JP2001330661A - Modulation reflector - Google Patents

Abstract

(57) [Summary] [Problem] A reflector to be attached to a target of a radar,
Be easily distinguishable from other objects. A modulation reflector is attached to a target of a radar. The radio wave of the radar 1 received by the reflector antenna 3 of the modulation reflector is periodically switched to a terminator 5 and a reflector 6 by a switch 4 controlled by a clock of a clock generator 7. The terminator 5 absorbs the radio wave and does not reflect it. The reflector 6 reflects the radio wave as it is. Since the reflection cross-sectional area of the modulation reflector changes periodically, the modulation reflector is observed by the radar 1 as an object whose reflected wave intensity repeatedly changes in intensity at the clock cycle. Therefore, the modulation reflector can be easily distinguished from other objects having no periodicity in the reflected wave intensity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modulation reflector, and more particularly, to a modulation reflector which is installed on a vehicle or a road to support smooth and safe traffic and facilitates detection of a target by radar observation. .

[0002]

2. Description of the Related Art A conventional reflector for facilitating detection of a target by radar observation includes a reflector for radar observation having a configuration as shown in FIG. A conventional reflector will be described with reference to FIG. In FIG. 5, a radar 1 is a device that emits a radio wave and detects an object from a reflected wave. The radar antenna 2 is an antenna that transmits a radar wave and receives a reflected wave. Reflector 16
Is a reflector that reflects radar radio waves.

[0003] The transmission power generated by the radar 1 is emitted from a radar antenna 2. The emitted transmission wave is reflected by the reflector 16 attached to the target and received by the radar antenna 2. For example, in a pulse radar, the distance to a target is measured by measuring the time from when a radio wave is emitted by the radar 1 to when a received wave is detected.

In general, the shape of a target is complicated, and the intensity of the reflected wave fluctuates greatly, so that the reflected wave may not be received in some cases. In order to improve this, a reflector having a sufficiently large reflection cross section is attached to the target.

[0005]

However, in the reflector as described above, when a plurality of objects are detected,
There is a problem that a target object cannot be distinguished from other objects.

[0006] The present invention solves the above-mentioned conventional problems, and even when a plurality of objects are detected by a radar, a target object and a target object are detected.
It is an object of the present invention to provide a reflector capable of distinguishing from other objects.

[0007]

In order to solve the above-mentioned problems, according to the present invention, a modulation reflector for facilitating identification by attaching to a target observed by a radar is provided in a transmitting / receiving antenna and a transmitting / receiving antenna. A single-circuit multi-contact switch to which a third terminal is connected, a terminator connected to the first terminal of the switch, a reflector connected to the other terminal of the switch, and a switch for periodically switching the transmission and reception antenna The configuration includes a clock generator that controls the first terminal and the other terminal to be connected alternately.

With this configuration, the reflectance of the modulation reflector can be changed with regularity over time, and the target object can be easily identified by the radar.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.

(First Embodiment) A first embodiment of the present invention is a modulation reflector that periodically repeats reflection and absorption.

FIG. 1 is a functional block diagram of a modulation reflector according to the first embodiment of the present invention. In FIG. 1, a radar 1 is a device that emits a radio wave and detects an object from a reflected wave. The radar antenna 2 is an antenna that transmits a radar wave and receives a reflected wave. The reflector antenna 3 is an antenna that receives and reflects radar radio waves. The switch 4 is means for switching between the terminator and the reflector. The terminator 5 is a means for absorbing radar radio waves.
The reflector 6 is a means for reflecting radar radio waves. The clock generator 7 is a means for generating a signal for periodically switching the switch. The reflector antenna 3, the switch 4, the terminator 5, the reflector 6, and the clock generator 7
For example, it is attached to a target to be detected such as a car.

The operation of the modulation reflector according to the first embodiment of the present invention configured as described above will be described. The transmission power generated by the radar 1 is emitted as a radio wave from the radar antenna 2 and received by the reflector antenna 3. The received power from the reflector antenna 3 is guided to the terminator 5 or the reflector 6 through the switch 4. Here, the switch 4 periodically repeats switching with a clock signal from the clock generator 7.

When the switch 4 connects the reflector antenna 3 to the reflector 6 and the received power is guided to the reflector 6,
All the received power is reflected by the reflector 6, returns to the reflector antenna 3 through the switch 4, is radiated again into the air as radio waves, and is received by the radar 1.

On the other hand, when the reflector antenna 3 is connected to the terminator 5 by the switch 4 and the received power is guided to the terminator 5, the total received power is consumed by the terminator 5 and is radiated again to the air. Absent. The radar 1 receives a weak reflected wave from a portion of the target other than the reflector. Therefore, the reflector antenna 3 is observed by the radar 1 as an object whose reflected wave intensity repeats its intensity at the clock cycle, and can be distinguished from other objects having no periodicity in the reflected wave intensity.

As described above, in the first embodiment of the present invention, the modulation reflector is configured to periodically repeat reflection and absorption, so that it can be easily distinguished from other objects by radar.

(Second Embodiment) A second embodiment of the present invention is a modulation reflector that periodically reflects circularly polarized waves having the same turning direction.

FIG. 2 is a functional block diagram of a modulation reflector according to a second embodiment of the present invention. The basic configuration of the second embodiment is the same as that of the first embodiment. The difference is that the antennas are a circularly polarized radar antenna 8 and a circularly polarized reflector antenna 9.

In FIG. 2, a circularly polarized radar antenna 8
Is an antenna that transmits a circularly polarized radar wave and receives a reflected wave. The circularly polarized wave reflector antenna 9 is an antenna that receives a radar wave and reflects it with a circularly polarized wave. The polarization directions of the circularly polarized radar antenna 8 and the circularly polarized reflector antenna 9 are the same turning direction.

The operation of the modulation reflector according to the second embodiment of the present invention configured as described above will be described. The transmission power generated by the radar 1 is emitted as a circularly polarized radio wave from the circularly polarized radar antenna 8 and received by the circularly polarized reflector antenna 9. Circularly polarized reflector antenna 9
Is transmitted to the terminator 5 or the reflector 6 through the switch 4. The operations of the switch 4, the terminator 5, the reflector 6, and the clock generator 7 are the same as those of the first embodiment. Therefore, the circularly polarized reflector antenna 9 is observed by the radar 1 as an object whose reflected wave intensity repeats its strength at the clock cycle, and can be distinguished from other objects having no periodicity in the reflected wave intensity.

In the case of a circularly polarized wave, if the surface of the object to be reflected is a plane, the direction of rotation of the polarized wave after reflection is reversed. Also, in an object having a complicated shape, the reflected wave is not completely circularly polarized but becomes elliptically polarized. In any case, since the turning direction of the polarization of the reception wave does not match the turning direction of the polarization of the transmission wave, the power of the radio wave reflected by an object other than the reflector and received by the radar 1 decreases. I do. on the other hand,
Circularly polarized radar antenna 8 and circularly polarized reflector antenna 9
Are in the same turning direction, the power when the reflected wave from the modulation reflector is received by the radar 1 includes:
There is no loss due to the difference in the direction of polarization rotation. Therefore,
The ratio of the power of the reception wave from the modulation reflector to the power of the reception wave from other objects can be increased as compared with the case where a linearly polarized antenna is used for the radar.

Therefore, the reflection cross-sectional area of the modulation reflector is changed with time regularity, and the reception intensity of the reflected wave from an object other than the modulation reflector is reduced by using the circularly polarized antenna. Thus, the modulation reflector can be more easily identified.

As described above, in the second embodiment of the present invention, the modulation reflector is configured to periodically reflect circularly polarized waves in the same turning direction, so that the radar can more easily reflect another object with the radar. Can be distinguished.

(Third Embodiment) A third embodiment of the present invention is a modulation reflector for amplifying a received wave and re-emitting it periodically.

FIG. 3 is a functional block diagram of a modulation reflector according to the third embodiment of the present invention. The basic configuration of the third embodiment is the same as that of the first embodiment. The difference is that a circulator and an amplifier are provided. In FIG. 3, a circulator 10 is a directional coupler that separates a reception wave and a transmission wave. Amplifier 11
This is means for amplifying the received wave.

The operation of the thus configured modulator according to the third embodiment of the present invention will be described. The transmission power generated by the radar 1 is emitted as a radio wave from the radar antenna 2 and received by the reflector antenna 3. The received power from the reflector antenna 3 is guided to the terminator 5 or the amplifier 11 through the switch 4. The switch 4 repeats switching periodically with the clock from the clock generator 7. When the switch 4 connects the reflector antenna 3 to the amplifier 11, the received power is guided to the amplifier 11. The received power is amplified by the amplifier 11,
After returning to the reflector antenna 3 through the circulator 10, it is radiated again into the air and received by the radar 1.

On the other hand, when the reflector 4 is connected to the terminator 5 by the switch 4, the received power is guided to the terminator 5. All the received power is consumed by the terminator 5 and is not radiated again into the air. The radar 1 receives a weak reflected wave from a portion of the target other than the reflector. Therefore, the modulation reflector is observed by the radar 1 as an object whose reflected wave intensity repeats strength and weakness in the cycle of the clock,
It can be distinguished from other objects having no periodicity in the reflected wave intensity.

When the radio wave received by the reflector antenna 3 is re-emitted, the power is amplified by the amplifier 11, so that a reflector that reflects all the input power is used.
The intensity ratio of the reflected wave intensity can be increased. Therefore, by changing the reflection cross-sectional area of the modulation reflector with regularity over time, and increasing the strength ratio of the reflected wave intensity by power-amplifying and re-radiating the received wave, the modulation reflector can be used. It can be more easily identified.

As described above, in the third embodiment of the present invention, the modulation reflector is configured to amplify the received wave and re-emit it periodically, so that the radar can more easily distinguish it from other objects. it can.

(Fourth Embodiment) A fourth embodiment of the present invention is a modulation reflector that rotates a received linearly polarized wave by 90 degrees and re-radiates it periodically.

FIG. 4 is a functional block diagram of a modulation reflector according to the fourth embodiment of the present invention. The basic configuration of the fourth embodiment is the same as that of the first embodiment. The difference is that a radar antenna 12, a reflector antenna 13, a switch 14, and a terminator 15 are provided.

In FIG. 4, a radar antenna 2 is an antenna for transmitting a radar wave. Radar antenna 12
Is an antenna for receiving a reflected wave. The reflector antenna 3 is an antenna that receives radar radio waves. The reflector antenna 13 is an antenna that re-radiates the received radar radio waves. The switch 14 is a means for switching between the terminator and the switch 4. The terminator 15 is a means for absorbing radar radio waves.

Radar antenna 2 and reflector antenna 3
Are linearly polarized antennas having the same polarization direction. The radar antenna 12 and the reflector antenna 13 are linearly polarized antennas having the same polarization direction. The polarization directions of the radar antenna 2 and the radar antenna 12 are orthogonal.

The operation of the modulation reflector according to the fourth embodiment of the present invention configured as described above will be described. The transmission power generated by the radar 1 is emitted as a radio wave from the radar antenna 2 and received by the reflector antenna 3. The received power from the reflector antenna 3 is guided to the terminator 5 or the switch 14 through the switch 4. The switch 4 and the switch 14 are periodically switched in synchronization with the clock from the clock generator 7.
When the switch 4 connects the reflector antenna 3 to the switch 14, the received power is guided to the reflector antenna 13 and radiated again into the air. At this time, the polarization direction of the radio wave radiated from the reflector antenna 13 is rotated by 90 degrees. This radio wave is received by the radar 1 through the radar antenna 12 having the same polarization as the reflector antenna 13.

On the other hand, when the reflector antenna 3 is connected to the terminator 5 by the switch 4, all the received power is consumed by the terminator 5 and is not radiated to the air again. The radar 1 receives a weak reflected wave from a portion of the target other than the reflector. Therefore, the modulation reflector is an object whose reflected wave intensity repeats strong and weak at the cycle of the clock.
Since it is observed by the radar 1, it can be distinguished from other objects having no periodicity in reflected wave intensity.

The direction of polarization of the reflected wave from the object is not completely the same in the case of an object having a complicated shape, but is substantially the same as the transmission wave emitted from the radar antenna 2. Therefore, the polarization direction of the reflected wave from an object other than the modulation reflector is orthogonal to the polarization direction of the radar antenna 12, so that the power of the radio wave received by the radar 1 decreases. On the other hand, since the polarization directions of the reflector antenna 13 and the radar antenna 12 are the same, there is no loss due to the difference in polarization in the power when the radar 1 receives the radio wave from the modulation reflector. Therefore, compared to a radar using a transmitting antenna and a receiving antenna in the same polarization direction, the ratio of the received power from the modulation reflector to the power from other objects can be increased.

Therefore, the reflection cross-sectional area of the modulation reflector is changed with regularity in time, and the polarization of the transmission antenna and the reception antenna of the radar are made orthogonal to each other, so that the reflection wave from the object other than the modulation reflector is reduced. By reducing the reception intensity, the modulation reflector can be more easily identified.

As described above, in the fourth embodiment of the present invention, the modulation reflector is configured to rotate the received linearly polarized wave by 90 degrees and re-emit periodically, so that it is easier to use the radar. Can be distinguished from other objects.

[0038]

As is apparent from the above description, according to the present invention, a modulation reflector for attaching to a target observed by a radar and facilitating identification is provided with a transmitting / receiving antenna and a third terminal at the transmitting / receiving antenna. A connected one-circuit multi-contact switch, a terminator connected to the first terminal of the switch, a reflector connected to the other terminal of the switch, and a switch for periodically switching the transmission / reception antenna to the first terminal. And a clock generator that controls the connection alternately to the terminals of the modulation reflector, so that the reflection cross-section of the modulation reflector can be changed with regularity over time, and the target object can be detected by the radar. The effect of being able to easily identify is obtained.

Further, a modulation reflector for facilitating identification by being attached to a target observed by the radar is provided by a circularly polarized wave transmitting / receiving antenna and a one-circuit multi-contact having a third terminal connected to the circularly polarized wave transmitting / receiving antenna. A switch, a terminator connected to a first terminal of the switch, a reflector connected to another terminal of the switch, and a switch periodically switched to alternately connect a third terminal to the first terminal and the other terminal. And a clock generator that controls the reception in this manner, the intensity of reception from objects other than the modulation reflector can be reduced due to the difference in polarization between the transmission wave and the reception wave, and the target object can be easily detected by radar. Is obtained.

A modulating reflector for facilitating identification by being attached to a target observed by the radar is provided with a transmitting / receiving antenna, a circulator having input / output terminals connected to the transmitting / receiving antenna, and a third terminal connected to an output terminal of the circulator.
A one-circuit multi-contact switch having terminals connected thereto, an amplifier having an input terminal connected to a specific terminal of the switch and an output terminal connected to the input terminal of the circulator, and a third terminal which is periodically switched to switch the third terminal to the first terminal And a clock generator that controls the connection to a specific terminal alternately, so that the power re-radiated from the modulation reflector can be amplified and the target object can be easily identified by the radar. The effect is obtained.

A modulation reflector for facilitating identification by being attached to a target observed by radar is provided with a linearly polarized wave transmitting antenna, and a linearly polarized wave receiving antenna whose polarization direction is orthogonal to the linearly polarized wave transmitting antenna. A one-circuit multi-contact first switch having a third terminal connected to the linearly polarized reception antenna, a first terminator connected to the first terminal of the first switch, and a first terminal connected to the linearly polarized transmission antenna. 1 with 3 terminals connected
A second switch having multiple contacts of the circuit, a second terminator connected to the first terminal of the second switch, means for connecting the second terminal of the first switch to the second terminal of the second switch, A clock generator that controls the third terminal to be switched alternately to the corresponding first terminal and the other terminal alternately and synchronously, so that the polarization orthogonal to the transmission wave is provided. Reflected wave can be transmitted, and an effect that a target object can be easily identified by the radar can be obtained.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a modulation reflector according to a first embodiment of the present invention;

FIG. 2 is a functional block diagram of a modulation reflector according to a second embodiment of the present invention;

FIG. 3 is a functional block diagram of a modulation reflector according to a third embodiment of the present invention;

FIG. 4 is a functional block diagram of a modulation reflector according to a fourth embodiment of the present invention;

FIG. 5 is a functional block diagram of a conventional reflector.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 radar 2, 12 radar antenna 3, 13 reflector antenna 4, 14 switch 5, 15 terminator 6 reflector 7 clock generator 8 circularly polarized radar antenna 9 circularly polarized reflector antenna 10 circulator 11 amplifier 16 corner reflector

Claims (4)

[Claims] 1. A modulation reflector for facilitating identification by being attached to a target observed by a radar,
A transmitting / receiving antenna, a single-circuit multi-contact switch having a third terminal connected to the transmitting / receiving antenna, and a first switch of the switch
And a reflector connected to the other terminal of the switch, and the switch is periodically switched to control the transmission / reception antenna to be alternately connected to the first terminal and the other terminal. A modulation reflector, comprising: a clock generator. 2. A modulation reflector for facilitating identification by being attached to a target observed by a radar,
A circularly polarized wave transmitting / receiving antenna, a one-circuit multi-contact switch having a third terminal connected to the circularly polarized wave transmitting / receiving antenna, a terminator connected to a first terminal of the switch, and another terminal connected to the switch. A modulation reflector comprising: a reflector; and a clock generator that controls the third terminal to be alternately connected to the first terminal and the other terminal by periodically switching the switch. 3. A modulation reflector for facilitating identification by being attached to a target observed by a radar,
A transmitting / receiving antenna, a circulator having an input / output terminal connected to the transmitting / receiving antenna, and a one-circuit multi-contact switch having a third terminal connected to an output terminal of the circulator;
An amplifier having an input terminal connected to a specific terminal of the switch and an output terminal connected to an input terminal of the circulator;
A modulation reflector, comprising: a clock generator for periodically switching the switch to control a third terminal to be alternately connected to a first terminal and a specific terminal. 4. A modulation reflector mounted on a target observed by a radar for easy identification,
A linearly polarized wave transmitting antenna, a linearly polarized wave receiving antenna whose polarization direction is orthogonal to the linearly polarized wave transmitting antenna, and a one-circuit multi-contact first switch having a third terminal connected to the linearly polarized wave receiving antenna. A first terminator connected to a first terminal of the first switch, a one-circuit multi-contact second switch having a third terminal connected to the linearly polarized wave transmitting antenna, and a first terminal of the second switch. A second terminator connected to a terminal; a means for connecting a second terminal of the first switch to a second terminal of the second switch; and a third terminal for periodically switching each of the switches synchronously. And a clock generator for controlling the clock signal to be alternately connected to a corresponding first terminal and another terminal.