value setting unit 13 receives the vehicle door locking signal from the door locking / unlocking detection unit 3, the threshold setting unit 13 performs measurement of the propagation distance D at the initial time in order to set the threshold value Dk for unauthorized intrusion determination. At this time, since there are no unauthorized intruders in the room, the ultra-wideband radio wave Suwb transmitted from the transmitter 6 reaches the receiver 7 by a direct wave.

  FIG. 4 illustrates a method for calculating the propagation distance D. The propagation time of the ultra-wideband radio wave Suwb is “t”, the time when the ultra-wideband radio wave Suwb is transmitted by the transmitter 6 is “T1”, and the time for the ultra-wideband radio wave Suwb data to be transmitted inside the transmitter 6 is “ It is assumed that the time when the receiver 7 receives the ultra-wideband radio wave Suw b is “T2”, and the time during which the data of the ultra-wideband radio wave Suwb is transmitted inside the receiver 7 is “t2”. In this case, the propagation distance D of the ultra-wideband radio wave Suwb is calculated by the equation (α) in the figure. Note that “c” in the formula (α) is an electromagnetic wave, that is, the speed of light. “T1” is the time required for the data of the ultra-wideband radio wave Suwb output from a device such as the CPU of the transmitter 6 to be transmitted from the antenna of the transmitter 6. “T2” is, for example, the time required for the data of the ultra-wideband radio wave Suwb received by the antenna of the receiver 7 to reach a device such as the CPU of the receiver 7. “T1” and “t2” are fixed values uniquely determined from each transmitter 6 and receiver 7. The threshold value setting unit 13 sets the threshold value Dk calculated in this way as a reference for a normal state in which there is no intruder in the room.

  For example, when the vehicle door is locked and the threshold value Dk is set, the intruder presence / absence determination unit 8 turns on the intruder detection system 5. That is, the intruder detection function is enabled in order to monitor unauthorized intrusion into the vehicle when the vehicle is parked. Therefore, the intruder presence / absence determination unit 8 transmits the ultra-wideband radio wave Suwb from the transmitter 6 regularly or irregularly, and periodically measures the propagation distance D. The propagation distance calculation unit 11 calculates the propagation distance D by calculating the propagation time t of the ultra-wideband radio wave Suwb every time it receives the ultra-wideband radio wave Suwb. The propagation distance validity judgment unit 12 compares the propagation distance D with the threshold value Dk each time, thereby determining whether the ultra-wideband radio wave Suwb just received is a direct wave or a non-direct wave. .

[Operation in normal state]
As shown in FIG. 5, when there is no intruder in the room and there is no intruder, there is nothing to block the ultra-wideband radio wave Suwb transmitted from the transmitter 6, so the ultra-wideband radio wave Suwb is transmitted directly to the receiver 7 as a wave. reach. For this reason, the propagation distance D calculated by the propagation distance calculation unit 11 matches or approximates the threshold value Dk. Therefore, the propagation distance validity determination unit 12 confirms that the calculated propagation distance D satisfies the threshold value Dk, and therefore determines that there is no unauthorized intruder in the room. Accordingly, no warning or the like is notified.

[Operation when there is an intruder]
As shown in FIG. 6, when an intruder enters the room illegally, the ultra-wideband wave Suwb transmitted from the transmitter 6 is blocked by the intruder. reach. That is, the receiver 7 receives not a direct wave but a non-direct wave. For this reason, the propagation distance D calculated by the propagation distance calculation unit 11 does not coincide with the threshold value Dk. Therefore, the propagation distance validity determination unit 12 confirms that the calculated propagation distance D does not satisfy the threshold value Dk, and therefore determines that there is an unauthorized intruder in the room. Note that it is also determined that there is an intruder when the ultra-wideband radio wave Suwb does not reach the receiver 7 at all. When the security ECU 2 detects that there is an unauthorized intruder in the room, the security ECU 2 sounds an alarm.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) The intruder detection system 5 detects the presence / absence of an unauthorized intruder in the room using ultra-wideband Suwb communication (UWB communication method). By the way, the ultra-wideband radio wave Suwb has the characteristics that the amount of attenuation with respect to the human body is large, the straightness is high, and the wraparound is small. Therefore, if the intruder detection system 5 of this example is used, it is possible to determine the presence or absence of an intruder with higher accuracy than when various sensors are used. Therefore, the detection accuracy of unauthorized intrusion can be ensured.

  (2) The propagation distance D is calculated from the propagation time t of the ultra-wideband radio wave Suwb, and the existence of an intruder is determined by confirming the validity of the propagation distance D. Therefore, intruder detection can be performed with high accuracy using the measurement principle of the propagation distance D.

  (3) When there is no person in the room, the propagation distance D is measured, the state is set as a normal state, and a threshold value Dk necessary for identifying a direct wave or an indirect wave is set. Therefore, since an appropriate threshold value Dk is set, it is further advantageous for ensuring the detection accuracy of unauthorized intrusion.

  (4) Since the threshold value Dk is set at the time of door locking when there is a high possibility that there is no person in the room, it is more advantageous for setting the optimum threshold value Dk. That is, even if a bag or the like is placed on the seat, the threshold value Dk based on that is set. Therefore, it becomes more advantageous for ensuring the detection accuracy of unauthorized intrusion.

  (5) The ultra-wideband radio wave Suwb uses an impulse wave having a very short pulse width. For this reason, the ultra-wideband radio wave Suwb has a high distance resolution and an improved distance measurement accuracy. Therefore, it becomes more advantageous for ensuring the detection accuracy of unauthorized intrusion.

  (6) If the data rate of the ultra-wideband radio wave Suwb is set to an appropriate data rate according to the indoor environment, it is possible to accurately discriminate between direct waves and indirect waves. Specific examples of appropriate data rate setting include a format in which the pulse length of the ultra-wideband radio wave Suwb is set longer.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. This example is one specific example of intruder detection, and the basic configuration is the same as that of the first embodiment. Therefore, the same parts as those in the first embodiment are denoted by the same reference numerals, detailed description thereof is omitted, and only different parts are described in detail.

  As shown in FIGS. 7A to 7C, the propagation distance calculation unit 11 sets the propagation distance D by the pulse I 1 received in the first wave among the pulses of the ultra-wideband radio wave Suwb received by the receiver 7. taking measurement. This is because the pulse received by the receiver 7 includes, for example, a pulse I2 that is reflected by an object outside the vehicle, and if the propagation distance D is measured by this pulse I2, it propagates due to the movement of the object outside the vehicle. This is because the distance D may deviate from the threshold value Dk, which leads to a false alarm.

Next, operation | movement of the intruder detection system 5 is demonstrated using Fig.7 (a)-(c).
[Operation in normal state]
As shown in FIG. 7A, the transmitter 6 transmits one impulse I as an ultra-wideband radio wave Suwb. This impulse I is received by the receiver 7. In the figure, a pulse I1 that has reached the receiver 7 by a direct wave and a plurality (or one) of pulses I2 that have reached the receiver 7 by being reflected by an object outside the vehicle are illustrated. Incidentally, the pulse I1 that has reached the receiver 7 by a direct wave reaches the receiver 7 as it is without being blocked by an object, so that the electric field strength is high. On the other hand, the pulse I2 that reaches the receiver 7 by being reflected by an object outside the vehicle is attenuated by being blocked by the object, so that the electric field strength is low.

  The propagation distance calculation unit 11 calculates the propagation distance D using the first wave pulse I1 received by the receiver 7. Here, since the case of normal time when no intruder exists in the room is taken as an example, the propagation distance D matches or approximates the threshold value Dk. Therefore, the propagation distance validity determination unit 12 confirms that the calculated propagation distance D satisfies the threshold value Dk, and therefore determines that there is no unauthorized intruder in the room. Accordingly, no warning or the like is notified.

[Operation when there is an intruder]
As shown in FIG. 7B, when an intruder enters the room illegally, the impulse I transmitted from the transmitter 6 is blocked by the intruder and reaches the receiver 7 as an indirect wave. That is, the first pulse I1 is received at a time when the phase is delayed by a predetermined amount with respect to the normal time. For this reason, the propagation distance D calculated from the pulse I1 of the first wave whose phase is delayed does not coincide with the threshold value Dk. Therefore, the propagation distance validity determination unit 12 confirms that the calculated propagation distance D does not satisfy the threshold value Dk, and therefore determines that there is an unauthorized intruder in the room. As a result, an alarm or the like that indicates an unauthorized intruder is notified.

[Operation when a change outside the passenger compartment appears]
As shown in FIG. 7C, it is assumed that in a normal state where there is no intruder in the room, reflection occurs in an object outside the vehicle, for example, when a person passes outside the vehicle, and the state of the received pulse changes. The change of the impulse I reflected by the object outside the vehicle appears after the first wave. However, in the case of this example, the propagation distance D is measured by the pulse I1 received at the first wave, so that these reflected waves are not affected. Therefore, even if there is a person's movement outside the vehicle, this does not trigger an alarm, which is advantageous in preventing false alarms.

According to the configuration of the present embodiment, the following effects can be obtained in addition to (1) to (6) described in the first embodiment.
(7) Since the intruder is detected by the pulse I1 received in the first wave, the presence / absence of the intruder is determined by the pulse I2 after the second wave reaching the receiver 7, for example, by reflecting off an outdoor obstacle. You do n’t have to. Therefore, even if there is a person's movement outside the room, this does not affect the determination of intruder detection, which is further advantageous in ensuring the accuracy of detecting unauthorized intrusion.

(8) Since the impulse I is reflected, diffracted, etc., a human body can be detected even if a load or the like is placed between the transmitter 6 and the receiver 7.
Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.

  -In each embodiment, as shown in FIG. 8, the intruder detection system 5 may be constructed | assembled from the transmitter / receivers 31 and 32 which make a pair. In the case of this system configuration, when the second transmitter / receiver 32 receives the ultra-wideband radio wave Suwb transmitted from the transmitter 6 of the first transmitter / receiver 31, it returns this to the first transmitter / receiver 31. Then, the propagation distance D is calculated from the ultra-wideband radio wave Suwb received by the first transmitter / receiver 31, and the presence / absence of an unauthorized intruder is determined based on the propagation distance D. In this case, since it is not necessary to synchronize the first transmitter / receiver 31 and the second transmitter / receiver 32, the operation control can be simplified.

  In each embodiment, the frequency of the ultra-wideband radio wave Suwb can be 1 value in various ranges such as 1 to 100 GHz, 1 to 50 GHz, 1 to 30 GHz, 1 to 20 GHz, 2 to 20 GHz, and 2 to 15 GHz.

  In each embodiment, the determination period for intruder detection may be either regular or irregular. For example, the distance measurement cycle may be increased as the elapsed time from turning on the intruder detection system 5 becomes longer. That is, the number of determinations per unit time is reduced. In this case, it is advantageous for power saving of the in-vehicle battery.

In each embodiment, the timing for turning on the intruder detection system 5 may be any timing, for example, after a predetermined time has elapsed since the vehicle door was locked.
In each embodiment, the setting of the threshold value Dk is not limited to being performed when the vehicle door is locked. For example, when the electronic key leaves the communication area of the electronic key system of the vehicle 1, that is, when ID verification with the electronic key is not established. Moreover, it is good also as time control which sets the threshold value Dk after fixed time progress from a certain vehicle operation. As an example of this, for example, after the vehicle door is closed or after the vehicle door is locked, the setting operation of the threshold value Dk is performed after a predetermined time has elapsed.

In each embodiment, the threshold value Dk may be a fixed value.
In each embodiment, the presence or absence of an intruder may be determined using the propagation time t as a parameter.

  In each embodiment, the monitoring target is not limited to the vehicle 1 and can be applied to, for example, a building (house).

  DESCRIPTION OF SYMBOLS 5 ... Intruder detection system, 6 ... Transmitter, 7 ... Receiver, 8 ... Intruder presence / absence determination unit, 11 ... Propagation distance calculation unit, 12 ... Propagation distance validity determination unit, 13 ... Threshold setting unit, 31 ... No. DESCRIPTION OF SYMBOLS 1 transmitter / receiver, 32 ... 2nd transmitter / receiver, Suwb ... Ultra-wideband radio wave, D ... Propagation distance, Dk ... Threshold value, I ... Impulse.

Claims (7)

A transmitter having an ultra-wide bandwidth and capable of transmitting an ultra-wide wave in the microwave band;
A receiver capable of receiving the ultra-wideband radio wave;
An intruder comprising an intruder presence / absence determining unit that determines whether there is an intruder by confirming whether the ultra-wideband radio wave received by the receiver is a direct wave or a non-direct wave Person detection system. The intruder presence determination unit
A propagation distance calculation unit for calculating a propagation distance required until the ultra wideband radio wave of the transmitter reaches the receiver;
A propagation distance validity determining unit that determines whether or not there is an intruder by confirming whether the propagation distance takes a value according to a direct wave or a non-direct wave. The described intruder detection system. When there is no person in the room, a threshold setting unit is provided for setting a threshold necessary for identifying direct waves or indirect waves,
The intruder presence / absence determination unit identifies the radio wave as a direct wave when the ultra-wideband radio wave received by the receiver satisfies the threshold value, and identifies the radio wave as an indirect wave when the threshold value is not satisfied. The intruder detection system according to claim 1 or 2, characterized in that: The intruder detection system according to claim 3, wherein the threshold setting unit executes the setting of the threshold when a door that opens and closes the room is locked. The intruder detection system according to claim 1, wherein the ultra-wideband radio wave is an impulse. The intruder presence / absence determining unit uses the first wave of the impulse to check whether the ultra-wideband radio wave received by the receiver is a direct wave or a non-direct wave. The intruder detection system according to claim 5. A first transceiver in which the transmitter and the receiver are integrated;
A second transceiver for receiving the ultra-wideband radio wave transmitted from the transmitter and returning it to the first transceiver;
The intruder presence / absence determining unit determines presence / absence of an intruder using the ultra-wideband radio wave transmitted from the first transceiver and returning through the second transceiver. The intruder detection system according to any one of 6.