JP2010091301A - Radar system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radar system which provides favorable detection performance without design constraints. <P>SOLUTION: The radar system 7 detects an object around a vehicle. The radar system 7 is placed within a combination lamp 2 which the vehicle includes. The radar system 7 is preferably placed on the back of a reflex reflector 6 or a pseudo reflex reflector provided within the combination lamp 2. More preferably, a plurality of antennas, which the radar system 7 includes, are arranged so that the distance between the antennas matches the distance which is an integral multiple of one period of protrusions and recesses formed on the back of the reflex reflector 6 or the pseudo reflex reflector. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radar device mounted on a vehicle.

  Conventionally, a radar device may be mounted on a vehicle in order to detect an obstacle or the like around the vehicle. Conventionally, the radar apparatus is generally installed on the back side of the bumper.

Japanese Patent Application Laid-Open No. 2004-228561 describes a technique for simplifying vehicle assembly by creating a camera or the like integrally with a rear combination lamp. Specifically, Patent Document 1 describes that an installation storage unit is formed in a case of a rear combination lamp, and a camera or the like is installed in the installation storage unit.
Registered Utility Model No. 3099374

  When the radar apparatus is installed on the back side of the bumper, since the radar wave passes through the bumper, the amount of attenuation of the received wave becomes large, which may deteriorate the detection performance of the radar apparatus. In particular, in vehicles with metallic paint, the amount of attenuation may increase due to the influence of aluminum chips contained in the paint. In addition, it is conceivable to provide a dedicated cover in place of the bumper only in the portion where the radar apparatus is installed in order to reduce the attenuation, but there are design limitations.

  Therefore, an object of the present invention is to provide a radar device with good detection performance without any design restrictions.

  In order to solve the above problems, the present invention employs the following configuration. That is, the present invention is a radar device that detects an object around a vehicle. The radar device is disposed inside a combination lamp included in the vehicle.

  According to the above, since the radar device is arranged inside the combination lamp, there is no possibility that the detection performance is deteriorated by painting (metallic painting) as in the case where the radar device is arranged on the bumper. Further, since it is not necessary to provide a dedicated cover as in the case where the radar apparatus is disposed on the bumper, there is no restriction on the design of the vehicle. From the above, it is possible to provide a radar device with good detection performance without design restrictions.

  Further, the radar apparatus may be disposed on the back side of a reflex reflector or a pseudo reflex reflector provided inside the combination lamp.

  According to the above, by disposing the radar device behind the reflex reflector or the pseudo reflex reflector, the radar device becomes inconspicuous from the outside of the vehicle, so that it is possible to prevent the design of the vehicle from being impaired.

  The radar apparatus may include a plurality of antennas. At this time, the reflex reflector or the pseudo reflex reflector has periodic irregularities formed on the back surface. The plurality of antennas are arranged such that the distance between the antennas coincides with a distance that is an integral multiple of one cycle of the irregularities on the back surface.

  According to the above, for example, when the phase monopulse method is used, the phase of the received wave can be prevented from being shifted by the reflex reflector (or the pseudo reflex reflector), and the detection performance of the radar apparatus can be further improved. it can.

  Further, the plurality of antennas may be arranged such that the positions of the peaks or valleys in the unevenness on the back surface coincide with the positions of the antennas.

  According to the above, since the conditions (phase distribution and amplitude distribution) on the left side and the right side of the antenna can be made equal for each antenna, the detection performance can be further improved.

  The radar apparatus may further include a radome that functions as a reflex reflector or a pseudo reflex reflector.

  According to the above, since the reflex reflector and the radome can be configured by one member, the number and thickness of the resin layers arranged in front of the radar apparatus can be reduced. Thereby, the detection performance of the radar apparatus can be further improved.

  Further, the reflex reflector or the pseudo reflex reflector may be fixed in front of the radar apparatus and may be configured separately from the combination lamp.

  Based on the above, it is possible to easily manage and adjust the distance between the antenna of the radar apparatus and the reflex reflector. Therefore, a radar device with good detection performance can be easily created.

  As described above, according to the present invention, it is possible to provide a radar device with good detection performance without disposing restrictions on the design by arranging the radar device inside the combination lamp.

(First embodiment)
The radar apparatus according to the first embodiment of the present invention will be described below. FIG. 1 is a diagram in which a radar apparatus according to a first embodiment is arranged in a vehicle. FIG. 1 shows a cross section of the rear part of the vehicle as viewed from above. In FIG. 1, rear combination lamps 2 are attached to the left and right ends of the rear portion of the vehicle body 1. The rear combination lamp 2 includes a case 3, an outer lens 4, a lamp 5, and a reflex reflector 6. The case 3 is attached to the concave portion of the rear portion of the body 1, and the outer lens 4 is attached to the case 3 so as to cover the concave portion. The lamp 5 is attached inside the outer lens 4 and inside the case 3. A reflex reflector 6 is attached to the inner side of the outer lens 4. The reflex reflector 6 is disposed outside the case 3. That is, the lamp 5 and the reflex reflector 6 are partitioned by the case 3.

  The radar device 7 detects an object around the vehicle (here, the rear of the vehicle). The radar apparatus 7 includes one or more antennas, a circuit unit such as an RF circuit, and a radome. As shown in FIG. 1, the radar device 7 is disposed inside the rear combination lamp 2, that is, inside the outer lens 4. Preferably, the radar device 7 is disposed on the back side of the reflex reflector 6. Thus, by arranging the radar device 7 inside the rear combination lamp 2 (preferably on the back side of the reflex reflector 6), the radar device 7 can be arranged without impairing the design of the vehicle 1.

  Here, when the radar device 7 is arranged behind the reflex reflector 6, the radar wave (reflected wave) transmitted / received by the radar device 7 passes through the reflex reflector 6, so that the detection performance of the radar device 7 is as follows. It is affected by the reflex reflector 6. FIG. 2 is a diagram illustrating the detection performance of the radar apparatus when a reflex reflector is disposed in front of the radar apparatus. The horizontal axis of the graph shown in FIG. 2 represents the distance between the radar device 7 and the reflex reflector 6, and the vertical axis represents the radio wave transmission attenuation between the transmission wave and the reception wave. In FIG. 2, similarly to the configuration shown in FIG. 1, the radar wave represents the amount of radio wave transmission attenuation when the radar wave passes through the reflex reflector 6 and the outer lens 4. In the present embodiment, it is assumed that the radar apparatus 7 uses a 76.5 [GHz] millimeter wave radar. In the graph, the distance is changed from 10 [mm] to 12 [mm] within a range of 2 [mm] (1/2 wavelength of the radar wave) because the interference between the transmitted wave and the received wave This is because the distance at which the above occurs is included in the above range and the radio wave transmission attenuation amount at the distance is expressed.

  From the graph shown in FIG. 2, the radio wave transmission attenuation amount is uniformly smaller than 10 [dB] in the above range, and the difference in the radio wave transmission attenuation amount in the above range is small, and good transmission performance is obtained. You can see that Here, it is assumed that the radar apparatus can be used if the radio wave transmission attenuation is 12 [dB] or less as the detection performance of the radar apparatus. From the graph shown in FIG. 2, it can be seen that there is no problem in the detection performance of the radar device 7 even if the reflex reflector 6 and the outer lens 4 are present in front of the radar device 7. As described above, even if the radar device 7 is arranged behind the reflex reflector 6, there is no problem in the detection performance of the radar device 7, and the radar device 7 having sufficient detection performance can be provided.

  As described above, according to the present embodiment, the radar device 7 is arranged inside the rear combination lamp 2 (preferably on the back side of the reflex reflector 6), so that the design of the vehicle 1 is not impaired. A high-performance radar device can be realized.

  In the first embodiment, the radar device 7 is disposed on the back side of the reflex reflector 6. However, in the vehicle, a pseudo reflex reflector is used together with the reflex reflector 6 for design reasons. Sometimes. Here, the pseudo-reflex reflector refers to a pseudo-reflex reflector that does not have a sufficient reflection function as compared with a regular reflex reflector. FIG. 3 is a diagram illustrating the detection performance of the radar apparatus when a reflex reflector or a pseudo-reflex reflector is disposed in front of the radar apparatus. The horizontal axis of the graph shown in FIG. 3 represents the distance between the radar device and the reflex reflector (or pseudo reflex reflector), and the vertical axis represents the radio wave transmission attenuation amount between the transmission wave and the reception wave. Also, in FIG. 3, unlike FIG. 2, the radar wave represents the radio wave transmission attenuation when the radar wave passes only through the reflex reflector (or the pseudo reflex reflector).

  From the graph shown in FIG. 3, it can be seen that the detection performance of the radar device 7 is almost the same between the case where the reflex reflector 6 is present and the case where the pseudo reflex reflector is present. Therefore, in the first embodiment (the same applies to other embodiments described later), when the rear combination lamp 2 includes a pseudo-reflex reflector, the radar device 7 is disposed on the back side of the pseudo-reflex reflector. Also good.

  In the present embodiment, as shown in FIG. 1, the reflex reflector (or the pseudo reflex reflector) is fixed in front of the radar device 7 and is configured separately from the rear combination lamp 2. preferable. Here, as described in the description of FIG. 2, the detection performance of the radar device 7 varies depending on the distance between the antenna and the reflex reflector 6, and therefore it is necessary to accurately manage and adjust this distance. By managing the reflex reflector 6 separately from the rear combination lamp 2 and fixing it to the radar device 7, the distance can be easily managed and adjusted. Further, the position of the radar device 7 itself can be easily adjusted.

(Second Embodiment)
Next, a radar apparatus according to the second embodiment of the present invention will be described. Also in the second embodiment, the arrangement position of the radar device in the vehicle is the same as in the first embodiment, and the radar device is arranged on the back side of the reflex reflector. Here, in the second embodiment, the radar apparatus has a plurality of antennas, and the plurality of antennas are arranged at positions corresponding to the unevenness of the back surface of the reflex reflector. Details of the second embodiment will be described below. In the second embodiment, the same components as those shown in FIG. 1 will be described with the same reference numerals.

  FIG. 4 is a diagram illustrating a positional relationship between the antenna and the reflex reflector in the second embodiment. In the second embodiment, the radar apparatus 7 detects an object by a phase monopulse method, and includes two antennas, first and second antennas 11 and 12. In addition, in 2nd Embodiment, although the radar apparatus 7 demonstrates as a structure which is not provided with the radome, the structure provided with a radome may be sufficient.

  In FIG. 4, triangular irregularities are periodically formed on the back surface of the reflex reflector 6. In addition, the unevenness | corrugation of the back surface of the reflex reflector 6 is formed regarding the vertical direction and the horizontal direction, and the back surface of the actual reflex reflector 6 has a shape in which triangular pyramids are arranged side by side with respect to the plane. is there.

  Here, in the phase monopulse method, the azimuth of the detection target is detected based on the phase difference between the reflected wave signals received by the two antennas 11 and 12. On the other hand, the material of the reflex reflector 6 is generally resin, and has a dielectric constant several times that of the atmosphere. Therefore, when the radar wave passes through the reflex reflector 6, the phase of the radar wave (reflected wave) received by the antenna varies depending on the distance through which the reflected wave passes through the reflex reflector 6. Therefore, when the reflected waves from a certain direction are received by the two antennas 11 and 12, respectively, the distances through which the reflected waves received by the antennas 11 and 12 pass through the reflex reflector 6 may be different from each other. For example, the amount of phase shift differs between the two received reflected waves. As a result, the direction of the detection target may not be detected accurately.

  Therefore, in the present embodiment, as shown in FIG. 4, the antennas 11 and 12 are arranged such that the distance between the antennas 11 and 12 is equal to a distance that is an integral multiple of one cycle of the unevenness on the back surface of the reflex reflector 6. Be placed. Specifically, each of the antennas 11 and 12 is disposed at a position corresponding to a concavo-convex mountain (convex) portion on the back surface of the reflex reflector 6. As a result, the distance from the antennas 11 and 12 to the reflex reflector 6 is the same for each antenna 11 and 12 with respect to each direction from the antenna. As a result, the distances through which the reflected waves received by the antennas 11 and 12 pass through the reflex reflector 6 are equal, and the antennas 11 and 12 can receive the reflected waves under the same conditions, and the direction of the detection target Can be detected accurately. As described above, according to the second embodiment, when the radar device 7 is disposed on the back side of the reflex reflector 6, the detection performance can be further improved.

  In the second embodiment, the two antennas 11 and 12 are arranged at positions corresponding to the uneven (convex) portions on the back surface of the reflex reflector 6. And 12 may be arranged so as to coincide with a distance that is an integral multiple of one period of the irregularities on the back surface of the reflex reflector 6. For example, the two antennas 11 and 12 may be arranged at positions corresponding to the concave and convex valley (concave) portions on the back surface of the reflex reflector 6. In addition, by arranging the antennas 11 and 12 at positions corresponding to the peak portions or the valley portions, the conditions of the left and right sides of the antennas can be made equal for each of the antennas 11 and 12, so that the detection performance Can be further improved. When the uneven reflex reflector 6 is arranged in front of the radar apparatus 7 as in the present embodiment, the phase distribution is uneven as described above, and the reflection characteristics of the radar wave change depending on the direction from the antenna. For this reason, the amplitude distribution also becomes uneven. On the other hand, by arranging the antennas 11 and 12 at positions corresponding to the peak portions or the valley portions, the phase distribution and the amplitude distribution can be made symmetrical, and the deviation of the radar detection range can be eliminated. it can. In addition, when making the position of an antenna correspond to the position of the uneven | corrugated peak part (or trough part) in the back surface of the reflex reflector 6, if the position is matched at least with respect to the direction in which each antenna 11 and 12 is arranged side by side Good. For example, when a vertically long array antenna is used as each antenna 11 and 12, each antenna 11 and 12 is arranged side by side in the horizontal direction (lateral direction), so the position of each antenna 11 and 12 at least in the horizontal direction, What is necessary is just to make the position of the uneven | corrugated peak part (or trough part) in the back surface of the reflex reflector 6 correspond.

  In the second embodiment, the case where there are two antennas has been described as an example. However, the present invention can also be applied to a case where there are three or more antennas. May be arranged.

(Modification)
In the first and second embodiments, the radome included in the radar device 7 and the reflex reflector 6 are separate, but in other embodiments, the radome and the reflex reflector 6 are integrated. It is good. In other words, the radome may have the function of a reflex reflector. Hereinafter, a radar apparatus according to a modification of the present embodiment will be described with reference to FIG.

  FIG. 5 is a diagram illustrating a radar apparatus according to a modification of the present embodiment. In FIG. 5, the radar apparatus 20 includes a case 21, an antenna unit 22, a circuit unit 23, a radome 24, and a see-through prevention film 25. The case 21 has a box shape having an opening. The antenna unit 22 including one or more antennas and the circuit unit 23 including a circuit such as an RF circuit are accommodated in the case 21. The radome 24 is attached to the case 21 so as to close the opening of the case 21. The radome 24 protects the antenna unit 22 and the circuit unit 23 inside the case 21 from the outside. Further, the see-through prevention film 25 is provided between the antenna unit 22 and the radome 24.

  In this modification, the radome 24 functions as a reflex reflector (or a pseudo reflex reflector). In other words, in this modification, the reflex reflector (or pseudo reflex reflector) of the rear combination lamp is attached so as to close the opening of the case 21. In this modification as well, as in the first embodiment, the radar apparatus 20 is disposed inside the rear combination lamp 2 shown in FIG. 1, but in this modification, a reflex reflector 6 is separately provided. There is no need. Also in this modification, a plurality of antennas may be arranged at positions corresponding to the unevenness of the back surface of the reflex reflector (radome), as in the second embodiment.

  According to the above modification, the detection performance of the radar device 20 can be improved by integrating the radome and the reflex reflector as compared with the case where the radome and the reflex reflector are provided separately. That is, when a radome and a reflex reflector are provided separately, three layers of a radome, a reflex reflector, and an outer lens are arranged in front of the radar apparatus 20, and antenna detection is performed by reflected waves at each layer. Performance deteriorates. Further, if the sum of the thicknesses of the three layers increases, the radio wave transmission attenuation amount increases. On the other hand, when the radome and the reflex reflector are integrated, the influence of the reflected wave and the radio wave transmission attenuation can be reduced by reducing the number of layers and the thickness of the layer that generate the reflected wave. And the detection performance of the radar apparatus 20 can be improved. Further, by reducing the number of parts, there is an effect that manufacturing can be simplified and cost can be reduced.

  Moreover, in this modification, the transparency preventing film 25 is provided between the antenna portion 22 and the radome 24 so that the inside of the radar device 20 cannot be seen from the outside of the vehicle. In addition, when there is no necessity (it is small), such as when the inside of the radar apparatus 20 is hardly visible by the radome 24, the radar apparatus 20 may have a configuration without the see-through prevention film 25. Also in the first and second embodiments described above, a see-through prevention film 25 may be provided between the antenna of the radar device 7 and the reflex reflector 6 as necessary.

(Other)
In the above embodiment, the case where the radar device is mounted inside the rear combination lamp has been described as an example. However, the present invention is also applied to the case where the radar device is mounted inside the front combination lamp mounted on the front portion of the vehicle. Is possible.

  The present invention can be used as, for example, a radar apparatus installed inside a rear combination lamp for the purpose of providing a radar apparatus with good detection performance without any design restrictions.

The figure which has arranged the radar device concerning a 1st embodiment in vehicles The figure which shows the detection performance of the radar equipment when the reflex reflector is arranged in front of the radar equipment The figure which shows the detection performance of a radar apparatus when a reflex reflector or a pseudo reflex reflector is arranged in front of the radar apparatus The figure which shows the positional relationship of an antenna and a reflex reflector in 2nd Embodiment. The figure which shows the radar apparatus in the modification of this embodiment

Explanation of symbols

2 Rear combination lamp 3 Case 4 Outer lens 5 Lamp 6 Reflex reflector 7, 20 Radar device 11, 12 Antenna 21 Case 22 Antenna part 23 Circuit part 24 Radome 25 Transparent film

Claims (6)

A radar device for detecting objects around a vehicle,
A radar apparatus, which is disposed inside a combination lamp included in the vehicle.   The radar apparatus according to claim 1, wherein the radar apparatus is disposed on a back side of a reflex reflector or a pseudo reflex reflector provided inside the combination lamp. With multiple antennas,
The reflex reflector or pseudo-reflex reflector is formed with periodic irregularities on the back surface,
The radar device according to claim 2, wherein the plurality of antennas are arranged such that a distance between the antennas coincides with a distance that is an integral multiple of one cycle of the unevenness of the back surface.   4. The radar device according to claim 2, wherein the plurality of antennas are arranged such that a peak position or a valley position in the unevenness of the back surface coincides with a position of each antenna. 5. .   The radar device according to any one of claims 2 to 4, further comprising a radome that functions as the reflex reflector or the pseudo reflex reflector.   The radar apparatus according to any one of claims 2 to 5, wherein the reflex reflector or the pseudo reflex reflector is fixed in front of the radar apparatus and is configured separately from the combination lamp.

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