JP2007139650A - Moving direction detection radar system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radar system capable of surely detecting the moving direction of an object. <P>SOLUTION: In this moving direction detection radar system equipped with a radar transmitter/receiver and a detection reflector, the radar transmitter/receiver is characterized by including a means for detecting a time when the level wherein a radar radio wave reflected from the object moving across the interval between the radar transmitter/receiver and the detection reflector installed in the direction in a main robe range offset from the maximum gain direction of a radar beam of the radar transmitter/receiver is received shows the maximum value, a means for detecting a time when the level wherein the radar radio wave reflected from the detection reflector is received is blocked by the object and shows the minimum value, and a means for determining the moving direction of the object by the context of the time when the maximum value is shown and the time when the minimum value is shown. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radar system, and more particularly to a radar system suitable for use in reverse direction vehicle detection and warning output on a one-way road.

  Application of millimeter wave radar is considered for detection of passing vehicles on roads and the like and detection of vehicles entering an intersection. For example, in order to detect a vehicle entering a railroad crossing, there is a radar in which a radar and a detection reflector are installed facing each other on both sides of the road within the railroad crossing, and an approach is detected by blocking a radar signal (see Patent Document 1).

  In addition, there is a millimeter wave radar that uses a Doppler frequency to detect the approach direction of a vehicle at an intersection (see Patent Document 2). Conventionally, the CW radar or the most common FM-CW (Frequency Modulated Continuous Wave) radar is used as the moving speed detection by the Doppler frequency.

In order to detect the distance to the object and the moving direction by the FM-CW radar, the radar is installed toward the moving axis direction of the object in order to use the Doppler effect of the reflected radio wave. The FM-CW radar extracts a beat signal that is a frequency difference between a signal that is FM-modulated with a triangular wave and a signal that has received a reflected wave from an object, and performs frequency analysis by FFT (Fast Fourier Transform). Frequency analysis is performed for the rising and falling intervals of FM modulation by triangular waves, and two beat frequencies corresponding to each are obtained, the distance is determined by the average value of both, and the speed is determined by the Doppler frequency obtained from the difference between the two. And the moving direction is determined by the vertical relationship between the two beat frequencies.
JP 2004-98984 A JP 7-105500 A

  In the first example of the background art described above, the radar radio wave reflected by the detection reflector installed on the opposite side of the radar transceiver is shielded by the vehicle entering the vicinity of the crossing breaker, and the reception level decreases. Is detected to detect the approach of the vehicle, but the direction of travel cannot be detected. Therefore, even if the above-mentioned conventional technology is applied, the alarm system for the violating vehicle on the one-way road has a disadvantage that it cannot distinguish between the violating vehicle that has entered in the reverse direction and the correct traveling vehicle that moves in the forward direction. .

  In the second example of the background art described above, the moving direction of the vehicle is detected based on the Doppler frequency value. As described in the background art, the FM-CW radar detects the moving speed and direction by detecting the Doppler frequency based on the frequency analysis of the beat signal. However, if the speed is low, the measurement accuracy is limited and cannot be detected. That is, a case where a minute Doppler frequency due to a vehicle entering at a relatively low speed at the entrance of a one-way road cannot be detected occurs. The limit of this detection accuracy is determined by the design parameters of the FM-CW radar. In a feasible FM-CW millimeter wave radar, the speed accuracy that can be detected is about 10 km / h. There is a problem in reliably detecting.

  In addition, a radar transmitter / receiver and a system in which multiple detection reflectors are installed on opposite sides across the road detect the time when the radar wave is blocked by multiple reflectors, and calculate the direction of the blocked moving object A method is conceivable. Problems caused by this method will be described with reference to FIGS.

  In FIG. 1, 101 is a T-shaped intersection, 102 is a one-way road, 103 is a normal road, 104 is a radar transceiver, 105 is a radar transceiver antenna, 106a and 106b are detection reflectors, 107 is a transmission / reception radar beam, and 108 is reverse. A direction moving vehicle, 109 indicates a forward direction, and 110 indicates a reverse direction.

A radar system according to the prior art is arranged at the T-shaped intersection 101, and the one-way road 102 is connected to the road 103 at the exit. On one side of the exit of the one-way road 102, an FM-CW radar transceiver 104 equipped with a transmission / reception antenna 105 is installed, and on the opposite side, two detection reflectors 106a and 106b that reflect radar radio waves are installed. . The radar beam 107 by the transmission / reception antenna is directed in the middle direction between the two detection reflectors 106a and 106b in the beam center direction where the gain is maximized. A vehicle 108 represents a vehicle that enters the one-way road 102 from the road 103 in the reverse direction. _Rx represents the distance from the radar transceiver 104 to the backward moving vehicle 108, and _R0 represents the distance from the radar transceiver 104 to the detection reflectors 106a and 106b.

  FIG. 2 shows a change in the reception level of the radar transceiver 104 by the radar system of FIG.

  In FIG. 2, 201 indicates a reception level from the vehicle, 202 indicates a peak level of the reception level 201, 203 indicates a threshold value, 204 indicates a reception level from the detection reflector, 205 indicates a minimum value level of 204, and 206 indicates a threshold value.

When the vehicle 108 enters the one-way road 103 in the reverse direction from the road 103 at the T-shaped intersection 101, the reception level 201 of the distance _Rx is obtained by the distance detection function of the FM-CW radar 104 and its level detection. The reception level 201 gradually increases when the vehicle 108 enters the range of the radar beam 107, and shows a broad peak value 202 having a substantially constant width when the vehicle exceeds the threshold value 203 at time t ₁ and enters the beam, smaller than the threshold value 203 at time _{t 4} when the vehicle 108 passes by. For the detection reflectors 106a and 106b, the reception level 204 of the distance _R0 is obtained. The reception level 204 indicates a constant value equal to or higher than the threshold value 206 when there is no obstacle between the radar transceiver 104 and the detection reflector 106a or 106b, and suddenly when the vehicle 108 enters the range of the radar beam 107. decreased, when the vehicle enters the beam below the threshold 206 at time t ₂ shows an almost constant minimum level 205, at time t ₃ is close to the end of the forward passage of the vehicle 108 has two detection reflector in It recovers to the threshold value 206 or more. The two detection reflectors 106a and 106b having the distance _R0 are arranged at intervals within the radar beam width, and the reflected waves from the two cannot be separated, so that the minimum value 205 does not show two valleys.

  If the detection reflectors 106a and 106b are installed apart from the width of the radar beam 107, the system cannot be established because one radar transceiver 104 cannot cover both detection reflectors at the same time.

  As described above, the radar system shown in FIG. 1 can detect a vehicle passing through the exit of a one-way road, but cannot detect a moving direction, and therefore cannot detect a backward entry vehicle on a one-way road. There is.

  Accordingly, one of the objects of the present invention is to provide a radar system that can reliably detect the moving direction of an object.

  The present invention is not limited to the above-mentioned object, and is a result derived from each configuration shown in the best mode for carrying out the invention described later, and has an effect that cannot be obtained by conventional techniques. It can be positioned as one of the purposes.

(1) In the present invention, in the moving direction detection radar system including the radar transceiver and the detection reflector, the radar transceiver is offset from the maximum gain direction of the radar transceiver and the radar beam of the radar transceiver. Means for detecting the time at which the level at which the radar radio wave reflected from an object moving across the detection lobe installed in the direction within the main lobe range has a maximum value is received, and reflected from the detection reflector Means for detecting a time at which a level at which radar radio waves are received is blocked by the object and indicating a minimum value; and means for determining a moving direction of the object based on a relationship between the time indicating the maximum value and the time indicating the minimum value A moving direction detecting radar system characterized by being provided is used.

  Preferably, the radar transceiver further has a correction of multiplying a level at which the radar radio wave reflected from the object is received by the fourth power of the distance to the object, and an effect of reducing a radar scattering cross section at a close distance. Means for correcting, means for determining a maximum value of the received level exceeding a threshold set by a radar reception level corresponding to a radar scattering cross section specific to the type of the object, and the two means. The object moved across between the transceiver and the detection reflector includes means for identifying the type as an object having a radar scattering cross section larger than that inherent to the object corresponding to the set threshold value. The moving direction detection radar system according to Appendix 1 is used.

  Preferably, the means for determining the moving direction is that when the time when the maximum value is shown is earlier than the time when the minimum value is shown, the object has moved from the center direction of the radar beam to the detection reflector installation direction. The means for determining and, when the time at which the maximum value is shown is later than the time at which the minimum value is shown, means for determining that the detection reflector has moved from the direction in which the detection reflector is installed toward the center of the radar beam. 1 is used.

Preferably, the moving direction detection radar system further includes means for issuing an alarm when it is determined that the moving direction of the object determined by the means for determining the moving direction is opposite to a predetermined direction. The moving direction detecting radar system according to claim 1 is used.
(2) In the present invention, in a moving direction detection radar system including a radar transceiver including a plurality of antennas and a plurality of detection reflectors installed at positions facing the plurality of antennas, the radar transceiver includes: , Including two horizontally polarized antennas and two vertically polarized antennas for transmission, and two horizontal or vertical identical polarization antennas for reception, and the plurality of detection reflectors have the same polarization as the input polarization And a second detection reflector that reflects with a polarization different from the input polarization, and the radar transceiver is configured to transmit the horizontally polarized antenna for transmission at a predetermined period. Means for switching between vertically polarized antennas, means for switching between the two identically polarized antennas for reception at the predetermined period, and the level at which the radar radio wave reflected from the first detection reflector is received, Said Means for detecting the time at which blocking was initiated by an object moving across the first transmitter / receiver and the first detection reflector and the time at which the blocked level was restored;
Means for detecting the level at which the radar radio wave reflected from the second detection reflector is received by the object and the time when the blocked level is restored; A moving direction detecting radar system is provided, comprising: means for determining a moving direction of the object.

  Preferably, the predetermined period for switching between the transmitting horizontal polarization antenna and the vertical polarization antenna is such that the level at which the radar radio wave reflected from the first detection reflector is received by the advance of the front end of the object starts to be cut off From the first detection reflector according to the first time interval from the time when the radar signal reflected from the second detection reflector is received until the time when the level at which the radar radio wave received starts to be cut off, and the rear end of the object. A second time interval from the time when the blocked level of the reflected radar radio wave recovers until the time when the level of the radar radio wave reflected from the second detection reflector recovers; The switching period is 2 or more in the shortest of the three time intervals of the third time interval where the interception intervals of the reception levels of the radar radio waves reflected from the first and second detection reflectors overlap. The moving direction detecting radar system according to claim 2 is used.

Preferably, the time when the received level starts to be cut off and the time when the cut off level is restored are a predetermined level smaller than the received level determined by the distance from the radar transceiver to the detection reflector and the radar scattering cross section. 3. The moving direction detecting radar system according to claim 2, wherein the moving direction detecting radar system is determined based on a time crossing a threshold set in the value.
(3) Further, the moving direction detection radar system includes a center of the horizontal polarization antenna for transmission of the radar transceiver and one of the same polarization antennas for reception, and the vertical polarization antenna for transmission. And the distance between the center of the receiving polarization antenna and the other one of the receiving antennas and the installation interval between the first detection reflector and the second detection reflector should not be detected. The time interval in which the radar radio wave reflected from the first detection reflector is interrupted by the object and the second detection is greater than or equal to the length of the object traveling direction and less than or equal to the traveling direction length of the object to be detected. The moving direction according to claim 2, further comprising means for determining that the object to be detected is detected when a radar wave reflected from a reflector overlaps with a time interval in which the object is blocked by the object. Detection radar system System.

  Preferably, the means for determining the moving direction is configured so that the radar wave reflected from the first detection reflector is blocked by the object and the radar wave reflected from the second detection reflector is caused by the object. It is a means for determining that the object has moved in the direction of the detection reflector whose blocking time is later from the detection reflector whose blocking start time is earlier when the blocked time intervals overlap. A moving direction detecting radar system according to claim 2 is used.

Preferably, the moving direction detection radar system further includes means for issuing an alarm when it is determined that the moving direction of the object determined by the means for determining the moving direction is opposite to a predetermined direction. The moving direction detecting radar system according to claim 2 is used.
(4) In the present invention, in the moving direction detection radar system comprising a plurality of sets of radar transceivers and detection reflectors installed at positions facing the radar transceivers and a moving object determination device, the radar transceiver Each of which receives a radar radio wave reflected from the detection reflector placed opposite to the radar transceiver, is blocked by an object moving across the radar transceiver and the detection reflector. Means for detecting the time when the shut-off level is recovered and the time when the shut-off level is recovered, and the moving object determination device detects the shut-off start time and the shut-off time detected and output by the plurality of radar transceivers, respectively. A moving direction detection radar system comprising means for determining the moving direction of the object based on the anteroposterior relationship with the end time is used.

  Preferably, in the moving direction detecting radar system, the antenna of each radar transceiver uses different polarized waves with respect to the antennas of adjacent radar transceivers. Use a radar system.

  Preferably, the time when the received level starts blocking and the time when the blocked level recovers are based on a distance from the radar transceiver to the opposing detection reflector and a reception level determined by a radar scattering cross section. 5. The moving direction detecting radar system according to claim 4, wherein the moving direction detecting radar system is determined based on a time crossing a threshold set to a small predetermined value.

  Preferably, the moving direction detection radar system should detect an installation interval between the plurality of radar transceivers and an installation interval between the plurality of detection reflectors that are equal to or longer than the length in the traveling direction of an object that should not be detected. The radar radio wave reflected from the detection reflector placed opposite to each radar transceiver is cut off in the adjacent radar transceiver among the plurality of radar transceivers. 5. The moving direction detecting radar system according to claim 4, further comprising means for determining that the object is an object to be detected when the time intervals overlap each other.

  Preferably, the means for determining the moving direction is such that when the sections where the radar radio waves reflected from the detection reflectors arranged facing each other in each radar transceiver are blocked overlap each other, 5. The moving direction detecting radar system according to claim 4, wherein the moving direction detecting radar system is a means for determining that the object has moved in the direction of the detection reflector that is later in time from the earlier detection reflector. Is used.

Preferably, the moving direction detection radar system further includes means for issuing an alarm when it is determined that the moving direction of the object determined by the means for determining the moving direction is opposite to a predetermined direction. The moving direction detecting radar system according to claim 4 is used.
(5) In the present invention, in a moving direction detection radar system including a plurality of sets of a radar transceiver and a detection reflector installed at a position opposite to the radar transmitter and a moving object determination device,
Each of the radar transceivers has a level at which the radar radio wave reflected from the detection reflector installed facing the radar transceiver crosses between the radar transceiver and the detection reflector. Means for detecting the time at which blocking was started by a moving object and the time at which the blocked level was recovered; means for detecting the time at which reception of radar radio waves reflected from the object was started and the time at which reception was terminated; The moving object determination device includes: a detection start time, a stop end time, a reception start time, and a reception end time that are detected and output by each of the plurality of radar transceivers. A moving direction detection radar system characterized by comprising means for determining the moving direction is used.

  Preferably, the radar transceiver further has a correction of multiplying the level at which the radar radio wave reflected from the object is received by the fourth power of the distance to the moving object, and an effect of reducing the radar scattering cross section at the polar distance. The time when the threshold value set by the radar receiving level corresponding to the radar scattering cross section specific to the object type and the radar type that is specific to the object type is set as the reception start time, and the time that falls below the threshold value is determined as the reception end time. And a moving direction detecting radar system according to claim 5.

  Preferably, the radar transmitter / receiver sets a reception start time of a radar radio wave reflected from the object, a time interval in which the reception level subjected to the correction exceeds the threshold, and a radar radio wave reflected from the detection reflector. Means for determining the reception time of the radar radio wave reflected from the object as a first time of a time interval in which the reception level of the object overlaps with the time interval blocked by the object, Means for determining as the last time of the time interval in which the time interval in which the threshold value exceeds the threshold and the time interval in which the reception level of the radar radio wave reflected from the detection reflector is blocked by the object overlaps, 6. A moving direction detecting radar system according to claim 5, wherein the moving direction detecting radar system is provided.

  Preferably, the moving direction detection radar system includes an installation interval between adjacent radar transceivers among the plurality of radar transceivers, and between the detection reflectors disposed to face each of the adjacent radar transceivers. Is set to be equal to or longer than the traveling direction length of the object that should not be detected and not longer than the traveling direction length of the object to be detected, and in each of the plurality of radar transceivers, And a means for determining that the object to be detected is an object to be detected when the time intervals in which the radar radio waves reflected from the detection reflector installed facing the radar transceiver are interrupted overlap each other. The moving direction detection radar system according to claim 5 is used.

  Preferably, the means for determining the moving direction is such that when the sections where the radar radio waves reflected from the detection reflectors arranged facing each other in each radar transceiver are blocked overlap each other, 6. The moving direction detecting radar system according to claim 5, wherein the moving direction detecting radar system is a means for judging that the object has moved in the direction of the detection reflector having a later time when the blocking is started from the earlier detection reflector. Is used.

  Preferably, the moving direction detection radar system further includes means for issuing an alarm when it is determined that the moving direction of the object determined by the means for determining the moving direction is opposite to a predetermined direction. A moving direction detection radar system according to claim 5 is used.

  According to the present invention, it is possible to discriminate between a person and a vehicle passing on the road and to detect the moving direction of the vehicle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In this embodiment, one radar transceiver and one detection reflector detect a backward moving vehicle to a one-way road and issue an alarm, and a passerby identifies the vehicle and does not issue an alarm. To do.
・ "Configuration of radar system"
FIG. 3 shows the configuration of the moving direction detection radar system and the arrangement of each part in this embodiment.

In FIG. 3, 301 is a T-shaped intersection, 302 is a one-way road, 303 is a normal road, 304 is a radar transceiver, 305 is a radar transceiver antenna, 306 is an alarm, 307 is a transceiver beam, 308 is a detection reflector, 309 is a backward moving vehicle, 310 is a forward moving vehicle, 311 is a forward direction, 312 is a reverse direction, 313 is a C direction, and 314 is a D direction. R ₀ represents the distance from the radar transceiver 304 to the detection reflector 308, R _X1 represents the distance from the radar transceiver 304 to the vehicle 310, and R _X2 represents the distance from the radar transceiver 304 to the vehicle 309.

  A radar system according to this embodiment is arranged at a T-shaped intersection 301, and a one-way road 302 is connected to a road 303 at an exit. On one side of the exit of the one-way road 302, a radar transceiver 304 is installed with a transmission / reception antenna 305, and a detection reflector 308 that reflects radar radio waves is installed on the opposite side. The beam center 307 having the maximum gain is directed to the C direction 313 offset from the detection reflector 308, and the detection reflector 308 is installed in the D direction 314 offset from the C direction 313. The alarm 306 displays a warning whistle when the radar transceiver 304 determines that the passing vehicle has entered one direction in the opposite direction, that is, moves in the direction opposite to the predetermined direction. Is output to the driver of the vehicle 309.

The radar transceiver 304 is an FM-CW radar, which measures the distance to the object by analyzing the reflected signal from the object in the beam 307 to determine whether the reflection level from the detection reflector 308 is a vehicle. 309 or the level of reflection by the vehicle 310 is identified. That is, in the radar transceiver 304, the level analyzed as the distance R ₀ is the reflection level from the detection reflector 308, and the level analyzed as the distance R _X2 is the level analyzed as the reflection level from the vehicle 309 and the distance R _X1. Is identified as the level of reflection by the vehicle 310.
・ "Detection method of moving direction"
FIG. 4 shows the time change of the reflected wave level received by the radar transceiver 304 when the vehicle 310 moves in the forward direction on the one-way road 302.

  In FIG. 4, 401 is a reception level from the vehicle, 402 is a peak level of the reception level 401, 403 is a threshold value, 404 is a reception level from the detection reflector, 405 is a minimum value level of 404, and 406 is a threshold value.

When the vehicle 310 moves on the one-way road 302 in the forward direction, that is, in a predetermined direction at the T-shaped intersection 301, the reception level 401 of the distance R _X1 is obtained by the distance detection function of the FM-CW radar 304 and its level detection. The peak value 402 is indicated because the radar beam reaches the maximum gain direction at time t ₁ when the vehicle 310 comes in the C direction. At time t ₂ came to the D direction to move the vehicle 310 is further reflected wave reception level from the vehicle 310 is decreased by a value from the maximum gain of the radar beam. On the other hand, the reflected wave reception level 404 from the distance R ₀ indicating the reflection level from the detection reflector is blocked by the vehicle 310 at time t ₂ and shows a minimum value 405. As described above, when the time t ₁ is before t ₂ , the radar transceiver 304 determines that the moving direction of the vehicle 310 is the forward direction 311.

  FIG. 5 shows a temporal change in the reflected wave level received by the radar transceiver 304 when the vehicle 309 enters the one-way road 302 in the reverse direction.

  In FIG. 5, reference numeral 501 denotes a reception level from the vehicle 309, 502 denotes a peak level of the reception level 501, 503 denotes a threshold value, 504 denotes a reception level from the detection reflector, 505 denotes a minimum value level of 504, and 506 denotes a threshold value. .

When the vehicle 309 enters the one-way road 302, the reception level 501 of the distance R _X2 is obtained by the distance detection function of the FM-CW radar 304 and its level detection. Reflected wave reception level 501 by the vehicle 309 is increased in accordance with fall within the scope of the radar beam, a peak value 502 at time t ₄ since the vehicle 309 is come in the direction C to the maximum gain direction of the radar beam. On the other hand, the reflected wave reception level 504 from the distance R ₀ indicating the reflection level from the detection reflector 308 is blocked by the vehicle 309 at time t ₃ and shows a minimum value 506. In this case, the minimum peak time t ₃ of the reflected wave reception level from the detection reflector is smaller than the maximum peak time t ₄ of the reflected wave reception level by the passing vehicle, and the moving direction of the vehicle 309 is determined to be the reverse direction 312. .

・ "Vehicle and person identification method"
Further, since the prohibition of intrusion in the reverse direction of the one-way path is applied to the vehicle and not to the passer-by, the radar according to the present invention distinguishes between the vehicle and the person.

  The reflectivity of radar radio waves varies depending on the radar frequency and the size and material of the reflecting object, and is quantified by the radar scattering cross section (hereinafter RCS). In the millimeter wave in this embodiment, the RCS of the passenger car has a value about 20 dB larger than that of a person. In addition, since the reception level in the radar is inversely proportional to the fourth power of the distance, the radar reception level decreases even in the same vehicle as the distance between the radar and the reflecting object increases. These relationships are expressed by equation (1) as a radar equation, where Pt is the output level of the radar transmitter, Gt and Gr are antenna gains for transmission and reception, λ is the wavelength of the radio wave, σ is RCS, and R is the distance. .

In order to identify the type of reflecting object using the reception level Pr, the reception level of the radar transceiver represented by the equation (1) is corrected by the distance R. Therefore, using the distance R to the reflecting object detected by the FM-CW radar, if multiplied by the R ⁴ to the reception level Pr, reflecting objects independent of (1) Pr becomes corrected value by an equation, the distance The value is proportional to the RCS. For example, when the distance R = 1 m is set as a reference, the correction value of the reception power of the reflecting object having the distance R = 3 m is 3 ⁴ = 81 times, and the dB value is corrected to increase by 19 dB.

In addition, since the RCS value of the received power from the reflective object at a close distance of several meters changes even if the reflective object is the same, the correction of the received power by the detection distance is not only by multiplying the above R ⁴ but also by RCS. such a combination of correction for changing the distance may be used by adding the correction by the data of the difference between the data obtained by experiments and Pr of the theoretical value by (1) the correction of multiplication of the R ^4.

  The reception level as a result of performing the correction as described above is 501 in FIG. 5, which indicates a peak value of the reception level unique to the vehicle. The threshold value 503 is set higher than the corrected reception level by the passerby and lower than the corrected reception level by the vehicle. As a result, the corrected reception level exceeds the threshold value 503 in the case of a vehicle, but the corrected reception level becomes smaller than the threshold value 503 in the case of a passerby so that only the vehicle can be detected as a moving object.

  By the above method, the moving direction detection radar system of the present invention detects only the vehicle in which the radar transceiver 304 enters in the reverse direction of the one-way path and notifies the alarm device 306 of it. The alarm device 306 warns the driver of the backward moving vehicle 309 by an alarm and an electric bulletin board.

The second embodiment is different from the first embodiment in the configuration of the radar transceiver and the configuration of the detection reflector. In this embodiment, one radar transmitter / receiver that switches between a horizontally polarized wave and a vertically polarized wave transmitting antenna and two horizontally polarized wave receiving antennas, and the same polarized wave as the input radio wave are reflected. A detection reflector that consists of a detection reflector that reflects and changes the input radio wave to a different polarization, and detects a backward moving vehicle to a one-way road and issues an alarm, An example will be described in which a passerby is identified as a vehicle and no warning is issued.

・ "Configuration of radar system"
FIG. 6 shows the configuration of the moving direction detection radar system and the arrangement of each part in this embodiment.

  In FIG. 6, 601 is the whole T-shaped intersection, 602 is a one-way road, 603 is a normal road, 604 is a radar transceiver, 605a, 605b, 605c and 605d are radar antennas, 606 is an alarm device, 607 and 608 are radio waves. A propagation path, 609 is a backward moving vehicle, 610a and 610b are detection reflectors, 611 is a forward direction, and 612 is a reverse direction.

  One-way road 602 is connected to road 603 at the exit. On one side of the exit of the one-way road 602, a radar transceiver 604 is installed with a horizontally polarized wave 605a as a transmitting antenna, a vertically polarized wave 605c, and two horizontally polarized waves 605b and 605d as receiving antennas, On the opposite side, a detection reflector 610a that reflects the input radar radio wave with a different polarization and a detection reflector 610b that reflects the same polarization are installed. Reference numeral 607 denotes a zone in which the horizontally polarized wave propagates, and 608 denotes a zone in which the vertically polarized wave enters and is reflected and propagated by the horizontally polarized wave. A vehicle 609 represents a vehicle that enters the one-way road 602 from the road 303 in the reverse direction. The forward travel direction of the one-way road 602 is indicated by 611 and the reverse travel direction is indicated by 612. When the radar transmitter / receiver 604 determines that the vehicle 609 has entered in the reverse direction, the alarm device 606 gives an alarm to the driver of the vehicle 609 with a horn and display.

  FIG. 7 is a diagram showing in detail the configuration of switching between a plurality of antennas in the radar transmission / reception unit of the present embodiment. 7, the same components as those in FIG. 6 are given the same numbers.

  In FIG. 7, reference numeral 701 denotes a control signal, 702 denotes a radar transmission wave, 703a and 703b denote switches, and 704 denotes a radar reception wave.

  The two transmission antennas 605a and 605c are alternately switched by a changeover switch 703a and transmit a radar transmission wave 702. The two receiving antennas 605b and 605d are alternately switched by a changeover switch 703b, and an input radar received wave is selected to obtain a radar received wave 704.

  The switch 703a operates in response to the control signal 701. When the control signal pulse is 1, the switch 703a connects the transmission wave 702 to the antenna 605a, and when the pulse is 0, the switch 703a connects to the antenna 605c. At the same time, the switch 703b operates according to the control signal 701. When the pulse of the control signal is 1, the received wave 704 is selected from the antenna 605b, and when the pulse is 0, the switch 703b is selected from the antenna 605d.

  Reference numeral 607 denotes a propagation path of a radio wave, which is a path from a horizontally polarized wave transmitted from the transmission antenna 605a reflected by the detection reflector 610b with a horizontal polarization until received by the receiving antenna 605b. Reference numeral 608 denotes the other radio wave propagation path, which is a path from which the vertically polarized radio wave transmitted from the transmitting antenna 605c is converted into horizontal polarized wave by the detection reflector 610a and reflected and received by the receiving antenna 605d. Indicates.

  In this embodiment, the radar transceiver 604 transmits a horizontally polarized radio wave when the pulse is 1, and the detection reflector 610b reflects the input horizontally polarized radio wave with the same horizontal polarization as the input. The detection reflector 610a reflects the input horizontal polarization radio wave with vertical polarization, and the two receiving antennas of the radar transceiver 604 receive only the horizontal polarization, so the radar transceiver 604 is one section of the pulse. Inside, only the reflected radio wave from the detection reflector 610b is received. On the other hand, the radar transceiver 604 transmits a vertically polarized radio wave when the pulse is 0, and the detection reflector 610b reflects the input vertical polarized radio wave with the same vertical and horizontal polarization as the input, 610a reflects the input radio wave of vertical polarization with horizontal polarization, and the two receiving antennas of the radar transmitter / receiver 604 receive only the horizontal polarized wave, so the radar transmitter / receiver 604 detects within the 0 interval of the pulse. Only the reflected radio wave from the reflector 610a is received.

  With the above operation, even if the installation interval d of the detection reflectors is close enough to fall within the beam width of the transmission / reception antennas 605a, 605b, 605c, and 605d of the radar, it is reflected from either of the two detection reflectors 610a and 610b and received. Can be identified.

  When the same polarization is used as in the prior art, the signals are received at the same level from both of the two detection reflectors 610a and 610b if they are close enough to fall within the beam width of the transmission / reception antennas 605a, 605b, 605c, and 605d of the radar. Therefore, it is not possible to identify the reflection level from which detection reflector.

  In this embodiment, two horizontally polarized waves are used as the receiving antenna, but the same effect can be obtained even when two vertically polarized waves are used as the receiving antenna (not shown). That is, the transmitter / receiver 604 receives only the reflected radio wave from the detection reflector 610a in the section in which the pulse is 1 and the polarization received in the section in which the pulse is 1 is reversed. Since only the reflected radio wave from the detection reflector 610b is received in the interval where the pulse is 0, it is possible to identify which of the two detection reflectors 610a and 610b is reflected and received.

As described above, since the distance d between the two detection reflectors can be set short by using different polarized waves, identification of a person having a small width is performed in the “vehicle and person identification method” described later. Is possible.
・ "Detection method of moving direction"
FIG. 8 shows the polarization switching control signal pulse waveform for detecting the moving direction of the vehicle according to this embodiment, the change in the reception level waveform due to each polarization, and the temporal relationship between the waveforms.

  In FIG. 8, reference numeral 801 denotes a control signal pulse, 802 denotes a reception level through the propagation path 608, 803 denotes a reception level through the propagation path 607, and 804 and 805 denote reception level thresholds.

When the control signal pulse 801 is 1, the radar transmission wave is connected to the transmission antenna 605a and transmitted by horizontal polarization. The transmitted horizontal polarization is reflected by the same horizontal polarization by the detection reflector 610b installed on the opposite side of the one-way road, passes through the propagation path 607, and is received by the horizontal polarization reception antenna 605b of the radar. If there is no obstacle such as a vehicle in the propagation path 607, the reception level is a threshold value 805 or more. The control signal pulse is repeated at the period Ts, and the radio wave is cut off at time t _{1 of} the pulse where the obstacle appears, so that the reception level becomes the threshold value 805 or less, and the time interval T from time t ₁ to time t ₃ in FIG. _{At 01} , it is detected that the propagation path 607 is blocked by an obstacle.

When the control signal pulse 801 is 0, the radar transmission wave is connected to the transmission antenna 605c and transmitted by vertical polarization. The transmitted vertically polarized wave is reflected by the horizontally polarized wave having a different polarization by the detection reflector 610a installed on the opposite side of the one-way road, passes through the propagation path 608, and is received by the horizontally polarized wave receiving antenna 605d of the radar. Is done. If there is no obstacle such as a vehicle in the propagation path 608, the reception level is equal to or higher than the threshold value 804. The control signal pulse is repeated at the period Ts, and the radio wave is cut off at time t _{2 of} the pulse where the obstacle appears, so that the reception level becomes the threshold value 804 or less, and the section T ₀₂ from time t ₂ to time t ₄ in FIG. It is detected that the propagation path 608 is blocked by an obstacle.

In this case, cut off the start time t ₁ of the reception level when the control signal pulse is 1, since the pre-shutoff start time t ₂ of the reception levels of 0, the moving direction of the obstacle from the detected reflector 610b The direction toward the detection reflector 610a, that is, the reverse direction 612 of the one-way road is determined.

Obstacle such as a vehicle, whereas when the move-way street in the forward direction 611, the time t ₁ is later than time t _2. Since the detection method is the same as described above, the description thereof is omitted.

Thus, the radar transceiver of the present invention by the context of the start of the reception level blocking time t ₁ and t _2, whereas it detects the moving direction of the moving object in the way streets.

・ "Vehicle and person identification method"
In this embodiment, the center of the antennas 605a and 605b, the center distance d of the antennas 605c and 605d, and the installation distance d of the detection reflectors 610a and 610b in FIG. Vehicle length L or less.

  The distance between the centers of the antennas 605c and 605d is set so that the interval of the blocking time by the moving object traveling on the one-way road 602 is the same on the side close to the radar transceiver 604 and the side close to the detection reflectors 610a and 610b. The installation interval between the detection reflectors 610a and 610b is the same d.

  For example, assume that d = 0.5 m, and a small passenger car with a vehicle length of 3.7 m is identified from a passerby with a width of 0.5 m or less. The installation interval d can be set as appropriate depending on the object that is not detected and the type of the target vehicle that is to be detected.

FIG. 8 shows a case where the vehicle length L of the backward entry vehicle 609 is longer than the installation interval d between the detection reflectors 610a and 610b. In this case, since the front end of the vehicle 609 starts to pass through the propagation path 608 before the rear end passes through the propagation path 607 when viewed from the moving direction of the vehicle 609, the times t _{1 to} t in FIG. ₄ is t ₁ <t ₂ <t ₃ <t ₄ , and the cut-off section T ₀₁ of the propagation path 607 and the cut-off section T ₀₂ of the propagation path 608 overlap at the time t ₂ to t ₃ .

In the case of a person who enters the one-way road in the reverse direction, the distance d between the two detection reflectors in FIG. 7 is wider than the width of the human body. The radar wave on the road 608 is blocked. That is, the relationship between the times t _{1 to} t ₄ of each waveform in FIG. 8 is t ₁ <t ₃ <t ₂ <t ₄ , and the cut-off sections T ₀₁ and T ₀₂ do not overlap.

Therefore, when the overlap and time period T ₀₁ and T _02, for example a long object than the distance d such as a vehicle, also when no overlap with the time interval T ₀₁ and T _02, rather than the distance d such as a human It can be determined that the short object is moving.

In addition, since the time t ₁ when the vehicle enters the radio wave propagation path 607 and the time t ₂ until the vehicle enters the radio wave propagation path 608 can be determined only for each half cycle of the pulse signal, the order of the detection times is not mistaken. , It is necessary that at least one entire Ts / 2 of the pulse 1 is included in the time length of t ₂ −t ₁ . For this purpose, two or more pulse periods Ts must be present in the time length of t ₂ -t ₁ . This condition is expressed by equation (2), where Ts is the pulse period, d is the installation interval between the detection reflectors 610a and 610b, and v is the vehicle speed.

Furthermore, it is necessary that at least one entire section Ts / 2 of the pulse 1 is always included in the time length of t ₃ -t ₂ where the cutoff section T ₀₁ and the cutoff section T ₀₂ overlap. For this purpose, two or more pulse periods Ts must exist in the time length of t ₃ -t ₂ . This condition is expressed by equation (3).

  For example, the center distance d between the antenna sets 605a and 605b and the antenna sets 605c and 605d and the installation interval d between the detection reflectors 610a and 610b are shorter than those of a small passenger vehicle having a vehicle length L = 3.7 m, If the distance d is longer than the length d = 0.5 m, Ts ≦ 0.01 sec from the formula (2) when the maximum vehicle speed v = 80 km / s. Further, from the expression (3), Ts ≦ 0.07 sec. In this case, both conditions are satisfied by Ts ≦ 0.01 sec. Therefore, the pulse repetition frequency fs is fs ≧ 100 Hz.

  The pulse repetition period Ts is not limited to the above-mentioned numerical value, but the minimum value L of the vehicle length that needs to be detected, the maximum value v of the vehicle speed v, the distance between the antennas and the detection reflectors that is shorter than L and longer than the human traveling direction length Using the installation interval d, it can be set by the equations (2) and (3).

  As described above, whether the moving object is a vehicle or a person can be identified based on the presence or absence of overlapping of sections in which the two reception levels 802 and 803 are equal to or less than the threshold.

  Only the vehicle entering in the reverse direction of the one-way path is detected by the above method, and the alarm transmission is instructed to the alarm device 606. The alarm device 606 warns the driver of the approaching vehicle 609 by an alarm and an electric bulletin board.

  The third embodiment is different from the first and second embodiments in the configuration of the radar transceiver and the configuration of the detection reflector. In the second embodiment, in order to identify the size of the moving object, a configuration in which one radar transceiver includes a plurality of transmitting antennas and a plurality of receiving antennas has been described. In order to identify the size, a configuration is provided in which a plurality of radar transceivers each having the same transmission / reception antenna as in the first embodiment are installed. In this embodiment, a radar system is constituted by two radar transmitters / receivers and two detection reflectors facing the respective radar transmitters / receivers, and according to the relationship between the cutoff times of the reception levels of the two radar receivers. The direction and size of a passing object are judged, a backward moving vehicle to a one-way road is detected and an alarm is issued, and a passerby is identified as a vehicle and no alarm is issued.

・ "Configuration of radar system"
FIG. 9 shows the configuration of the moving direction detection radar system and the arrangement of each part in this embodiment.

  In FIG. 9, 901 is the entire T-shaped intersection, 902 is a one-way road, 903 is a normal road, 904a and 904b are radar transceivers, 905a and 905b are radar transceiver antennas, 906 is a moving object determination device, 907 is an alarm, 908 and 909 are radio wave propagation paths, 910 is a vehicle, 911 is a passerby, 912a and 912b are detection reflectors, 913 is a forward direction, and 914 is a reverse direction.

  One-way road 902 is connected to road 903 at the exit. On one side of the exit of the one-way road 902, radar transceivers 904a and 904b are installed at a predetermined interval d, and are provided with 905a and 905b as transmission / reception antennas, respectively. On the opposite side of the road, detection reflectors 912a and 912b that reflect the radar radio wave of each radar transceiver are installed at a predetermined interval d.

  The two radio wave propagation paths 908 and 909 are formed by the beam characteristics of the radar transmitting / receiving antennas 905a and 905b and the reflection characteristics of the detection reflectors 912a and 912b, and the detection reflectors 912a and 912b are not overlapped and interfere with each other. It is necessary to set the installation interval d at a certain distance or more. Adjacent radar transceivers 904a and 904b may use different polarizations in order to shorten the installation interval d and eliminate interference. For example, the radar transmitting / receiving antenna 905a and the detection reflector 912a can use horizontal polarization, and the radar transmission / reception antenna 905b and the detection reflector 912b can use vertical polarization. A vehicle 910 indicates a vehicle that enters a one-way street 902 in the reverse direction 914.

The installation interval d between the radar transceivers 904a and 904b and the installation interval d between the detection reflectors 912a and 912b are set to be shorter than the vehicle length L and longer than the traveling direction length W of the passerby.
・ "Detection method of moving direction"
FIG. 10 shows a temporal change in the reflected wave level received by the radar transceivers 904a and 904b when the vehicle 910 enters the reverse direction 914 on the one-way road 902.

  In FIG. 10, 1001 is the reception level of the radar transceiver 904a, 1002 is the minimum value level of the reception level 1001, 1003 is the threshold value, 1004 is the reception level of the transceiver 904b, 1005 is the minimum value level of 1004, and 1006 is the threshold value. Show.

By the distance detection function and the level detection of the FM-CW radars 904a and 904b, reception levels 1001 and 1004 of the distance _R0 from each radar to the opposing detection reflector are obtained. When there is no obstacle between the radar transmitter / receiver and the detection reflector, that is, the radio wave propagation path 908 and the radio wave propagation path 909, constant values of 1003 and 1006 or more are shown.

When the vehicle 910 enters the one-way road 902 and blocks the radio wave propagation path 908 at time t ₁ , the reception level of the radar 904 a becomes equal to or less than the threshold 1003 at time t ₁ , indicating the minimum level 1002. If the vehicle 910 passes end the radio wave propagation path 908 at time _{t 3,} it recovers to a constant value the reception level becomes at time _{t 3} threshold 1003 or more 904a.

Restricting the radio wave propagation path 909 in the vehicle 910 time _{t 2, the} receiving level of the radar 904a indicates the minimum level 1005 becomes at time _{t 2} to a threshold 1006 or less. When the vehicle 910 is a radio wave propagation path 909 passes ends at time _{t 4,} to recover a constant value the reception level becomes at time _{t 4} threshold 1006 or more 904b.

On the other hand, although not shown in FIG. 9, when an obstacle such as a vehicle moves in the forward direction 913 on the one-way road, time t ₁ is later than time t ₂ . Since the time detection method is the same as described above, the description thereof is omitted.

As described above, when the relationship between the cutoff start time t ₁ of the radar reception level obtained by the radar transceiver 904 a and t ₂ obtained by the radar transceiver 904 b is t ₁ <t ₂ , both radar transceivers receive the time t ₁ . and moving object determining device 906 to obtain the information of t _2, on the one hand the movement direction of the moving object passing the road is judged to reverse 914.

・ "Vehicle and person identification method"
FIG. 10 shows a case where the installation interval d of the radar transceivers 904a and 904b and the installation interval d of the detection reflectors 912a and 912b are longer than the traveling direction length W of the passerby and shorter than the vehicle length L. A time relationship of level change when a passing object longer than the installation interval d such as 910 is moving in the reverse direction 914 is shown. In this case, t ₁ <t ₂ <t ₃ <t ₄ , and there is a section T ₂ where the reception level cutoff sections of the radar transceivers 904a and 904b overlap.

On the other hand, when the passing object is shorter than the installation interval d, such as the passer-by 911, the sections where the reception levels 1001 and 1004 in FIG. In other words, the relationship between the times is t ₁ <t ₃ <t ₂ <t ₄ , and there is no section T ₂ where the interception sections of the reception levels of the radar transceivers 904a and 904b overlap (not shown).

As described above, the presence or absence of overlapping _{T 2} of the section in which the two reception levels 1001 and 1004 is equal to or less than the threshold at the same time, the time information _t 1 from the moving object determination unit 906 two radar transceivers 904a and 904b, t Judgment is made based on ₂ , t ₃ and t ₄ to identify whether the moving object is an object longer than the installation interval d such as a vehicle or an object shorter than d such as a person.

  By the above method, the moving direction detection radar system according to the present invention can not only detect the moving direction of the moving object, but also identify the type (size) of the object, and in the reverse direction of the one-way path. Only the invading vehicle is detected, and the moving object determination device 906 can instruct the alarm device 907 to issue an alarm. The alarm device 907 warns the driver of the approaching vehicle 910 by an alarm and an electric bulletin board.

  In this embodiment, a radar system is constituted by two radar transmitters / receivers and two sets of detection reflectors facing the respective radar transmitters / receivers, and the direction of a passing object is determined by the shape of the reception level of the two radar receivers. The size of the vehicle is determined, a backward moving vehicle to the one-way road is detected and an alarm is issued, and the passerby is identified as a vehicle and no alarm is issued.

  As in the third embodiment, the fourth embodiment includes a configuration in which a plurality of radar transceivers each having the same transmission / reception antenna as the first embodiment are installed in order to identify the size of a moving object. The present invention provides an identification method suitable for detection when there are many passersby on a one-way road and overlaps with a vehicle and passes through a radar beam.

・ "Configuration of radar system"
FIG. 11 shows the configuration of the moving direction detection radar system and the layout of each part in this embodiment.

  In FIG. 11, what is different from FIG. 9 is a passerby group indicated by 1101a and 1101b, and the other parts that are the same as in FIG. 9 are given the same numbers.

・ "Vehicle and person identification method"
As described in the first embodiment, the radar radio wave reflectance varies depending on the radar frequency, the size and material of the reflecting object, and is quantified by the radar scattering cross section (RCS). In the millimeter wave according to the present embodiment, the RCS of the passenger car has a value about 20 dB larger than that of a person. Further, since the reception level at the radar is inversely proportional to the fourth power of the distance, the reception level of the radar becomes smaller even in the same vehicle as the distance between the radar and the reflecting object increases. These relationships are expressed by the radar equation (1) described in the first embodiment by the output level of the radar transmitter, the antenna gain for transmission and reception, the wavelength of radio waves, RCS, and the distance R.

  As described in the first embodiment, by correcting the reception level from the reflecting object at a distance R from the radar transceiver for each distance R, the level can be converted into a specific level value depending on the type of the reflecting object. The corrected reception level is shown in FIG.

  In FIG. 12, 1201 is a level reflected from the detection reflector 912 a and received by the radar 904 a, 1202 is reflected by a moving object passing through the road 902, and is received by 904 a, 1203 is a threshold value for 1202, and 1204 is a threshold value for 1201. 1205 is a level reflected from the detection reflector 912b and received by the radar 904b, 1206 is a level reflected by a moving object passing through the road 902, and received at 904b, 1207 is a threshold value for 1206, and 1208 is a threshold value for 1205. Each is shown.

The level reflected from the detection reflectors 912a and 912b is detected as a level from the distance _R0 by the distance detection function of the FM-CW radar 904a and its level detection function, and the level reflected by the object moving in the road is , Detected as levels from the distances R _x1 and R _x2, and both are identified.

  As described in the first embodiment, the reflection reception level Pr from the object is expressed by the equation (1) by the radar scattering cross section (RCS) which varies depending on the radar frequency and the size and material of the reflection object. In the millimeter wave in this embodiment, the RCS of the passenger car has a value about 20 dB larger than that of a person.

In order to identify the type of reflecting object using the reception level Pr, the reception level of the radar transceiver represented by the equation (1) is corrected by the distance R. Therefore, using the distance R to the reflecting object detected by the FM-CW radar, if multiplied by the R ⁴ to the reception level Pr, reflecting objects independent of (1) Pr becomes corrected value by an equation, the distance The value is proportional to the RCS. For example, when the distance R = 1 m is set as a reference, the correction value of the reception power of the reflecting object having the distance R = 3 m is 3 ⁴ = 81 times, and the dB value is corrected to increase by 19 dB.

In addition, since the RCS value of the received power from the reflective object at a close distance of several meters changes even if the reflective object is the same, the correction of the received power by the detection distance is not only by multiplying the above R ⁴ but also by RCS. such a combination of correction for changing the distance may be used by adding the correction by the data of the difference between the data obtained by experiments and Pr of the theoretical value by (1) the correction of multiplication of the R ^4.

  The results of the above correction are the reception levels 1201, 1202, 1205, and 1206 in FIG.

Passerby group 1101b for passing one-way street 902 in FIG. 11 in the reverse direction, it enters the radio path 909, reflecting the reception level 1205 from the detection reflector 912b in the radar 904b, the threshold at time _{t 2} in FIG. 12 1208 Smaller. At the same time, the reception level 1206 reflected by the passerby group 1101b increases but is smaller than the threshold value 1207. Then, the vehicle 910 is a state reflecting the reception level that are blocked from 912b enters the radio path 909 continues, the reflection level from the vehicle 910 is larger than the passers group 110b, exceeds the threshold value 1207 at time _{t 2x} . Passers groups 1101b and the vehicle 910, past the radio path 909, the reception level 1206 at time _{t 4x} return to minimum values smaller than the threshold value 1207, a threshold 1208 at time _{t 4} since the receiving level 1205 blocking is eliminated The maximum value is recovered.

Also with respect to the propagation path 908 is first reflected reception level 1201 from the detection reflector 912a in the radar 904a by the vehicle 909 is smaller than the threshold value 1204 at time _{t 1.} Even the radio path 908 to complete the vehicle 901 passes, since passersby group 1101a is passing, blocking state of the reception level 1201 continues, at time _{t 3} when _the passage of the passer group 1101a is completed, the reception level 1201 exceeds the threshold 1204 and recovers to the maximum value.

Further, the reflection level 1202 from the passing object in the propagation path 908 first exceeds the threshold 1203 at the time t _1x by the vehicle 910, and becomes smaller than the threshold 1203 at the time t _3x when the vehicle completes passing through the radio wave propagation path 908. After time t _{3x, the} reception level by the passer-by group 1101a remains, and continues until time t ₃ when the pass-through of the passer-by group 1101a is completed.

  In this embodiment, both the increase in the reception level of the reflected wave by the passing object and the decrease in the reception level by the detection reflector are used. However, in the determination only by the former, the side lobe of the antenna 905a of the radar transceiver 904a, for example, There is a possibility that a large passing object such as a truck traveling on a general road 903 distant from the radio wave propagation path 908 may be erroneously detected. If blocking of the reflection level from the detection reflector 912a is used in combination, only an object passing through the radio wave propagation path 908 can be detected reliably.

In this embodiment, it is not necessary to distinguish the distances R _x1 and R _x2 from the radar transceiver 904a to the vehicle 910 and the passerby group 1101a, and it is only necessary to identify the distance R ₀ to the detection reflector. There is no problem even if the passing object is very close. Since the distance R ₀ from the radar transceiver 904a to the detection reflector 912a is far from the road, R ₀ can be distinguished from R _X1 and R _X2 .

  Further, in this embodiment, since the installation interval d of the radar transceivers 904a and 904b and the installation interval d of the detection reflectors 912a and 912b in FIG. 11 are set shorter than the vehicle length L, an object moving on the road 902 In the case of a vehicle, in FIG. 12, there are sections where the sections Ta and Tb where the reception levels from the passing vehicles in the radar transceivers 904a and 904b are equal to or greater than the threshold value overlap.

Only the vehicle that has moved on the road can be detected by the above method.
・ "Detection method of moving direction"
In FIG. 12, the increase in the reflection level 1202 from the vehicle 910 in the radar 904a starts at t _1x , and then the increase in the reflection level 1206 from the vehicle 910 in the radar 904b starts at t _2x and then from the vehicle 910 in the radar 904a. The reflection level 1202 of the radar starts at t _3x , then the reflection level reduction from the vehicle 910 at the radar 904b starts at t4x, and the increase in the reflection level from the vehicle at each radar is from the detection reflector. It is determined that the vehicle has moved in the reverse direction 914 when it occurs in the section where the reception level is blocked.

When this is indicated by the time at which each level crosses the threshold, t _1x <t _2x <t _3x <t _4x , and t ₁ <t _1x , t ₂ <t _2x , t _3x <t ₃ , t _4x <t ₄ Is when all of the above are true.

In FIG. 12, when the vehicle alone passes, the cutoff start time t ₁ of the reception level 1201 from the detection reflector and the detection start time t _1x of the reflection level 1202 from the vehicle are a cutoff event and a reflection event due to one object. It may be difficult to determine the context because it is the start time of.

As a countermeasure in such a case, the times t ₁ , t ₂ , t ₃ , and t ₄ relating to the cutoff of the reception level from the detection reflector are used by using the time lengths _Ta and T _b in which the reflection level by the vehicle is detected. The correction may be made as follows. The shut-off start times t ₁ and t ₂ are increased by m × T _a and m × T _b to t _1h and t _2h , respectively, and the shut-off completion times t ₃ and t ₄ are set to m × T _a and m × T _b , respectively. The correction is made at t _3h and t _4h later. However, m is a value not less than 0 and less than 0.5. For example, if m = 0.1 is set, the time correction values at the start of shut-off are t _1h = t ₁ −0.1 × Ta and t _2h = t ₂ −0, respectively. .1 × Tb, and the respective time correction value of the cutoff completion _{t 3h = t 3 + 0.1 ×} Ta, a _{t 4h = t 4 + 0.1 ×} Ta. Using this corrected time value, t _1x <t _2x <t _3x <t _4x , t _1h <t _1x , t _2h <t _2x , t _3x <t _3h , t _4x <t _4h It may be when all of the above are established.

  m can be selected according to the shortest length of the vehicle to be detected. If only a truck with a long vehicle length is detected, m is increased. It is possible to reliably determine the time of day by extending the interception section of the reception level.

  Only the vehicle entering in the reverse direction of the one-way path is detected by the above method, the moving object determination device 906 notifies the alarm device 907, and the alarm device 907 warns the driver of the approaching vehicle 910 by an alarm and an electric bulletin board. It becomes possible.

  FIG. 13 shows an operation flow of this embodiment.

In Figure 13, S1301 is a step to start the system, the step of radar transceiver 904a determines blocking of the reflected reception level from 912a S1302, the radar transceiver 904a time information _{S1303 t 1, t 1x, t} 3 , T _3x to notify the moving object determination device 906, S1304 is a step in which the radar transmitter / receiver 904b determines the cutoff of the reflected reception level from the detection reflector 912b, and S1305 is a step in which the radar transmitter / receiver 904b receives time information t. ₂ , t _2x , t ₄ , t _4x are determined and notified to the moving object determination device 906, S 1306 is a step of determining t _1x <t _2x <t _3x <t _4x in 906, S 1307 is a time in 906 calculating a correction value _{t 1h, t 2h, t 3h} , the _{t 4h} S1308 in _{906 t 1h <t 1x, t} 2h <t 2x and _t 3x _{<t 3h,} determining _t 4x _{<t 4h,} S1309 is a step for instructing to alert the 906 907, S1310 is 907 A step of issuing an alarm, S1311 indicates a step in which 906 resets the time data to zero.

In step 1301, the operation of the entire system is started. In step 1302, the radar transceiver 904a compares the reception level 1201 due to reflection from the detection reflector 912a with the threshold 1204 to determine whether or not the radio wave propagation path 908 is blocked. To do. If there is no interruption, repeat the radar measurement. If blocked, the reception start time t ₁ of the reflection reception level from the detection reflector 912a in step 1303, the recovery time t ₃ and the reception start time t _1x of the reflection level from the moving vehicle on the one-way road 902, the reception end Time t _3x is determined and notified to moving object determination device 906.

In parallel with the operation of the radar transmitter / receiver 904a, in step 1304, the radar transmitter / receiver 904b compares the reception level 1205 due to reflection from the detection reflector 912b with the threshold value 1208 to determine whether the radio wave propagation path 909 is blocked. Judging. If there is no interruption, repeat the radar measurement. If blocked, the reception start time t ₂ of the reflection reception level from the detection reflector 912 _b , the recovery time t ₄ , the reception start time t _2x of the reflection level from the moving vehicle on the one-way road 902, and reception end in step 1305. The time t _4x is determined and notified to the moving object determination device 906.

Receiving the time notification, the moving object determination device 906 determines whether or not t _1x <t _2x <t _3x <t _4x holds in the context of each time in step S1306.

  If the above condition is not satisfied, it is determined that the event is caused by the passing of a vehicle moving in the forward direction or a passerby who is not a vehicle, and the process returns to the next radar measurement.

If the above condition is satisfied, in the next step S1307, correction is performed to widen the blocking time width of the reflection level from the detection reflector. This correction is performed in order to reliably determine the time when the reception level from the moving vehicle starts and ends when the reception level from the detection reflector is cut off when a moving object to be detected such as a vehicle passes alone. Do. The correction result times are t _1h , t _2h , t _3h , and t _4h with _respect to times t ₁ , t ₂ , t ₃ , and t ₄ .

In step S1308, the corrected times t _1h , t _2h , t _3h , t _4h and the notified times t _1x , t _2x , t _3x , t _4x are used, and t _1h <t _1x , t _2h <t _It is determined whether _2x , t _3x <t _3h , and t _4x <t _4h are all satisfied.

  If the above condition is not satisfied, it is determined that the event is caused by a moving object outside the one-way road, and the next radar measurement is returned.

  When the above condition is satisfied, it is determined that the vehicle has moved in the reverse direction on the one-way road, and the moving object determination device 906 instructs the alarm device 907 to issue an alarm in the next step S1309. In step 1310, the alarm device 907 warns the driver of the approaching vehicle 910 by outputting an alarm and an electric bulletin board. In Step 1311, the time data is reset and the next radar measurement is returned.

By the above method, the moving direction detection radar system of the present invention can detect an object moving in a direction different from a predetermined direction and having a width greater than a predetermined length in the fourth embodiment. It is possible to detect only a vehicle entering in the reverse direction of the one-way road, and the moving object determination device 906 can instruct the alarm device 907 to issue an alarm.
(Appendix 1)
In a moving direction detection radar system including a radar transceiver and a detection reflector,
The radar transceiver is reflected from an object moving across the radar transceiver and a detection reflector installed in a direction within a main lobe range offset from the maximum gain direction of the radar beam of the radar transceiver. Means for detecting the time at which the level at which the radar radio wave is received has a maximum value;
Means for detecting a time at which a level at which a radar radio wave reflected from the detection reflector is received is blocked by the object and indicates a minimum value;
A moving direction detecting radar system comprising: means for determining a moving direction of the object based on a front-rear relationship between the time indicating the maximum value and the time indicating the minimum value.
(Appendix 2)
The radar transceiver further includes:
Correction for multiplying the level at which radar radio waves reflected from the object are received by the fourth power of the distance to the object, and means for correcting the effect of reducing the radar scattering cross section at close range;
Means for determining a maximum value of the received level exceeding a threshold set by a radar reception level corresponding to a radar scattering cross section specific to the object type;
An object moved across the radar transceiver and the detection reflector by the two means as an object having a radar scattering cross section larger than the radar scattering cross section inherent to the object corresponding to the set threshold value. The moving direction detection radar system according to appendix 1, further comprising: means for identifying the type.
(Appendix 3)
The means for determining the movement direction determines that the object has moved from the center direction of the radar beam to the detection reflector installation direction when the time indicating the maximum value is earlier than the time indicating the minimum value; The movement according to claim 1, wherein when the time indicating the maximum value is later than the time indicating the minimum value, the movement is a means for determining that the movement from the detection reflector installation direction toward the center of the radar beam. Direction detection radar system.
(Appendix 4)
The moving direction detection radar system further includes:
The moving direction detection according to claim 1, further comprising means for issuing an alarm when it is determined that the moving direction of the object determined by the means for determining the moving direction is opposite to a predetermined direction. Radar system.
(Appendix 5)
In a moving direction detection radar system comprising a radar transceiver having a plurality of antennas and a plurality of detection reflectors installed at positions facing the plurality of antennas,
The radar transceiver includes two horizontally polarized antennas and two vertically polarized antennas for transmission, and two horizontal or vertical identical polarization antennas for reception,
The plurality of detection reflectors include a first detection reflector that reflects with the same polarization as the input polarization, and a second detection reflector that reflects with a polarization different from the input polarization,
The radar transceiver is
Means for switching between the horizontally polarized antenna and the vertically polarized antenna for transmission at a predetermined period;
Means for switching the two reception-same polarization antennas at the predetermined period;
The level at which the radar radio wave reflected from the first detection reflector is received is blocked from the time when the block starts by an object moving across the radar transceiver and the first detection reflector. Means for detecting when the level has recovered,
Means for detecting when the level at which the radar radio wave reflected from the second detection reflector is received is blocked by the object and when the blocked level is restored;
Means for determining the moving direction of the object according to the context of each time;
A moving direction detection radar system comprising:
(Appendix 6)
The predetermined period for switching between the transmitting horizontally polarized antenna and the vertically polarized antenna is from the time when the level at which the radar radio wave reflected from the first detection reflector is received by the front end of the object starts to be cut off. Radar reflected from the first detection reflector by the first time interval until the time when the level at which the radar radio wave reflected from the second detection reflector is received starts to be cut off and the rear end of the object. A second time interval from the time when the cut off level of the radio wave recovers to the time when the cut off level of the radar radio wave reflected from the second detection reflector is restored; The switching period is 2 or more in the shortest of the three time intervals of the third time interval, where the interception intervals of the reception level of the radar wave reflected from the second detection reflector overlap. The moving direction detection radar system according to appendix 5, which is a feature.
(Appendix 7)
The time when the received level starts blocking and the time when the blocked level recovers are set to predetermined values smaller than the received level determined by the distance from the radar transceiver to the detection reflector and the radar scattering cross section. The moving direction detecting radar system according to claim 5, wherein the moving direction detecting radar system is determined according to a time at which the threshold value is crossed.
(Appendix 8)
The moving direction detection radar system includes: a center of the transmitting horizontally polarized antenna and one of the receiving polarization antennas of the radar transceiver; and the transmitting vertically polarized antenna and the receiving same antenna. The distance between the centers of the polarized antennas and the center of the other antenna and the distance between the first detection reflector and the second detection reflector in the direction of travel of the object that should not be detected Above and below the length of the object to be detected,
further,
When the time interval in which the radar wave reflected from the first detection reflector is blocked by the object and the time interval in which the radar wave reflected from the second detection reflector is blocked by the object overlap, The moving direction detection radar system according to appendix 5, further comprising means for determining that the object is an object to be detected.
(Appendix 9)
The means for determining the moving direction is such that the radar wave reflected from the first detection reflector is blocked by the object and the radar wave reflected from the second detection reflector is blocked by the object. When the time intervals overlap, it is a means for judging that the object has moved in the direction of the detection reflector with the later time when the blocking is started from the detection reflector with the earlier time when the blocking was started. The moving direction detection radar system according to appendix 5.
(Appendix 10)
The moving direction detection radar system further includes:
The moving direction detection according to claim 5, further comprising means for issuing an alarm when it is determined that the moving direction of the object determined by the means for determining the moving direction is opposite to a predetermined direction. Radar system.
(Appendix 11)
In a moving direction detection radar system comprising a plurality of sets of a radar transceiver and a detection reflector installed at a position opposite to the radar transmitter and a moving object determination device,
Each of the radar transceivers is
The time at which the level at which the radar radio wave reflected from the detection reflector placed opposite the radar transceiver is received is blocked by an object that moves across the radar transceiver and the detection reflector And means for detecting when the blocked level has recovered,
The moving object determination device includes:
A moving direction detection comprising: means for determining a moving direction of the object based on a front-rear relationship between the time of start of shutoff and the time of end of shutoff that are detected and output by each of the plurality of radar transceivers. Radar system.
(Appendix 12)
12. The moving direction detecting radar system according to claim 11, wherein in each of the moving direction detecting radar systems, the antennas of the respective radar transceivers use different polarized waves with respect to the antennas of the adjacent radar transceivers.
(Appendix 13)
The time when the received level starts blocking and the time when the blocked level recovers are a predetermined level smaller than the received level determined by the distance from the radar transceiver to the opposing detection reflector and the radar scattering cross section. 12. The moving direction detecting radar system according to appendix 11, wherein the moving direction detecting radar system is determined based on a time crossing a threshold set in the value.
(Appendix 14)
The moving direction detection radar system is configured such that an installation interval between the plurality of radar transceivers and an installation interval between the plurality of detection reflectors are equal to or longer than a traveling direction length of an object that should not be detected and an object to be detected is traveling. Less than the direction length,
further,
In the adjacent radar transceivers among the plurality of radar transceivers, when the time intervals in which the radar radio waves reflected from the detection reflectors installed facing the respective radar transceivers are blocked overlap each other The moving direction detection radar system according to claim 11, further comprising means for determining that the object is an object to be detected.
(Appendix 15)
The means for determining the moving direction is such that when the sections where the radar radio waves reflected from the detection reflectors installed facing each other in the respective radar transceivers are blocked overlap each other, the time when the blocking is started earlier 12. The moving direction detecting radar system according to claim 11, wherein the moving direction detecting radar system is a means for determining that the object has moved in the direction of the detection reflector that is later in time from the detection reflector.
(Appendix 16)
The moving direction detection radar system further includes:
The moving direction detection according to claim 11, further comprising means for issuing an alarm when it is determined that the moving direction of the object determined by the means for determining the moving direction is opposite to a predetermined direction. Radar system.
(Appendix 17)
In a moving direction detection radar system comprising a plurality of sets of a radar transceiver and a detection reflector installed at a position opposite to the radar transmitter and a moving object determination device,
Each of the radar transceivers is
The time at which the level at which the radar radio wave reflected from the detection reflector placed opposite the radar transceiver is received is blocked by an object that moves across the radar transceiver and the detection reflector And means for detecting when the blocked level has recovered,
Means for detecting a time at which reception of radar radio waves reflected from the object is started and a time at which reception is terminated;
A means for determining the moving direction of the object based on the sequence of the block start time, block end time, reception start time, and reception end time detected and output by each of the plurality of radar transceivers; A moving direction detection radar system.
(Appendix 18)
The radar transceiver further includes:
Correction for multiplying the level received radar wave reflected from the object by the fourth power of the distance to the moving object, and means for correcting the effect of reducing the radar scattering cross section at the polar distance;
Means for determining, as a reception start time, a time that exceeds a threshold set by a radar reception level corresponding to a radar scattering cross section specific to the object type, and a time that falls below the threshold as a reception end time;
18. A moving direction detecting radar system according to appendix 17, characterized by comprising:
(Appendix 19)
The radar transceiver is
The reception start time of the radar radio wave reflected from the object is blocked by the object from the time interval in which the reception level corrected in Appendix 18 exceeds the threshold and the reception level of the radar radio wave reflected from the detection reflector. Means for determining as the first time of the time interval overlapped with the time interval being
The reception end time of the radar radio wave reflected from the object is blocked by the object from the time interval in which the reception level subjected to the correction of Appendix 18 exceeds the threshold and the reception level of the radar radio wave reflected from the detection reflector. Means for determining as the last time of the time interval overlapped with the time interval being
18. A moving direction detecting radar system according to appendix 17, characterized by comprising:
(Appendix 20)
The moving direction detection radar system includes:
Among the plurality of radar transceivers, an installation interval between adjacent radar transceivers and an installation interval between the detection reflectors installed opposite to each of the adjacent radar transceivers are not detected. More than the length of the direction of travel, less than the length of the direction of the object to be detected,
further,
In the adjacent radar transceivers among the plurality of radar transceivers, when the time intervals in which the radar radio waves reflected from the detection reflectors installed facing the respective radar transceivers are blocked overlap each other The moving direction detection radar system according to claim 17, further comprising means for determining that the object is an object to be detected.
(Appendix 21)
The means for determining the moving direction is such that when the sections where the radar radio waves reflected from the detection reflectors installed facing each other in the respective radar transceivers are blocked overlap each other, the time when the blocking is started earlier 18. The moving direction detection radar system according to claim 17, wherein the moving direction detection radar system is a means for determining that the object has moved in the direction of the detection reflector that is later in time from the detection reflector.
(Appendix 22)
The moving direction detection radar system further includes:
The moving direction detection according to claim 17, further comprising means for issuing an alarm when it is determined that the moving direction of the object determined by the means for determining the moving direction is opposite to a predetermined direction. Radar system.

It is a figure which shows the structural example of the moving vehicle detection radar system by a prior art. It is a figure which shows the time change of the reflection level by the moving vehicle in a prior art. It is a figure which shows the structural example of the radar system by Example 1. FIG. It is a figure which shows the time change example of the radar receiving level in Example 1. FIG. It is a figure which shows the time change example of the radar receiving level in Example 1. FIG. It is a figure which shows the structural example of the radar system by Example 2. FIG. It is a figure which shows the detailed structural example of the radar system by Example 2. FIG. It is a figure which shows the signal timing of the radar system in Example 2. FIG. It is a figure which shows the structural example of the radar system by Example 3. FIG. It is a figure which shows the example of a radar reception level in Example 3. FIG. It is a figure which shows the structural example of the radar system by Example 4. FIG. It is a figure which shows the example of a radar reception level in Example 4. FIG. It is a figure which shows the example of a movement direction detection flow in Example 4. FIG.

Explanation of symbols

101 T-shaped intersection 102 One-way road 103 Normal road 104 Radar transceiver 105 Radar transmission / reception antenna 106a Detection reflector 106b Detection reflector 107 Transmission / reception radar beam 108 Reverse moving vehicle 109 Forward direction 110 Reverse direction 201 Reception level 202 from vehicle Level 201 Peak level 203 Threshold 204 Received level from detection reflector 205 204 Minimum value level 206 Threshold 301 T-shaped intersection 302 One-way road 303 Normal road 304 Radar transceiver 305 Radar transceiver antenna 306 Alarm 307 Transmitter / receiver radar beam 308 Detection reflector 309 Reverse moving vehicle 310 Forward vehicle 311 Forward direction 312 Reverse direction 313 C direction 314 D direction 401 Reception level 402 from vehicle Reception level 401 peak level 403 Threshold 404 Reception level from reflector 405 404 Minimum level 406 404 Threshold 501 Reception level 502 from vehicle 309 Reception level 501 peak level 503 Threshold 504 Reception level from detection reflector 505 504 minimum level 506 Threshold 601 T-shaped intersection Overall 602 One-way road 603 Normal road 604 Radar transceiver 605a Radar antenna 605b Radar antenna 605c Radar antenna 605d Radar antenna 606 Alarm 607 Radio wave propagation path 608 Radio wave propagation path 609 Reverse moving vehicle 610a Detection reflector 610b Detection reflector 611 Forward direction 612 Reverse direction 701 Control signal 702 Radar transmission wave 703a Switch 703b Switch 704 Radar reception wave 801 Control signal pulse 802 Reception level by propagation path 608 Reception 803 Reception by propagation path 607 Level 804 Reception level threshold 805 Reception level threshold 901 Overall T-shaped intersection 902 One-way road 903 Normal road 904a Radar transceiver 904b Radar transceiver 905a Radar transceiver antenna 905b Radar transceiver antenna 906 Moving object determination device 907 Alarm 908 Propagation path 909 Radio wave propagation path 910 Vehicle 911 Passerby 912a Detection reflector 912b Detection reflector 913 Forward direction 914 Reverse direction 1001 Reception level 1002 of the radar transceiver 904a Minimum level 1003 of the reception level 1001 Threshold 1004 Reception of the transceiver 904b Level 1005 Minimum value of 1004 Level 1006 Threshold 1101a Passer group 1101b Passer group 1201 Received level 1202 from detection reflector 912a Pair with received level 1203 1202 from moving object Threshold 1205 for threshold 1204 1201 Received level 1206 from detection reflector 912b Received level 1207 from moving object Threshold for threshold 1208 1205 for level 1207 1206

Claims (5)

In a moving direction detection radar system including a radar transceiver and a detection reflector,
The radar transceiver is reflected from an object moving across the radar transceiver and a detection reflector installed in a direction within a main lobe range offset from the maximum gain direction of the radar beam of the radar transceiver. Means for detecting the time at which the level at which the radar radio wave is received has a maximum value;
Means for detecting a time at which a level at which a radar radio wave reflected from the detection reflector is received is blocked by the object and indicates a minimum value;
A moving direction detecting radar system comprising: means for determining a moving direction of the object based on a front-rear relationship between the time indicating the maximum value and the time indicating the minimum value. In a moving direction detection radar system comprising a radar transceiver having a plurality of antennas and a plurality of detection reflectors installed at positions facing the plurality of antennas,
The radar transceiver includes two horizontally polarized antennas and two vertically polarized antennas for transmission, and two horizontal or vertical identical polarization antennas for reception,
The plurality of detection reflectors include a first detection reflector that reflects with the same polarization as the input polarization and a second detection reflector that reflects with a polarization different from the input polarization.
The radar transceiver is
Means for switching between the horizontally polarized antenna and the vertically polarized antenna for transmission at a predetermined period;
Means for switching the two reception-same polarization antennas at the predetermined period;
The level at which the radar radio wave reflected from the first detection reflector is received is blocked from the time when the block starts by an object moving across the radar transceiver and the first detection reflector. Means for detecting when the level has recovered,
Means for detecting when the level at which the radar radio wave reflected from the second detection reflector is received is blocked by the object and when the blocked level is restored;
Means for determining the moving direction of the object according to the context of each time;
A moving direction detection radar system comprising: The moving direction detecting radar system according to claim 2, wherein the radar transceiver includes a center of the transmitting horizontally polarized antenna and one of the receiving identically polarized antennas, and the transmitting vertically polarized antenna. An object that should not detect the center-to-center distance from the other one of the receiving polarization antennas and the installation interval between the first detection reflector and the second detection reflector Is longer than the traveling direction length of the object and less than the traveling direction length of the object to be detected,
further,
When the time interval in which the radar wave reflected from the first detection reflector is blocked by the object overlaps the time interval in which the radar wave reflected from the second detection reflector is blocked by the object, The moving direction detection radar system according to claim 2, further comprising means for determining that the object is an object to be detected. In a moving direction detection radar system comprising a plurality of sets of a radar transceiver and a detection reflector installed at a position opposite to the radar transmitter and a moving object determination device,
Each of the radar transceivers is
The time at which the level at which the radar radio wave reflected from the detection reflector placed opposite the radar transceiver is received is blocked by an object that moves across the radar transceiver and the detection reflector And means for detecting when the blocked level has recovered,
The moving object determination device includes:
A moving direction detection comprising: means for determining a moving direction of the object based on a front-rear relationship between the time of start of shutoff and the time of end of shutoff that are detected and output by each of the plurality of radar transceivers. Radar system. In a moving direction detection radar system comprising a plurality of sets of a radar transceiver and a detection reflector installed at a position opposite to the radar transmitter and a moving object determination device,
Each of the radar transceivers is
The time at which the level at which the radar radio wave reflected from the detection reflector placed opposite the radar transceiver is received is blocked by an object that moves across the radar transceiver and the detection reflector And means for detecting when the blocked level has recovered,
Means for detecting a time at which reception of radar radio waves reflected from the object is started and a time at which reception is terminated;
A means for determining the moving direction of the object based on the sequence of the block start time, block end time, reception start time, and reception end time detected and output by each of the plurality of radar transceivers; A moving direction detection radar system.

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