JP2006119129A - Target detection device and target detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a target detection device smaller than a conventional vehicle detection device, allowing protection from breakage, and also to provide a target detection system detecting a direction of a target in addition to presence/absence of the target. <P>SOLUTION: A microwave signal 1a generated by a microwave oscillator 1 is divided into first and second reference signals u<SB>1</SB>, u<SB>2</SB>and a third transmission signal 4a; the third transmission signal 4a is irradiated to the target 6; the first and second reference signals u<SB>1</SB>, u<SB>2</SB>and first and second reception signals w<SB>1</SB>, w<SB>2</SB>reflected by the target 6, are inputted to first and second detectors 81, 82; and first and second detection signals 8a, 8b are obtained. Detection data x, y obtained by A/D-converting the detection signals 8a, 8b by first and second A/D converters are arithmetically processed to decide the presence/absence of the target 6. The direction of the target 6 is decided by positive/negative of a phase difference between signal vectors outputted from the respective target detection devices by use of two target detection devices. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a target detection device and a target detection system that detect, for example, the presence or absence of a target in a parking section and the direction of the target.

  Conventional devices for detecting the presence or absence of a vehicle or a person in a parking lot include a light blocking method, an ultrasonic reflected wave detection method, a magnetic field change detection method using a coil, and the like.

  In vehicle detection devices that employ light blocking and ultrasonic reflected wave detection methods, a pole is set up near the entrance of each parking block, and a light-emitting device or an ultrasonic oscillator is installed in the pole. A light-emitting device or an oscillator is attached to emit light or ultrasonic waves toward the block, and in the case of light, the light shielding by the vehicle is detected. In the case of ultrasonic waves, the reflected wave that changes depending on the presence of the vehicle is detected. Captures and detects the presence of a vehicle.

  Further, in the magnetic field change detection method using a coil, a coil is embedded in each parking block, and the presence or absence of the vehicle is detected by detecting a change in the inductance of the coil due to the vehicle being positioned in that block.

An example of the light blocking type vehicle detection device is disclosed in Patent Literature 1, and an example of an ultrasonic reflected wave detection type vehicle detection device is disclosed in Patent Literature 2, and uses a coil. As a conventional magnetic field change detection type vehicle detection device, for example, there is one disclosed in Patent Document 3.
JP 2004-102860 A JP 2001-222791 A Japanese Patent No. 2587746

  In the conventional vehicle detection device, the light blocking method and the ultrasonic reflected wave detection method have a problem that the device becomes large because it is necessary to build a pole.

  In addition, when the light emitting device or the oscillator is incorporated at a low position of the pole, the light emitting device or the oscillator may be damaged due to mischief or the like. In the light blocking method, even if the light emitting device is mounted on a high place such as a ceiling to prevent the above-described mischief, the light receiving unit must be installed on the floor surface. May be blocked and malfunction.

  Moreover, in the magnetic field change detection system using a coil, since a coil is embed | buried under the ground, damage can be prevented, but since a coil becomes large, there exists a problem of taking a place.

  Accordingly, an object of the present invention is to provide a target detection apparatus that can detect a target including not only a vehicle but also a human body and the like, which is smaller and can be protected from breakage than a conventional vehicle detection apparatus.

  Moreover, it aims at providing the target detection system which can detect not only the presence or absence of a target but the direction.

  The target detection apparatus of the present invention includes a microwave oscillator that generates a microwave signal, a transmission antenna that transmits the microwave signal, and a signal obtained by reflecting the microwave signal transmitted from the transmission antenna on a target Receiving antenna for receiving the received signal and outputting the received signal; detection means for mixing and detecting the transmission signal and the received signal; outputting the detected signal; and A / D converting the detected signal to output detected data An A / D converter and an arithmetic processing means for determining presence / absence of a target based on the detection data are provided.

  The target detection apparatus of the present invention includes a microwave oscillator that generates a microwave signal, a power distributor that distributes the microwave signal into a first distribution signal and a second distribution signal, and the first A first directional coupler that divides the distributed signal into a first reference signal and a first transmission signal, and a second that divides the second distributed signal into a second reference signal and a second transmission signal. A directional coupler; a power combiner that combines the first transmission signal and the second transmission signal to output a third transmission signal; and a transmission antenna that transmits the third transmission signal. A first reception antenna that receives a signal reflected by a target from the third transmission signal transmitted from the transmission antenna and outputs a first reception signal; and the third reception antenna that is transmitted from the transmission antenna. Receive the signal reflected by the target and output the second received signal. A second receiving antenna, a first detecting means for detecting a signal input by mixing the first reference signal and the first received signal and outputting a first detected signal; A second detection means for detecting a signal input by mixing two reference signals and the second received signal and outputting a second detection signal; and A / D converting the first detection signal. A first A / D converter for outputting first detection data and a second A / D converter for A / D converting the second detection signal to output second detection data; The difference between the first detection data when the target is not present and the first detection data when the target is present, and the second detection data and the target when the target is not present Based on the magnitude of the signal vector obtained by calculating the difference from the second detection data in the presence of the target, Characterized by comprising a determining processing means the existence of standing.

  Moreover, the target detection system of the present invention is a target detection system in which two target detection devices according to claim 1 or 2 are arranged, and is detected data that is detected in the absence of the target. And a first target detection device that outputs a first signal vector obtained by obtaining a difference between detection data detected in the presence of the target and detection in the absence of the target A second target detection device for outputting a second signal vector obtained by obtaining a difference between the data and detection data detected in the presence of the target; the first signal vector; and the second signal vector. And an arithmetic processing unit for determining the direction of the target based on the phase difference.

  Since the target detection device of the present invention uses microwaves, the size of the device can be reduced compared to conventional vehicle detection devices, and since microwaves are permeable, a cover is attached to the microwave sensor. It can be protected from breakage.

  In addition, according to the target detection system of the present invention, by performing arithmetic processing for obtaining the phase difference between the signal vectors output by each of the two target detection devices, not only the presence / absence of the target but also the direction thereof is determined. Can be detected.

  An embodiment of a target detection device and a target detection system of the present invention will be described below with reference to the drawings.

[First Example]
FIG. 1 shows the configuration of a first embodiment of the target detection apparatus of the present invention.

Target object detection apparatus 100 of this embodiment includes a microwave oscillator 1 for generating a microwave signal 1a, the power distribution for distributing the microwave signal 1a to the first distributed signal v ₁ and the second distributed signal v ₂ 2, a first directional coupler 31 that divides the first distribution signal v ₁ into a first reference signal u ₁ and a first transmission signal z ₁ , and a second distribution signal v ₂ as a second The second directional coupler 32 that divides the reference signal u ₂ into the second transmission signal z ₂ , the first transmission signal z _1, and the second transmission signal z ₂ are combined into a third transmission. The power combiner 4 that outputs the signal 4 a, the transmission antenna 5 that transmits the third transmission signal 4 a, and the signal that the third transmission signal 4 a transmitted from the transmission antenna 5 is reflected by the target 6 is received. a first receiving antenna 71 for outputting a first received signal w _1, first transmitted from the transmitting antenna 5 Transmission signal 4a of the second receiving antenna 72 for outputting a received signal w ₂ of the second receiving the reflected signal at the target 6, the first reference signal u ₁ and the first received signal w ₁ is a first detector 81 for outputting a first detection signal 8a is inputted, the second detection the second reference signal u ₂ and the second received signal w ₂ is to output a second detection signal 8b is inputted A first amplifier 91 that amplifies the first detection signal 8a, a second amplifier 92 that amplifies the second detection signal 8b, and a first detection signal 8a that is A / D-converted to perform a first conversion. A first A / D converter 101 that outputs one detection data x, and a second A / D converter 102 that A / D converts the second detection signal 8b and outputs second detection data y. A CPU 12 having a built-in ROM and RAM and processing the first and second detection data x, y to determine the presence or absence of the target 6 Is provided.

  For example, diodes are used as the first and second detectors 81 and 82, and operational amplifiers are used as the first and second amplifiers 91 and 92, for example.

  The circuit shown in FIG. 1 is implemented by arranging the transmitting antenna 5 and the first and second receiving antennas 71 and 72 in the rear surface of the antenna unit arranged in the same plane as shown in FIG. The algorithm for determining the presence or absence of the target 6 using the first and second A / D converters 101 and 102 and the CPU 12 is executed by a remote computer.

Here, the basic operation of the target detection apparatus 100 of the present embodiment will be described. The microwave oscillator 1 generates a microwave signal 1 a and supplies it to the power distributor 2. Power divider 2 divides the microwave signal 1a to the first distributed signal v ₁ and the second and the distributed signal v _2, first distributing signal v _1, the first and second distributed signals v _2, respectively The second directional couplers 31 and 32 are supplied. The first directional coupler 31 divides the first distribution signal v ₁ into a first reference signal u ₁ and a first transmission signal z ₁ and supplies the first transmission signal z ₁ to the power coupler 4. The second directional coupler 32 divides the second distribution signal v ₂ into the second reference signal u ₂ and the second transmission signal z _2, and the second transmission signal z ₂ is converted into the power coupler 4. To supply. The power combiner 4 combines the first transmission signal z ₁ and the second transmission signal z ₂ and supplies the third transmission signal 4 a to the transmission antenna 5.

Next, the transmission antenna 5 irradiates the target 6 with the third transmission signal 4a, and the first and second reception antennas 71 and 72 are the target 6 that has been irradiated with the third transmission signal 4a. The reflected signal is received and first and second received signals w ₁ and w ₂ are output, respectively. The first reference signal u ₁ and the first reception signal w ₁ are input to the first detector 81 and the first detection signal 8 a is output, and the second reference signal is supplied to the second detector 82. u ₂ and the second received signal w ₂ are input, and the second detection signal 8 b is output. The first and second amplifiers 91 and 92 amplify the first and second detection signals 8a and 8b, respectively, and supply the amplified signals to the first and second A / D converters 101 and 102, respectively.

  The first and second A / D converters 101 and 102 A / D convert the first and second detection signals 8a and 8b and supply the first and second detection data x and y to the CPU 12. To do.

  And CPU12 performs a process according to the program which performs the below-mentioned arithmetic processing memorize | stored in ROM, and memorize | stores the below-mentioned offset voltage temporarily by RAM.

次に、第１及び第２の検波データｘ，ｙから物標の有無を検出する方法を図３に示すベクトル図を参照して説明する。 Here, the target detection procedure of the target detection apparatus 100 of the present embodiment will be described with reference to the flowchart shown in FIG. The flowchart shown in FIG. 4 is stored in the ROM as a calculation program.

Next, a method for detecting the presence or absence of a target from the first and second detection data x and y will be described with reference to the vector diagram shown in FIG.

The first and second detection data x, y are
x = b ₁ + acos (2βR + θ ₁ ) (Formula 1)
y = b ₂ + acos (2βR + θ ₂ ) (Formula 2)
It is expressed. Here, b ₁ and b ₂ are DC offset voltages, a is a term proportional to the amplitude of the received signal of the target reflected wave, β = 2π / λ ₀ , λ ₀ is the wavelength of frequency f ₀ , and f ₀ = At 24 GHz, λ ₀ = 1.25 cm.

The phases θ ₁ and θ ₂ pass through the waveguides of lengths l ₁ and l ₂ until the first and second received signals w ₁ and w ₂ reach the first and second detectors 81 and 82, respectively. Phase change that occurs when
θ ₁ = β _g l ₁ (Formula 3)
θ ₂ = β _g l ₂ (Formula 4)
It is. Here, β _g = 2π / λ _g and λ _g are wavelengths on the waveguide.

As a phase amount by l ₁ and l ₂ , for example,

If you choose
x = b ₁ + acos2βR (Formula 6)
y = b ₂ + asin2βR (Formula 7)
It becomes. If these are expressed together as a vector,

It is.

  Therefore, as shown in FIG. 3C, a circle with a radius α is provided, and the presence or absence of the target 6 can be determined by whether or not (Equation 12) is equal to or higher than a certain level α.

That is,

Then, it is determined that a target 6 such as a car or a person exists,

If so, it is determined that the target 6 does not exist.

  Since the target detection apparatus 100 of the present embodiment uses microwaves, the apparatus is compared with a conventional vehicle detection apparatus using a light blocking method, an ultrasonic reflected wave detection method, and a magnetic field change detection method using a coil. Miniaturization is possible, and since the microwave is transmissive, a cover can be attached to the microwave sensor, so that it can be protected from breakage.

Although two receiving antennas are used in FIG. 1, the interval between them is sufficiently smaller than the wavelength λ ₀ or the antenna arrangement of FIG. 2 is used vertically. Further, as shown in FIG. 5, if the power distributor 13 is used, only one receiving antenna 14 is required.

[Second Example]
FIG. 6 shows the configuration of a second embodiment of the target detection apparatus of the present invention. In addition, the same code | symbol is attached | subjected to the structure same as the structure of the 1st Example shown in FIG. 1, and detailed description is abbreviate | omitted.

The target detection apparatus 600 according to the present embodiment includes a microwave oscillator 1, a transmission / reception antenna 51, and N detection units K _{1 to} K installed on a waveguide connecting the microwave oscillator 1 and the antenna 51. _N , N amplifiers F _{1 to} F _N connected to the detectors K _{1 to} K _N , respectively, and N A / D converters AD _{1 to} AD _N connected to the amplifiers F _{1 to} F _N , respectively. And a CPU 12.

Note that the structure from the detection unit _K 1 ~K _N is a diode _D 1 to D _N, the diode _D 1 to D _N for the load and the other end is connected to one end to the respective output side is grounded resistor _r 1 ~r _N Is done.

Here, the basic operation of the target detection apparatus 600 of the present embodiment will be described. The microwave oscillator 1 generates a microwave signal 1a. The microwave signal 1a acts as a transmission signal _{e t} simultaneously with the reference signal e _l1 to e _{l N.}

The antenna 51 radiates the transmission signal e _t against the target 6, also outputs the received signal e _r receives a signal reflected by the target 6 those that receive a radiation of the transmission signal e _t .

Detection section _K 1 ~K the _N reference signals e _l1 to e _{l N} and the received signal _e r1 _{to e rN} is inputted detection signal _e 1 to e _N is outputted.

Thereafter, the amplifier _F 1 to F _N are supplied to the A / D converter _AD 1 to AD _N amplifies the detection signal _e 1 to e _N, A / D converter _AD 1 to AD _N is the detection signal _e 1 ~ supplies detected data _x 1 ~x _N to CPU12 to e _N a / D conversion on. The CPU 12 performs the same process as in the first embodiment.

In this embodiment, the detectors K _{1 to} K _N are placed on the waveguide, and the same effect as that of the first embodiment can be obtained.

However, in general, it is difficult to perform such accurate setting. Therefore, if a detection unit is installed at a sufficient number of N locations (N ≧ 2) and these N detection outputs are used, the presence of the target can be determined. Become more certain.

  Next, an embodiment of the target detection system 800 of the present invention will be described with reference to FIGS.

[Third embodiment]
FIG. 8 shows the configuration of a third embodiment of the target detection system 800 of the present invention.

  The target detection system 800 of the present embodiment is connected to the first and second target detection devices 100A and 100B and the first and second target detection devices 100A and 100B arranged at appropriate intervals. An arithmetic processing unit 15 is provided.

The first and second target detection devices 100A and 100B have the same configuration as the target detection device 100 of FIG. The reference numerals of the respective parts in FIG. 8 are obtained by adding A for the first target detection apparatus 100A and B for the second target detection apparatus 100B after the reference numerals of the respective parts in FIG. Each indicates the same part as each part of the target detection apparatus 100 of FIG.

  And the arithmetic processing unit 15 performs a process according to the program which performs the below-mentioned arithmetic process.

Next, the target detection procedure of the target detection system 800 of the present embodiment will be described with reference to the flowchart shown in FIG. 7 is stored in the arithmetic processing unit 15 as an arithmetic program.

The phase difference Δθ shown in FIG.

If you

Can be calculated from
Δθ = β (R _B −R _A ), β = 2π / λ ₀ (Equation 19)
It becomes. Here, R _A and R _B are distances from the first and second target detection devices 100A and 100B to the target.

The position coordinates of the target are (X, Y), the coordinates of the first target detection apparatus 100A are (d, 0), the coordinates of the second target detection apparatus 100B are (-d, 0), and the object from the origin. the distance to the target and _{R 0,} if d«R _0,

It is represented by

Therefore, (Formula 19) is

It becomes.

  Therefore, the direction can be determined by the sign of X. When Δθ> 0, the target is on the right side, when Δθ <0, the target is on the left side, and when Δθ = 0, the target is on the front side.

  As described above, according to the present embodiment, two target detection devices are arranged, and the phase difference of the signal vector of the reflected signal detected by each target detection device is obtained. In addition, the direction can be detected.

  In this embodiment, two target detection devices are used, but three or more target detection devices may be used.

It is the schematic which shows the structure of the 1st Example of the target detection apparatus of this invention. It is the schematic which shows arrangement | positioning of the transmitting antenna and receiving antenna of the target detection apparatus shown in FIG. It is a vector diagram explaining the method of determining the presence or absence of a target with the target detection apparatus shown in FIG. It is a flowchart which shows the procedure which determines the presence or absence of a target with the target detection apparatus shown in FIG. It is the schematic which shows the structure of a receiving antenna and power divider | distribution in the case of comprising one receiving antenna in the target detection apparatus shown in FIG. It is the schematic which shows the structure of the 2nd Example of the target detection apparatus of this invention. It is a flowchart which shows the procedure which discriminate | determines the direction in which the target exists in the 3rd Example of the target detection system of this invention. It is the schematic which shows the structure of the 3rd Example of the target detection system of this invention. It is a figure which shows the positional relationship of the 1st and 2nd target detection apparatus and target in the 3rd Example of the target detection system of this invention. It is a figure which shows the relationship between the signal vector which the 1st and 2nd target detection apparatus detected in the 3rd Example of the target detection system of this invention, and the phase difference of each vector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microwave oscillator 2 Power divider 31 1st directional coupler 32 2nd directional coupler 4 Power coupler 5 Transmitting antenna 51 Antenna 6 Target 71 1st receiving antenna 72 2nd receiving antenna 81 1st 1 detector 82 2nd detector 91 1st amplifier 92 2nd amplifier 101 1st A / D converter 102 2nd A / D converter 12 CPU
13 power divider 14 receiving antenna 15 processor 100 target detection device 600 target detection device 800 target detection system _K 1 ~K _N detection section _D 1 to D _N diodes _r 1 ~r _N load resistor _F 1 ~ F _N amplifiers _AD 1 _{~AD N} a / D converters 100A first target detection apparatus 100B second target detection apparatus

Claims (3)

A microwave oscillator for generating a microwave signal;
A transmitting antenna for transmitting the microwave signal;
A receiving antenna that receives the signal reflected from the target by the microwave signal transmitted from the transmitting antenna and outputs a received signal;
Detection means for mixing and detecting the transmission signal and the reception signal, and outputting a detection signal;
An A / D converter for A / D converting the detection signal and outputting detection data;
Computation processing means for judging presence / absence of a target based on the detection data. A microwave oscillator for generating a microwave signal;
A power distributor that distributes the microwave signal into a first distribution signal and a second distribution signal;
A first directional coupler that divides the first distribution signal into a first reference signal and a first transmission signal;
A second directional coupler for dividing the second distribution signal into a second reference signal and a second transmission signal;
A power combiner that combines the first transmission signal and the second transmission signal to output a third transmission signal;
A transmission antenna for transmitting the third transmission signal;
A first receiving antenna that receives the signal reflected by the target from the third transmission signal transmitted from the transmitting antenna and outputs a first received signal;
A second receiving antenna that receives a signal reflected by a target of the third transmission signal transmitted from the transmitting antenna and outputs a second received signal;
First detection means for detecting a signal inputted by mixing the first reference signal and the first reception signal and outputting a first detection signal;
Second detection means for detecting a signal input by mixing the second reference signal and the second reception signal and outputting a second detection signal;
A first A / D converter for A / D converting the first detection signal and outputting first detection data;
A second A / D converter for A / D converting the second detection signal and outputting second detection data;
The difference between the first detection data when the target is not present and the first detection data when the target is present, and the second detection data and the target when the target is not present Arithmetic processing means for determining the presence / absence of a target based on the magnitude of a signal vector obtained by calculating a difference from the second detection data in a state where the target is present Target detection device. A target detection system in which two target detection devices according to claim 1 or 2 are arranged,
A first target detection device that outputs a first signal vector obtained by obtaining a difference between detection data detected in the absence of the target and detection data detected in the presence of the target; ,
A second target detection device for outputting a second signal vector obtained by obtaining a difference between detection data detected in the absence of the target and detection data detected in the presence of the target; ,
A target detection system comprising: an arithmetic processing unit that obtains a phase difference between the first signal vector and the second signal vector and determines a direction of the target based on the phase difference.

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