JP2007248058A - Optical axis adjustment method of radar device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical axis adjustment method of a radar device performing optical axis adjustment, having simple constitution and a relatively easy method. <P>SOLUTION: The radar device 10 mounted on a vehicle body 11 includes a reference axis 101 along the front direction of the vehicle body 11. An antenna device 20 provided to the radar device 10 includes an optical axis 201. The antenna device 20 performs object detection, while performing beam scanning orthogonal to the optical axis 201 along a scanning axis 301 that is substantially parallel to the front of the vehicle 11. A reflective object 1 moves along the movement axis 100, orthogonal to a reference axis 101 and substantially parallel to the scanning axis 301. With reference to the optical axis 201, the azimuth with which a reflecting object distance is minimum is calculated, on the basis of the detection result, and the correction is performed so that the calculated azimuth coincides with the direction of the reference axis 101 (azimuth of 0°). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical axis adjustment method for a radar apparatus, and more particularly to an optical axis adjustment method for performing correction to eliminate an error between a detection angle of a radar apparatus and an actual azimuth angle.

  Currently, for the purpose of avoiding collision of automobiles, there is a type in which a radar device is installed on a vehicle body that is a mounted body. This radar device includes an antenna device having a radiation surface facing a detection region such as the front, transmits an electromagnetic wave from the antenna device to the detection region, and receives a reflected wave from an object (for example, a preceding vehicle) in the detection region. Then, the speed and distance of the object are detected using the transmission wave and the reception wave.

  And the reference axis of such a radar apparatus and the reference axis of the vehicle body on which this radar apparatus is mounted must coincide with the optical axis of the antenna, and there are various methods for adjusting the optical axis as shown in Patent Document 1. It has been devised.

In Patent Document 1, a receiving antenna is installed at a reference position that is a predetermined distance (approximately 20 m to 40 m) away from a vehicle body on which a radar device (antenna device) is mounted. In this method, the transmission wave transmitted from the antenna device is received by the receiving antenna, and the optical axis of the antenna device is adjusted based on the electric field strength distribution of the received signal.
JP 2001-174540 A

  However, in the optical axis adjustment method described in Patent Document 1, the receiving antenna for adjusting the optical axis is set apart from the radar device at a distance of about 20 m to 40 m, and further, the axis is shifted from the received intensity distribution by the receiving antenna. A processing device for calculating the quantity had to be installed separately. Furthermore, in order to obtain an accurate reception intensity, it has to be performed in a place such as an anechoic chamber. For this reason, the measurement system for adjusting the optical axis becomes large and very expensive. Furthermore, the operation becomes complicated by separately preparing a measurement system for the amount of deviation of the optical axis.

  Therefore, an object of the present invention is to provide an optical axis adjustment method for a radar apparatus that performs optical axis adjustment with a simple configuration and a relatively easy method.

  (1) An optical axis adjustment method for a radar apparatus according to the present invention includes: a radar apparatus having a predetermined reference axis with respect to a detection region; or an optical axis of an antenna apparatus provided on a mounted body on which the radar apparatus is mounted. It matches the reference axis. In this optical axis adjustment method, the reflecting object is moved in a trajectory that passes perpendicularly to the reference axis at one point at a predetermined distance from the antenna device on the reference axis. The antenna device transmits a transmission wave in the moving area of the reflection object, and receives a reflection wave of the reflection object with respect to the transmission wave. This optical axis adjustment method is characterized in that the amount of deviation between the optical axis and the reference axis is detected based on the change over time of the detection result of the reflecting object obtained by the radar apparatus.

  In this method, a transmission wave is transmitted from the antenna device to the detection area in the same manner as normal detection, and a reflected wave from within the detection area is received. When the reflecting object moves on the reference axis in the detection area in a trajectory that passes perpendicularly to the reference axis (changes in position over time), the signal intensity of the reflected wave is changed according to the position change of the reflecting object with time. The reflected wave arrival direction (azimuth) changes. At this time, the radar apparatus detects changes with time in the distance and speed of the reflecting object in accordance with this change. At this time, the position (distance) and speed of the reflecting object are calculated from the difference between the transmission timing and the reception timing and the difference between the transmission frequency and the reception frequency (Doppler frequency), and take characteristic values in the reference axis direction. The amount of deviation between the optical axis and the reference axis is calculated based on the change with time of the detected value.

  (2) Further, according to the method of adjusting the optical axis of the radar apparatus of the present invention, the radar apparatus detects a change in the distance from the antenna apparatus to the reflecting object from the transmitted wave and the reflected wave, and minimizes the distance in the detected distance change. It is characterized in that the amount of deviation is detected based on the angle detection result in the radar device when the value is obtained.

  In this method, a change in distance is calculated as a specific change over time. Then, using the fact that the reflecting object is closest to the antenna device on the reference axis, the amount of deviation from the optical axis is calculated with the point where the calculated distance becomes the minimum value as the reference axis direction.

  (3) Further, according to the optical axis adjustment method of the radar apparatus of the present invention, the radar apparatus detects a change in Doppler speed of the reflecting object with respect to the antenna apparatus from the transmission wave and the reflected wave, and the absolute value of the detected Doppler speed is detected. It is characterized in that the amount of deviation is detected based on the angle detection result in the radar apparatus when the minimum value is obtained.

  In this method, a change in Doppler velocity is calculated as a specific change over time. Then, using the fact that the Doppler velocity of the reflecting object with respect to the antenna device on the reference axis becomes “0”, the amount of deviation from the optical axis is calculated with the point where the calculated Doppler velocity becomes the minimum value as the reference axis direction.

  (4) According to the radar apparatus optical axis adjustment method of the present invention, the radar apparatus detects a change in the distance from the antenna apparatus to the reflecting object from the transmitted wave and the received wave, and the distance in the detected distance change. The position of the reflecting object corresponding to the local minimum value of the reflection wave and the position of the reflecting object corresponding to the maximum value of the reception intensity of the reflected wave are matched.

  In this method, utilizing the fact that the received signal intensity from the optical axis direction is the strongest, the maximum direction of the received intensity of the reflected wave is detected as the optical axis direction of the antenna device. Then, the amount of deviation between the optical axis and the reference axis is calculated from the optical axis direction obtained from the received signal intensity and the reference axis direction obtained from the minimum distance.

  (5) Further, according to the optical axis adjustment method of the radar apparatus of the present invention, the radar apparatus detects a change in Doppler speed of the reflecting object with respect to the antenna apparatus from the transmitted wave and the received wave, and the absolute value of the detected Doppler speed is detected. It is characterized in that a process of matching the position of the reflecting object corresponding to the minimum value of the value and the position of the reflecting object corresponding to the maximum value of the reception intensity of the reflected wave is performed.

  In this method, utilizing the fact that the received signal intensity from the optical axis direction is the strongest, the maximum direction of the received intensity of the reflected wave is detected as the optical axis direction of the antenna device. Then, the amount of deviation between the optical axis and the reference axis is calculated from the optical axis direction obtained from the received signal intensity and the reference axis direction obtained from the minimum value (“0”) of the absolute value of the Doppler velocity.

  (6) According to the optical axis adjustment method of the radar apparatus of the present invention, a transmission wave obtained by beam scanning is transmitted from the antenna apparatus, and the reflecting object is placed in a plane parallel to a plane including the scanning axis and the optical axis of the beam scanning. The optical axis is adjusted in a direction parallel to a plane including the scanning axis and the optical axis.

  In this method, a reflection object is moved in parallel with a plane including a scanning axis and an optical axis of a beam with respect to a radar apparatus that performs beam scanning of a transmission wave with an antenna apparatus. Thereby, the position and position change of the reflecting object along the beam scanning axis, that is, the distance from the antenna device to the reflecting object and the Doppler velocity of the reflecting object with respect to the antenna device are detected by each transmission wave beam.

  (7) According to the optical axis adjustment method of the radar apparatus of the present invention, a transmission wave obtained by beam scanning from the antenna apparatus is transmitted, and the reflecting object is reflected in a plane perpendicular to the plane including the scanning axis and the optical axis of the beam scanning. The optical axis is adjusted in a direction perpendicular to a plane including the scanning axis and the optical axis.

  In this method, a reflection object is moved perpendicularly to a plane including a beam scanning axis and an optical axis for a radar apparatus that performs beam scanning of a transmission wave with an antenna apparatus. Thereby, the position and position change of the reflecting object along the direction perpendicular to the beam scanning axis, that is, the distance from the antenna device to the reflecting object and the Doppler velocity of the reflecting object with respect to the antenna device are detected by each transmission wave beam.

  (8) According to the optical axis adjustment method of the radar apparatus of the present invention, a transmission wave obtained by beam scanning from the antenna apparatus is transmitted, and is a circumferential surface parallel to a plane including the scanning axis of the beam scanning. The reflective object is moved so that the distance to the reflective object is the shortest on the axis.

  In this method, the distance between the reflecting object and the antenna device greatly changes as the reflecting object moves away from the position on the reference axis, rather than moving the reflecting object along the beam scanning axis.

  (9) Further, according to the optical axis adjustment method of the radar apparatus of the present invention, a plurality of radar apparatuses each provided with an antenna apparatus and parallel to each reference axis are mounted on the mounted body, and the direction in which the reference axes are arranged It is characterized by moving the reflecting object in parallel.

  In this method, since the distance and Doppler velocity of one moving reflecting object are detected by each of the plurality of antenna devices, the reference axis and light are individually detected for each antenna device and simultaneously for all antenna devices. The amount of deviation from the axis is detected.

  According to this invention, since the amount of deviation between the optical axis and the reference axis is detected simply by moving the reflecting object in a predetermined direction, an accurate optical axis can be obtained without using a large-scale measurement system as in the prior art. Can be adjusted at low cost.

  In addition, according to the present invention, since the amount of deviation of the optical axis is detected using items used for normal object detection such as distance and Doppler velocity, it is not necessary to perform a dedicated process for measuring the amount of optical axis deviation. Adjustments can be made in a simple way.

  In addition, according to the present invention, the amount of deviation between the optical axis and the reference axis is detected by calculating the minimum value of the distance and the Doppler velocity and calculating the maximum value of the received intensity and detecting the corresponding direction. Thus, the optical axis can be adjusted.

  In addition, according to the present invention, the distance of the reflecting object in the direction parallel to the beam scanning direction and the Doppler velocity are detected by moving the reflecting object along the beam scanning axis. The optical axis of the direction can be adjusted.

  In addition, according to the present invention, the distance and Doppler velocity of the reflecting object in the direction perpendicular to the beam scanning direction can be detected by moving the reflecting object along the direction perpendicular to the beam scanning axis. Even in the direction perpendicular to the axis, it is possible to adjust the optical axis by detecting the amount of deviation between the optical axis and the reference axis.

  Further, according to the present invention, by moving the object circumferentially on the plane including the beam scanning axis, the distance difference and the Doppler speed difference between the positions of different reflecting objects are increased, and the more accurate and compact size is achieved. The amount of deviation between the optical axis and the reference axis can be detected by the system.

  In addition, according to the present invention, it is possible to simultaneously detect the amount of deviation between the optical axis and the reference axis with a plurality of radar devices each including an antenna device. Thereby, the optical axis can be adjusted simultaneously by a plurality of radar apparatuses.

An optical axis adjustment method for a radar apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view showing the relationship between each device and an object used in the optical axis adjustment method of the radar device according to the present embodiment. In the present embodiment, the reference axis of the radar apparatus and the reference axis of the vehicle body that is the mounted body are matched, and the reference axis of the radar apparatus and the optical axis of the antenna apparatus are shifted (not matched). ) Indicates the case. In this embodiment, an FM-CW radar device will be described as an example of the radar device.
In the vicinity of the front end portion of the vehicle body 11, the vehicle body 11 and the radar apparatus 10 are installed so that the reference axis 101 coincides. Near the front end of the radar apparatus 10, an antenna apparatus that transmits a continuous wave subjected to frequency modulation to a detection area in front of the vehicle body 11 and receives a reflected wave from the reflective object 1 existing in the detection area. 20 is installed.

  The antenna device 20 is provided with a transmission antenna 22 that transmits a continuous wave to the detection area and a plurality of reception antennas 21A to 21N that receive reflected waves from the detection area. The receiving antennas 21 </ b> A to 21 </ b> N are linearly arranged in a direction perpendicular to the front direction of the antenna device 20 and substantially parallel to the vehicle width direction of the vehicle body 11. Received signals based on the reflected waves acquired by the receiving antennas 21 </ b> A to 21 </ b> N are given to the radar device 20. The radar apparatus 20 performs predetermined phase difference processing on the reception signals of the reception antennas 21A to 21N, thereby forming reception beams 31A to 31I having directional central axes in different directions. The radar apparatus 20 generates a beat signal for each beam using the reception beams 31A to 31I and the transmission signal, and detects the distance to the reflecting object 1 in the detection region and the Doppler velocity.

  The directivity central axes of the reception beams 31A to 31I are set in a fan shape at equal angular intervals according to the design with respect to the antenna device 20, and the central axis of the fan beam region formed by the reception beams 31A to 31I is the antenna. It becomes the optical axis 201 of the apparatus 20. A direction perpendicular to the optical axis 201 and parallel to the chord of the fan-shaped beam region is a beam scanning axis 301.

  The reflecting object 1 is formed of a metal ball, a metal plate, a corner reflector, or the like, and is perpendicular to the reference axis 101 and a beam scanning axis 301 at a position (for example, about 5 m) away from the antenna device 20 in front of the vehicle body 11 by a predetermined distance. A movement axis 100 is moved as an axis substantially parallel to the axis. At this time, the reflecting object 1 moves so as to pass perpendicularly to the reference axis 101 at least at the intersection of the reference axis 101 and the movement axis 100. The mechanism for moving the reflecting object 1 includes a mechanism for transporting the reflecting object 1 using rails and guides, a mechanism for transporting it by a belt conveyor, and the like.

Next, a method for detecting the deviation angle θ in such a situation will be described with reference to the drawings.
FIG. 2A is a diagram showing the relationship between the position of the reflecting object 1 on the moving shaft 100 and the distance from the antenna device 20 to the reflecting object 1, and FIG. 2B is a diagram showing the relationship between FIG. 6 is a diagram showing a relationship between the azimuth angle of the reflecting object 1 corresponding to the distance from the antenna device 20 to the reflecting object 1. FIG. In FIG. 2, a solid line indicates a case where the reference axis 101 and the optical axis 201 coincide with each other, and a broken line indicates a case where the reference axis 101 and the optical axis 201 are shifted by a deviation angle θ. 2A, the intersection of the reference axis 101 and the movement axis 100 is set as the origin on the movement axis 100, and in FIG. 2B, the intersection direction of the reference axis 101 and the movement axis 100 is set. The azimuth angle is set to 0 °. Further, this result shows an example in which the reflecting object 1 is installed so that the reflecting object 1 passes through the antenna apparatus 20 at a position of 5 m on the reference axis 101.

  When the reflecting object 1 is moved along the moving axis 100, the distance between the antenna device 20 and the reflecting object 1 becomes shorter as the reflecting object 1 is closer to the reference axis 101. For this reason, the reflection object distance becomes minimum at the position of the intersection of the movement axis 100 and the reference axis 101. Therefore, if the reference axis 101 and the optical axis 201 coincide with each other, as shown by the solid line in FIG. 2A, the reflecting object distance becomes minimum at the origin position on the moving axis 100, and the direction corresponding to this. Is the position in the direction of the reference axis 101.

  However, if the reference axis 101 and the optical axis 201 do not coincide with each other, the reflecting object distance is minimized at a position other than the origin on the moving axis 100 according to the deviation angle θ. For example, as shown by a broken line in FIG. 2A, the reflection object distance becomes minimum at a position of about +0.2 m (upward direction in FIG. 1) on the movement axis. Therefore, the intersection of the reference axis 101 and the movement axis 100 is a position of about +0.2 m on the movement axis 100 when the optical axis 201 is the reference (origin direction). Position.

  As a result, it can be detected that the optical axis 201 and the reference axis 101 are shifted by about 0.2 m at a position 5 m from the antenna device 20. The shift amount L on the moving axis in such a situation can be converted into the azimuth angle θ from the antenna device 20 by the following equation.

θ = arctan (L / 5)
For example, if the deviation is 0.2 m as described above, the azimuth angle θ is
θ = arctan (0.2 / 5) ≈2.26 °
It becomes. This is exactly the deviation angle between the reference axis 101 of the radar apparatus 10 and the optical axis 201 of the antenna apparatus 20. By performing such calculation processing, the result relating to the deviation amount shown in FIG. 2A is converted into the result relating to the deviation angle shown in FIG.

  Based on the deviation angle θ between the reference axis 101 and the optical axis 201 calculated in this way, the radar apparatus 20 matches the center direction of the optical axis 201, that is, the reception beam region formed by all the reception beams, with the reference axis 101. Shift processing is performed. For example, in the case of FIGS. 1 and 2, the optical axis 201 is shifted to −2.26 ° (upward direction in FIG. 1). Specifically, an object azimuth detection process is performed after adding an offset amount corresponding to the shift amount to each reception beam signal including reception signals acquired by the antennas 21A to 21N.

  By performing such processing, the optical axis correction can be performed by easily matching the reference axis 101 and the optical axis 201 of the radar apparatus 10 without using a large-scale measurement system. Since the reference axis 101 and the optical axis 102 coincide with each other, the orientation of the object can be accurately detected.

  Further, by using a reflecting object that moves as in the present invention, it is easy to distinguish from a surrounding stationary body, so that a large-scale facility for measurement is not required.

  In the above description, the minimum value is calculated from the continuous measurement results. However, the minimum value may be calculated by approximately calculating a quadratic curve from the measurement results.

  More specifically, since the measurement results are obtained discretely, an even function such as a quadratic curve is approximately calculated from these measurement results, and the minimum value of the even function is calculated. By calculating the minimum value using such an approximate function, it is possible to calculate the minimum value with higher accuracy than when the measurement result is used as it is, and thus to adjust the optical axis with higher accuracy. . Furthermore, by extracting the measurement results of two points that are approximately the same distance across the calculated minimum value, calculating each angle, and by taking the average (center) of these two measurement results as the angle of the minimum point, The influence of noise can be removed, and the deviation angle can be detected with higher accuracy.

  FIG. 3 is a diagram illustrating the relationship between the detection direction (the direction based on the optical axis 201) and the reflection object direction (the direction based on the reference axis 101) when only the measurement result is used and when the approximation process is performed. In FIG. 3, the broken line represents the approximation result, the thin solid line represents the measurement result, and the axis of the detection direction corresponds to the reference axis 101. As shown in FIG. 3, in the method using only the measurement result, the measurement value at the intersection of the reference axis 101 and the moving axis 100 is set as it is regardless of the measurement value of the other position, but the approximation is approximated. By doing so, the amount of deviation at the intersection is calculated from a plurality of measured values including the measured value at the other position. Thereby, since the influence of the error by measurement can be reduced, the minimum value can be calculated with higher accuracy.

  In the above description, an example in which the reflecting object 1 is moved along the movement axis 100 using a rail, a belt conveyor, or the like has been described. However, in the present embodiment, it is not necessary to move the reflecting object 1 continuously. The reflecting objects 1 may be discretely arranged and moved at predetermined intervals along the axis 100. In this case, although a continuous curve as shown in FIG. 2 cannot be obtained, a minimum value may be calculated by calculating a quadratic curve approximately from the measurement result.

  In the above description, the case where the reflecting object 1 is moved in one direction along the movement axis 100 has been shown. However, measurement is performed a plurality of times, such as reciprocating on the movement axis 100, and the measurement result is obtained. By averaging, the minimum value can be calculated with higher accuracy. Furthermore, if the minimum value is calculated by calculating a quadratic function approximately from the results obtained by the multiple measurements, the influence of errors due to the measurement can be further reduced, so the minimum value can be obtained with higher accuracy. Can be calculated.

  In the above description, the method of correcting the deviation between the reference axis and the optical axis by the signal processing of the radar apparatus has been described. However, the radar installation worker mechanically rotates the antenna apparatus according to the calculated deviation amount. It may be moved to correct the optical axis.

  In the above description, the example in which the moving axis 100 of the reflecting object 1 and the reference axis 101 are spatially orthogonal is shown. However, as shown in FIG. 4, the reflecting object 1 is orthogonal to each other in a plan view. May be moved. FIG. 4 is a conceptual diagram when the moving axis 100 and the reference axis 101 are not spatially orthogonal. As described above, the movement axis 100 and the reference axis 101 may be offset by a predetermined amount (yoff) in a direction perpendicular to both at a position where the movement axis 100 and the reference axis 101 intersect in a plane. That is, the reflective object 1 may pass through a position away from the reference axis 101 by a predetermined distance at a position where the movement axis 100 and the reference axis 101 intersect in a plane.

Next, an optical axis adjustment method of the radar apparatus according to the second embodiment will be described with reference to the drawings. This embodiment has the same configuration as that of the first embodiment, but uses a Doppler velocity as a measurement amount.
FIG. 5 is a diagram showing the relationship between the position of the reflecting object 1 on the moving shaft 100 and the Doppler speed of the reflecting object 1 with respect to the antenna device 20. In FIG. 5, a solid line indicates a case where the reference axis 101 and the optical axis 201 coincide with each other, and a broken line indicates a case where the reference axis 101 and the optical axis 201 are shifted by a predetermined angle θ in the scanning axis direction. This result shows an example in which the reflecting object 1 moves at a speed of 10 km / h at a position of 5 m on the reference axis 101 from the antenna device 20.

  As in the first embodiment, when a continuous wave is transmitted from the transmitting antenna 22 of the antenna device 20 and the reflected waves are received by the receiving antennas 21A to 21N, the radar device 20 generates a beat signal, and the beat signal The Doppler velocity at each measurement position is calculated by a known method. Here, since the reflecting object 1 moves on the moving axis 100 perpendicular to the reference axis 101, the calculated Doppler speed decreases as the reference axis 101 is approached, and becomes “0” on the reference axis 101. Then, the distance from the reference axis 101 increases. For this reason, the position where the calculated Doppler speed is “0” corresponds to the intersection with the reference axis 101 (see the solid line in FIG. 5). If the reference axis 101 and the optical axis 201 do not coincide with each other, the Doppler speed becomes “0” at a predetermined position on the moving axis as shown by a broken line in FIG. Since this point is a point on the original reference axis 101, the amount of deviation of the position on the moving axis is the amount of deviation between the reference axis 101 and the optical axis 201 at a position 5 m from the antenna device 20. Then, the shift angle between the reference axis 101 and the optical axis 201 can be calculated by converting this shift amount into a shift angle using the above-described equation. Thereby, the effect similar to 1st Embodiment can be acquired.

  In this embodiment, the example in which the minimum value is calculated from the continuous measurement results has been described. However, an odd function such as a linear function may be approximately calculated from these measurement results to calculate the zero cross point.

  Also in this embodiment, the measurement may be performed a plurality of times, such as reciprocating on the moving shaft 100 at a constant speed, and the zero cross point may be calculated after averaging the measurement results. A value can be calculated.

  Further, since the Doppler velocities at symmetrical positions with respect to the intersection with the reference axis 101 have the same absolute value and only different signs, the two positions on the moving axis where the Doppler speeds have different signs are determined. The amount of deviation may be calculated from the position obtained by averaging.

  Further, as in the first embodiment, if the reference axis and the movement axis are orthogonal to each other in a plan view, there may be a predetermined offset with respect to the reference axis.

Next, an optical axis adjustment method of the radar apparatus according to the third embodiment will be described with reference to the drawings.
FIG. 6A is a plan view showing the relationship between each device and an object used in the optical axis adjustment method of the radar apparatus according to this embodiment, and FIG. 6B is a side view thereof.
As shown in FIG. 6, in the present embodiment, the moving axis 100 is perpendicular to the reference axis 101 and the optical axis 201 and also perpendicular to the scanning axis 301, and the other configuration is the first configuration. It is the same as FIG. 1 of the embodiment.

  Even in such a process, the reception beam 31 (31A to 31I) has a predetermined beam spread, and therefore the distance and speed of the reflecting object 1 moving in the direction perpendicular to the scanning axis 301 and the optical axis 201 are set. Can be detected. Therefore, as in the case where the scanning axis 301 and the moving axis 101 are substantially parallel (FIGS. 2 and 3), the measurement results of the reflecting object distance and the Doppler velocity can be obtained.

  At this time, the direction in which the received signal intensity from the reflecting object is maximized substantially coincides with the optical axis 201 with respect to the plane including the scanning axis. The direction in which the distance of the reflecting object is minimized, or the direction in which the absolute value of the Doppler velocity is minimized is the direction of the reference axis 101. For this reason, the deviation between the direction in which the received signal intensity is maximized and the direction in which the absolute value of the distance or Doppler velocity is minimized is the deviation amount (deviation angle) of the optical axis.

  FIG. 7 shows the relationship between the received signal intensity and the reflection object distance with respect to the position on the movement axis when the movement axis 100 and the scanning axis 301 are orthogonal to each other and the optical axis 201 and the reference axis 101 do not match. FIG. In FIG. 7, the solid line indicates the reflecting object distance, and the broken line indicates the received signal strength.

  As shown in FIG. 7, the received signal intensity has a maximum value, and the reflection object distance has a minimum value. Since the maximum value of the received signal intensity corresponds to the case where the reflecting object 1 is detected by the reception beam in the direction of the optical axis 201, the maximum value on the moving axis corresponds to the point in time when the position on the movement axis is detected by the reception beam in the direction of the optical axis 201. . On the other hand, the minimum value of the reflecting object distance corresponds to the case where the reflecting object 1 is detected when passing through the reference axis 101, and therefore the position on the moving axis corresponding to the minimum value corresponds to the direction of the reference axis 101. Therefore, if the difference between the position on the moving axis corresponding to the maximum value of the received signal intensity and the position on the moving axis corresponding to the minimum value of the reflection object distance is calculated and the angle is converted, the optical axis 201 and the reference axis 101 are calculated. Can be detected. Then, correction (optical axis adjustment) for matching the optical axis with the reference axis can be performed using the deviation angle. As shown in FIG. 7, when the optical axis 201 and the reference axis 101 do not coincide with each other, the radar installation worker mechanically rotates the antenna device or the radar device according to the deviation angle to adjust the optical axis. Do.

  In this embodiment as well, the deviation angle can be calculated with higher accuracy by using averaging, multiple measurements, and the like as shown in the above embodiments.

  In this embodiment, the beam is not scanned in the direction of the movement axis. Therefore, the method of this embodiment can be applied to a radar apparatus that performs only distance measurement without performing beam scanning. At this time, the beam is not scanned and the distance is measured with the received signal having a certain extent, but the measurement is performed several times for each position on the moving axis, and the received signal strength characteristics and the reflection object distance are measured. If processing such as approximating the characteristics is performed, the error factor due to the spread of the received signal can be reduced, and the amount of deviation can be calculated accurately.

Next, an optical axis adjustment method for a radar apparatus according to the fourth embodiment will be described with reference to the drawings.
FIG. 8A is a plan view showing the relationship between each device and an object used in the optical axis adjustment method of the radar apparatus according to this embodiment, and FIG. 8B is a side view thereof.
The method of adjusting the optical axis of the radar apparatus according to the present embodiment is to move the reflecting object 1 on a moving trajectory 100 ′ composed of a circular trajectory having a circular surface parallel to a plane including the scanning axis 301. At this time, the reflecting object 1 is disposed so as to pass orthogonally to the reference axis 101 at the intersection of the moving track 100 ′ and the reference axis 101. As a result, the distance to the reflecting object 1 on the reference axis 101 is minimized, or the absolute value of the Doppler velocity of the reflecting object 1 is minimized. The reflecting object 1 moves at a predetermined angular velocity along the moving track 100 ′ by rotating the rotating shaft of the mounting device that rotatably supports the reflecting object 1 so as to form the circular orbit. And as this attachment apparatus, the thing which has a rotating arm-like member and the thing which has a disk-shaped member which can mount the reflective object 1 are utilized. The other configuration is the same as the optical axis adjustment method of the radar apparatus shown in the first embodiment.

  As described above, when the reflecting object is moved in a circular orbit, the distance X from the antenna device 20 to the reflecting object 1 and the azimuth φ with respect to the reference axis 101 with respect to the antenna device 20 have a relationship as shown in FIG. .

  FIG. 9 is a conceptual diagram of the distance x and the azimuth φ of the reflecting object 1 in a circular orbit. In FIG. 9, R indicates the distance from the antenna device 20 (radar device 10) to the intersection with the reference axis 101 on the antenna device 20 side on the circular orbit, r indicates the radius of the circular orbit, and ψ indicates the reference axis. The angle of the reflecting object with respect to the center of the circular orbit with reference to the direction of the intersection with 101 is shown.

  In such a case, the distance x and the azimuth θ of the reflecting object 1 can be expressed by the following equations, respectively.

x = SQRT {(R + r) ² + r ² −2 · (R + r) · r · cos ψ}
φ = arcsin (r · sinψ / x)
Based on this, when the distance x with respect to the angle ψ of the reflecting object 1 in the case of R = 5 (m) and r = 0.2 (m) is calculated, the relationship of FIG. 10 is obtained.

  FIG. 10 shows a relational expression between the azimuth φ of the reflecting object 1 and the distance x.

  As described above, since the amount of change in the distance x can be obtained with a small change in angle (orientation) by rotating the reflecting object 1, the reflecting object 1 is moved linearly as in the first embodiment. Rather, the amount of change in distance due to the deviation angle between the optical axis 201 and the reference axis 101 can be increased. Thereby, it is possible to detect the deviation angle with high accuracy with a small configuration.

  At this time, the Doppler velocity Vdop of the reflecting object 1 can be calculated and used separately from the distance x.

  FIG. 11 is a conceptual diagram of the Doppler velocity Vdop and the direction φ of the reflecting object 1. In addition, the same code | symbol is attached | subjected to the same element as FIG. 9, and description is abbreviate | omitted.

  In such a case, the Doppler velocity Vdop of the reflecting object 1 can be expressed by the following equation when the angular velocity is ω.

Vdop = ω · r · cos (π / 2−ψ−φ)
Based on this, the relationship of FIG. 12 is obtained by calculating the Doppler velocity Vdop with respect to the direction φ of the reflecting object 1 in the case of R = 5 (m), r = 0.2 (m), and ω = 2π (rad / s). It is done.

FIG. 12 shows a relational expression between the azimuth φ of the reflecting object 1 and the Doppler velocity Vdop.
Thus, by rotating the reflecting object 1, a large change amount of the Doppler velocity Vdop can be obtained with a small change in angle (orientation). Therefore, the reflecting object 1 is linearly formed as in the second embodiment described above. The amount of change in the Doppler speed due to the deviation angle between the optical axis 201 and the reference axis 101 can be made larger than the movement. Thereby, it is possible to detect the deviation angle with high accuracy with a small configuration.

Next, an optical axis adjustment method for a radar apparatus according to the fifth embodiment will be described with reference to the drawings.
FIG. 13 is a conceptual diagram of an optical axis adjustment method for a plurality of radar apparatuses according to this embodiment.
FIG. 14 is a conceptual diagram when a plurality of radar devices are mounted on one vehicle body and the optical axes of these radar devices are adjusted.

  In the first embodiment described above, the case where one radar device (antenna device) is mounted on the vehicle body has been described. However, in the present embodiment, the number of radar devices (number of antenna devices) is set to be a plurality of values. The optical axis of the radar apparatus (antenna apparatus) shown in the embodiment is adjusted.

  As shown in FIG. 13, when adjusting the optical axes 201A to 201E of the antenna apparatus with respect to the plurality of radar apparatuses 10A to 10E, all the radar apparatuses 10A to 10A to be parallel so that the reference axes 101 of all the apparatuses are parallel. 10E is placed. Then, the moving axis 100 is set parallel to the arrangement direction of the radar apparatuses 10A to 10E, and the reflecting object 1 is moved so as to pass through the reception beam areas of all the radar apparatuses 10A to 10E.

  With such a configuration, each of the radar devices 10A to 10E corresponds to the radar device 10 of the first embodiment. Therefore, in each of the radar devices 10A to 10E, the deviation angle correction of the first embodiment is performed. If processing is performed, the optical axes of all the radar apparatuses 10A to 10E can be adjusted simultaneously.

  As shown in FIG. 14, when the radar devices 10 </ b> B to 10 </ b> D are installed on the front surface of the vehicle body 11 and the radar devices 10 </ b> A and 10 </ b> E are installed on the side surfaces, the front direction of the vehicle body 11 is set to the reference axis 101 direction. . Furthermore, a direction parallel to the width direction of the vehicle body 11 and perpendicular to the reference axis 101 is set as the movement axis 100. If the reflecting object 1 is moved along the movement axis 100, the optical axes of the radar apparatuses 10A to 10E can be adjusted simultaneously.

  In each of the above-described embodiments, the case where the optical axis of the antenna device is made to coincide with the reference axis of the radar device and the mounted body is shown. However, the antenna device and the radar device are fixed, and the radar device and the mounted body are fixed. Can be corrected, the processing may be performed so that the optical axis of the radar apparatus matches the reference axis of the mounted body.

It is a top view which shows the relationship between each apparatus used for the optical axis adjustment method of the radar apparatus which concerns on 1st Embodiment, and an object. The figure which showed the relationship between the position of the reflective object 1 on the movement axis 100, and the distance from the antenna apparatus 20 to the reflective object 1, The relationship between the azimuth of the reflective object 1 and the distance from the antenna apparatus 20 to the reflective object 1 FIG. It is the figure which showed the relationship between the detection azimuth | direction (direction based on the optical axis 201) and the reflective object azimuth | direction (direction based on the reference axis 101) in the case of only a measurement result, and the case where an approximation process is performed. It is a conceptual diagram in case the moving axis 100 and the reference axis 101 are not spatially orthogonal. It is the figure which showed the relationship between the position of the reflective object 1 on the moving shaft 100 which concerns on 2nd Embodiment, and the Doppler speed of the reflective object 1 with respect to the antenna apparatus 20. FIG. It is the top view and side view which show the relationship between each apparatus and object which are used for the optical axis adjustment method of the radar apparatus which concerns on 3rd Embodiment. FIG. 6 is a diagram illustrating a relationship between a received signal intensity and a reflection object distance with respect to a position on the movement axis when the movement axis 100 and the scanning axis 301 are orthogonal to each other and the optical axis 201 and the reference axis 101 do not coincide with each other. It is the top view and side view which show the relationship between each apparatus and object which are used for the optical axis adjustment method of the radar apparatus which concerns on 4th Embodiment. It is a conceptual diagram of distance x and azimuth | direction (phi) of the reflective object 1 of a circular orbit. A relational expression between the azimuth φ of the reflecting object 1 and the distance x is shown. It is a conceptual diagram of the Doppler velocity Vdop and the direction φ of the reflective object 1. The relational expression between the azimuth φ of the reflecting object 1 and the Doppler velocity Vdop is shown. It is a conceptual diagram of the optical axis adjustment method of the some radar apparatus which concerns on 5th Embodiment. It is a conceptual diagram in the case of mounting a plurality of radar devices on one vehicle body and adjusting the optical axes of these radar devices.

Explanation of symbols

1-reflective object, 10, 10A-10E-radar apparatus, 20-antenna apparatus, 21,21A-21N-receiving antenna, 22-transmitting antenna, 31, 31A-31I-receiving beam,
100-movement axis, 100'-movement trajectory, 101-reference axis, 201, 201A to 201E-optical axis, 301-scanning axis

Claims (9)

A method of adjusting an optical axis of a radar apparatus that matches an optical axis of a radar apparatus having a predetermined reference axis with respect to a detection region or an antenna apparatus provided on a mounted object on which the radar apparatus is mounted, to the reference axis. And
Moving the reflecting object in a trajectory that passes perpendicularly to the reference axis at a point at a predetermined distance from the antenna device on the reference axis;
The antenna device transmits a transmission wave in the moving area of the reflective object, and receives a reflected wave of the reflective object with respect to the transmission wave,
Detecting the amount of deviation between the optical axis and the reference axis based on the change over time of the detection result of the reflective object obtained by the radar device;
An optical axis adjustment method for a radar device.   In the radar device, a change in distance from the antenna device to a reflecting object is detected from the transmission wave and the reflected wave, and a minimum value of the distance in the detected distance change is obtained in the radar device. The method of adjusting an optical axis of a radar apparatus according to claim 1, wherein the deviation amount is detected based on an angle detection result.   The radar device detects a change in Doppler velocity of a reflecting object with respect to the antenna device from the transmission wave and the reflected wave and obtains a minimum value of the absolute value of the detected Doppler velocity. The method of adjusting an optical axis of a radar apparatus according to claim 1, wherein the amount of deviation is detected based on a result of angle detection.   The radar device detects a change in the distance from the antenna device to the reflective object from the transmission wave and the received wave, and the position of the reflective object corresponding to the minimum value of the distance in the detected distance change; The method of adjusting an optical axis of a radar apparatus according to claim 1, wherein processing for matching the position of the reflecting object corresponding to the maximum value of the reception intensity of the reflected wave is performed.   The radar device detects a change in Doppler velocity of the reflecting object with respect to the antenna device from the transmission wave and the received wave, and the position of the reflecting object corresponding to a minimum value of the absolute value of the detected Doppler velocity. The method of adjusting an optical axis of a radar apparatus according to claim 1, wherein a process of matching the position of the reflection object corresponding to the maximum value of the reception intensity of the reflected wave is performed. Transmitting a beam scanning beam from the antenna device,
The optical axis is adjusted in a direction parallel to a plane including the scanning axis and the optical axis by moving the reflecting object in a plane parallel to a plane including the scanning axis of the beam scanning and the optical axis. The optical axis adjustment method of the radar apparatus in any one of 1-5. Transmitting a beam scanning beam from the antenna device,
The optical axis is adjusted in a direction perpendicular to a plane including the scanning axis and the optical axis by moving the reflecting object in a plane perpendicular to a plane including the scanning axis of the beam scanning and the optical axis. The method of adjusting an optical axis of a radar device according to claim 4 or 5. Transmitting a beam scanning beam from the antenna device,
The radar apparatus according to any one of claims 1 to 7, wherein the reflecting object is moved so as to have a shortest distance on a reference axis along a circumferential surface parallel to a plane including a scanning axis of the beam scanning. Optical axis adjustment method. Each is equipped with an antenna device, and a plurality of radar devices each having a parallel reference axis are mounted on the mounted body,
The method of adjusting an optical axis of a radar apparatus according to claim 1, wherein the reflecting object is moved in parallel with a direction in which the reference axes are arranged.

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