JP2010117218A - Radar equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radar equipment being hardly affected by the noise from outside and hardly allowing water drops to infiltrate into the radar, while satisfying the conditions of miniaturization and restriction of the vehicle component shape. <P>SOLUTION: Since an inner wall 29 is located corresponding to the position of the planner antenna 14 when an antenna unit 1 is in storage and of the maximum turning angle θ of the planner antenna 14, the radar equipment is hardly affected by a noise from outside indicated by an arrow A, and hardly allows water drops such as rain to infiltrate into the radar equipment. Further, the height H of the inner wall 29 is set so as to not affect the transmission and reception of radio waves as shown by C. Also, since an outer wall 28 is positioned lower than the position of the planner antenna 14 when the antenna unit 1 is in storage, the conditions for the miniaturization and restriction of the vehicle component shape are satisfied. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an on-vehicle radar device that detects an object by transmitting and receiving radio waves for automatic driving of a vehicle and collision prevention.

  An in-vehicle radar device includes an antenna unit that is disposed in front or rear of a vehicle so that a radio wave transmission / reception surface is perpendicular to the vehicle, and that transmits and receives radio waves, and a case that houses the antenna unit ( For example, Patent Document 1).

  As an antenna unit, a mechanical scan type has been proposed. In this case, the power of the motor is transmitted to the planar antenna via the flying hole and the crank, and the planar antenna rotates at a predetermined angle by the transmitted power. When the planar antenna is rotated, the antenna unit repeatedly transmits and receives radio waves at arbitrary intervals.

  The outer wall of the case had the same height as that of the planar antenna when the antenna unit was accommodated. However, the height of the outer wall of the case was reduced depending on the size of the radar device and restrictions on the shape of the vehicle parts. It tends to be lower than the height of the planar antenna during housing. In this case, the height of the inner wall of the case is set to the same height as the outer wall of the case, that is, the height of the inner wall of the case is set lower than the height of the planar antenna when the antenna unit is accommodated.

JP 2004-258044 A

  However, when the inner wall and outer wall of the case are made lower than the height of the planar antenna when the antenna unit is accommodated, there is an inconvenience that it becomes easy to be affected by noise from outside and water droplets such as rain easily enter the inside of the radar device. Arise.

  An object of the present invention is to provide a radar apparatus that is less susceptible to external noise while satisfying the requirements for downsizing and restrictions on the shape of vehicle parts, and that water droplets such as rain are less likely to enter the interior. .

A radar apparatus according to the present invention has a planar antenna, and transmits and receives radio waves while rotating the planar antenna at a predetermined rotation angle;
The antenna unit is accommodated, and the outer wall is located at a position lower than the position of the planar antenna when the antenna unit is accommodated, and the position corresponding to the position of the planar antenna and the rotation angle of the planar antenna when the antenna unit is accommodated. A case having an inner wall;
It is provided with.

  According to the present invention, since the inner wall of the case is at a position corresponding to the position of the planar antenna when the antenna unit is accommodated and the rotation angle of the planar antenna, it is less susceptible to external noise and water drops such as rain It becomes difficult to enter inside the radar. Further, since the outer wall of the case is located at a position lower than the position of the planar antenna when the antenna unit is accommodated, the conditions for size reduction and restrictions on the vehicle part shape are satisfied.

Embodiments of a radar apparatus according to the present invention will be described in detail with reference to the drawings. In the drawings, the same members are denoted by the same reference numerals.
FIG. 1 is an exploded perspective view of a radar apparatus according to the present invention. In the present embodiment, the radar apparatus is realized as a millimeter wave radar using a 76 GHz millimeter wave band as a transmission / reception wave, and a mechanical scan type antenna unit 1 for transmitting / receiving radio waves, and a case 2 for housing the antenna unit 1. And a radome 3 that covers the case 2, and a gasket (O-ring) 4 that is interposed between the case 2 and the radome 3.

  FIG. 2 is a perspective view of the antenna unit housed in the case. An antenna unit 1 shown in FIG. 2 is a conventionally known mechanical scan type antenna unit, and includes a transmission / reception unit 11, an antenna scanning unit 12, and a detection unit 13.

  FIG. 3 is a block diagram of the antenna unit housed in the case. In FIG. 3, the transmission / reception unit 11 includes a transmission antenna 15 and a reception antenna 16 constituting a planar antenna 14, a voltage controlled oscillator 17, a directional coupler 18, a mixer 19, and a triangular wave generation circuit 20. The antenna scanning unit 12 includes a motor drive circuit 21, a motor 22, and an encoder 23. Further, the detection unit 13 includes an A / D converter 24 and a signal processing unit 25.

  FIG. 4 is a diagram for explaining the operation of the antenna unit. The antenna scanning unit 12 further includes a flywheel 26 and a crank 27 not shown in FIG. When the power of the motor 22 is transmitted to the transmission / reception unit 11, that is, the planar antenna 14 via the flying hole 26 and the crank 27, the planar antenna 14 rotates at a predetermined angle by the transmitted power, and the planar antenna 14 The state changes from the horizontal state shown in FIG. 4A to the rotating state shown in FIG. 4B or the rotating state shown in FIG. 4C. When the planar antenna 14 is rotated, the antenna unit 1 repeatedly transmits and receives radio waves at an arbitrary interval.

  5 is a cross-sectional view of the radar apparatus according to the present invention when the planar antenna is in a horizontal state, FIG. 6 is a partially enlarged view of FIG. 5, and FIG. 7 is a diagram when the planar antenna is in a rotating state. It is sectional drawing of the radar apparatus by this invention. As shown in FIGS. 5 to 7, the case 2 includes an outer wall 28 that is lower than the position of the planar antenna 14 when the antenna unit 1 is accommodated, the position of the planar antenna 14 when the antenna unit 1 is accommodated, and the planar antenna. It has a height that takes into account 14 rotation angles.

When the height of the planar antenna 14 when the antenna unit 1 is accommodated is h1, the length of the effective surface of the planar antenna 14 is L, and the maximum rotation angle (for example, ± 14 °) of the planar antenna 14 is θ. The height H of the inner wall 29 is
H ≧ h1 + Lsin θ / 2
Represented by That is, the position of the inner wall 29 is higher than the positions of both ends a and b (one end a in the case of FIG. 7) of the planar antenna when the planar antenna 14 is rotated at the maximum rotation angle θ. Further, when the height of the outer wall is h2, between the height h1 of the planar antenna 14 and the height h2 of the outer wall,
h1> h2
Have the relationship.

  According to the present embodiment, the inner wall 29 is at a position corresponding to the position of the planar antenna 14 and the maximum rotation angle θ of the planar antenna 14 when the antenna unit 1 is accommodated. In addition to being hardly affected by external noise, water droplets such as rain as shown by arrow B in FIG. 6 are less likely to enter the inside of the radar apparatus. The height H of the inner wall 29 is a height that does not affect transmission / reception of radio waves as indicated by C. Further, since the outer wall 28 is located at a position lower than the position of the planar antenna 14 when the antenna unit 1 is accommodated, the conditions for size reduction and restrictions on the shape of the vehicle parts are satisfied. Furthermore, by disposing the gasket 4 on the outside of the inner wall 29, the effect of suppressing the intrusion of water droplets into the radar apparatus can be enhanced.

  FIG. 8 is a diagram showing measurement results obtained by measurement of the radar device according to the present invention having an inner wall at a position corresponding to the position of the planar antenna and the rotation angle of the planar antenna when the antenna unit is accommodated. It is a figure which shows the measurement result obtained by the measurement of the conventional radar apparatus which has an inner wall lower than the height of the planar antenna at the time of antenna unit accommodation. 8 and 9, the vertical axis represents the distance (m) and power (dBv) from the radar apparatus, and the horizontal axis represents the counter value.

  The measurement results shown in FIGS. 8 and 9 are results obtained by performing an evaluation by an EMC (electromagnetic compatibility) test. The waveforms on the upper side of FIGS. 8 and 9 are waveforms for viewing the target level, and if this waveform level is disturbed, erroneous detection of the target occurs. The waveforms on the lower side of FIGS. 8 and 9 are waveforms for viewing the distance to the target. If this waveform level is disturbed, a distance detection deviation occurs.

  In the radar apparatus according to the present invention, as shown in FIG. 8, there is almost no distance shift and target loss due to measurement. On the other hand, in the conventional radar apparatus, as shown in FIG. 9, target misdetection and distance detection deviation due to measurement become prominent.

  The present invention is not limited to the above-described embodiment, and many changes and modifications can be made. For example, in the above embodiment, the case where a 76 GHz millimeter wave band is used as a transmission / reception wave has been described. However, radio waves other than millimeter waves (microwaves, etc.), light, laser, ultrasonic waves, and the like are used as transmission / reception waves. You can also.

  In addition, a member that shields radio waves (for example, a metal piece such as a thin plate) can be insert-molded into the radome to block noise from the outside.

It is a disassembled perspective view of the radar apparatus by this invention. It is a perspective view of the antenna unit accommodated in a case. It is a block diagram of the antenna unit accommodated in a case. It is a figure for demonstrating operation | movement of an antenna unit. It is sectional drawing of the radar apparatus by this invention when a planar antenna is a horizontal state. FIG. 7 is a partially enlarged view of FIG. 6. It is sectional drawing of the radar apparatus by this invention when a planar antenna is a rotation state. It is a figure which shows the measurement result obtained by the measurement of the radar apparatus by this invention. It is a figure which shows the measurement result obtained by the measurement of the conventional radar apparatus.

Explanation of symbols

1 Antenna unit 2 Case 3 Radome 4 Gasket (O-ring)
DESCRIPTION OF SYMBOLS 11 Transmission / reception part 12 Antenna scanning part 13 Detection part 14 Planar antenna 15 Transmission antenna 16 Reception antenna 17 Voltage controlled oscillator (VCO)
DESCRIPTION OF SYMBOLS 18 Directional coupler 19 Mixer 20 Triangle wave generation circuit 21 Motor drive circuit 22 Motor 23 Encoder 24 A / D converter 25 Signal processing part 26 Flywheel 27 Crank 28 Outer wall 29 Inner wall

Claims (4)

An antenna unit having a planar antenna and transmitting and receiving radio waves while rotating the planar antenna at a predetermined rotation angle;
The antenna unit is accommodated, and the outer wall is located at a position lower than the position of the planar antenna when the antenna unit is accommodated, and the position corresponding to the position of the planar antenna and the rotation angle of the planar antenna when the antenna unit is accommodated. A case having an inner wall;
A radar apparatus comprising:   The radar apparatus according to claim 1, wherein the position of the inner wall is higher than the positions of both ends of the planar antenna when the planar antenna is rotated at the maximum rotation angle.   The radar apparatus according to claim 1, further comprising a gasket disposed outside the inner wall.   The radar apparatus according to any one of claims 1 to 3, wherein the antenna unit further includes a rotating unit that rotates the planar antenna at a predetermined rotation angle.

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