JP4503000B2 - In-vehicle intrusion detection device - Google Patents

Description

  The present invention relates to an in-vehicle intrusion detection device for preventing illegal intrusion into a vehicle using radio waves and ultrasonic waves, and particularly an in-vehicle intrusion detection device configured to be able to effectively prevent erroneous detection. About.

  FIG. 1 is a block diagram showing a schematic configuration of an in-vehicle intrusion detection device that detects an intruder into a vehicle. In the figure, 1 is an in-vehicle intrusion detection device, and 2 is an object such as an intruder. The in-vehicle intrusion detection apparatus 1 includes an oscillator 11 that emits a radio wave output of 2.45 GHz, a transmission antenna 12, a reception antenna 13, and a frequency converter 14, for example, and is attached to, for example, a part of the ceiling in the vehicle. .

  In the apparatus of FIG. 1, for example, the output of 2.45 GHz generated by the oscillator 11 is irradiated to the object 2 via the antenna 12. The reflected wave from the object 2 is received by the receiving antenna 13, and the transmission wave and the reflected wave are mixed by the frequency converter 14 to generate a beat signal.

The in-vehicle intrusion detection device detects a moving object in the vehicle as an intruder when it is set in an operating state. For detecting a moving object, a Doppler effect generated in a reflected wave from the object is used. If the object 2 is moving now, the frequency of the reflected wave is slightly shifted by the Doppler effect. For example, if the transmission frequency is f ₀ , the reflection frequency is f ₀ + Δ. Here, the shift amount Δ is derived by the following equation.

Δ = reflection frequency−transmission frequency = (2v / c) f ₀ (1)
v = relative speed of the object 2 with respect to the sensor C = light speed As is clear from the equation (1), the value of Δ is extremely small compared to the frequency of the transmission wave f ₀ . For example, when the transmission frequency is 2.45 GHz, Δ is about several tens of Hz. Therefore, since it is difficult to directly measure the shift amount Δ, beats of the transmission wave and the reception wave are taken and a signal having a frequency that matches the shift amount Δ is output.

  However, in the in-vehicle intrusion detection device as shown in FIG. 1, when the soccer ball hits the vehicle body or the vehicle body is shaken by a gust of wind, the in-vehicle intrusion detection device itself shakes due to an impact applied to the vehicle body. Then, even if the reflecting object does not move, relative movement occurs, so that this may be erroneously recognized as an abnormality and an alarm output may be performed. Alternatively, when the soccer ball hits the vehicle body and the vehicle body is temporarily deformed and returned to the original state, or when the user temporarily deforms the hood during the car wash, the in-vehicle intrusion detection device is accompanied by such vehicle body deformation. As a result, a relative movement occurs between the in-vehicle intrusion detection device and the reflecting object, and a false alarm may be output.

  Accordingly, an object of the present invention is to provide an in-vehicle intrusion detection device that does not erroneously determine a vehicle body shake or the like that is not related to theft as described above as an intrusion. It is a thing.

In order to solve the above problems, equipment of the present invention analyzes a transmission means for transmitting transmission waves to a vehicle, a receiving means for receiving a reflected wave by the car object of the transmitted wave, said receiving means output A signal processing means for detecting intrusion into the vehicle, wherein the signal processing means includes a first counter for measuring the time when the output of the receiving means is equal to or higher than a predetermined level, and the reception A second counter for measuring the time when the output of the means is less than the predetermined level, and determining that the first counter has entered when the first counter has measured the first predetermined time. When the time measurement exceeds a second predetermined time shorter than the first predetermined time, the first counter is reset, and when the time measurement by the second counter is equal to or shorter than the second predetermined time, And it is configured so as to continue the time measurement by the serial first counter.

  When the vehicle body is shaken by a gust of wind or when an impact is applied from the outside, the influence of the vehicle body on the vehicle body is completed in a short time. Therefore, if the duration of the receiving means output exceeds a certain level at which intrusion can be recognized is within a predetermined time, it is not determined that the intrusion is caused by a human or the like, thereby avoiding false detection. be able to.

Accordingly, the in-vehicle intrusion detection equipment of the present invention, a signal indicating an intrusion occurrence caused by a phenomenon does not appear to relate to theft, can be distinguished from the probability is high signal related to theft effectively. As a result, an in-vehicle intrusion detection device and method with high reliability for detecting the occurrence of illegal intrusion can be obtained.

  FIG. 2 is a block diagram showing a circuit configuration of the in-vehicle intrusion detection apparatus according to the embodiment of the present invention. In the figure, 20 is an oscillation circuit, 22 is a transmission circuit, 24 is a reception circuit that receives a reflected wave, 26 is a mixing circuit for mixing a transmission wave and a reception wave to obtain a beat signal, and 28 is amplifying the output of the mixing circuit. An amplifier circuit for performing the operation, and 30 is a power supply circuit.

  In FIG. 2, reference numeral 40 denotes a microcomputer which receives the output of the amplifier circuit 28 and analyzes the signal to detect entry into the vehicle. The output of the microcomputer 40 is transmitted to an alarm ECU (electronic control unit) 44 via a driver circuit 42, where an alarm notifying that an abnormality has occurred is output. The alarm ECU 44 may operate only with respect to the in-vehicle intrusion detection device, but is generally an ECU having a function of notifying abnormality by analyzing a signal of a sensor such as a door sensor.

  In FIG. 2, a portion indicated by a dotted line in the figure is generally configured as a sensor 50, and is attached to an appropriate place in the vehicle interior, for example, a ceiling. Alternatively, it can be attached near the map lamp in the passenger compartment. It is also possible to configure the microcomputer 40 and the driver circuit 42 together as sensors.

FIG. 3 is a signal waveform diagram for explaining the operating principle of the in-vehicle intrusion detection apparatus according to the first reference example of the present invention. The signal waveform at the time of rectification is shown.

  When a soccer ball hits the vehicle, the deformation of the vehicle due to the impact occurs in a short time and ends in a short time. Therefore, the intensity of the beat wave formed by the mixing circuit 26 rises rapidly from the time when the existence of the beat wave is recognized, reaches a maximum value, and tends to decrease rapidly. On the other hand, the beat wave intensity when a person enters the vehicle interior increases at a relatively slow speed as the intrusion moves. Therefore, when a sudden rise is detected in the beat wave signal, it can be determined that the impact is not an intrusion related to theft or the like but a simple impact applied to the vehicle body from the outside.

  Therefore, in the signal waveform (sensor signal) of the beat wave as shown in FIG. 3, level 1 (200 mV in the illustrated example) that is a threshold that can be recognized as having an intrusion, and a level that is larger than this and lower than the maximum value. 2 (800 mV in the illustrated example) is set, and the time ΔT at which the output exceeds level 1 and reaches level 2 is measured. If ΔT is less than a certain time t, it is determined that this is due to an impact and is not regarded as an illegal intrusion. The constant time t is selected based on various experiments so as to sufficiently distinguish between output fluctuations based on mere impacts and output fluctuations based on human intrusion. If ΔT is equal to or longer than the fixed time determined in this way, it can be determined that the person has illegally entered. As a result, it is possible to prevent the output of a false alarm associated with the shaking of the vehicle body that has nothing to do with theft. Level 1 may be a value higher than the above threshold, but a value sufficiently smaller than level 2 is selected. Level 2 is selected to be a relatively high value that occurs when there is an intrusion.

FIG. 4 is a flowchart showing a processing procedure when the microcomputer 40 executes the erroneous recognition prevention principle described above. Note that the processing routine shown in FIG. 4 is repeatedly executed at a constant cycle. First, in step S1, A / D input processing is executed to convert the analog signal input from the amplifier circuit 28 into a digital signal, and full-wave rectification is further executed. Next, in step S2, it is determined whether or not the value of the input signal is equal to or higher than the first level. In this reference example , the first level is 200 mV.

  If NO in step S2, that is, if the intensity is less than the intensity at which it can be recognized that a beat signal is generated, the counter value is initialized (0) in step S3, and this process is terminated to prepare for the next cycle. . If YES in step S2, that is, if the intensity has reached an intensity at which it can be recognized that a beat signal is generated, the counter value is incremented by 1 in step S4.

Next, in step S5, it is determined whether or not the level of the beat signal is equal to or higher than the second level. In this reference example , the second level is set to 800 mV. If NO in step S5, the process ends and prepares for the next cycle. Therefore, if the signal is level 1 or higher but level 2 or lower, the counter is incremented in step S4 in synchronization with the signal sampling period, and the time ΔT is measured.
In this way, if the signal output exceeds level 2, it is determined YES in step S5. Therefore, in the next step S6, the counter value at that time, that is, ΔT reaches a predetermined constant value t, for example, 50 milliseconds. It is determined whether or not.

  If YES in step S6, that is, if the time for the beat signal intensity to reach level 2 from level 1 is smaller than t (50 milliseconds), it can be determined that this occurrence is due to a simple impact from the outside. In S7, the alarm prohibition flag is turned on. When the alarm prohibition flag is on, the microcomputer 40 does not recognize the situation as an intrusion even if the output signal exceeds the threshold value, and therefore does not output an alarm (alarm) signal.

  If NO is determined in step S6, the time ΔT from level 1 to level 2 is sufficiently large. Therefore, it is determined that the situation is caused by an illegal intrusion. This is recognized as abnormal in a flow different from the flow, and an alarm signal is output.

In the first reference example described above, the signal rises suddenly after the abnormality is detected, and the change in the output signal intensity is similar to the case where a sudden vibration occurs when the soccer ball hits the vehicle body. Suitable for false detection when large.

Figure 5 is a waveform diagram of a beat signal indicating the operating principle of the implementation of the invention, FIG 6 is a diagram showing an operation flow in the case of carrying out the present embodiment in the microcomputer 40. In this embodiment, as shown in FIG. 5, the duration ΔT1 when the output signal exceeds a threshold (for example, the first level, 200 mV) at which abnormality can be recognized is detected, and the value of ΔT1 is a predetermined constant value. If the value is less than or equal to t1, it is not considered that an illegal intrusion has occurred and an abnormal alarm is not output. On the other hand, if a signal exceeding a certain level continues and is generated for a certain time t1 or more, it is considered that an illegal intrusion has occurred and an abnormal alarm is output.

  This is because, in the case of human intrusion, the generation of an output signal indicating an abnormality continues for a relatively long time, while the abnormal signal based on the shaking of the vehicle body caused by a gust of wind, the user denting the bonnet during car washing, etc. By utilizing the fact that it ends in a relatively short time, false detection is prevented.

  Next, the processing procedure of this embodiment will be described with reference to the flowchart of FIG. First, in step S10, A / D input conversion processing is performed. Next, in step S11, it is determined whether the signal intensity is a threshold value (level 1), for example, 200 mV or more. If YES in step S11, that is, if the signal output exceeds the threshold value for detecting an abnormality, the counter CT2 is incremented in step S12 to prepare for the sampling of the next signal. In the next signal sampling, if the signal output is 200 mV or more again, the counter is further incremented. In this way, the period during which the signal is 200 mV or higher is indicated as the content of the counter CT2.

  If NO in step S11, that is, if the signal is less than 200 mV, no abnormality has originally occurred and the signal output is below the threshold value, or as shown in period A in FIG. There is one of them. Therefore, in this embodiment, the counter CT1 that counts a period in which the signal output is equal to or less than the threshold is provided, and when the counter content is a predetermined time, for example, 300 milliseconds or less, it is determined that the preceding and following signals are a series of signals in the occurrence of an abnormality. . When the counter content exceeds 300 milliseconds, that is, when the period A exceeds 300 milliseconds, the counter CT2 that recognizes that the preceding and following signals are signals based on the occurrence of different abnormalities and counts the period during which the output is equal to or greater than the threshold value. At that time.

  That is, in step S13, the counter CT1 is incremented, and in step S14, it is determined whether or not the value of the counter CT1 exceeds 300 milliseconds. If the content of the counter CT1 exceeds 300 milliseconds in step S14 (YES in step S14), the preceding and following signals are not regarded as continuous signals as described above. Therefore, when the counter CT2 is 500 milliseconds or less in the next step S15 (YES in step S15), the alarm prohibition flag is turned on in step S16 and the output of the alarm is stopped. Further, the respective counters are cleared in step S17 and step S18.

  On the other hand, if the counter CT2 has already counted 500 milliseconds or more in step S15, a signal indicating an abnormality has been output over a period exceeding 500 milliseconds, but now the signal is interrupted. Without going through the step of turning on the alarm prohibition flag in step S16, the counter CT1 and the counter CT2 are reset to the initial value 0 in steps S17 and S18 to prepare for the next sampling.

If the value of the counter CT1 is less than 300 seconds in step S14, the signals before and after in the waveform diagram of FIG. 5 can be regarded as continuous signals based on some abnormality, so the value of the counter CT2 is not 0 in step S19. This is confirmed (NO in step S19), and the value of the counter CT2 is incremented in step S20, and the duration of the signal is counted. If the value of the counter CT2 is 0 in step S19 (YES in step S19), the counter CT1 is reset to the initial value in step S21 to prepare for the next sampling cycle.
It can be said that the above control details determine whether or not a period in which the maximum output in one cycle of the signal is equal to or greater than the threshold continues for a predetermined period (500 milliseconds).

  In the present embodiment, as described above, when the generation of a continuous signal that is considered to be based on a single abnormality continues for more than 500 milliseconds, for example, the state is regarded as an illegal intrusion. If it is 500 mS or less, the state is not regarded as an illegal intrusion and no alarm is output. Accordingly, it is possible to prevent erroneous recognition that the in-vehicle intrusion detection device captures a momentary impact applied to the vehicle body and is illegal intrusion.

  In the present embodiment, for example, an abnormality signal is generated based on the fact that the vehicle body is shaken by a gust of wind, or the abnormality is generated more than a case where a human intrusion occurs, such as when a person dents a hood during a car wash. It is suitable for preventing erroneous detection when the period is short and the signal is not so strong.

FIG. 7 is a waveform diagram of an input signal for explaining the operation principle of the second reference example of the present invention. In this reference example , the frequency band of a signal generated by illegal human intrusion is specified, and when the generated signal deviates from this frequency band, for example, the level at which the intensity of the signal is determined to have occurred, i.e. Even when the threshold value is exceeded, false detection is prevented by not determining that it is an intrusion.

  Accordingly, frequency calculation is performed on the input signal in a period until the signal exceeds the threshold level 1 (for example, 200 mS) and reaches a level 2 that is set to a value indicating a sufficient strength, and the value is human. If the value is equal to or lower than a lower limit value (for example, 3 Hz) that can be determined as the movement of the signal, the signal is not determined to be due to intrusion. This prevents false detection.

Next, the process in the microcomputer 40 in this reference example will be described with reference to the flowchart of FIG. First, in step S30, A / D conversion processing of the input signal is executed. Next, it is determined whether or not the level of the signal input in step S31 exceeds a threshold value (level 1) of 200 mV.

  If YES in step S31, frequency calculation is performed on the input signal (step S32). Next, in step S33, it is determined whether or not the level of the input signal has reached level 2, that is, 800 mV. If so (YES in step S33), the signal frequency at that time is 3 Hz in step S34. It is determined whether or not:

  If YES in step S34, it cannot be considered that a signal is generated due to the intrusion of a human, so the alarm prohibition flag is turned on in step S35. On the other hand, in the case of NO in step S33 and step S34, the process is terminated as it is to prepare for the next signal sampling.

  On the other hand, if NO is determined in step S31, the counter CT1 for detecting whether or not adjacent signals are continuous signals is incremented (step S36). Next, in step S37, it is determined whether or not the value of the counter CT1 is 300 milliseconds or more. If YES in step S37, the adjacent signals are not considered to be continuous signals. Therefore, in step S38, the frequency calculation is cleared and the process is terminated to prepare for the next signal sampling.

  If NO is determined in step S37, the interval between adjacent signals does not exceed the time that is not regarded as a continuous signal. Therefore, in step S39, it is determined whether or not the frequency is being calculated. If yes (YES in step S39), the process is terminated as it is to prepare for next signal sampling. If NO in step S39, it can be considered that the input of the signal has been cut off, so the counter CT is reset to 0 to prepare for the next signal sampling.

As described above, it can be determined from the frequency of the input signal whether the signal is really based on illegal human intrusion or is caused by the movement of the vehicle body not related to any theft. As a result, the output of a false alarm can be prevented and the reliability of the alarm can be improved. In this reference example , the signal generated based on the slow movement of the vehicle body, such as when the vehicle body is shaken by the wind or when the vehicle body is shaken by the user during a car wash operation, Suitable for distinction.

Although the embodiment of the present invention described above can be implemented alone, it constitutes a device that checks all the conditions of each reference example, and if any of the conditions is met, the input signal is illegal. You may comprise the apparatus which is not judged to be by intrusion.

Alternatively, an apparatus that has a function of checking both the conditions of the first reference example and the embodiment of the present invention and that does not determine that an input signal is caused by illegal intrusion when these conditions are both satisfied. It is also possible to configure. In this case, it is possible to obtain a device that does not determine that an intrusion has occurred when both the limitation due to the rise time of the abnormal signal and the limitation due to the duration time are satisfied.

Alternatively, an apparatus that has a function of checking both the conditions of the embodiment of the present invention and the second reference example and that does not determine that an input signal is caused by an illegal intrusion when these conditions are both satisfied. It is also possible to configure. In this case, when both the limitation due to the rise time of the abnormal signal and the limitation due to the signal frequency are satisfied, it is possible to obtain a device that does not determine that the input signal is due to illegal intrusion.

Schematic which shows the structure of the conventional vehicle-mounted intrusion detection apparatus. The block diagram which shows the structure of the vehicle-mounted intrusion detection apparatus concerning the 1st reference example of this invention. The wave form diagram which shows the principle of operation of the vehicle-mounted intrusion detection apparatus concerning the 1st reference example of this invention. The flowchart with which it uses for operation | movement description of the vehicle-mounted intrusion detection apparatus concerning the 1st reference example of this invention. Waveform diagram showing the operating principle of the in-vehicle intrusion detection system according to the implementation embodiments of the present invention. Flowchart illustrating the operation of a vehicle-mounted intrusion detection apparatus according to the implementation embodiments of the present invention. The wave form diagram which shows the principle of operation of the vehicle-mounted intrusion detection apparatus concerning the 2nd reference example of this invention. The flowchart with which it uses for operation | movement description of the vehicle-mounted intrusion detection apparatus concerning the 2nd reference example of this invention.

DESCRIPTION OF SYMBOLS 20 Oscillation circuit 22 Transmission circuit 24 Reception circuit 26 Mixing circuit 28 Amplification circuit 30 Power supply circuit 40 Microcomputer 42 Driver circuit 44 Alarm ECU

Claims (1)

In-vehicle provided with transmission means for transmitting a transmission wave into the vehicle, reception means for receiving a reflected wave of the transmission wave by an object in the vehicle, and signal processing means for analyzing the output of the reception means and detecting entry into the vehicle Intrusion detection device for
The signal processing means includes
A first counter that measures the time when the output of the receiving means is equal to or higher than a predetermined level; and a second counter that measures the time when the output of the receiving means is less than the predetermined level. When the counter measures the first predetermined time, it is determined that the intrusion has occurred, and when the time measurement by the second counter exceeds a second predetermined time shorter than the first predetermined time, the first counter is reset. And when the time measurement by the said 2nd counter is below the said 2nd predetermined time, the time measurement by the said 1st counter is continued, The vehicle-mounted intrusion detection apparatus characterized by the above-mentioned .

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