JP2007040895A - Crime preventive sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crime preventive sensor of high reliability capable of detecting exactly a detection object all the time, irrespective of a moving direction and a position thereof. <P>SOLUTION: This crime preventive sensor is provided with a microwave sensor 320 for transmitting a microwave toward a detection area to receive a reflected wave form the object existing within the detection area, and for outputting distance information corresponding to a distance up to the object, and directional information of the object, a detection object existence determining means 332 for recognizing a moving pattern of the object based on a time-serial change of two-dimensional object position information obtained thereby, and for determining the presence of the detection object within the detection area, based on the moving pattern, and an alarm signal output control means 333 for controlling an alarm signal to be output, when the presence of the detection object within the detection area is determined by the detection object existence determining means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a security sensor incorporating a microwave sensor, and more particularly to a security sensor that improves reliability by avoiding the occurrence of false alarms as much as possible.

  Conventionally, as one of crime prevention devices, microwaves are transmitted toward a detection area, and when a human body (intruder) exists in the detection area, a reflected wave from the human body (a microwave modulated by the Doppler effect) ) Is detected (see, for example, Patent Document 1).

  Further, a type of microwave sensor has been proposed in which a distance to a detection target object such as a human body existing in a detection area is measured using a plurality of microwaves having different frequencies. This type of sensor transmits, for example, two types of microwaves having different frequencies toward a detection area, and detects a phase difference between two IF signals based on the respective reflected waves. This phase difference has a correlation with the distance to the detection target object, and the phase difference tends to increase as the distance to the detection target object increases. In other words, the distance to the detection target object can be measured by obtaining this phase difference. It is also possible to determine whether or not the detection target object in the detection area is moving by recognizing the temporal change in the phase difference. Thereby, for example, it becomes possible to identify only the detection target object moving in the detection area.

  By the way, when this type of sensor is used as a security sensor and the change in the phase difference over time is recognized so that only the detection target object moving in the detection area is recognized, the following is performed. There was a serious problem. For example, when installed outdoors, the vegetation may be misdetected as an object to be detected due to shaking of the vegetation due to the wind, and a false alarm may be generated. Similarly, when installed indoors, objects other than the human body (non-detection target objects) are detected by rotating the fan for ventilation, shaking of the blinds and curtains by the wind, or vibration of the microwave sensor itself. There was a possibility that it would be erroneously detected due to false detection of the target object.

  Therefore, the inventor of the present invention has already proposed a technique for accurately discriminating between a detection target object such as a human body and a non-detection target object other than a human body to avoid false reports (see Patent Document 2).

This proposal measures the amount of change per unit time of the relative distance to an object existing in the detection area based on each reflected wave, and detects that object only when the amount of change is equal to or greater than a predetermined threshold. It is determined that the object is a target object. In other words, the moving distance of plants and plants that are swaying by the wind is small, but the moving distance is large for detection target objects such as human bodies. Whether or not it is determined accurately. In the following description, such a false alarm prevention measure will be referred to as a “vegetation measure”, and the above threshold will be referred to as a “vegetation measure level”.
JP 7-37176 A JP 2003-207462 A

  However, in the microwave sensor as described above, since a transmission / reception antenna having a relatively wide directivity is used with its transmission / reception direction fixed, an intruder or the like that is an original detection target object is not necessarily accurately detected. There was a possibility that it could not be done. For example, it may be affected by the approach of rain, insects, etc., the location of installation or the vibration of the microwave sensor itself, and may cause false alarms.

  In addition, when the above-mentioned “plant and plant countermeasures” are taken, if the detection target object moves in a direction perpendicular to the direction directly opposite the microwave sensor, the distance to the detection target object may not change significantly. In some cases, so-called “missing information” cannot be detected. In particular, when guarding near a window or fence, this sometimes becomes a problem that cannot be neglected depending on the installation direction.

  In view of such a problem of the prior art, an object of the present invention is to provide a highly reliable crime prevention sensor that can always perform accurate detection regardless of the moving direction and position of a detection target object.

  In order to achieve the above object, the security sensor of the present invention transmits a plurality of microwaves having different frequencies toward a detection area, and receives a reflected wave of each of the microwaves from an object present in the detection area. A microwave sensor for outputting distance information corresponding to the distance to the object, a direction variable antenna device capable of changing the transmission / reception directions of the plurality of microwaves by the microwave sensor within a predetermined angle range, and the direction By instructing the variable antenna device to scan within the predetermined angle range in the transmission / reception direction, and monitoring the distance information during the scanning, the information includes the direction information where the object exists and the distance information to the object. Scan measurement means for obtaining two-dimensional object position information, and the two-dimensional object position information obtained by the scan measurement means A detection target object presence determining means for recognizing a movement pattern of the object based on a temporal change and determining whether a detection target object is present in the detection area based on the movement pattern; And a warning signal output control unit that controls to output a warning signal when it is determined by the target object presence determination unit that a detection target object is present.

  Here, examples of the direction variable antenna device include a phased array antenna, but the present invention is not limited to this. In addition, the detection target object presence determination unit detects within the detection area if a unit-time moving distance of the object obtained based on a temporal change in the two-dimensional object position information is equal to or greater than a first predetermined value. It may be determined that the target object exists.

  According to the security sensor having such a configuration, accurate detection is always possible regardless of the moving direction of the intruder, and the reliability as the security sensor can be improved.

  Further, in the security sensor, the detection target object presence determining means has a unit-time moving distance of the object obtained based on a temporal change of the two-dimensional object position information being a first predetermined value or more, In addition, when the temporal change in the two-dimensional object position information is continuous, it may be determined that a detection target object exists in the detection area. Furthermore, it may be added to this determination condition that the moving speed obtained based on the temporal change of the two-dimensional object position information is within a predetermined speed range.

  According to the security sensor having such a configuration, it is possible to further suppress the false alarm and further improve the reliability as the security sensor.

  Further, in the security sensor, the detection target object presence determining means is configured to detect the detection area when the object is found to have crossed a first predetermined width area centered on the front surface of the security sensor in the detection area. It may be determined that the detection target object exists in the inside. The first predetermined width may be variable, or may be variable according to the distance from the security sensor.

  According to the security sensor having such a configuration, it is possible to accurately detect the movement in the direction orthogonal to the direction facing the security sensor, and the reliability as the security sensor can be improved.

  Further, in the security sensor, the detection target object presence judging means crosses the second predetermined width area including the front side of the security sensor in the detection area, and the object is not less than a predetermined time thereafter. If it is recognized that the object remains in the vicinity of the region boundary, it may be determined that the detection target object exists in the detection area. The second predetermined width may be variable.

  According to the security sensor having such a configuration, detection can be performed based on a typical behavior of an intruder, and for example, it is possible to prevent as much as possible false alarms caused by accidental approach of a small animal or the like. become.

  Further, in the security sensor, a passive infrared sensor that receives infrared rays from the detection area and outputs an infrared detection signal indicating the presence of a detection target object in the detection area based on a temperature difference from the surroundings. The warning signal output control means stores position information of an effective infrared detection region of the passive infrared sensor, and the detection target object is detected by the infrared detection based on this information and the two-dimensional object position information. When it is recognized that the object is within the area, it may be determined that the detection target object exists in the detection area.

  According to the security sensor having such a configuration, it is possible to minimize the possibility of false or misreporting due to the fact that the detection area of the microwave sensor and the effective infrared detection area of the passive infrared sensor do not completely overlap. Therefore, reliability as a combination sensor can be increased.

  Alternatively, the security sensor of the present invention transmits a microwave toward a detection area, receives a reflected wave of the microwave from an object existing in the detection area, and corresponds to a distance to the object. A microwave sensor that outputs information and direction information of the object, and based on temporal changes in the distance information and the two-dimensional object position information obtained from the direction information output from the microwave sensor A detection target object presence determination unit that recognizes a movement pattern of the object and determines whether or not a detection target object exists in the detection area based on the movement pattern, and is detected by the detection target object presence determination unit. A warning signal output control means for controlling to output a warning signal when it is determined that the target object exists. Door that may be characterized.

  Here, examples of the microwave sensor include one that outputs direction information of an object by a monopulse method using a plurality of antennas for reception. Specifically, for example, an amplitude comparison monopulse method using a plurality of antennas in which a part of a beam overlaps for reception, and a phase comparison monopulse method are used. These monopulse systems process one pulse (monopulse) at one beam position.

  With this type of security sensor, accurate detection is always possible regardless of the direction and position of the intruder, and it is difficult to be affected by fluctuations in the reflected wave over time or interference. The reliability as a security sensor can be further improved by avoiding as much as possible.

  Further, in the crime prevention sensor, the detection target object presence determination unit is configured so that the unit time moving distance of the object obtained based on a temporal change in the two-dimensional object position information is equal to or greater than a first predetermined value. You may discriminate | determine that the detection target object exists in a detection area.

  Further, in the security sensor, the detection target object presence determining means has a unit-time moving distance of the object obtained based on a temporal change of the two-dimensional object position information being a first predetermined value or more, In addition, when the temporal change in the two-dimensional object position information is continuous, it may be determined that a detection target object exists in the detection area. Furthermore, it may be added to this determination condition that the moving speed obtained based on the temporal change of the two-dimensional object position information is within a predetermined speed range.

  Further, in the security sensor, the detection target object presence determining means is configured to detect the detection area when the object is found to have crossed a first predetermined width area centered on the front surface of the security sensor in the detection area. It may be determined that the detection target object exists in the inside. The first predetermined width may be variable, or may be variable according to the distance from the security sensor.

  Further, in the security sensor, the detection target object presence judging means crosses the second predetermined width area including the front side of the security sensor in the detection area, and the object is not less than a predetermined time thereafter. If it is recognized that the object remains in the vicinity of the region boundary, it may be determined that the detection target object exists in the detection area. The second predetermined width may be variable.

  Further, in the security sensor, a passive infrared sensor that receives infrared rays from the detection area and outputs an infrared detection signal indicating the presence of a detection target object in the detection area based on a temperature difference from the surroundings. The warning signal output control means stores position information of an effective infrared detection region of the passive infrared sensor, and the detection target object is detected by the infrared detection based on this information and the two-dimensional object position information. When it is recognized that the object is within the area, it may be determined that the detection target object exists in the detection area.

  According to the security sensor of the present invention, accurate detection is always possible regardless of the moving direction and position of the intruder, and the reliability as a security sensor can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is a block diagram showing a schematic configuration of a security sensor 100 according to the first embodiment of the present invention.

  As shown in FIG. 1, a security sensor 100 includes a phased array antenna 110 that can change the transmission / reception direction of microwaves, and a microwave sensor that detects a detection target object such as a human body using the phased array antenna 110. 120 and a one-chip microcomputer 130 for controlling them.

  The phased array antenna 110 includes a plurality of antenna elements 111 arranged at equal intervals in the same direction, and a phase shift control circuit 112 that controls a phase shift amount in a signal transmission path between these antenna elements 111 within a predetermined range. And have. Note that the directivity of the phased array antenna 110 is preferably narrow. The phase shift control circuit 112 is of a type in which the transmission / reception direction is continuously variable by continuously changing the phase shift amount.

  The microwave sensor 120 is a type that transmits and receives microwaves having two different frequencies, and transmits the microwaves from the phased array antenna 110 to the detection area. The transmitted microwave is reflected when any object is present in the detection area, and a part of the reflected microwave is received back toward the phased array antenna 110. The microwave sensor 120 is configured to detect a phase difference between the two IF signals based on the received reflected waves and output a detected object distance signal based on the phase difference.

  The one-chip microcomputer 130 includes a scanning measurement unit 131, a detection target object presence determination unit 132, and a warning output control unit 133. These are realized by the embedded software of the one-chip microcomputer 130, but the realization method is not limited to software.

  The scanning measurement unit 131 instructs the phase shift control circuit 112 to control the amount of phase shift and monitors the detected object distance signal output from the microwave sensor 120 to detect direction information where the detected object exists and the detected object. Find distance information. Thereby, the two-dimensional position information of the detected object can be obtained in a polar coordinate system determined by the distance and direction from the security sensor 100.

  The detection target object presence determination unit 132 constantly or periodically monitors the two-dimensional position information of the detection object, recognizes the movement pattern of the detection object based on the temporal change, and detects the detection area from the movement pattern. It is determined whether or not a detection target object exists in the area. Regarding recognizable patterns, a plurality of patterns may be prepared in advance so that they can be switched automatically. Alternatively, a DIP switch or the like connected to the input port of the one-chip microcomputer 130 may be provided so that it can be switched manually. A specific example will be described later.

  The output format of the warning signal Dout1 of the warning output control unit 133 is open drain or open collector. The output of the warning signal Dout1 is ON when the detection target object presence determination unit 132 determines that the detection target object exists, and is open when it is determined that the detection target object does not exist. Shall.

  FIG. 2 is an explanatory diagram of one method for determining that a detection target object exists by the security sensor 100.

  As shown in FIG. 2, for example, the position P1 of the detected object at a certain point in time is a distance d1 and a direction angle θ1 from the security sensor 100, and the position P2 of the detected object after a predetermined time has passed is a distance d2 from the security sensor 100. Consider the case where the direction angle is θ2. The reference for the direction angle is the front direction of the security sensor 100, and the right side is the plus direction.

  In such a case, the movement distance Δd of the detected object within a predetermined time can be calculated by the following equation.

そして、この移動距離Δｄを予め定めておいた所定閾値と比較し、移動距離Δｄがその所定閾値以上であれば、検知エリア内に侵入者などの検知対象物体が存在していると判別する。このように、単位時間内に所定閾値以上移動した物体のみを侵入者などの検知対象物体として判別することで、例えば、屋外の風で揺れている草木などを誤って検知対象物体であると検知してしまうことを極力防止できる。

Then, the movement distance Δd is compared with a predetermined threshold value, and if the movement distance Δd is equal to or greater than the predetermined threshold value, it is determined that a detection target object such as an intruder exists in the detection area. In this way, by detecting only objects that have moved by a predetermined threshold or more within a unit time as detection target objects such as intruders, for example, vegetation swaying in the outdoor wind is erroneously detected as a detection target object. Can be prevented as much as possible.

  By adopting the above configuration and determination method, accurate detection can always be performed regardless of the moving direction of the intruder, and the reliability as a security sensor can be improved.

  It is obtained based not only on the moving distance Δd but also whether the change in the position of the detected object during the predetermined time has been continuous, and further based on the change in the position of the detected object over time (the position is differentiated by time). By considering whether or not the moving speed is within a predetermined speed range assumed as a normal intruder, it is possible to further suppress the false alarm and further increase the reliability as a security sensor.

  FIG. 3 is an explanatory diagram of another method for determining that the detection target object is present by the security sensor 100, and (a) is a view from above when the security sensor 100 is installed inside the fence 11. (B) is a graph showing an example of a temporal change in the position of the intruder 10.

  As illustrated in FIG. 3A, when the security sensor 100 targets the inside of the fence 11 or the like, an elongated elliptical detection area A100 formed in the front direction of the security sensor 100 is the inside of the fence 11. It is installed along.

  Here, an orthogonal coordinate system is defined in which the front direction of the security sensor 100 is the y-axis, the direction orthogonal thereto is the x-axis, and the center of the front surface of the security sensor 100 is the origin of both axes. It is assumed that the detected two-dimensional position information of the detected object is converted into this orthogonal coordinate system by the detection target object presence determination unit 132.

  In this case, if there is an intruder 10 from the outside to the inside of the fence 11, the detection area A100 will be crossed regardless of what intrusion route is followed. In order to detect such an intruder 10, it is only necessary to make a determination by paying attention to the temporal change of only the x coordinate in the two-dimensional position information of the detected object.

  Specifically, for example, as shown in FIG. 3B, a range of a predetermined width W1 centered on the origin of the x axis is set, and the x coordinate of the detected object passes within this range within a predetermined time. What is necessary is just to discriminate | determine that the detection target objects, such as the intruder 10, exist when it is detected. In FIG. 3A, this corresponds to the intruder 10 crossing the region R1 having the predetermined width W1 in the front direction of the security sensor 100.

  The predetermined width W1 may be variable by a DIP switch connected to an input port of the one-chip microcomputer 130.

  By adopting the above configuration and determination method, it is possible to accurately detect the movement in the direction orthogonal to the direction facing the security sensor 100, and the reliability as the security sensor can be improved.

  FIG. 4 is an explanatory diagram of still another method for determining that a detection target object is present by the security sensor 100, and FIG. 4A is a case where the security sensor 100 is installed outside the wall 12 and the window 13. The positional relationship seen from above is shown, and (b) is a graph showing an example of the temporal change of the position of the intruder 10.

  As shown in FIG. 4A, when the security sensor 100 targets the outside such as the wall 12 and the window 13, the elongated elliptical detection area A100 formed in the front direction of the security sensor 100 is a wall. 12 and the outside of the window 13 are installed.

  Here, as in the case of FIG. 3, the orthogonal coordinate system is defined in which the front direction of the security sensor 100 is the y-axis, the direction orthogonal thereto is the x-axis, and the center of the front side of the security sensor 100 is the origin of both axes. As described above, it is assumed that the two-dimensional position information of the detected object obtained in the polar coordinate system is converted into this orthogonal coordinate system by the detection target object presence determining unit 132.

  In this case, as a typical behavior of the intruder 10, it is conceivable that first approach the window 13 and pry the window 13 in some way before entering the building, but the time required to pry the window 13 is The intruder 10 stays at substantially the same position. For this reason, in the discrimination method described with reference to FIG. 3, there is a possibility that the intruder 10 cannot be accurately detected depending on the set position of the detection area A100 or the like.

  Therefore, for example, as shown in FIG. 4B, a range of a predetermined width W2 including the origin of the x axis is set (the center of this range is arranged on the side farther from the wall 12 than the front surface of the security sensor 100). The intruder 10 or the like when it is detected that the x coordinate of the detected object remains in the vicinity of the upper limit of the range for a certain time T1 or more after the x coordinate of the detected object passes through the range within a predetermined time. What is necessary is just to discriminate | determine that this detection target object exists. In FIG. 4 (a), after the intruder 10 or the like has crossed the region R2 having a predetermined width W2 in the front direction of the security sensor 100 (the center thereof is located on the side farther from the wall 12 than the front of the security sensor 100). This corresponds to the intruder 10 staying in the vicinity of the front surface of the security sensor 100 or in front of the window 13 for a while.

  Note that the predetermined width W2 and the amount of deviation from the front center of the security sensor 100 may be variable by a DIP switch connected to the input port of the one-chip microcomputer 130 or the like.

  By adopting the configuration and determination method as described above, detection can be performed based on the typical behavior of the intruder 10, so that, for example, false alarms caused by accidental approach of small animals, etc. are prevented as much as possible. It becomes possible to do.

<Modification of First Embodiment>
In the determination method described with reference to FIG. 3 described above, it is detected that the intruder 10 or the like has crossed the region R1 having the predetermined width W1 in the front direction of the security sensor 100. However, when the security sensor 100 has a wide area or the number of antenna elements of the phased array antenna is small, the entire width of the detection area A100 is widened.

  If the above-mentioned predetermined width W1 is also enlarged accordingly, the predetermined width W1 becomes larger than the effective width of the actual detection area A100 in a portion very close to the security sensor 100. At this time, even if the intruder 10 crosses the area, the two-dimensional position information of the detected object outside the detection area A100 cannot be obtained. As a result, the intruder 10 cannot be detected. .

  However, if the predetermined width W1 is reduced in accordance with the width of the detection area A100 that is very close to the security sensor 100, the predetermined width W1 is larger than the effective width of the detection area A100 at a distance from the security sensor 100. It will be much smaller and on the contrary it will be more likely to be misreported.

  Therefore, as a configuration of the security sensor 100a according to the modification of the first embodiment, a region R100a having an appropriate width for detecting the intruder 10 in the detection area A100a is obtained in advance, and the security sensor 100a The width of the region R100a corresponding to the distance is stored in the detection target object presence determination unit 132. For example, as shown in FIG. 5, the width of the region R100a at a distance of about three locations may be stored, and the width of the region R100a may be calculated from a complementary calculation based on these stored widths at the intermediate distance. Further, the width of the region R100a at a greater distance may be stored.

  Then, when the temporal change in the two-dimensional position information of the detected object indicates that the region R100a has been crossed, it may be determined that a detection target object such as the intruder 10 exists.

  By adopting the above configuration and determination method, accurate detection is always possible regardless of the movement direction and position of the intruder, and false alarms and false alarms are avoided as much as possible to further increase the reliability as a security sensor. be able to.

Second Embodiment
When combining a microwave sensor and a passive infrared sensor (hereinafter referred to as “PIR sensor”) to form a combination sensor that performs so-called AND detection, an erroneous report that the effective detection areas of these sensors do not completely overlap And misinformation. Therefore, a configuration that suppresses the possibility of such false or misreporting as much as possible using the fact that the two-dimensional position information of the detected object by the microwave sensor can be obtained as described above will be described below as a second embodiment. explain. It should be noted that the same constituent elements as those in the above-described embodiments are denoted by the same reference numerals, and the description will mainly be made on differences.

  FIG. 6 is a block diagram showing a schematic configuration of a security sensor 200 according to the second embodiment of the present invention. FIG. 7 is a schematic explanatory diagram of a detection area A200 of the security sensor 200.

  As shown in FIG. 6, in addition to the components of the first embodiment, the security sensor 200 receives infrared rays from the detection area and indicates the presence or absence of a detection target object based on a temperature difference from the surroundings. For example, a PIR sensor 240 that outputs a high level when there is a detection target object and a low level when there is no detection target object is provided. Further, the one-chip microcomputer 230 is different in that the output of the PIR sensor 240 is connected to the warning output control unit 233, and the output of the PIR sensor 240 is taken into account in controlling the output of the warning signal Dout2.

  Further, the detection target object presence determination unit 232 stores area information of the effective detection area A240 of the PIR sensor 240, and indicates that the two-dimensional position information of the detection object is inside the detection area A240. It is determined that the detection target object exists only when

  The output of the warning signal Dout2 of the warning output control unit 233 indicates that the detection target object presence determination unit 232 determines that the detection target object exists, and the output of the PIR sensor 240 also includes the detection target object. The warning signal Dout2 is turned ON.

  According to the configuration as described above, the combination sensor can minimize the possibility of false or misreporting due to the fact that the detection area A200 of the microwave sensor 120 and the detection area A240 of the PIR sensor 240 are not completely overlapped. As a result, it becomes possible to improve the reliability.

<Third Embodiment>
In each of the above-described embodiments, a phased array antenna is used to recognize the direction of the detection object. However, since reception data at a plurality of beam positions having different reception times is used, reflection of microwaves from the detection object is performed. There are also problems that errors occur when the intensity varies with time, and that they are easily affected by interference waves.

  Therefore, as another method for obtaining the direction information (angle information) of the detected object, a third embodiment adopting a monopulse system that obtains angle information by processing one pulse (monopulse) at one beam position. Will be described below. It should be noted that the same constituent elements as those in the above-described embodiments are denoted by the same reference numerals, and the description will mainly be made on differences.

  FIG. 8 is a block diagram showing a schematic configuration of a security sensor 300 according to the third embodiment of the present invention.

  As shown in FIG. 8, the security sensor 300 obtains (measures) the direction information of the detected object by the amplitude comparison monopulse method, and outputs microwaves of two different frequencies as in the above embodiments. A microwave sensor 320 capable of outputting distance information to the detected object by transmitting and receiving, and a one-chip microcomputer 330 having a detection target object presence determination unit 332 and a warning output control unit 333 are provided.

  The detection target object presence determination unit 332 constantly or periodically monitors the distance information and the direction information of the detection object output from the microwave sensor 320, thereby changing the two-dimensional position information of the detection object over time. The movement pattern of the detected object is recognized, and it is determined from the movement pattern whether a detection target object such as an intruder exists in the detection area. Specifically, the same determination as in the above-described embodiments may be performed.

  The output format of the warning signal Dout3 of the warning output controller 333 is open drain or open collector. The output of the warning signal Dout3 is ON when the detection target object presence determination unit 332 determines that the detection target object exists, and is open when it is determined that the detection target object does not exist. Shall.

  FIG. 9 is a block diagram showing a schematic configuration of a main part of the microwave sensor 320.

  As shown in FIG. 9, two antennas 321A and 321B in which a part of antenna beams overlap each other are used as a set for receiving microwaves. In the subsequent stage, a pre-comparator 323 is placed to combine the outputs of these antennas 321A and 321B to obtain a sum signal (Σ) and a difference signal (Δ). The mixer 324A and the IF amplifier 326A are sequentially connected to one output of the pre-comparator 323, and the mixer 324B and the IF amplifier 326B are sequentially connected to the other output of the pre-comparator 323. A local oscillator 325 is connected to the mixers 324A and 324B.

  With such a configuration, the sum signal (Σ) is output from the IF amplifier 326A, the difference signal (Δ) is output from the IF amplifier 326B, and these outputs are input to the computing means 327. Based on these outputs, the calculation means 327 calculates the amount of deviation (angle error) from the front direction of the antennas 321A and 321B according to the principle described later.

  On the other hand, for microwave transmission, one antenna 321 </ b> C and a transmitter 329 are connected via a modulator 328. If the modulator 328 transmits microwaves having two different frequencies as in the above-described embodiments, distance information to the sensing object can be obtained. Other methods for obtaining the distance information include an FMCW (Frequency Modulated Continuous Wave) method and a pulse method.

  10A and 10B show the principle of angle error detection by the amplitude comparison monopulse method, where FIG. 10A is a graph showing beam patterns of two antennas, FIG. 10B is a graph showing sum signals and difference signals, and FIG. It is a graph which shows an error.

As shown in FIG. 10A, a sum signal (Σ) and a difference signal (Δ) as shown in FIG. 10B are obtained from signals received by two antennas in which part of the antenna beam overlaps each other. can get. Then, by normalizing the difference signal (Δ) with the sum signal (Σ), that is, calculating “Δ / Σ”, the angle error represented by the S-shaped graph as shown in FIG. The voltage ε can be obtained. Note that if you try to obtain the angle error from only the difference signal (Δ), the signal strength changes depending on the target size and distance, and accurate measurement cannot be performed. is doing.

  With the configuration described above, accurate detection is always possible regardless of the direction and position of the intruder, and it is not easily affected by temporal fluctuations in the reflected wave or interference waves, and avoids false or missed reports as much as possible. Reliability as a security sensor can be further increased.

<Modification of Third Embodiment>
Although the microwave sensor 320 of the third embodiment employs the amplitude comparison monopulse method, it may adopt a phase comparison monopulse method instead. In that case, the configuration of the receiving side of the microwave sensor 320 is changed as follows.

  FIG. 11 is a block diagram showing a schematic configuration on the receiving side of a microwave sensor of a security sensor according to a modification of the third embodiment of the present invention.

  As shown in FIG. 11, a pre-comparator 423 is placed after the antennas 421A and 421B arranged at a distance d in order to obtain a sum signal (Σ) and a difference signal (Δ). The sum signal (Σ) output from the pre-comparator 423 is input to the arithmetic means 427 as it is, and the difference signal (Δ) is input to the arithmetic means 427 via the phase displacement means 440. The computing means 427 calculates the angle error ε based on these inputs.

Here, when the outputs of the antennas 421A and 421B are A and B, respectively, and the phase difference of each is Ψ, Ψ = (2πdζ) / λ
It becomes. Here, ζ is a direction cosine cos (α) of an angle α (an angle formed by a direction orthogonal to the front direction of the antenna and the direction of the object), and λ is a transmission wavelength.

  At this time, a sum signal (Σ) and a difference signal (Δ) of A and B are taken by the pre-comparator 423 in substantially the same manner as the amplitude comparison monopulse method.

Σ = A + B = 2A cos (Ψ / 2) · e ^−j Ψ ^{/ 2}
Δ = A−B = 2jAsin (Ψ / 2) · e ^−j Ψ ^{/ 2}
Then, after the phase of the difference signal (Δ) is rotated by 90 degrees by the phase displacement means 440, the difference signal (Δ) enters the computing means 427 and is divided by the sum signal (Σ) (by being normalized), thereby obtaining the angle An error ε is calculated.

  This angle error ε is tan (ψ / 2), and is a value approximately proportional to ψ near the center of the antenna beam. Therefore, the deviation of the target from the front direction of the antenna can be detected by this angular error ε, similarly to the amplitude comparison monopulse method employed in the third embodiment.

<Other embodiments>
The phased array antenna 110, the microwave sensor 120, and the scanning measurement unit 131 of the first embodiment correspond to the microwave sensor 320 in the second embodiment. Any of these can be regarded as a microwave sensor that can output two-dimensional position information composed of distance information and direction information about a detected object.

  Therefore, the method for discriminating an intruder described in the first embodiment, the modification thereof, the second embodiment, and the like can be similarly applied to the third embodiment and the modification.

  It should be noted that the present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiments are merely examples in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

It is a block diagram showing a schematic structure of a security sensor concerning a 1st embodiment of the present invention. It is explanatory drawing of the one method which discriminate | determines that the detection target object exists with the security sensor which concerns on 1st Embodiment of this invention. It is explanatory drawing of another method which discriminate | determines that the detection target object exists by the security sensor which concerns on 1st Embodiment of this invention, (a) is upper direction when a security sensor is installed inside the fence (B) is a graph which shows the example of the time change of the position of an intruder. It is explanatory drawing of another method to discriminate | determine that the detection target object exists by the security sensor which concerns on 1st Embodiment of this invention, (a) is the security sensor installed in the outer side of a wall and a window The positional relationship seen from the upper direction of a case is shown, (b) is a graph which shows the example of the time change of the position of an intruder. It is a schematic explanatory drawing of the detection area of the security sensor which concerns on the modification of 1st Embodiment of this invention. It is a block diagram which shows schematic structure of the security sensor which concerns on 2nd Embodiment of this invention. It is a schematic explanatory drawing of the detection area of the security sensor which concerns on 2nd Embodiment of this invention. It is a block diagram which shows schematic structure of the security sensor which concerns on 3rd Embodiment of this invention. It is a block diagram which shows schematic structure of the principal part of the microwave sensor with which the security sensor which concerns on 3rd Embodiment of this invention is provided. It is an angle error detection principle by the amplitude comparison monopulse method, (a) is a graph showing beam patterns of two antennas, (b) is a graph showing sum signals and difference signals, and (c) is a graph showing angle errors. It is. It is a block diagram which shows schematic structure of the receiving side of the microwave sensor of the security sensor which concerns on the modification of 3rd Embodiment of this invention.

Explanation of symbols

100 Security sensor (first embodiment)
110 Phased Array Antenna 111 Antenna Element 112 Phase Shift Control Circuit 120 Microwave Sensor 130 One-Chip Microcomputer 131 Scanning Measurement Unit 132 Detection Target Object Presence Determination Unit 133 Warning Output Control Unit 100a Security Sensor (Modification of First Embodiment)
200 Security sensor (second embodiment)
230 One-chip microcomputer 232 Detection target object presence determination unit 233 Warning output control unit 233 PIR sensor 300 Security sensor (third embodiment)
320 Microwave sensor 330 One-chip microcomputer 332 Detection target object presence determination unit 333 Warning output control unit

Claims (24)

Transmits multiple microwaves with different frequencies to the detection area, receives the reflected waves from the objects in the detection area, and outputs distance information corresponding to the distance to the object A microwave sensor,
A direction variable antenna device capable of changing the transmission and reception directions of the plurality of microwaves by the microwave sensor within a predetermined angle range;
By instructing the variable direction antenna device to scan within the predetermined angle range in the transmission / reception direction and monitoring the distance information during the scanning, the direction information where the object exists and the distance information to the object Scanning measurement means for obtaining two-dimensional object position information comprising:
The movement pattern of the object is recognized based on the temporal change of the two-dimensional object position information obtained by the scanning measurement means, and whether or not the detection target object exists in the detection area based on the movement pattern. Detection target object presence determination means for determining whether or not
A security sensor comprising: a warning signal output control unit that controls to output a warning signal when it is determined by the detection target object presence determination unit that a detection target object is present. The security sensor according to claim 1,
The detection target object presence determination unit is configured to detect a detection target object in the detection area if a unit time movement distance of the object obtained based on a temporal change in the two-dimensional object position information is equal to or greater than a first predetermined value. A security sensor characterized in that it is determined that an alarm exists. The security sensor according to claim 1,
The detection target object presence determining means has a unit-time moving distance of the object obtained based on a temporal change in the two-dimensional object position information that is equal to or greater than a first predetermined value, and the two-dimensional object position. A security sensor, wherein when a change in information with time is continuous, it is determined that a detection target object exists in the detection area. The security sensor according to claim 1,
The detection target object presence determining means has a unit-time moving distance of the object obtained based on a temporal change in the two-dimensional object position information that is equal to or greater than a first predetermined value, and the two-dimensional object position. When the temporal change of information is continuous and the moving speed obtained based on the temporal change of the two-dimensional object position information is within a predetermined speed range, the detection target is within the detection area. A security sensor characterized by determining that an object is present. The security sensor according to claim 1,
The detection target object presence determining unit is configured to detect that the detection target object exists in the detection area when it is recognized that the object has crossed a first predetermined width area centered on the front side of the security sensor in the detection area. A security sensor characterized by being identified as having The security sensor according to claim 5,
The security sensor, wherein the first predetermined width is variable. The security sensor according to claim 5,
A security sensor characterized in that the first predetermined width is variable according to the distance from the security sensor. The security sensor according to claim 1,
The detection target object presence determining means crosses the second predetermined width region including the front side of the security sensor in the detection area, and the object remains in the vicinity of the region boundary for a predetermined time thereafter. And a security sensor that determines that a detection target object is present in the detection area. The security sensor according to claim 8,
The security sensor, wherein the second predetermined width is variable. The security sensor according to claim 1,
Furthermore, the apparatus includes a passive infrared sensor that receives infrared rays from the detection area and outputs an infrared detection signal indicating the presence of a detection target object in the detection area based on a temperature difference with the surroundings.
The warning signal output control means stores position information of an effective infrared detection area of the passive infrared sensor, and the detection target object is stored in the infrared detection area based on this information and the two-dimensional object position information. A security sensor characterized by determining that a detection target object exists in the detection area when it is recognized as being inside. The security sensor according to any one of claims 1 to 10,
A security sensor, wherein the direction variable antenna device is a phased array antenna. A microwave is transmitted toward the detection area, a reflected wave of the microwave from the object existing in the detection area is received, distance information corresponding to the distance to the object is output, and the object's A microwave sensor that outputs direction information;
The movement pattern of the object is recognized based on the temporal change of the two-dimensional object position information obtained from the distance information and the direction information output from the microwave sensor, and the detection area is detected based on the movement pattern. Detection target object presence determining means for determining whether a detection target object exists in
A security sensor comprising: a warning signal output control unit that controls to output a warning signal when it is determined by the detection target object presence determination unit that a detection target object is present. The security sensor according to claim 12,
The microwave sensor outputs a direction information of an object by a monopulse method using a plurality of antennas for reception. The security sensor according to claim 13,
The microwave sensor outputs a direction information of an object by an amplitude comparison monopulse method using a plurality of antennas in which a part of beams overlap for reception. The security sensor according to claim 13,
A crime prevention sensor characterized in that the monopulse method in the microwave sensor is a phase comparison monopulse method. The security sensor according to any one of claims 12 to 15,
The detection target object presence determination unit is configured to detect a detection target object in the detection area if a unit time movement distance of the object obtained based on a temporal change in the two-dimensional object position information is equal to or greater than a first predetermined value. A security sensor characterized in that it is determined that an alarm exists. The security sensor according to any one of claims 12 to 15,
The detection target object presence determining means has a unit-time moving distance of the object obtained based on a temporal change in the two-dimensional object position information that is equal to or greater than a first predetermined value, and the two-dimensional object position. A security sensor, wherein when a change in information with time is continuous, it is determined that a detection target object exists in the detection area. The security sensor according to any one of claims 12 to 15,
The detection target object presence determining means has a unit-time moving distance of the object obtained based on a temporal change in the two-dimensional object position information that is equal to or greater than a first predetermined value, and the two-dimensional object position. When the temporal change of information is continuous and the moving speed obtained based on the temporal change of the two-dimensional object position information is within a predetermined speed range, the detection target is within the detection area. A security sensor characterized by determining that an object is present. The security sensor according to any one of claims 12 to 15,
The detection target object presence determining unit is configured to detect that the detection target object exists in the detection area when it is recognized that the object has crossed a first predetermined width area centered on the front side of the security sensor in the detection area. A security sensor characterized by being identified as having The security sensor according to claim 19,
The security sensor, wherein the first predetermined width is variable. The security sensor according to claim 19,
A security sensor characterized in that the first predetermined width is variable according to the distance from the security sensor. The security sensor according to any one of claims 12 to 15,
The detection target object presence determining means crosses the second predetermined width region including the front side of the security sensor in the detection area, and the object remains in the vicinity of the region boundary for a predetermined time thereafter. And a security sensor that determines that a detection target object is present in the detection area. The security sensor according to claim 22,
The security sensor, wherein the second predetermined width is variable. The security sensor according to any one of claims 12 to 15,
Furthermore, the apparatus includes a passive infrared sensor that receives infrared rays from the detection area and outputs an infrared detection signal indicating the presence of a detection target object in the detection area based on a temperature difference with the surroundings.
The warning signal output control means stores position information of an effective infrared detection area of the passive infrared sensor, and the detection target object is stored in the infrared detection area based on this information and the two-dimensional object position information. A security sensor characterized by determining that a detection target object exists in the detection area when it is recognized as being inside.

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