JP2006133108A - Radar system, object detection method, radar device and radio reflector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an accurate object detection without being influenced by a setting environment or the like in object detection using a radar device and a radio reflector. <P>SOLUTION: A radar transceiver 10 comprises a horizontally polarized wave transmitting antenna 11a transmitting a polarized transmitting wave 21 of horizontal polarization to a detection reflector 30 and a vertical polarized wave receiving antenna 11c selectively receiving only vertically polarized wave. The detection reflector 30 is provided with the function of changing the polarization plane of the incoming polarized transmitting wave 21 by 90° and transmitting toward the transmitting and receiving antenna 11 as a polarized receiving wave 22 of vertical polarization. Even if a noise object is present in the vicinity of the detection reflector 30, the polarized transmitting wave 21 of horizontal polarization is reflected from the noise object as it is. Therefore, in the radar transceiver 10, the polarized receiving wave 22 of vertical polarization reflected from the reflector 30 can be selectively detected, and a change in receiving power in interruption of the polarized receiving wave 22 by an obstacle or the like can be detected with high accuracy. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a radar system, an object detection method, a radar apparatus, and a radio wave reflector, and more particularly to a technique effective when applied to an object detection technique such as obstacle monitoring and intrusion monitoring by a radar.

  Conventionally, as an obstacle detection technique using a radar, a technique disclosed in Patent Document 1 is known. That is, a radar transmitter / receiver and a reflector are arranged at positions facing each other across the monitoring target region, and the radar wave received power detected by the radar transmitter / receiver after reciprocating between the radar transmitter / receiver and the reflector ( An obstacle that crosses the space (monitoring target area) between the radar transmitter / receiver and the reflector is detected by a change in RCS level (Rader Cross Section Level).

  However, the installation environment of the radar transmitter / receiver and the reflector is various, and if there is an unnecessary object near the reflector, the reflected wave from the unnecessary object becomes noise and enters the radar transmitter / receiver from the reflector. There was a technical problem of being superposed on the radar wave and reducing the detection accuracy of the obstacle.

  That is, in the conventional technique such as Patent Document 1, when an unnecessary object or the like is present in the vicinity of the reflector, the reflected power from the unnecessary object is detected in addition to the reflected power from the reflector. When the unnecessary object is unstable, the RCS level fluctuates due to slight displacement such as vibration and wind.

  If there is a fluctuation in the RCS level that is larger than the reflected wave from the original reflector, the obstacle separation performance (that is, the determination accuracy of the presence or absence of the obstacle) is deteriorated, and the detection level fluctuation of the reflected wave from the unnecessary object is changed. There is a problem that the detection of obstacles may be hindered, such as false detection due to (detected that there are no obstacles due to fluctuations in detection level of reflected waves from unwanted objects even though there are no obstacles in the monitored area) there were.

In addition, there exists a technique shown by patent document 2 as another related prior art. In this Patent Document 2, normality of obstacle data on the side of the input / output control device is obtained by adding a check code to the obstacle data detected using the radar device and outputting it to an external input / output control device. Can be confirmed. However, Patent Document 2 does not recognize the technical problem of the present invention as described above.
JP 2001-325690 A JP 2002-37078 A

An object of the present invention is to provide a technique capable of highly accurate object detection in object detection using both a radar apparatus and a radio wave reflector.
Another object of the present invention is to realize highly accurate object detection without being affected by an installation environment or the like in object detection using both a radar device and a radio wave reflector.

According to a first aspect of the present invention, there is provided a radar apparatus including a transmission unit that transmits a first radio wave, and a reception unit that receives a second radio wave having a polarization plane different from that of the first radio wave.
A radio wave reflector that receives the first radio wave from the radar device and returns the first radio wave as the second radio wave;
A radar system comprising:

A second aspect of the present invention is an object detection method for detecting an object between the radar apparatus and the radio wave reflector by a change in radio waves reciprocating between the radar apparatus and the radio wave reflector.
The polarization planes of the first radio wave incident on the radio wave reflector from the radar device and the second radio wave returned from the radio wave reflector to the radar device are made different to change the intensity of the second radio wave to the radar device. Provided is an object detection method to detect in

According to a third aspect of the present invention, there is provided a radar apparatus including a transmission unit that transmits a first radio wave and a reception unit that receives a second radio wave having a polarization plane different from that of the first radio wave.
According to a fourth aspect of the present invention, there is provided a radio wave reflector including polarization changing means for returning a first radio wave received from a radar device as a second radio wave having a polarization plane different from that of the first radio wave.

  According to the present invention described above, the first radio wave radiated from the radar device toward the radio wave reflector and the second radio wave reflected from the radio wave reflector by the incidence of the first radio wave and returning to the radar device are mutually connected. Since it has different polarization planes, only the second radio wave reflected from the original radio wave reflector is selectively received by the receiving means of the radar device, and the object is detected based on the fluctuation of the received power of the second radio wave. It can be performed with high accuracy.

  Further, even if an unnecessary object exists around the radio wave reflector, the polarization plane of the first radio wave that is reflected from the unnecessary object and returns to the radar apparatus as a noise radio wave remains as it is radiated from the radar apparatus. Therefore, the detection level of the received power of the second radio wave having a different plane of polarization is not affected. Therefore, highly accurate object detection can be realized without being affected by the installation environment of the radar device and the radio wave reflector.

According to the present invention, in the object detection using both the radar device and the radio wave reflector, it is possible to obtain an effect that the object can be detected with high accuracy.
Further, in the object detection using both the radar apparatus and the radio wave reflector, it is possible to realize an object detection with high accuracy without being affected by the installation environment or the like.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a conceptual diagram showing an operation principle of a radar system according to an embodiment of the present invention, FIG. 2 is a block diagram showing an example of the configuration of a radar system according to the present embodiment, and FIG. It is an overhead view which shows an example of the installation state of the radar system of embodiment.

  The radar system RS1 of the present embodiment can be applied to, for example, detection of an intruder constituting a crime prevention system in a museum, a jewelry store, or the like, or detection of an obstacle such as a person or a car in a railroad crossing.

In the example of FIG. 3, the case where the radar system RS1 of the present embodiment is installed at the railroad crossing 101 to detect an obstacle 102 such as a person or a car is shown.
That is, at the crossing 101 that intersects with the track 100, a radar device including the radar transceiver 10 and the transmission / reception antenna 11 and a plurality of detection reflectors 30 are arranged so as to face each other across the crossing 101.

  As illustrated in FIG. 2, the radar transceiver 10 according to the present embodiment includes a transmission unit 12 and a reception unit 13 connected to the transmission / reception antenna 11 via a polarization changeover switch 15, and a radar signal processing control unit. 14, a microprocessor 16, a nonvolatile memory 17, an external input / output interface 18 and a user interface 19.

  The transmitting / receiving antenna 11 can function as a horizontally polarized wave transmitting antenna 11a, a vertically polarized wave transmitting antenna 11b, a vertically polarized wave receiving antenna 11c, and a horizontally polarized wave receiving antenna 11d.

  Then, one of the horizontal polarization transmission antenna 11 a and the vertical polarization transmission antenna 11 b on the transmission side is enabled by being connected to the transmission unit 12 by the polarization switching switch 15. In addition, one of the reception-side vertical polarization reception antenna 11c and the horizontal polarization reception antenna 11d is connected to the reception unit 13 by the polarization changeover switch 15 and becomes effective.

  The transmission unit 12 outputs a radar wave to the outside via the horizontal polarization transmission antenna 11a or the vertical polarization transmission antenna 11b. In the case of the present embodiment, a horizontally polarized polarization transmission wave 21 is output by using the horizontally polarized wave transmission antenna 11a.

  The receiving unit 13 selectively receives a horizontally polarized wave or a vertically polarized wave via the vertically polarized wave receiving antenna 11c or the horizontally polarized wave receiving antenna 11d. In the present embodiment, the vertically polarized wave receiving antenna 11c is connected to the receiving unit 13 to selectively receive the vertically polarized polarized wave 22.

  That is, in the case of the present embodiment, the transmitting / receiving antenna 11 radiates a horizontally polarized polarized transmission wave 21 toward the detection reflector 30 as a radar wave 20 and receives a vertically polarized polarized received wave 22. To do.

  The radar signal processing control unit 14 controls the transmission unit 12 and the reception unit 13, and based on the magnitude of the reception power of the polarization reception wave 22 detected by the reception unit 13 via the transmission / reception antenna 11, the transmission / reception antenna. 11 and the presence or absence of the obstacle 102 between the detection reflector 30 is determined.

  The microprocessor 16 controls the entire radar transceiver 10. The nonvolatile memory 17 stores control programs and data executed by the microprocessor 16. The external input / output interface 18 is used to output the detection result of the obstacle 102 in the radar signal processing control unit 14 to an external system or to input a control command to the microprocessor 16 from the outside.

The user interface 19 includes button switches, a keyboard, a display, and the like, and is used when an operator operates the radar transceiver 10.
On the other hand, as illustrated in FIG. 4, the detection reflector 30 of the present embodiment includes, as an example, a trihedral corner provided with three reflecting surfaces which are a reflecting surface 31, a reflecting surface 32, and a reflecting surface 33. It consists of a reflector.

  And the detection reflector 30 is installed in the attitude | position which orient | assigns the central axis which passes through the intersection (vertex 30a) of these three orthogonal reflective surfaces to the transmission / reception antenna 11. FIG. As a result, the incident wave (polarized transmission wave 21) incident on the detection reflector 30 from the transmission / reception antenna 11 is first reflected by the reflection surface 31, the reflection surface 32, and the reflection surface 33 as illustrated in FIG. After being sequentially reflected by the point 31a, the second reflection point 32a, and the third reflection point 33a, it is reflected to the transmission / reception antenna 11 side as a reflected wave (polarized wave 22).

  The radio wave reflection function by the trihedral corner reflector is described in, for example, the literature such as McGraw-Hill Book Company, 1961, “Antenna Engineering Handbook second edition”, P17-27, Fig.17-27, etc. Has been.

  In the case of the present embodiment, as illustrated in FIGS. 4 and 6, the polarization changing film covers the passage path of the reflected wave in the detection reflector 30 (the right half of the opening of the detection reflector 30). 34 is provided. This polarization changing film 34 has a function of converting a horizontally polarized polarized wave 21 that is an incident wave passing through the polarization changing film 34 into a vertically polarized polarized wave 22.

  That is, as illustrated in FIG. 7A, the polarization changing film 34 includes, for example, a metal strip pattern 34b and a metal strip arranged on both surfaces of the insulating film 34a so as to be inclined ± 45 ° in opposite directions. It consists of a millimeter wave conversion film composed of the pattern 34c. The width w and interval s of the metal strip pattern 34b and the metal strip pattern 34c are appropriately set according to the frequency of the incident wave. The electric field direction Ei (polarization plane) of the incident wave passing through the polarization changing film 34 having such a configuration is rotated by 90 ° to become the electric field direction Eo. As illustrated in the diagram of FIG. 7B, the incident wave passing through the polarization changing film 34 is not attenuated in intensity only by rotating the plane of polarization by 90 °.

The polarization changing film 34 is attached to the detection reflector 30 in a posture in which the incident surface of the horizontally polarized wave faces the reflection surface side of the detection reflector 30.
That is, in the case of the present embodiment, the polarization transmission wave 21 incident on the detection reflector 30 as a horizontal polarization is reflected by the reflection surface 33 and then passes through the polarization changing film 34 from the back surface side. The polarization plane rotates 90 ° with almost no attenuation, and is reflected as a vertically polarized polarized wave 22. Further, the radio wave incident on the surface (outgoing surface) side of the polarization changing film 34 is scattered.

Hereinafter, an example of the operation of the present embodiment will be described.
First, on the side of the radar transceiver 10, in the transmission / reception antenna 11, the horizontal polarization transmission antenna 11a is selected on the transmission side, and the vertical polarization reception antenna 11c is selected on the reception side.

  When the transmitter 12 is activated, a horizontally polarized polarized wave 21 is radiated toward the detection reflector 30. As shown in FIG. 5, the polarization transmission wave 21 is reflected three times by the reflection surface 31 to the reflection surface 33 of the detection reflector 30, passes through the polarization changing film 34, has its polarization plane converted, and then vertically It is reflected toward the transmission / reception antenna 11 as a polarization received wave 22 of polarization.

  That is, the path of the polarization transmission wave 21 in the detection reflector 30 is similar to the distance L1 from the center vertex 30a of the detection reflector 30 to the first first reflection point 31a, as shown in FIG. A locus in which the distance L2 from the vertex 30a of the corner reflector to the last third reflection point 33a is equal (point object) is created. As a result, the polarization transmission wave 21 that is incident on the detection reflector 30 is converted so as to pass through the polarization film only once and rotate the plane of polarization by 90 °, so that the polarization reception wave of vertical polarization is obtained. 22 is reflected by the transmission / reception antenna 11. Further, the transmission wave having a polarization plane different from the surface side of the polarization changing film 34 is scattered without entering the reflection surface of the detection reflector 30.

  In this way, the vertically polarized polarization reception wave 22 is reflected from the detection reflector 30 to the transmission / reception antenna 11 by the incidence of the horizontally polarized polarization transmission wave 21 from the transmission / reception antenna 11.

  Since the vertical polarization receiving antenna 11 c is selected on the receiving side of the radar transceiver 10, the signal of the vertically polarized polarized wave 22 that is reflected from the detection reflector 30 and arrives at the receiving unit 13. Only power is detected.

  Therefore, in the receiving unit 13, the vertically polarized polarized wave 22 reflected from the detection reflector 30 is based on the received power level fluctuation caused by being blocked by the obstacle 102 before reaching the transmitting / receiving antenna 11. Thus, the presence or absence of the obstacle 102 in the space between the transmitting / receiving antenna 11 and the detection reflector 30 (that is, the level crossing 101 to be monitored) can be detected with high accuracy.

  Further, in the installation environment as shown in FIG. 3, even if the polarization transmission wave 21 is incident on the noise object 103 existing in the vicinity of the detection reflector 30, the polarization transmission wave 21 in the horizontal polarization state is reflected. Even if this reflected horizontally polarized polarized wave transmission wave 21 is incident on the transmission / reception antenna 11 as noise, the polarization plane is different from the polarized wave reception wave 22 which is the original reflected wave. It is not detected by the receiving unit 13 via the polarization receiving antenna 11c.

  Therefore, even in a poor installation environment where the noise object 103 exists in the vicinity of the detection reflector 30, the space between the transmission / reception antenna 11 and the detection reflector 30 is not affected by the presence of the noise object 103 ( That is, it is possible to accurately detect the presence or absence of the obstacle 102 at the level crossing 101) to be monitored.

  FIG. 8 is a conceptual diagram showing a modification of the detection reflector in the present embodiment. This modification shows a case where an active reflector 40 having an amplification function of radio waves received by itself is used.

  The active reflector 40 includes a polarization receiving antenna 41, a polarization transmitting antenna 42, and an amplifier 43. The polarization receiving antenna 41 receives the polarization transmission wave 21 that is a horizontally polarized wave. The amplifier 43 amplifies the reception signal of the polarization receiving antenna 41 and outputs the amplified signal to the polarization transmitting antenna 42 side.

  In front of the polarization transmitting antenna 42, the above-described polarization changing film 34 is disposed. The radio wave radiated from the polarization transmitting antenna 42 is obtained by amplifying the polarization transmission wave 21 that is a horizontal polarization, and remains as a horizontal polarization. The amplified horizontal polarization is transmitted through the polarization changing film 34. By passing, it is converted into a vertically polarized polarized wave reception wave 22, and this polarized wave reception wave 22 is reflected toward the transmitting / receiving antenna 11.

  Accordingly, as in the case of using the detection reflector 30 described above, the vertically polarized polarized wave 22 reflected from the active reflector 40 is selectively transmitted to the receiving unit 13 via the vertically polarized wave receiving antenna 11c. Thus, the detection accuracy of the obstacle 102 in the space between the transmitting / receiving antenna 11 and the active reflector 40 can be improved.

  In addition, by providing the amplifier 43, even when the distance to the transmission / reception antenna 11 is large, the polarized transmission wave 21 that is attenuated and arrives from the transmission / reception antenna 11 is amplified, so that the polarization of highly polarized waves with high intensity The received wave 22 can be returned to the transmitting / receiving antenna 11. As a result, even when the distance between the transmitting / receiving antenna 11 and the active reflector 40 is large, that is, when the space such as the level crossing 101 to be monitored is wide, the accuracy is not affected by the attenuation of the polarization transmission wave 21. The obstacle 102 can be detected well.

  FIG. 9 is a conceptual diagram showing still another modified example of the detection reflector in the present embodiment. In the example of FIG. 9, the detection reflector 50 includes a reflection change plate 51 and a polarization change plate 52. Then, the horizontally polarized polarization transmission wave 21 incident from the transmission / reception antenna 11 is converted into a vertically polarized polarization reception wave 22 and reflected to the transmission / reception antenna 11.

  10A is a front view of the detection reflector 50, and FIG. 10B is a side view. As illustrated in FIG. 10A, the reflection changing plate 51 is configured by a grid formed of metal strip patterns 51a in the + 45 ° direction. The polarization changing plate 52 is composed of a grid composed of a metal strip pattern 52a in the −45 ° direction. Further, the interval between the reflection changing plate 51 and the polarization changing plate 52 is set to ¼ of the wavelength λ of the incident polarization transmission wave 21, that is, λ / 4.

  (A)-(c) of FIG. 10B is a conceptual diagram which shows the process of changing the polarization plane in this detection reflector 50. FIG. When the horizontally polarized wave is decomposed into + 45 ° component (V1) and −45 ° component (V2) as shown in (a), these travel by λ / 4 and are reflected by the reflection changing plate 51, (b ), The + 45 ° component (V1) and the −45 ° component (V2) are each inverted by 180 °. Then, the phase of the −45 ° component V1 reflected by the reflection changing plate 51 on the far side is further reversed by 180 ° by traveling back and forth through λ / 4, and as shown in (c). The -45 ° component (V1) is converted into a vertically polarized wave synthesized by a component obtained by inverting 180 ° and the original + 45 ° component (V2).

  As a result, the incident wave to the detection reflector 50 composed of the reflection changing plate 51 and the polarization changing plate 52 is always reflected after the plane of polarization is converted by 90 °. Further, the transmitted wave having a polarization plane different from that of the installed polarization changing plate 52 does not enter the reflection surface of the detection reflector 50 and is scattered.

  Therefore, an antenna (in this case, a vertically polarized wave receiving antenna 11c) that can receive a reflected wave having the same polarization plane as that of the detection reflector 50 (in this case, a vertically polarized wave receiving wave 22) is connected to the transmitting / receiving antenna 11. , The received power is suppressed (because the polarization is different) with respect to the reflected wave from the measurement object such as an unnecessary noise object 103 that does not have the polarization plane conversion function, and is reflected from the detection reflector 50. Only the received power of the vertically polarized polarized wave 22 can be detected.

It is possible to provide an obstacle detection means between the radar transceiver and the detection reflector after suppressing unnecessary measurement object detection by these means.
The radio wave reflection function by the grid is described in documents such as McGraw-Hill Book Company, 1961, “Antenna Engineering Handbook second edition”, P18-18, FIG.

FIG. 11 is a conceptual diagram showing still another modification of the detection reflector in the present embodiment.
The detection reflector 60 in the example of FIG. 11 is a trihedral corner reflector including three reflecting surfaces 61, a reflecting surface 62, and a reflecting surface 63 that are orthogonal to each other. In this case, each of the reflection surface 61, the reflection surface 62, and the reflection surface 63 includes a polarization changing plate 61a, a polarization changing plate 62a, and a polarization changing plate 63a like the detection reflector 50 described above.

  Each time the horizontally polarized polarized transmission wave 21 incident on the detection reflector 60 is reflected by each of the reflecting surfaces 61 to 63, the polarization plane changes by 90 °, and the above-described FIG. After a total of three reflections (odd number) as illustrated, the original polarization plane is a vertically polarized polarization reception wave 22 rotated by 90 °, and is returned to the transmission / reception antenna 11. .

  That is, the process of changing the polarization plane in each of the polarization changing plate 61a, the polarization changing plate 62a, and the polarization changing plate 63a in the detection reflector 60 is the case of the detection reflector 50 shown in FIG. 10A described above. It is the same.

As a result, the incident wave (horizontal polarization transmission wave 21) incident on the detection reflector 60 has its polarization plane converted by 90 ° and is reflected as a vertical polarization reception wave 22.
As a result, the reception side of the radar transceiver 10 detects the transmission / reception antenna 11 without being affected by noise by selecting the vertical polarization reception antenna 11c as the transmission / reception antenna 11 and receiving the polarization reception wave 22. The obstacle 102 in the space between the reflector 60 can be detected with high accuracy.

  Further, since the detection reflector 60 is configured to change the polarization plane using the reflection surface itself, the intensity of the polarization reception wave 22 generated when the polarization transmission wave 21 enters the detection reflector 60. There is also an advantage that can be increased.

  FIG. 12 is a conceptual diagram showing a configuration of a radar system RS2 which is another embodiment of the present invention. In the case of the embodiment of FIG. 12, a polarization transmission wave 21 and a polarization reception wave 22 having different polarization planes reciprocating between the transmission / reception antenna 11 and the detection reflector 30 are caused by the obstacle 102. Detection method using blocking (hereinafter referred to as blocking detection), and reflection caused by reflection of a radar wave such as the polarized transmission wave 21 radiated from the transmission / reception antenna 11 by the obstacle 102 itself A case will be described in which a method of detecting the obstacle 102 (hereinafter referred to as direct detection) is used in combination by directly detecting a wave with the transmission / reception antenna 11.

  In this case, the radar transceiver 10 performs the operation of the flowchart illustrated in FIG. 13 in order to realize the blocking detection and the direct detection. The operation of the flowchart of FIG. 13 is realized, for example, by the microprocessor 16 executing a control program mounted on the nonvolatile memory 17 and controlling the operation of the radar signal processing control unit 14 and the like.

  That is, until the obstacle 102 is detected by the interruption detection, only the interruption detection is performed, and after the obstacle 102 is detected, direct detection is performed. Thereby, it is possible to detect not only the presence or absence of the obstacle 102 between the transmission / reception antenna 11 and the detection reflector 30, but also the distance from the transmission / reception antenna 11 to the obstacle 102, the size of the obstacle 102, and the like. Become.

Initially, the horizontally polarized wave transmitting antenna 11a is selected on the transmitting side, and the vertically polarized wave receiving antenna 11c is selected on the receiving side, thereby starting blockage detection.
Then, a horizontally polarized polarized transmission wave 21 is radiated from the transmission / reception antenna 11 toward the detection reflector 30 (step 201).

  On the detection reflector 30 side, the polarization plane of the polarized transmission wave 21 arriving from the transmission / reception antenna 11 is changed by 90 ° and reflected to the transmission / reception antenna 11 as a vertically polarized polarization reception wave 22 (step 202).

The radar transmitter / receiver 10 selectively detects the vertically polarized polarized wave 22 by the vertically polarized wave receiving antenna 11c, and calculates received power (step 203).
Then, it is determined whether or not the amount of decrease in received power of the vertically polarized polarized wave 22 exceeds a predetermined threshold level, that is, whether the polarized wave 22 is blocked by the obstacle 102 (step 204). ) Step 201 to Step 203 are repeated until the obstacle 102 is detected.

  If it is determined in step 204 that the obstacle 102 has been detected, the radar transceiver 10 switches the receiving antenna to the horizontally polarized wave receiving antenna 11d and prepares for direct detection (step 205). ), The horizontally polarized transmission antenna 11a radiates the horizontally polarized polarization transmission wave 21 in the direction of the obstacle 102 detected by the above-described blocking detection (step 206). The horizontally polarized polarized wave 22 is reflected by the obstacle 102 as it is horizontally polarized (step 207). The reflected horizontally polarized polarized wave 22 is detected by the horizontal polarization receiving antenna 11d of the radar transceiver 10 and then received. Input to the unit 13 (step 208).

  In the receiving unit 13, the obstacle is based on the time from the transmission time of the polarization transmission wave 21 by the transmission unit 12 to the reception time of the polarization reception wave 22 in the reception unit 13 and the propagation speed of the radar wave. The distance to 102 is measured, and if necessary, the size of the obstacle 102 is measured based on the value of the received power of the polarized wave 22 (step 209).

  In the distance measurement in the direct detection, since it is determined that the obstacle 102 exists between the detection reflector 30 and the transmission / reception antenna 11, for example, when the radar transceiver 10 is a pulse radar system. In this case, the range ambiguity caused by secondary echo or the like is eliminated, and accurate distance measurement can be performed.

Thereafter, the radar transceiver 10 switches the receiving side horizontally polarized wave receiving antenna 11d to the original vertically polarized wave receiving antenna 11c, and shifts to block detection after step 201.
As described above, in the present embodiment, the presence / absence of the obstacle 102 between the transmission / reception antenna 11 and the detection reflector 30 is accurately determined using the difference in polarization plane between the polarization transmission wave 21 and the polarization reception wave 22. The detection of interruption is performed well, and after the obstacle 102 is detected by this interruption detection, the process shifts to direct detection, and the distance from the transmission / reception antenna 11 to the obstacle 102 and the size of the obstacle 102 are measured. To do.

  That is, before the direct detection, after the presence of the obstacle 102 between the transmission / reception antenna 11 and the detection reflector 30 (such as the direction of the obstacle 102 viewed from the radar transceiver 10) is determined, the obstacle by the direct detection is detected. 102, the measurement accuracy of the distance and size to the obstacle 102 in direct detection is improved.

  Information, such as the presence / absence of the obstacle 102, the distance to the obstacle 102, and the size of the obstacle 102, detected in this way is output to an external information processing system via the external input / output interface 18 as necessary. Is done.

FIG. 14 is a conceptual diagram showing an example of the configuration of a radar system RS3 that is still another embodiment of the present invention.
In the case of the radar system RS2 of this embodiment, a plurality of detection reflectors 30 are arranged for one radar transceiver 10 to detect the obstacle 102 in a relatively wide space. In this case, a horizontal wide beam antenna 11-1 that can radiate a radar wave (polarized transmission wave 21) into a space including a plurality of detection reflectors 30 is used.

In other words, in the example of FIG. 14, a plurality of detection reflectors 30 are arranged along the crossing 101 and the radar transceiver 10 is installed on the opposite side across the crossing 101.
The arrangement interval ΔG between two adjacent detection reflectors 30 is such that the difference ΔR between the distances R1 to R6 (for example, R1 and R2) with respect to each radar transceiver 10 (horizontal wide beam antenna 11-1) is It is set to be larger than the distance resolution.

  Therefore, each detection reflector 30 can be distinguished on the radar transceiver 10 side as a difference in distance to the horizontal wide beam antenna 11-1 (required round-trip time of the polarized wave transmission wave 21 and the polarization wave reception wave 22). .

  The directivity of the horizontal wide beam antenna 11-1 increases the radiated power of the polarization transmission wave 21 for the distant detection reflector 30, and the radiation of the polarization transmission wave 21 for the nearby detection reflector 30. A rectangular beam whose radiation intensity distribution is controlled so as to weaken the power can also be used. In this case, the fluctuation in the received power of the polarization reception wave 22 due to the blockage by the obstacle 102 can be determined for all of the plurality of detection reflectors 30 using a common threshold.

  In this case, the blocking detection by the obstacle 102 between the horizontal wide beam antenna 11-1 and each detection reflector 30 is performed by the polarization transmission wave 21 and the polarization according to the distance from the detection reflector 30. This is realized by setting the detection timing of the polarization reception wave 22 in the reception unit 13 in accordance with the round trip time of the reception wave 22.

  That is, the receiving unit 13 radiates the horizontally polarized polarized transmission wave 21 at an arbitrary timing and then vertically polarized polarized received wave for each time slot corresponding to the round trip time with the detection reflector 30. 22 reception power fluctuation determinations are sequentially executed. Thereby, the presence or absence of the obstacle 102 between each detection reflector 30 and the horizontal wide beam antenna 11-1 can be determined individually.

As described above, the radar system RS3 of the present embodiment can accurately detect the obstacle 102 in a relatively wide space.
Further, the obstacle 102 that moves across the plurality of detection reflectors 30 and the horizontal wide beam antenna 11-1 due to a temporal change in the detection state of the obstacles 102 between the individual detection reflectors 30. It is also possible to detect the movement state.

Needless to say, the present invention is not limited to the configuration exemplified in the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the description of each of the above-described embodiments, for the sake of simplicity, the transmission / reception antenna 11 is configured by individual horizontal polarization transmission antennas 11a to 11d, and these are switched by the polarization switching switch 15. However, the present invention is not limited to this.

  For example, in the case of the transmission / reception antenna 11 that can change the polarization planes of the radiation wave and the reception wave by rotating around the radiation direction, the transmission timing of the polarization transmission wave 21 having a specific polarization plane, In addition, by synchronizing the reception timing of the polarization reception wave 22 having a specific polarization plane and the rotational attitude of the transmission / reception antenna 11, different polarization planes may be used for the transmission wave and the reception wave.

(Appendix 1)
A radar apparatus including transmission means for transmitting a first radio wave, and reception means for receiving a second radio wave having a polarization plane different from that of the first radio wave;
A radio wave reflector that receives the first radio wave from the radar device and returns the first radio wave as the second radio wave;
A radar system comprising:

(Appendix 2)
The radar system according to appendix 1, wherein the radar apparatus further includes an object detection unit that detects an object between the radar and the radio wave based on a change in a detection level of the second radio wave coming from the radio wave reflector. A radar system characterized by comprising.

(Appendix 3)
The radar system according to claim 1, wherein each of the plurality of radio wave reflectors is arranged at a distance greater than a distance resolution of the radar device with respect to the radar device.

(Appendix 4)
The radar system according to appendix 1, wherein the radar device includes the first radio wave as a shaped beam including a plurality of radio wave reflectors arranged with respect to the radar device at a distance equal to or greater than a distance resolution of the radar device. A radar system, further comprising means for radiating light.

(Appendix 5)
The radar system according to appendix 1, wherein the radar apparatus further includes a function of transmitting and receiving the first and second radio waves having different polarization planes by switching antennas in a time division manner.

(Appendix 6)
The radar system according to appendix 1, wherein the radio wave reflector includes a polarization changing body that changes a polarization plane of the first radio wave transmitted or reflected by 90 °.

(Appendix 7)
The radar system according to claim 1, wherein the radio wave reflector is an active reflector having an amplification function of amplifying the received first radio wave and transmitting the amplified first radio wave as the second radio wave.

(Appendix 8)
An object detection method for detecting an object between the radar device and the radio wave reflector by a change in radio waves reciprocating between the radar device and the radio wave reflector,
The polarization planes of the first radio wave incident on the radio wave reflector from the radar apparatus and the second radio wave returned from the radio wave reflector to the radar apparatus are made different to change the intensity of the second radio wave to the radar apparatus. An object detection method characterized by detecting in the above.

(Appendix 9)
The object detection method according to appendix 8, wherein a polarization changing body is provided in the radio wave reflector, and a polarization plane of the first radio wave transmitted or reflected by the polarization changing body is changed by 90 ° to form the second radio wave. An object detection method comprising returning to a radar device.

(Appendix 10)
The object detection method according to attachment 8, wherein each of the plurality of radio wave reflectors is arranged with respect to the radar device at a distance equal to or greater than a distance resolution of the radar device, and the plurality of radio wave reflections from the radar device. The shaped beam is controlled so that the first radio wave is emitted as a shaped beam including a body, and the second radio wave has an intensity distribution proportional to the distance from each of the radio wave reflectors. An object detection method.

(Appendix 11)
The object detection method according to claim 8, wherein the radio wave reflector is an active reflector having an amplification function of amplifying the received first radio wave and transmitting the amplified first radio wave as the second radio wave. .

(Appendix 12)
A radar apparatus comprising: transmission means for transmitting a first radio wave; and reception means for receiving a second radio wave having a polarization plane different from that of the first radio wave.

(Appendix 13)
The radar device according to appendix 12, wherein the second radio wave is a radio wave arriving from a radio wave reflector that receives the first radio wave from the radar device, changes a polarization plane, and returns the second radio wave as the second radio wave. Radar device.

(Appendix 14)
The radar device according to attachment 12, wherein the second radio wave arrives from a radio wave reflector that receives the first radio wave from the radar device and returns the second radio wave as the second radio wave, and based on a change in a reception level of the second radio wave. A radar apparatus, further comprising object detection means for determining presence / absence of an object between the electromagnetic wave reflector and the radio wave reflector.

(Appendix 15)
The radar device according to appendix 12, wherein the radar device has the first radio wave as a shaped beam including a plurality of radio wave reflectors arranged with respect to the radar device at a distance equal to or greater than a distance resolution of the radar device. A radar apparatus, further comprising means for radiating light.

(Appendix 16)
A radio wave reflector comprising polarization changing means for returning a first radio wave received from a radar device as a second radio wave having a plane of polarization different from that of the first radio wave.

(Appendix 17)
The radio wave reflector according to appendix 16, wherein the radio wave reflector comprises a trihedral corner reflector having reflecting surfaces orthogonal to each other, and the polarization changing means is directed from the trihedral corner reflector toward the radar device. The second radio wave comprises a polarization plane conversion film disposed in a region through which the emitted first radio wave is transmitted, and the second radio wave when the first radio wave emitted toward the radar device passes through the polarization plane conversion film. Radio wave reflector characterized by being converted to

(Appendix 18)
The radio wave reflector according to appendix 16, wherein the radio wave reflector comprises a trihedral corner reflector having reflective surfaces orthogonal to each other, and the polarization changing means comprises a polarization plane converting film constituting the reflective surface, The radio wave reflector according to claim 1, wherein the first radio wave is reflected to the radar device as the second radio wave after being reflected an odd number of times by the polarization plane conversion film.

(Appendix 19)
The radio wave reflector according to appendix 16, wherein the radio wave reflector comprises a polarization changing plate that constitutes a reflecting surface facing the direction of the radar device, and the first radio wave is used as the second radio wave as the radar device. A radio wave reflector characterized by being reflected by the light.

(Appendix 20)
A radio wave reflector comprising: amplification means for amplifying a first radio wave received from a radar device and returning it as a second radio wave having a polarization plane different from that of the first radio wave.

It is a conceptual diagram which shows the principle of operation of the radar system which is one embodiment of this invention. It is a block diagram which shows an example of a structure of the radar system which is one embodiment of this invention. It is an overhead view which shows an example of the installation state of the radar system which is one embodiment of this invention. It is sectional drawing which shows an example of a structure of the detection reflector which comprises the radar system which is one embodiment of this invention. It is a front view which shows an example of the internal structure of the detection reflector which comprises the radar system which is one embodiment of this invention. It is a front view which shows an example of a structure of the detection reflector which comprises the radar system which is one embodiment of this invention. It is explanatory drawing which shows an example of a structure of the detection reflector which comprises the radar system which is one embodiment of this invention. It is a diagram which shows an example of an effect | action of the detection reflector which comprises the radar system which is one embodiment of this invention. It is a conceptual diagram which shows the modification of the detection reflector in one embodiment of this invention. It is a conceptual diagram which shows the further another modification of the detection reflector in one embodiment of this invention. It is explanatory drawing explaining the structure of the other modification of the detection reflector in one embodiment of this invention. It is explanatory drawing explaining the effect | action of the further another modification of the detection reflector in one embodiment of this invention. It is a conceptual diagram which shows the further another modification of the detection reflector in one embodiment of this invention. It is a conceptual diagram which shows the structure of the radar system which is other embodiment of this invention. It is a flowchart which shows an example of an effect | action of the radar system which is other embodiment of this invention. It is a conceptual diagram which shows an example of a structure of radar system RS3 which is further another embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Radar transceiver 11 Transmission / reception antenna 11-1 Horizontal wide beam antenna 11a Horizontal polarization transmission antenna 11b Vertical polarization transmission antenna 11c Vertical polarization reception antenna 11d Horizontal polarization reception antenna 12 Transmission part 13 Reception part 14 Radar signal processing control part 15 Polarization changeover switch 16 Microprocessor 17 Non-volatile memory 18 External input / output interface 19 User interface 20 Radar wave 21 Polarization transmission wave 22 Polarization reception wave 30 Detection reflector 31 Reflection surface 32 Reflection surface 33 Reflection surface 34 Polarization change Film 34a Insulating film 34b Metal strip pattern 34c Metal strip pattern 40 Active reflector 41 Polarization receiving antenna 42 Polarization transmitting antenna 43 Amplifier 50 Detection reflector 51 Reflection changing plate 51a Metal strip pattern 52 Polarization changing plate 52a Metal strip pattern 60 Detection reflector 61 Reflection surface 61a Polarization change plate 62 Reflection surface 62a Polarization change plate 63 Reflection surface 63a Polarization change plate 100 Line 101 Railroad crossing 102 Obstacle 103 Noise object RS1 Radar system RS2 Radar system RS3 Radar system

Claims (10)

A radar apparatus including transmission means for transmitting a first radio wave, and reception means for receiving a second radio wave having a polarization plane different from that of the first radio wave;
A radio wave reflector that receives the first radio wave from the radar device and returns the first radio wave as the second radio wave;
A radar system comprising:   2. The radar system according to claim 1, wherein the radar apparatus includes an object detection unit configured to detect an object between the radio wave reflector and the radio wave reflector based on a change in a detection level of the second radio wave arriving from the radio wave reflector. A radar system, further comprising:   2. The radar system according to claim 1, wherein each of the plurality of radio wave reflectors is arranged at a distance greater than a distance resolution of the radar apparatus with respect to the radar apparatus.   2. The radar system according to claim 1, wherein the radar device is a shaped beam including a plurality of radio wave reflectors arranged with respect to the radar device at a distance equal to or greater than a distance resolution of the radar device. A radar system, further comprising means for emitting radio waves.   2. The radar system according to claim 1, further comprising a function of transmitting and receiving the first and second radio waves having different polarization planes by switching antennas in a time division manner. .   The radar system according to claim 1, wherein the radio wave reflector includes a polarization changing body that changes a polarization plane of the first radio wave transmitted or reflected by 90 °.   2. The radar system according to claim 1, wherein the radio wave reflector is an active reflector having an amplification function of amplifying the received first radio wave and transmitting the amplified first radio wave as the second radio wave. An object detection method for detecting an object between the radar device and the radio wave reflector by a change in radio waves reciprocating between the radar device and the radio wave reflector,
The polarization planes of the first radio wave incident on the radio wave reflector from the radar device and the second radio wave returned from the radio wave reflector to the radar device are made different to change the intensity of the second radio wave to the radar device. An object detection method characterized by detecting in the above.   A radar apparatus comprising: transmission means for transmitting a first radio wave; and reception means for receiving a second radio wave having a polarization plane different from that of the first radio wave.   A radio wave reflector comprising polarization changing means for returning a first radio wave received from a radar device as a second radio wave having a plane of polarization different from that of the first radio wave.