JP2001228238A - Device and method for modifying bearing axis of electromagnetic waves, radar device, its bearing axis modifying method, and radome for radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To modify the bearing axis of electromagnetic waves. SOLUTION: An inclination θ is formed in the surface 22 and back surface 24 of a radome 20 which functions as a cover for a transmitting antenna 14a to transmit millimeter waves as electromagnetic waves and a receiving antenna 14b to receive reflected waves. As the refractive index of air is different from that of the radome 20, it is possible to refract millimeter waves by the Snell's law. By previously forming a plurality of radomes 20 with different inclinations θin the surfaces 22 and back surfaces 24 and selecting one radome 20 from among the plurality of radomes 20 according to the inclination of the bearing axis of millimeter waves, the bearing axis of millimeter waves is modified. Only by replacing the radome 20, it is possible to modify the bearing axis of millimeter waves and to prevent the increase of the number of components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave azimuth axis correcting device, an azimuth axis correcting method, a radar device, an azimuth axis correcting method thereof, and a radome for a radar device. The present invention relates to an azimuth axis correcting device and an azimuth axis correcting method for correcting an axis, a radar apparatus having an antenna for transmitting and receiving an electromagnetic wave, a azimuth axis correcting method thereof, and a radome functioning as an antenna cover of the radar apparatus.

[0002]

2. Description of the Related Art Conventionally, as this type of radar device, there has been proposed a radar device which transmits a millimeter wave from an antenna and receives a reflected millimeter wave to recognize a situation in a transmission direction. It has been proposed that such a radar device be mounted on a vehicle in order to reduce the burden on the driver.

[0003]

In such a radar device, it is extremely important for the radar function that the azimuth axis of the millimeter wave transmitted and received by the antenna is accurate. This is because an obstacle or the like recognized as having an incorrect azimuth axis exists in a direction different from the actual direction, or the detected distance differs from the actual distance.

An object of the azimuth axis correcting device and the azimuth axis correcting method for an electromagnetic wave and the radar device and the azimuth axis correcting method of the present invention are to correct the azimuth axis of the electromagnetic wave. Another object of the present invention is to correct the azimuth axis of the electromagnetic wave with a simple configuration.
An object of the radome for a radar device of the present invention is to correct an azimuth axis of an electromagnetic wave and to prevent damage to an antenna.

[0005]

SUMMARY OF THE INVENTION The azimuth axis correcting device and the azimuth axis correcting method for an electromagnetic wave, the radar device, the azimuth axis correcting method thereof, and the radome for the radar device according to the present invention have at least the above objects. The following measures were taken to achieve some.

An azimuth axis correction method for an electromagnetic wave according to the present invention is an azimuth axis correction apparatus for an electromagnetic wave for correcting an azimuth axis of an electromagnetic wave transmitted and received by an antenna, which is installed near the antenna and refracts the electromagnetic wave. The gist of the invention is to provide refraction means for correcting the azimuth axis.

In the electromagnetic wave azimuth axis correcting device of the present invention, the azimuth axis of the electromagnetic wave can be corrected by the refraction means provided near the antenna refracting the electromagnetic wave.

In the electromagnetic wave azimuth axis correcting device of the present invention, the refraction means may be formed of a material having a refractive index different from that of the atmosphere. In the electromagnetic wave azimuth axis correcting device according to the aspect of the present invention, the refraction means may be a plate member formed such that an incident surface and an emission surface of the electromagnetic wave form a predetermined angle.

Further, in the electromagnetic wave azimuth axis correcting apparatus according to the present invention, the refracting means may be a cover covered by the antenna. This makes it possible to correct the azimuth axis of the electromagnetic wave and prevent damage to the antenna.

The gist of the radar apparatus of the present invention is to include an antenna for transmitting and receiving an electromagnetic wave, and the above-described electromagnetic wave azimuth axis correcting apparatus of the present invention including each aspect.

In the radar device according to the present invention, since the azimuth axis correcting device for the electromagnetic wave corrects the azimuth axis of the electromagnetic wave, it is possible to detect a more accurate direction and distance to the radar object.

In the radar device of the present invention, the electromagnetic wave is a millimeter wave, and may be mounted on a vehicle. In this way, the burden on the driver can be reduced.

A radome for a radar apparatus according to the present invention is a radome functioning as a cover of the antenna in a radar apparatus having an antenna for transmitting and receiving an electromagnetic wave, wherein an incident surface and an emission surface of the electromagnetic wave form a predetermined angle. The gist of the present invention is as follows.

The radome for the radar apparatus according to the present invention comprises:
Since the incident surface and the emission surface of the electromagnetic wave are formed at a predetermined angle, the azimuth axis of the electromagnetic wave is changed by refracting the electromagnetic wave. Therefore, by adjusting the predetermined angle, the azimuth axis of the electromagnetic wave can be adjusted, and a more accurate azimuth axis can be obtained.

An azimuth axis correcting method for an electromagnetic wave according to the present invention is a method for correcting an azimuth axis of an electromagnetic wave transmitted and received by an antenna, wherein the azimuth axis of the electromagnetic wave is refracted by using a member having a refractive index different from that of the atmosphere. The point is to correct the azimuth axis.

According to the azimuth axis correction method of the present invention, the azimuth axis of the electromagnetic wave can be corrected by refracting the electromagnetic wave using a member having a refractive index different from that of the atmosphere.

The azimuth axis correcting method of the radar apparatus according to the present invention is as follows.
An azimuth axis correction method for a radar apparatus having an antenna for transmitting and receiving an electromagnetic wave, the azimuth axis of the radar apparatus correcting the azimuth axis of the electromagnetic wave, wherein the material has a refractive index different from that of the atmosphere and the electromagnetic wave is refracted at different refraction angles. Forming a refraction member in advance, selecting the plurality of refraction members based on an angle between the azimuth axis of the electromagnetic wave and a desired azimuth axis, and arranging the selected refraction member near the antenna so that the azimuth of the electromagnetic wave The gist is to modify the axis.

In the azimuth axis correcting method of the radar apparatus according to the present invention, the position axis can be corrected by using a refraction member having the most appropriate azimuth axis of the electromagnetic wave among the plurality of refraction members. That is, a refraction member having a different refraction angle may be prepared based on a manufacturing error and an allowable range, and correction may be performed using any of the refraction members.

In the azimuth axis correcting method for a radar apparatus according to the present invention, the plurality of refracting members are a plurality of plate members formed so that angles formed between the incident surface and the emission surface of the electromagnetic wave are different. It can be.

In the azimuth axis correcting method for a radar apparatus according to the present invention, the plurality of refraction members may be a plurality of plate members formed of materials having different refractive indexes.

Further, in the azimuth axis correcting method for a radar apparatus according to the present invention, the plurality of refracting members may be formed as a plurality of radomes functioning as a cover of the antenna. This makes it possible to correct the azimuth axis of the electromagnetic wave and prevent damage to the antenna. Moreover, the number of parts of the radar device does not increase.

[0022]

Next, embodiments of the present invention will be described with reference to examples. FIG. 1 shows a radome 20 used in an in-vehicle millimeter-wave radar device 10 according to one embodiment of the present invention.
FIG. 2 is an explanatory diagram for explaining how the azimuth axis of the millimeter wave is corrected by FIG.
FIG. 3 is an external view of the radome 20 of FIG. 2 viewed from the direction of the arrow (left direction).

As shown in FIGS. 1 and 2, a millimeter-wave radar device 10 according to an embodiment includes a high-frequency circuit section 12 having an oscillation element that oscillates at a predetermined frequency,
Antenna 14a that receives power from the transmitter and transmits millimeter waves
And a receiving antenna 14b for receiving the reflected wave, a signal processing unit 16 for processing the reflected wave received by the receiving antenna 14b, a cover for the transmitting antenna 14a and the receiving antenna 14b, and a millimeter wave. And a radome 20 for correcting the azimuth axis.

The radome 20 is formed of a resin (for example, polypropylene or the like) and has a rectangular front cover as an external appearance. As shown in FIG.
The back surface 24, which is the exit surface, is formed so as to have an inclination of the angle θ with respect to the front surface 22, which is the entrance surface of the reflected wave received at the point. The radome 20 has an angle θ between the front surface 22 and the rear surface 24.
, The millimeter wave transmitted from the transmitting antenna 14a and the reflected wave received by the receiving antenna 14b are refracted to correct the azimuth axis.

FIG. 4 is an explanatory diagram showing how an electromagnetic wave traveling in a medium having a different refractive index refracts. The refractive index of the air is n1, the refractive index of the radome 20 is n2, and the angle of the traveling direction of the electromagnetic wave in the air with respect to the perpendicular to the back surface 24 is Φ1,
Assuming that the angle of the traveling direction of the electromagnetic wave in the radome 20 with respect to the perpendicular of the back surface 24 is Φ2, the following expression (1) is established by Snell's law.

N1 sinΦ1 = n2 sinΦ2 (1)

The angle between the front surface 22 and the rear surface 24 is θ, and the angle between the traveling direction of the electromagnetic wave and the front surface 22 of the radome 20 is a right angle, so that θ = Φ2. Therefore,
The angle Φ1 can be adjusted by adjusting the angle θ between the front surface 22 and the rear surface 24 of the radome 20. For example, when the refractive index n2 of the radome 20 is 1.67 and the angle θ between the front surface 22 and the back surface 24 is 3 degrees, the angle Φ1 is about 2 degrees. The transmitted millimeter wave is refracted on the back surface 24 of the radome 20 and travels perpendicularly from the front surface 22, and the azimuth axis of the millimeter wave is corrected.

Next, how the azimuth axis of the millimeter wave is corrected by the millimeter wave radar device 10 of the embodiment will be described. FIG.
4 is a process diagram illustrating a process of correcting the azimuth axis of the millimeter wave in the millimeter wave radar device 10. FIG. The correction of the azimuth axis of the millimeter wave in the millimeter wave radar device 10 is performed first from the assembly of the millimeter wave radar (step S10). That is,
The antenna unit 14 and the signal processing unit 16 are assembled to the high-frequency circuit unit 12. Then, the surface 2 is
The basic radome 20 having no inclination is attached to the second and back surfaces 24 (Step S12), and the inclination of the azimuth axis of the millimeter wave is measured (Step S14). Next, the radome 20 which forms the angle θ at which the inclination of the measured azimuth axis of the millimeter wave can be corrected is selected (step S16), and the radome 20 for correcting the azimuth axis is attached (step S18). Complete.

Here, in the embodiment, as illustrated in FIG. 5, a plurality of radomes 20, 20a to 20d having different angles θ between the front surface 22 and the back surface 24 are formed, and the azimuth axis of the millimeter wave is formed. The azimuth axis correcting radomes 20a to 20d capable of correcting the inclination within an allowable range are selected. Assuming that the refractive index n2 of the radome 20 is 1.67 as described above, for example, as shown in the following Table 1, the radome 20 used for the inclination of the azimuth axis of the millimeter wave, and the azimuth axis correcting radome 20a to 20a.
20d can be uniquely determined. In this example, the allowable range is ± 0.5 degrees.

[0030]

[Table 1]

The millimeter wave radar device 1 of the embodiment described above
According to 0, the azimuth axis of the millimeter wave can be corrected by providing an inclination between the front surface 22 and the rear surface 24 of the radome 20. Moreover, a plurality of azimuth axis correcting radomes 20a to 20d having different angles θ between the front surface 22 and the back surface 24 in advance.
Is formed, the azimuth axis of the millimeter wave can be corrected only by replacing the radome 20 with any of the azimuth axis correcting radomes 20a to 20d. Also, since the radome 20 functioning as the cover of the antenna unit 14 has a function for correcting the azimuth axis of the millimeter wave, the azimuth axis of the millimeter wave can be corrected without increasing the number of components of the millimeter wave radar device 10. It is possible to prevent the transmission antenna 14a and the reception antenna 14b from being damaged.

In the millimeter wave radar apparatus 10 of the embodiment, the azimuth axis of the millimeter wave is corrected. However, since Snell's law of the equation (1) holds for general electromagnetic waves, radar using electromagnetic waves other than millimeter waves is used. The present invention can also be applied to the case where the azimuth axis of the device is corrected. In addition, the present invention can be applied to a case where the azimuth axis of an electromagnetic wave in a device other than the radar device, for example, an electromagnetic wave transmitting device, or the direction of an electromagnetic wave in an electromagnetic wave receiving device is corrected.

In the millimeter wave radar apparatus 10 of the embodiment, four azimuth axis correcting radomes 20a to 20d are formed in addition to the radome 20 with an allowable range of ± 0.5 degrees. The type of the correction radome may be any number, and the allowable range may be any number of times.

In the millimeter-wave radar device 10 of the embodiment, the azimuth axis of the millimeter wave is corrected by providing an inclination to the front surface 22 and the rear surface 24 of the radome 20, but a plate having an inclination to the front surface and the rear surface is formed. The azimuth axis of the millimeter wave may be modified by being attached inside or outside the radome. In this case, a plurality of plate members having different angles between the front surface and the back surface may be formed, and the plate material may be selected according to the inclination of the azimuth axis of the millimeter wave.

In the millimeter-wave radar device 10 of the embodiment, the azimuth axis of the millimeter wave is corrected by inclining the front surface 22 and the rear surface 24 of the radome 20 formed of the same material. A plurality of radomes may be formed to correct the azimuth axis of the millimeter wave. In this case, the inclination of the front surface and the rear surface of each radome may be the same or different.

In the millimeter wave radar apparatus 10 of the embodiment, the radome 20 refracts the millimeter wave once to correct the azimuth axis. However, a member for correcting a plurality of azimuth axes is attached and refracted a plurality of times. The azimuth axis of the millimeter wave may be corrected.

Although the millimeter wave radar device 10 of the embodiment has been described as being mounted on a vehicle, it is needless to say that the present invention can be applied to a millimeter wave radar device not mounted on a vehicle or a radar device using electromagnetic waves other than the millimeter wave.

The embodiments of the present invention have been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various embodiments may be made without departing from the scope of the present invention. Of course, it can be carried out.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a state in which an azimuth axis of a millimeter wave is corrected by a radome 20 used in an on-vehicle millimeter wave radar device 10 according to an embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating an outline of a configuration of an on-vehicle millimeter-wave radar 10 according to the embodiment.

FIG. 3 is an external view of the radome 20 of FIG. 2 viewed from a direction of an arrow (left direction).

FIG. 4 is an explanatory diagram showing a state of refraction of an electromagnetic wave traveling in a medium having a different refractive index.

FIG. 5 is a process diagram illustrating a process of correcting the azimuth axis of the millimeter wave in the millimeter wave radar device 10.

FIG. 6 is an azimuth axis correcting radome 20, 20a to 20d.
It is explanatory drawing which illustrates.

[Explanation of symbols]

10 millimeter wave radar device, 12 high frequency circuit section, 14
Antenna unit, 14a transmitting antenna, 14b receiving antenna, 16 signal processing unit, 20 radome, 20a to 20
d Azimuth axis correction radome, 22 front, 24 back.

Claims (12)

[Claims] 1. An electromagnetic wave azimuth axis correction device for correcting an azimuth axis of an electromagnetic wave transmitted and received by an antenna, comprising: a refraction unit installed near the antenna, for refracting the electromagnetic wave to correct the azimuth axis. Azimuth axis correction device. 2. The azimuth axis correcting device according to claim 1, wherein said refraction means is formed of a material having a refractive index different from that of the atmosphere. 3. The azimuth axis correcting device according to claim 2, wherein the refraction means is a plate member formed such that an incident surface and an emission surface of the electromagnetic wave form a predetermined angle. 4. The azimuth axis correcting device according to claim 1, wherein said refracting means is a cover covered by said antenna. 5. A radar apparatus comprising: an antenna for transmitting and receiving an electromagnetic wave; and the azimuth axis correcting device according to any one of claims 1 to 4. 6. The on-vehicle radar device according to claim 5, wherein said electromagnetic wave is a millimeter wave. 7. A radome functioning as a cover of an antenna in a radar device having an antenna for transmitting and receiving an electromagnetic wave, wherein the incident surface and the emission surface of the electromagnetic wave are formed so as to form a predetermined angle. 8. A method for correcting an azimuth axis of an electromagnetic wave transmitted and received by an antenna, the azimuth axis for correcting the azimuth axis by refracting the electromagnetic wave using a member having a refractive index different from that of the atmosphere. How to fix. 9. A method of correcting an azimuth axis of a radar apparatus having an antenna for transmitting and receiving an electromagnetic wave, the azimuth axis of the radar apparatus being corrected by a material having a refractive index different from that of the atmosphere. A plurality of refraction members to be refracted in advance are selected, and the plurality of refraction members are selected based on an angle between an azimuth axis of the electromagnetic wave with respect to the antenna and a desired azimuth axis, and the selected refraction member is provided near the antenna. An azimuth axis correcting method for a radar apparatus, wherein the azimuth axis of the electromagnetic wave is corrected by disposing the azimuth axis. 10. The azimuth axis of the radar device according to claim 9, wherein the plurality of refraction members are a plurality of plate members formed so that angles formed between an incident surface and an emission surface of the electromagnetic wave have different angles. How to fix. 11. The azimuth axis correcting method according to claim 9, wherein the plurality of refraction members are a plurality of plate members formed of materials having different refractive indexes. 12. The method according to claim 9, wherein the plurality of refraction members are formed as a plurality of radomes functioning as a cover of the antenna.