JPH11296757A - Radio-based trespass discrimination device and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a radio-based trespass discrimination device which correctly discriminates trespass of an object into an automobile compartment or a building. SOLUTION: Transmission/reception antennas 10A and 10B receive oscillation signals of self-oscillation circuits 20A and 20B to transmit radio waves having frequencies F1 and F2 to an automobile compartment. When these radio waves are reflected by a moving object, reflected radio waves are received as reception signals by the transmission/reception antennas 10A and 10B, and these reception signals are mixed with oscillation signals having frequencies F1 and F2 by the oscillation circuits 20A and 20B and are outputted as Doppler-shifted signals, and are amplified by amplification circuits 30A and 30B and are outputted as filtered signals from filter circuits 40A and 40B. When the comparison signal of a comparators 50A is in a high level and that of a comparator 50B is in a low level, a microcomputer 70 judges that there is an object trespassing into the compartment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio wave type intrusion judging device and an intrusion judging method suitable for use in a vehicle theft prevention device, a building security system, and the like.

[0002]

2. Description of the Related Art Conventionally, for example, in a vehicle radio wave type intrusion determining device, there is a device that determines whether a person has entered a vehicle cabin by using radio waves.

[0003]

As described above, the radio wave type intrusion judging device uses radio waves to judge the intrusion of a person. This radio wave is easily transmitted through the window glass of the vehicle by its nature. For this reason, even when the interior of the vehicle interior is set as the intrusion determination range, there is a problem that the movement of an object outside the vehicle is erroneously determined to be the intrusion of a person into the vehicle interior by radio waves transmitted through the window glass.

On the other hand, in order to prevent erroneous determination of the movement of an object outside the vehicle, it is conceivable to narrow down the determination sensitivity. In this case, if the determination sensitivity is excessively narrowed, it becomes impossible to determine the intrusion of an original person, and there is a problem that it is not useful for preventing theft. In view of the above, an object of the present invention is to provide a radio wave type intrusion determination device and an intrusion determination method which correctly determine the intrusion of an object into a vehicle interior or a building.

To achieve this object, the present inventors have
We examined in detail the relationship between radio waves and the penetration of objects into vehicles and the movement of objects outside vehicles. Radio waves have a certain wavelength. This wavelength can be longer or shorter depending on the frequency of the radio wave. If the size of the target object is shorter than the wavelength, the radio waves are less likely to be reflected at the object.

That is, when a radio wave having a short wavelength is used, the resolution of determination is high, so that the movement of a small object can be determined. Conversely, when a radio wave having a long wavelength is used, the resolution of the determination is low, so that only the movement of a large object can be determined.
Using such characteristics of radio waves, it is possible to determine only the intrusion of a target object by combining radio waves of different wavelengths. Here, a small object refers to an object that can enter through a window of a vehicle, and a large object refers to an object such as a vehicle or a door thereof.

The above will be described in more detail with reference to FIG. It is assumed that the object 1a is located near the antenna 1c which is a radio transmission / reception unit of the radio wave type intrusion determination device mounted on the vehicle. It is assumed that the object 1b is at a position farther from the antenna 1c than the object 1a. Note that both objects 1
a and 1b are made of the same material.

[0008] Further, as shown in FIG.
The cross-sectional areas of a and 1b are A1 and A2, respectively, and the object 1
The distance between a and the antenna 1c and the distance between the object 1b and the antenna 1c are D1 and D2, respectively. Further, the solid angle formed by the two objects 1a and 1b with respect to the antenna 1c with respect to the common central axis corresponds to the angle θ. Assuming this condition, the sectional area A2 of the object 1b is given by the following equation 1 in relation to the sectional area A1 of the object 1a and the distances D1 and D2.

[0009]

## EQU1 ## A2 = (D2 / D1) ² × A1 Now, the wavelength of the radio wave is the cross-sectional area A1, A of each of the two objects 1a, 1b.
Assuming that it is sufficiently short with respect to 2, if the attenuation of the radio wave is not taken into account, the reflection amounts of the radio waves from the respective objects 1a and 1b become equal to each other. That is, the object 1a and the object 1
Even if there is a boundary in the cabin between the object and the object b, it cannot be distinguished whether the object is an intruding object in the cabin or a moving object outside the car.

However, the wavelength of the radio wave is limited to the cross-sectional area A of the object 1a.
When the length is longer than 1, the reflection amount of the object 1a with respect to the radio wave is not sufficiently obtained. can get. Therefore, it is possible to determine only the object 1a by combining radio waves having different wavelengths.

[0011] As described above, by using a plurality of radio waves having different frequencies, the intrusion of an object such as a person or his arm into a vehicle interior or a building can be correctly distinguished from the movement of a vehicle or a person outside the vehicle or the building. It can be seen that the judgment can be made.

[0012]

In order to solve the above-mentioned problems, according to the first and second aspects of the present invention, first and second transmitting / receiving antennas (10A, 10A, 10A, 10B), first oscillating means (20A) for outputting a first oscillating signal at the first frequency so that radio waves are transmitted from the first antenna at a first frequency, and a first oscillating signal from the second antenna. And a second oscillating means (20B) for outputting a second oscillating signal at the second frequency so as to transmit a radio wave at a low second frequency. When the signal is reflected back and received as a received signal by the first antenna, a first Doppler shift signal is generated based on the received signal and the first oscillation signal, and the transmission wave of the second antenna is subjected to the Doppler effect by the moving object. A transmission / reception system that generates a second Doppler shift signal based on the received signal and the second oscillation signal when the signal is reflected back and received as a reception signal by the second antenna; and a first and second Doppler shift signal. Intrusion determination means (30A to 50A, 30B to 50B, 110
To 130) are provided.

[0013] Thus, the invasion of the object into the intruded object can be distinguished from the movement of the vehicle, the vehicle outside the building, the movement of the person, and the like by using the radio waves of the first and second frequencies different from each other, and correctly determined. it can. Here, as in the invention according to claim 2, the intrusion determining means determines that the level of the received signal of the first antenna is equal to or higher than a predetermined threshold and the level of the received signal of the second antenna is lower than the predetermined threshold. Even if it is determined that the intruded object has been invaded, the same operation and effect as the first aspect of the present invention can be achieved.

According to the third and fourth aspects of the present invention, the first and second transmitting / receiving antennas (10A, 10B) provided on an intruded object such as a vehicle or a building, and the first antenna and the first transmitting / receiving antenna. First oscillating means (20A) for outputting a first oscillating signal at the first frequency so as to transmit radio waves at the frequency
And a second oscillating means (20B) for outputting a second oscillation signal at the second frequency so that the second antenna transmits radio waves at a second frequency lower than the first frequency. When the transmitted radio wave is reflected by the moving object under the Doppler effect and received by the first antenna as a received signal, a first Doppler shift signal is generated based on the received signal and the first oscillation signal, A transmission / reception system that generates a second Doppler shift signal based on the received signal and the second oscillation signal when the transmission radio wave is reflected by the moving object under the Doppler effect and received by the second antenna as a reception signal; When the duration and frequency of the Doppler shift signal are equal to or longer than a second predetermined time and within a second predetermined frequency range corresponding to the movement of the moving object, the moving object enters the intruded target. Intrusion determination means (30A) that determines that the moving object has entered the intruded target when the duration and frequency of the second Doppler shift signal are not longer than the first predetermined time and within the second predetermined frequency range. To 80
A, 30B to 80B, 210, 220, 120, 13
0) is provided.

According to this, the same operation and effect as the first aspect can be achieved. Here, according to the invention described in claim 4, the intrusion determining means is configured to detect when the level of the reception signal of the first antenna is equal to or higher than the predetermined threshold and the level of the reception signal of the second antenna is lower than the predetermined threshold. Judge as intrusion into the intrusion target. Thereby, both the effects of the first and third aspects can be synergistically achieved.

According to the fifth aspect of the invention, a plurality of radio waves having different frequencies are transmitted, and each of these radio waves is reflected by a moving object under the Doppler effect and received as a reception signal. A radio wave type intrusion determination method is provided in which a Doppler shift signal is generated based on a signal, and an intrusion of an object into an intruded object is determined based on the Doppler shift signal.

Thus, the invasion of the object into the intruded object is distinguished from the vehicle, the vehicle outside the building, the movement of the person, and the like by utilizing the radio waves of the first and second frequencies different from each other, and is correctly determined. it can.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows an example in which the present invention is applied to a radio wave type intrusion determination device of a vehicle anti-theft device.

This radio wave type intrusion judging device comprises a pair of transmitting and receiving antennas 10A and 10B, a self-excited oscillation circuit 20A and a transmitting and receiving antenna 10B connected to the transmitting and receiving antenna 10A.
And a self-excited oscillation circuit 20B connected to the The two transmitting and receiving antennas 10A and 10B are, as shown in FIG.
It is supported together at the center of the inner wall of the ceiling in the cabin of the vehicle. In addition, the arrangement | positioning position of both transmitting / receiving antennas 10A and 10B may be the console box in a vehicle interior.

The transmitting / receiving antenna 10A receives an oscillation signal from the self-excited oscillation circuit 20A and receives a frequency F1 (for example, 2.
(45 GHz). When the radio wave of the frequency F1 is reflected as a radio wave of the frequency F1 + ΔF1 by the moving object, the transmitting / receiving antenna 10A receives the reflected radio wave and inputs the received radio wave to the self-excited oscillation circuit 20A as a reception signal. However, the transmitting and receiving antenna 10A is formed to have a dimension of a quarter wavelength of the radio wave of the frequency F1. The transmitting / receiving antenna 10A, including its connection circuit (to be described later), is housed in a casing of about 8 cm × 8 cm × 2 cm.

On the other hand, the transmitting / receiving antenna 10B receives the oscillation signal from the self-excited oscillation circuit 20B and transmits it as a radio wave of the frequency F2 (for example, 314.35 MHz). When the radio wave of the frequency F2 is reflected as a radio wave of the frequency F2 + ΔF2 by the moving object, the transmitting / receiving antenna 10B
The self-excited oscillation circuit 2 receives the reflected radio wave and receives it as a reception signal.
0B. However, the transmitting / receiving antenna 10B is formed to have a dimension of a half wavelength of the radio wave of the frequency F2.
The transmitting and receiving antenna 10B is accommodated in the casing, including its connection circuit (described later).

Here, since the frequency F1 is set to be large, the wavelength of the radio wave transmitted by the transmitting / receiving antenna 10A is about 1
It is as short as 2cm. Therefore, even if the reflecting object is small, a sufficient amount of radio wave reflection can be secured. Therefore, the transmitting and receiving antenna 1
The transmitted radio wave of 0A has a certain size (for example, 100 mm × 10
(0 mm) or more, and receives a Doppler effect when reflected by a moving object.

The reason why the radio wave of the frequency F1 becomes the radio wave of the frequency F1 + ΔF1 as described above is that the radio wave of the frequency F1 + ΔF1 depends on the moving speed of the moving object on the assumption that the vehicle is stopped.
This is because the frequency increases only due to the Doppler effect.
On the other hand, since the frequency F2 is set to be small as described above, the wavelength of the transmission radio wave of the transmission / reception antenna 10B is long.
Therefore, small objects (for example, 100 mm x 100 mm)
Does not provide a sufficient amount of radio wave reflection. However, when the light is reflected by a moving object having a certain size (for example, 800 mm × 800 mm) or more, a Doppler effect occurs.

The reason why the radio wave of the frequency F2 becomes the radio wave of the frequency F2 + ΔF2 as described above is that the radio wave of the frequency F2 + ΔF2 depends on the moving speed of the moving object on the assumption that the vehicle is stopped.
This is because the frequency increases only due to the Doppler effect.
In addition, when the transmission powers of the two transmitting and receiving antennas 10A and 20A are the same, the higher the frequency of the radio wave, the more the radio wave is attenuated due to the moisture in the air, and thus the shorter the reach.

In the first embodiment, the processing by the microcomputer 70 desirably causes the radio wave of the frequency F2 to reach farther, and the reach Ra (see FIG. 2) of the radio wave of the frequency F2 is at least as large as possible. It is better to include up to the outside of the vehicle. Therefore, the frequency F2 is set as described above. Note that the reach range Ra corresponds to a range in which an object of 1000 mm × 1000 mm can be determined using a radio wave of the frequency F2. Also, in FIG.
The symbol Rc corresponds to a range in which an object of 100 mm × 100 mm can be determined by a radio wave of the frequency F1.

The self-excited oscillation circuit 20A self-oscillates the oscillation signal having the above-described frequency F1 and transmits and receives
Output to 0A. When the transmitting / receiving antenna 10A inputs the reflected radio wave of the frequency F1 + ΔF1 to the self-excited oscillation circuit 20A as a received signal, the self-excited oscillation circuit 20A converts the received signal of the frequency F1 + ΔF1 into an oscillation signal of the frequency F1 under the Doppler shift effect. And the Doppler shift frequency (frequency F1 of the transmitted radio wave and frequency F1 + of the reflected radio wave)
(A difference ΔF1 from ΔF1). For example, for frequency F1, ΔF1
= 0 Hz to 33 Hz.

On the other hand, the self-excited oscillation circuit 20B self-oscillates an oscillation signal having the above-mentioned frequency frequency F2 and outputs the oscillation signal to the transmitting / receiving antenna 10B. In addition, transmitting and receiving antenna 1
0B is input to the self-excited oscillation circuit 20B as a received signal of the reflected radio wave of the frequency F2 + ΔF2.
0B is the frequency F2 + Δ under the Doppler shift effect.
The reception signal of F2 is mixed with the oscillation signal of frequency F2 to generate a Doppler shift signal having a Doppler shift frequency (corresponding to the difference ΔF2 between the frequency F2 of the transmission radio wave and the frequency F2 + ΔF2 of the reflected radio wave). For example, ΔF2 = 0 Hz to 4.2 Hz with respect to the frequency F2.

The amplification circuit 30A includes a self-excited oscillation circuit 20A.
The amplifier circuit 30B amplifies the Doppler shift signal from the self-excited oscillation circuit 20B to generate an amplified signal. The filter circuit 40A removes noise from the frequency component of the amplified signal of the amplifier circuit 30A and extracts a frequency component corresponding to a size of a small object or more such as an intruding object from the window into the vehicle interior from the frequency component. Generate a signal. On the other hand, the filter circuit 40B
Noise is removed from the frequency component of the amplified signal of 0B, and only a frequency component corresponding to a large object such as a moving object outside the vehicle is extracted from the frequency component to generate a filter signal.

The comparator 50A includes a filter circuit 40
The level of the filter signal from A
A is compared with the set reference level REF1 from A. And
When the level of the filter signal from the filter circuit 40A is higher than the set reference level REF1, the comparator 50
A generates a comparison signal at a high level. This comparison signal goes low when the level of the filter signal from the filter circuit 40A is equal to or lower than the set reference level REF1. Here, the set reference level REF1 from the reference level setter 60A is at a level corresponding to the movement of a small object such as an intruding object from the window into the vehicle interior.

On the other hand, the comparator 50B compares the level of the filter signal from the filter circuit 40B with the set reference level REF2 from the reference level setter 60B. When the level of the filter signal from the filter circuit 40B is higher than the set reference level REF2, the comparator 50B generates a comparison signal at a high level. This comparison signal goes low when the level of the filter signal from the filter circuit 40B is equal to or lower than the set reference level REF2. Here, the set reference level REF2 from the reference level setter 60B is at a level corresponding to the movement of a large object such as a moving object outside the vehicle.

The microcomputer 70 executes the computer program according to the flowchart shown in FIG. 3, and during this execution, the two comparators 50A, 50A,
Based on each output of 0B, a process of determining whether an object has entered the vehicle interior and a process of driving the buzzer circuit 80 are performed. The microcomputer 70 is always powered by the battery Ba and is in an operating state. The computer program is stored in the ROM of the microcomputer 70 in advance.

The buzzer circuit 80 includes a transistor 81 and a buzzer 82. The transistor 81 is turned on or off under the control of the microcomputer 70. The buzzer 82 sounds when the transistor 81 is turned on. In the first embodiment configured as described above,
It is assumed that the vehicle is in a stopped state. At this time, the microcomputer 70 is always operating by the power supply from the battery Ba, and stores the computer program in FIG.
In accordance with the flowchart of FIG.

When self-excited oscillation circuit 20A oscillates an oscillation signal at frequency F1 and self-excited oscillation circuit 20B oscillates an oscillation signal at frequency F2, transmission / reception antenna 1
0A receives the oscillation signal of self-excited oscillation circuit 20A and transmits a radio wave of frequency F1 into the vehicle interior, and transmission / reception antenna 10B receives the oscillation signal of self-excited oscillation circuit 20B and transmits an electric wave of frequency F2 into the interior of the vehicle interior. .

In such a state, it is assumed that another vehicle moves along one side of the vehicle. Then, each transmission radio wave of both transmission / reception antennas 10A and 20A passes through the window of the vehicle, enters another vehicle, and is reflected. At this time,
The frequency of each reflected radio wave becomes F1 + ΔF1 and F2 + ΔF2 due to the Doppler effect based on the moving speed of another vehicle.

Therefore, the radio wave of the frequency F1 + ΔF1 is
The signal is received by the transmitting / receiving antenna 10A through the window of the vehicle, and is input to the self-excited oscillation circuit 20A as a received signal.
On the other hand, the radio wave of the frequency F2 + ΔF2 passes through the window of the vehicle, is received by the transmitting / receiving antenna 10B, and the received signal is input to the self-excited oscillation circuit 20B. Then, the self-excited oscillation circuit 20A mixes the received signal having the frequency F1 + ΔF1 with the oscillation signal of the frequency F1 to generate a Doppler shift signal, while the self-excited oscillation circuit 20B outputs the frequency F2 +
The received signal having ΔF2 is mixed with the oscillation signal of frequency F2 to generate a Doppler shift signal.

The amplifier circuit 30A amplifies the Doppler shift signal from the self-excited oscillation circuit 20A to generate an amplified signal, while amplifying the Doppler shift signal from the self-excited oscillation circuit 20B and generates the amplified signal. I do. Next, the filter circuit 40A generates a filter signal based on the amplified signal from the amplifier circuit 30A, while the filter circuit 40B generates a filter signal based on the amplified signal from the amplifier circuit 30B.

When both filter signals are generated in this manner, the comparator 50A compares the filter signal from the filter circuit 40A with the reference level REF1 set by the reference level setting unit 60A, while the comparator 50A outputs the signal from the filter circuit 40A. Is compared with the set reference level REF1 of the reference level setter 60A. Here, as described above, another vehicle moves along one side of the vehicle. Therefore, the level of the filter signal of the filter circuit 40A is equal to or higher than the set reference level REF1, and the level of the filter signal of the filter circuit 40B is equal to or higher than the set reference level REF2. Therefore, both comparators 50A,
50B both generate a comparison signal at a high level and input it to the microcomputer 70 at step 100.

At this stage, as described above, since the respective comparison signals of both comparators 50A and 50B are both at the high level, the determination of NO is made in step 110, and the vehicle of the vehicle is determined in step 120. It is determined that there is no intruding object in the room. When an object enters through a window of the vehicle instead of moving along one side of the vehicle as described above, the transmission radio waves of the two transmitting / receiving antennas 10A and 20A are transmitted by the intruder. It is incident on an object and reflected.

Accordingly, both the filter circuits 40A and 40B generate a filter signal as described above. Here, as described above, an object enters from the window of the vehicle, and the intruding object is small. Therefore, the level of the filter signal of the filter circuit 40A is equal to or higher than the set reference level REF1, but the level of the filter signal of the filter circuit 40B is lower than the set reference level REF2. Accordingly, the comparison signal of the comparator 50A goes high, but the comparison signal of the comparator 50B goes low.

Accordingly, the high-level comparison signal of the comparator 50A and the low-level comparison signal of the comparator 50B are input to the microcomputer 70 in step 100. At this stage, as described above, the comparison signal of the comparator 50A is at the high level,
Since the comparison signal of 0B is at the low level, step 11
If the answer is YES in step 130, and step 130
It is determined that there is an intruding object from the window of the vehicle into the vehicle interior. Accordingly, in step 140,
A buzzer sounding process is performed. Therefore, the buzzer circuit 80
Turns on the transistor 81 to sound the buzzer 82 to give an alarm.

As described above, by using radio waves of different frequencies F1 and F2, only the intrusion of an object into the vehicle compartment can be correctly determined and an alarm can be given. Appropriately helps prevent theft of indoor items. In the first embodiment, the transmitting and receiving antennas 10 are used.
Since both A and 20A transmit radio waves at the same timing, it is possible to determine in real time whether or not an object has entered the vehicle interior. Since the difference between the two frequencies F1 and F2 is large, the transmission radio waves of the transmission / reception antennas 10A and 20A hardly affect each other.

Also, as in the first embodiment, the frequency F2
When the intrusion of an object into the vehicle interior is determined by the radio wave of the frequency F1 instead of the radio wave of the frequency F1, the value of the frequency F1 is changed to the range of the frequency F2 so as to narrow the reach of the radio wave of the frequency F1. It is desirable to set for the value of. (Second Embodiment) FIGS. 4 and 5 show a second embodiment of the present invention.

In the second embodiment, both waveform shaping circuits 8
0A and 80B are the two filter circuits 40A and 40B and the two reference level setting units 60A and 60A described in the first embodiment.
It is adopted instead of 60B. Waveform shaping circuit 80A
Generates a rectangular pulse signal by shaping the waveform of the filter signal of the filter circuit 40A and inputs the pulse signal to the microcomputer 70. On the other hand, the waveform shaping circuit 80B shapes the filter signal of the filter circuit 40B by a rectangular wave. Is generated and input to the microcomputer 70.

The microcomputer 70 executes a computer program according to a flowchart shown in FIG. 5 instead of the flowchart shown in FIG. Other configurations are as described in the first section above.
This is the same as the embodiment. In the second embodiment configured as described above, when both the filter circuits 40A and 40B generate the filter signal as in the first embodiment, the filter signal of the filter circuit 40A is changed to the waveform shaping circuit 80A.
, And the filter signal of the filter circuit 40B is shaped into a pulse signal by the waveform shaping circuit 80B. Then, each pulse signal of both the waveform shaping circuits 80A and 80B is obtained by the step 20 in FIG.
At 0, it is input to the microcomputer 70.

Thus, in step 210, a determination is made as to the generation time and frequency of the pulse signal from the waveform shaping circuit 80A. Here, if the generation time of the pulse signal from the waveform shaping circuit 80A is equal to or longer than the predetermined time T1 and the frequency of the pulse signal is within the predetermined frequency range Δf1,
The determination in step 210 is YES.

However, the predetermined time T1 and the predetermined frequency range Δ
f1 is a reflected radio wave (having a frequency F1) of a moving object having a size equal to or larger than a small object such as an intruding object entering a vehicle interior from a window.
Corresponds to the duration and frequency range of the pulse signal sequentially generated from the waveform shaping circuit 80A. In the present embodiment, the predetermined time T1 is set to, for example, 0.3 sec in order to eliminate a disturbance time in which an object rolls or suddenly falls down in the vehicle compartment, and the predetermined frequency range Δ
f1 is set to, for example, a frequency range corresponding to a wavelength range of 0.1 m / s to 0.5 m / s.

Next, at step 220, a determination is made as to the generation time and frequency of the pulse signal from the waveform shaping circuit 80B. Here, if the generation time of the pulse signal from the waveform shaping circuit 80B is equal to or longer than the predetermined time T2 and the frequency of the pulse signal is outside the predetermined frequency range Δf2,
The determination in step 220 is NO.

However, the predetermined time T2 and the predetermined frequency range Δ
f2 corresponds to a duration and a frequency range of a pulse signal sequentially generated from the waveform shaping circuit 80B due to a reflected radio wave (having the frequency F2) of a large object such as a moving object outside the vehicle. In the present embodiment, the predetermined time T
2 is, for example, 0.1 sec and the predetermined frequency range Δ
f2 is a frequency range corresponding to a wavelength range of 0.1 m / s or more.

When the determination in step 220 is NO, both steps 1 and 2 are performed as in the first embodiment.
Steps 30 and 140 are performed. Step 2
In step 10, when the determination of NO is made because the generation time of the pulse signal from the waveform shaping circuit 80A is less than the predetermined time T1 or the frequency of the pulse signal is outside the predetermined frequency range Δf1, In the above, when the determination of YES is made because the generation time of the pulse signal from the waveform shaping circuit 80B is less than the predetermined time T2 or the frequency of the pulse signal is within the predetermined frequency range Δf2, As in the embodiment, in step 120, it is determined that there is no intruding object in the vehicle interior.

Thus, according to the second embodiment,
As in the first embodiment, it is possible to correctly determine only an intruding object in the vehicle compartment and issue a warning, and as a result, it is useful for preventing theft of a vehicle and theft of articles in the vehicle compartment. Other functions and effects are the same as those of the first embodiment. It should be noted that the present invention is not limited to a vehicle, and may be applied to a case where a person enters a building.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement position of both transmitting / receiving antennas of FIG. 1 with respect to a vehicle and a range of radio waves.

FIG. 3 is a flowchart showing an operation of the microcomputer of FIG. 1;

FIG. 4 is a block circuit diagram showing a second embodiment of the present invention.

FIG. 5 is a flowchart showing the operation of the microcomputer of FIG.

FIGS. 6A and 6B are schematic diagrams showing the relationship between the wavelength of a radio wave from an antenna and the position of an object.

[Explanation of symbols]

10A, 10B: transmitting / receiving antenna, 20A, 20B: self-excited oscillation circuit, 30A, 30B: amplifying circuit, 40A, 4
0B: filter circuit, 50A, 50B: comparator,
60A, 60B: Reference level setting device, 70: Microcomputer, 80A, 80B: Waveform shaping circuit.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Fumio Asakura 14 Iwatani, Shimowasumi-machi, Nishio-shi, Aichi Japan Inside the Japan Automotive Parts Research Institute (72) Inventor Tadashi Nakamura 1-1-1, Showa-cho, Kariya-shi, Aichi Stock Inside the company DENSO

Claims (5)

[Claims] 1. A first device provided on an intruded object such as a vehicle or a building.
And a second transmitting / receiving antenna (10A, 10B), and a first outputting a first oscillation signal at the first frequency so that the first antenna transmits a radio wave at a first frequency.
Oscillating means (20A); and second oscillating means (20B) for outputting a second oscillating signal at the second frequency such that the second antenna transmits radio waves at a second frequency lower than the first frequency. When a radio wave transmitted from the first antenna is reflected by a moving object under the Doppler effect and received as a received signal by the first antenna, a first Doppler wave is generated based on the received signal and the first oscillation signal. A shift signal is generated, and when a transmission radio wave of the second antenna is reflected by the moving object under the Doppler effect and received as a reception signal by the second antenna, a shift signal is generated based on the reception signal and the second oscillation signal. A transmission / reception system that generates a second Doppler shift signal; and an intrusion determining unit that determines intrusion of an object into the intruded object based on the first and second Doppler shift signals. Judgment means (30
A to 50A, 30B to 50B, 110 to 130)
A radio wave type intrusion determination device comprising: 2. The intrusion determination means, wherein when the level of the signal received by the first antenna is equal to or higher than a predetermined threshold and the level of the signal received by the second antenna is lower than the predetermined threshold, the intruder determines The radio wave type intrusion determination device according to claim 1, wherein the determination is made. 3. A first device provided on an intruded object such as a vehicle or a building.
And a second transmitting / receiving antenna (10A, 10B), and a first outputting a first oscillation signal at the first frequency so that the first antenna transmits a radio wave at a first frequency.
Oscillating means (20A); and second oscillating means (20B) for outputting a second oscillating signal at the second frequency so that the second antenna transmits radio waves at a second frequency lower than the first frequency. When a radio wave transmitted from the first antenna is reflected by a moving object under the Doppler effect and received as a received signal by the first antenna, a first Doppler wave is generated based on the received signal and the first oscillation signal. A shift signal is generated, and when a transmission radio wave of the second antenna is reflected by the moving object under the Doppler effect and received as a reception signal by the second antenna, a shift signal is generated based on the reception signal and the second oscillation signal. A transmission / reception system that generates a second Doppler shift signal, wherein the duration and frequency of the first Doppler shift signal are equal to or longer than a second predetermined time and the moving object moves. When the frequency is within the corresponding second predetermined frequency range, it is determined that the moving object has entered the intruded object, and the duration and frequency of the second Doppler shift signal are equal to or longer than the first predetermined time and within the second predetermined frequency range. If not, the intrusion determination means (30A to 80A, 30B to 80A) for determining that the moving object has entered the intruded object.
B, 210, 220, 120, and 130). 4. The intrusion judging means, when the level of the signal received by the first antenna is equal to or higher than a predetermined threshold and the level of the signal received by the second antenna is lower than the predetermined threshold, The radio wave type intrusion determination device according to claim 3, wherein the determination is made. 5. A plurality of radio waves having different frequencies are transmitted, each of these radio waves is reflected by a moving object under a Doppler effect and received as a reception signal, and a Doppler shift signal is generated based on the reception signal. A radio wave type intrusion determination method for determining an intrusion of an object into the intruded object based on each Doppler shift signal.