JP5821025B2 - Moving body detection device - Google Patents

Description

  The present invention relates to a moving body detection apparatus that detects the presence or absence of an object moving in a monitoring space.

  2. Description of the Related Art Conventionally, a method using an impact detector and a method using an ultrasonic moving object detector are known as an anti-theft device for an automobile that protects the equipment in the automobile. The former method using an impact detector has an impact sensor attached to the window glass of an automobile, and when the window glass is broken with the intention of entering the automobile, the impact sensor detects the impact, An alarm is issued. The latter method using an ultrasonic moving object detector is equipped with an ultrasonic sensor on the ceiling of a car cabin, etc., and detects if there is something that breaks the window glass and enters the vehicle, alarming, etc. It is something that emits.

  Conventionally, an impact detector, an ultrasonic moving object detector that starts transmitting ultrasonic waves when an impact is detected by the impact detector, and detects the presence or absence of a moving object in the automobile, and an alarm device are provided. An anti-theft device for automobiles is known and disclosed in Patent Document 1.

  Conventionally, a vehicular security sensor in which a glass break sensor is functionally integrated with an intrusion sensor is known and disclosed in Patent Document 2. The conventional example described in Patent Document 2 includes a security sensor, and intermittently transmits ultrasonic waves to the vehicle interior of the vehicle for a predetermined period, and when the ultrasonic waves are reflected in the vehicle interior, A sound wave is received, and whether or not a person has entered the passenger compartment is detected based on the received reflected ultrasonic wave. The security sensor receives an ultrasonic wave generated by the breakage of the window glass every time the ultrasonic wave is not transmitted, and detects the breakage of the window glass based on the received ultrasonic wave.

JP-A 61-135845 JP 2001-253319 A

  However, in the conventional example described in Patent Document 1, detection of the presence or absence of a moving object is not started unless an impact applied to the window glass is detected. For this reason, for example, when the door is opened without breaking the window glass, it can enter the automobile without breaking the window glass. However, in the conventional example described in Patent Document 1, a moving object cannot be detected in this case. There was a problem. Further, the conventional example described in Patent Document 1 has a problem that the number of parts increases because it is necessary to provide an impact detector in addition to the ultrasonic object movement detector.

  On the other hand, in the conventional example described in Patent Document 2, unlike the conventional example described in Patent Document 1, both the detection of the breakage of the window glass and the detection of the presence or absence of the moving body are executed by using ultrasonic waves. In addition, it is not necessary to provide an impact detector. However, even in the conventional example described in Patent Document 2, it is necessary to provide a configuration different from the configuration for detecting a moving object such as an envelope detection circuit or a comparison circuit in order to detect that the window glass has been broken. Therefore, there is a problem that the number of parts increases.

  The present invention has been made in view of the above points, and a moving body capable of executing both detection of presence / absence of impact applied to a window glass and detection of presence / absence of a moving body without increasing the number of parts. An object is to provide a detection device.

A moving body detection device of the present invention includes an oscillation circuit that oscillates a transmission signal having a predetermined frequency, a transmitter that transmits ultrasonic waves into the vehicle using the transmission signals, and the ultrasonic waves that are transmitted from the vehicle. A receiver that receives a reflected wave that is reflected by a moving body existing inside or an ultrasonic wave that is generated when an impact is applied to the window glass of the vehicle and outputs a received signal; and A phase detection circuit that outputs a Doppler signal based on a frequency difference between a reference signal having the same frequency as the signal and the received signal, and the presence / absence of the moving object based on a vector rotation angle obtained by calculation from the Doppler signal. A moving body determination unit that determines an amplitude component of the Doppler signal, compares the amplitude component with a preset determination value, and determines that there is an impact when the amplitude component exceeds the determination value A determination unit, and the phase Filter circuit is provided in plurality, the reference signal inputted to the each phase detection circuit, characterized in that the different phases.

  In this moving body detection apparatus, it is preferable that the number of the phase detection circuits is two, and the reference signals input to the phase detection circuits are out of phase with each other by 90 degrees.

In this moving body detection apparatus, the impact determination unit squares each Doppler signal output from each phase detection circuit and compares the amplitude component of the sum signal obtained by adding the squared signals and the determination value. However, it is preferable to determine that there is an impact when the amplitude component exceeds the determination value .

In this moving body detection apparatus, the determination value is two determination values having different sizes, and the impact determination unit determines the smaller determination value of the two determination values as the amplitude of the Doppler signal. When the component exceeds, it is determined that there is a small impact that does not break the window glass, and when the amplitude component of the Doppler signal exceeds the larger determination value of the two determination values, the window glass is It is preferable to determine that there is an impact that is large enough to crack .

  In this mobile body detection device, it is preferable that the impact determination unit determines whether or not there is an impact when the mobile body determination unit does not determine that the mobile body exists.

  The present invention has an effect that it is possible to execute both the detection of the presence or absence of an impact applied to the window glass and the detection of the presence or absence of a moving body without increasing the number of parts.

It is the schematic which shows embodiment of the mobile body detection apparatus which concerns on this invention. It is the schematic of the vehicle by which a mobile body detection apparatus same as the above is installed. In a mobile body detection apparatus same as the above, it is a wave form diagram which shows an example of the received signal based on the ultrasonic wave by the impact added to a window glass.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a moving body detection apparatus according to the present invention will be described with reference to the drawings. As shown in FIG. 1, the present embodiment includes a detection unit 1, a moving body determination unit 2, and an impact determination unit 3. In addition, since this embodiment is used in combination with the vehicle-mounted alarm device including the comprehensive determination unit 4, the main alarm unit 5, and the preliminary alarm unit 6, the following description will be given as the present embodiment including the vehicle-mounted alarm device. To do.

  The detection unit 1 is a so-called ultrasonic Doppler sensor, and includes a transmitter 10, a receiver 11, an oscillation circuit 12, a phase shift circuit 13, a first phase detection circuit 14, and a second phase detector. Phase detector circuit 15, first amplifier circuit 16, and second amplifier circuit 17. The oscillation circuit 12 oscillates a transmission signal having a predetermined frequency. The transmitter 10 receives the transmission signal from the oscillation circuit 12 and transmits ultrasonic waves having the same frequency as the oscillation frequency of the oscillation circuit 12 to the monitoring space. In the present embodiment, for example, as shown by a black dot in FIG. 2, the vehicle B1 is installed on the ceiling above the front seat, and the inside of the vehicle B1 is used as a monitoring space. In addition, about this vehicle-mounted alarm device among this embodiment, you may install in a place different from a mobile body detection apparatus. As shown in FIG. 1, the receiver 11 is added to a reflected wave generated by reflection on the moving body A <b> 1 existing in the monitoring space, or a component constituting the monitoring space (in this embodiment, the window glass of the vehicle B <b> 1). It receives ultrasonic waves due to impact and outputs a received signal E0.

  The first phase detection circuit 14 mixes (mixes) the received signal E0 and the first reference signal E1, thereby performing a Doppler signal E3 based on the frequency difference between the received signal E0 and the first reference signal E1. Is output. Further, the second phase detection circuit 15 mixes the received signal E0 and the second reference signal E2, thereby generating a Doppler signal E4 based on the frequency difference between the received signal E0 and the second reference signal E2. Output.

  Originally, the Doppler signals E3 and E4 are generated based on the frequency difference between the received signal E0 based on the reflected wave generated by reflection on the moving body A1 and the reference signals E1 and E2. On the other hand, since the ultrasonic wave due to the impact applied to the window glass is not a reflected wave from the moving body A1, there is usually a difference in frequency between the reference signals E1 and E2 regardless of the Doppler effect. Therefore, in the present embodiment, the received signal E0 based on the ultrasonic wave due to the impact can be detected as the Doppler signals E3 and E4 by mixing the reference signals E1 and E2 with the phase detection circuits 14 and 15, respectively.

  Here, since both the first reference signal E1 and the second reference signal E2 are signals output from the oscillation circuit 12, they have the same frequency as the oscillation frequency of the oscillation circuit 12. However, since the second reference signal E2 is input to the second phase detection circuit 15 via the phase shift circuit 13, the first reference signal E1 and the second reference signal E2 have different phases. (In this embodiment, the phases are different by 90 °). Accordingly, the Doppler signals E3 and E4 output from the phase detection circuits 14 and 15 also have different phases. The Doppler signals E3 and E4 are amplified by the first amplifier circuit 16 and the second amplifier circuit 17, respectively, and then input to the moving body determination unit 2 described later.

  The moving body determination unit 2 includes a sampling circuit 20, a memory 21, a vector rotation angle calculation circuit 22, a rotation angle integration circuit 23, and a threshold circuit 24. The sampling circuit 20 samples the input pair of Doppler signals E3 and E4 at a predetermined sampling period and quantizes them to convert them from analog values to digital values. The converted digital values are sequentially stored in the nonvolatile memory 21.

Here, the digital value obtained by converting one Doppler signal E3 X _n, a digital value obtained by converting the other of the Doppler signal E4 and Y _{n (n} is a positive integer), and the starting point the origin of the two-dimensional orthogonal coordinate system and A vector R _n whose end point is (X _n , Y _n ) is defined. The size of the vector R _n corresponds to the amplitude of the Doppler signals E3, E4.

The vector rotation angle calculation circuit 22 has an angle (vector rotation angle) φ _n formed by the vector R _{n −1} obtained by the previous sampling and stored in the memory 21 and the vector R _n obtained by the current sampling. Is calculated. The vector rotation angle calculation circuit 22 calculates the vector rotation angle φ _n using the following equation.

_{φ n = arctan {(X n} -1 Y n -Y n-1 X n) / (X n-1 X n + Y n-1 Y n)}
Therefore, if the mobile A1 approaches, since the vector R _n rotates counterclockwise, the polarity of the vector rotation angle phi _n becomes positive, if the mobile A1 moves away, the vector R _n rotates clockwise because, the polarity of the vector rotation angle phi _n becomes negative.

Rotation angle integrating circuit 23 integrates the vector rotation angle phi _n determined by the vector rotation angle calculation circuit 22. This integrated value (= φ ₁ + φ ₂ +... Φ _n +...) Is proportional to the moving distance of the moving body A1. The threshold circuit 24 compares the integrated value obtained by the rotation angle integrating circuit 23 with a predetermined threshold, and outputs a detection signal when the integrated value exceeds the threshold. This detection signal is input to the comprehensive determination unit 4 described later.

  The impact determination unit 3 calculates the amplitude components of the pair of Doppler signals E3 and E4, respectively, and based on a comparison result between the larger amplitude component of the Doppler signals E3 and E4 and a predetermined determination value. Determine whether there is any impact on the window glass. That is, the impact determination unit 3 determines that there is an impact when the amplitude components of the Doppler signals E3 and E4 exceed the determination value, and outputs a determination signal. In this embodiment, the impact determination unit 3 has two different determination values. When the amplitude component exceeds the smaller determination value, the first determination signal is output, and the amplitude component exceeds the larger determination value. And the second determination signal is output. Thus, by using two determination values, the impact determination unit 3 can determine the impact applied to the window glass in two stages.

  Note that the smaller determination value is larger than the amplitude component due to the ultrasonic wave generated by the vehicle B1 shaking so that a small impact that is intentionally applied to the window glass and the window glass is not broken can be determined. It is desirable to set. Further, it is desirable that the larger determination value is set so that a larger impact can be determined as the window glass breaks.

  By the way, the received signal E0 based on the ultrasonic wave due to the impact applied to the window glass is shifted in phase each time it is generated, as indicated by a solid line and a broken line in FIG. In addition, since the timing at which the ultrasonic waves are generated by the impact is unknown, every time the phase detection circuit mixes the received signal E0 based on the ultrasonic waves and the reference signal, the phase difference from the reference signal is also mixed. Different. Furthermore, ultrasonic waves due to impact are generated only at the moment of impact, and the phase detection circuit is configured to prevent malfunctions by passing only signals in a limited frequency band among the input signals. For this reason, the amplitude component of the obtained Doppler signal varies greatly depending on the phase difference between the reference signal and the received signal E0. Therefore, even if an ultrasonic wave due to an impact is generated, if the amplitude component of the obtained Doppler signal is small, the amplitude component of the Doppler signal does not exceed the determination value in the impact determination unit 3, and the impact is not detected. There is a fear.

  Therefore, it is desirable to provide a plurality of phase detection circuits and to make the reference signals input to each phase detection circuit have the same frequency and different phases. With this configuration, even if the amplitude component of the Doppler signal obtained by any one of the phase detection circuits is minimum, the amplitude component of the Doppler signal obtained by another phase detection circuit is not at least minimum. . Therefore, when an ultrasonic wave due to an impact is generated, the impact determination unit 3 can increase the probability that the amplitude component of the obtained Doppler signal exceeds the determination value, and can reduce the probability of failing to detect the impact.

  In particular, in this embodiment, two phase detection circuits are provided, and reference signals E1 and E2 whose phases are shifted from each other by 90 ° are input to the phase detection circuits 14 and 15, respectively. In this case, even if the amplitude component of the Doppler signal E3 obtained by the first phase detection circuit 14 is minimum, the amplitude component of the Doppler signal E4 obtained by the second phase detection circuit 15 is maximized. That is, the probability of failing to detect an impact with only the two phase detection circuits 14 and 15 can be effectively reduced.

  Based on the detection signal output from the mobile body determination unit 2 and the first determination signal or the second determination signal output from the impact determination unit 3, the comprehensive determination unit 4 Determine which is to be issued. Here, “preliminary alarm” refers to an alarm for threatening a suspicious person trying to break a window glass. Indicates. When the detection signal is not input and the first determination signal is input, the comprehensive determination unit 4 determines that a preliminary alarm should be issued, and issues a warning to the preliminary alarm unit 6 A command signal is output. In addition, when the detection signal or the second determination signal is input, the comprehensive determination unit 4 determines that this alarm should be issued, and issues a command signal to the alarm unit 5 to issue the alarm. Output.

  When a command signal for issuing an alarm is input from the comprehensive determination unit 4, the alarm unit 5 issues this alarm by, for example, ringing a horn of the vehicle B 1 or a siren provided separately. . Further, when a command signal for issuing a warning from the comprehensive determination unit 4 is input, the preliminary warning unit 6 issues a preliminary warning by, for example, blinking the hazard lamp of the vehicle B1 several times.

  Here, as a preliminary alarm, it is sufficient to intimidate only a suspicious person, and it is not preferable to ring a horn or the like because of the property that it should not bother other people as much as possible. Of course, even if the hazard lamp blinks as a preliminary alarm as described above, there is a risk of annoying the surrounding people, but it is not annoying as compared with the case where a horn or the like is ringed. This is desirable because it also has a secondary effect of attracting attention to B1.

  Hereinafter, the operation of this embodiment will be described. First, when a suspicious person tries to break the window glass of the vehicle B1 and an ultrasonic wave is generated by an impact, the received signal E0 based on the ultrasonic wave is mixed with the reference signals E1 and E2 by the phase detection circuits 14 and 15, respectively. As a result, a pair of Doppler signals E3 and E4 are generated. The impact determination unit 3 compares the larger amplitude component of the Doppler signals E3 and E4 with the determination value, and outputs a first determination signal when the amplitude component exceeds the smaller determination value. If the amplitude component exceeds the larger determination value, a second determination signal is output. At the stage where the suspicious person tries to break the window glass, the suspicious person has not entered the vehicle B1, so the mobile body determination unit 2 does not determine the suspicious person as the mobile body A1, and therefore the threshold circuit 24 No detection signal is output.

  When the first determination signal is input, the comprehensive determination unit 4 outputs a command signal to cause the preliminary alarm unit 6 to issue an alarm. And the preliminary warning part 6 threatens a suspicious person by issuing a preliminary warning. At this stage, since there is no impact to the extent that the window glass breaks, if the suspicious person is successfully intimidated by the preliminary alarm, the vehicle can be prevented from being stolen without breaking the window glass.

  On the other hand, when the second determination signal is input, the comprehensive determination unit 4 outputs a command signal to cause the alarm unit 5 to issue the alarm. The alarm unit 5 issues the alarm to threaten the suspicious person and notify the surroundings of the occurrence of an abnormality. At this stage, there is a high possibility that the window glass will be broken, but if the suspicious person is successfully intimidated by this warning, theft on the vehicle can be prevented.

  Next, when a suspicious person breaks the window glass of the vehicle B1 and enters the vehicle, the suspicious person is determined as the moving object A1 by the moving object determining unit 2, and a detection signal is output from the threshold circuit 24. When the detection signal is input, the comprehensive determination unit 4 outputs a command signal to cause the alarm unit 5 to issue an alarm. The alarm unit 5 issues the alarm to threaten the suspicious person and notify the surroundings of the occurrence of an abnormality. Thus, if the suspicious person who has entered the vehicle B1 is successfully threatened, theft on the vehicle can be prevented.

  Here, you may comprise the comprehensive determination part 4 so that the determination process of the impact determination part 3 may be stopped, if a detection signal is input. In this case, the impact determination unit 3 determines the presence or absence of an impact only when the moving body determination unit 2 does not determine the moving body A1. Thereby, since the determination process of the impact determination part 3 does not disturb while the mobile body determination part 2 determines the mobile body A1, malfunction of the mobile body determination part 2 can be prevented. Further, power consumption can be reduced by not causing the impact determination unit 3 to perform unnecessary processing.

  When the overall determination unit 4 is configured as described above, the impact determination unit 3 may be configured to perform the determination process using only the smaller determination value without using the larger determination value. . In this case, when it is determined that there has been an impact, only a preliminary warning is issued, but the effect of preventing on-the-vehicle theft can be sufficiently expected.

  As described above, in this embodiment, since the impact determination unit 3 is provided in addition to the moving body determination unit 2, both the detection of the presence / absence of an impact applied to the window glass and the detection of the presence / absence of the moving body are executed. be able to. Therefore, for example, when a shock applied to the window glass is detected, threatening by issuing an alarm or the like can prevent the vehicle from being stolen without breaking the window glass. In addition, even if it fails to detect an impact, it can also detect a moving object, so even if the window glass is broken, it can be used to threaten the vehicle by stealing it by issuing an alarm. Can be prevented.

  Furthermore, the impact determination unit 3 of the present embodiment only has to perform processing for calculating the amplitude component of the pair of Doppler signals E3 and E4 and comparing the amplitude component with the determination value. It is possible to configure in software using a microcomputer. Therefore, it is possible to detect the presence or absence of an impact applied to the window glass without increasing the number of parts compared to the conventional example.

  In the present embodiment, as described above, the impact determination unit 3 compares the larger amplitude component of the pair of Doppler signals E3 and E4 with the determination value. However, since the amplitude component varies depending on the timing of the impact even if the magnitude of the ultrasonic wave due to the impact is the same, the magnitude of the ultrasonic wave due to the impact and the amplitude component do not correspond one-to-one. Therefore, in the impact determination unit 3, each Doppler signal E3, E4 is squared by a square conversion unit (not shown), a sum signal obtained by adding the squared signals is obtained, and an amplitude component of the sum signal is obtained. You may determine the presence or absence of an impact by comparing with a determination value. In this case, since the magnitude of the ultrasonic wave due to the impact and the amplitude component of the sum signal correspond one-to-one regardless of the timing of the impact, the presence or absence of the impact can be determined stably.

DESCRIPTION OF SYMBOLS 10 Transmitter 11 Receiver 12 Oscillation circuit 14 1st phase detection circuit 15 2nd phase detection circuit 2 Mobile body determination part 3 Impact determination part

Claims (5)

An oscillation circuit that oscillates a transmission signal of a predetermined frequency, a transmitter that transmits an ultrasonic wave into the vehicle by the transmission signal, and the ultrasonic wave is reflected on a moving body that exists in the vehicle. A receiver that receives a reflected wave generated in response to an ultrasonic wave generated when an impact is applied to the window glass of the vehicle and outputs a received signal; a reference signal having the same frequency as the transmitted signal; and A phase detection circuit that outputs a Doppler signal based on a frequency difference with a received signal, a moving body determination unit that determines the presence or absence of the moving body based on a vector rotation angle obtained by calculation from the Doppler signal, and An impact determination unit that calculates an amplitude component of the Doppler signal, compares the amplitude component with a preset determination value, and determines that there is an impact when the amplitude component exceeds the determination value; and the phase detection Multiple circuits are provided. It said reference signal input to each phase detection circuit, the moving object detection apparatus characterized by different phases.   2. The moving body detection apparatus according to claim 1, wherein the number of the phase detection circuits is two, and the reference signals input to the phase detection circuits are out of phase with each other by 90 degrees. The impact determination unit squares each Doppler signal output from each phase detection circuit , compares the amplitude component of the sum signal obtained by adding the squared signals and the determination value, and the amplitude component is The moving body detection device according to claim 2, wherein when it exceeds the determination value, it is determined that there is an impact . The determination value is two determination values having different sizes, and the impact determination unit determines that the window when the amplitude component of the Doppler signal exceeds the smaller determination value of the two determination values. It is determined that there is a small impact that does not break the glass, and if the amplitude component of the Doppler signal exceeds the larger determination value of the two determination values, there is a large impact that the window glass breaks. The moving body detection apparatus according to claim 1, wherein determination is performed .   5. The mobile body according to claim 1, wherein the impact determination unit determines whether or not there is an impact when the mobile body determination unit does not determine that the mobile body is present. 6. Detection device.

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