JP2003270327A - Radar, radar system, and method for setting reference direction for radar - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate the substantial adjustment of a beam axis by extremely facilitating the setting of reference direction. <P>SOLUTION: A corner reflector 101 is provided as a reference direction for a vehicle 102, for example, in the direction of its front-to-back axis Am. A radar 100 mounted on the vehicle 102 detects the direction of the reflector and stores therein this direction as a reference direction θo. A host device utilizing this radar 100 or utilizing the result of finding by this radar modifies direction data on a found target by the amount of the reference direction θo. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar for detecting a target using radio waves, a radar system, and a radar reference azimuth setting method.

[0002]

2. Description of the Related Art Conventionally, as a method of adjusting a beam axis of a radar, Japanese Patent Laid-Open No. 8-170984 and Japanese Patent No. 31570 have been proposed.
91 is disclosed.

The radar of (3) uses a polygon mirror to store the offset angle when the laser beam is scanned within a predetermined scanning angle range. The radar of (1) moves the scanning angle range based on the radar module.

[0004]

However, since the radar of (1) controls the scanning means itself for adjusting the optical axis, the load required for the control and processing is large, and the size and cost are high. Becomes Another radar is
Since this is a method of adjusting the optical axis by controlling the scanning range of the scanning means, the mechanism or control for changing the scanning range of the control means operating at high speed becomes large-scale, and also the size and cost are high. Will be invited.

An object of the present invention is to provide a radar, a radar system, and a method for setting a reference azimuth of a radar, which makes it possible to set a substantial reference azimuth very easily and solves the above-mentioned problems.

[0006]

According to the present invention, a beam is scanned within a predetermined scanning angle range, and a reflected wave from a target within the scanning angle range is received to detect the azimuth of the target. Target azimuth detecting means and means for obtaining the reference azimuth in the reference azimuth setting mode based on the azimuth data detected by the target azimuth detecting means with the reflector installed at a predetermined position within the scanning angle range. A reference azimuth storing means for storing the reference azimuth, and azimuth data correcting means for correcting the azimuth data detected by the target azimuth detecting means in the normal mode to azimuth data based on the reference azimuth. It is characterized by having.

Further, the radar of the present invention comprises a communication means for communicating with a host device or other device,
The reference azimuth storing means stores the reference azimuth in response to an instruction from the communication means.

The radar system according to the present invention scans the beam within a predetermined scanning angle range, receives reflected waves from the target within the scanning angle range, detects the direction of the target, and detects the direction of the target. A radar having a target azimuth detecting means for outputting data, a means for obtaining a reference azimuth based on the azimuth data input from the radar in the reference azimuth setting mode in a state where the reflector is installed, and the reference azimuth. A host device comprising a reference azimuth storing means for storing the azimuth and an azimuth data correcting means for correcting the azimuth data input from the radar to the azimuth data based on the reference azimuth in a normal mode. It has a feature.

According to the radar reference azimuth setting method of the present invention, the radar is mounted on a body to be mounted, and a reflector is installed at a predetermined relative position with respect to the direction of the body to be mounted. It is characterized in that the reference orientation is stored in the memory by switching to.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of a radar according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a beam scanning range in a state where a radar is attached to a mounted object such as a vehicle. Here, 102 is a vehicle which is a body to which the radar is attached, and 100 is a radar mounted on the vehicle 102. Am is an axis parallel to a central axis extending in the front-rear direction of the vehicle 102 (hereinafter, referred to as “vehicle front-rear axis”), and Ar is a radar central axis that faces the front of the radar 100. The beam scanning means of the radar 100 scans the beam with a width of θr in the left-right direction about the radar central axis Ar. Further, θm is an angle range having a predetermined angle range in the left-right direction with the vehicle front-rear axis Am as the center.
This angle θm is an angle range to be actually detected (required by the host device). θr is wider than θm and θm
It is made wider with a margin in advance so as to cover the entire range. The radar 100 is mounted on the vehicle front-rear axis Am.
With respect to No. 02, the center axis of the radar 100 is the axis to which the center axis of the radar 100 faces when it is accurately mounted without any angular displacement in the azimuth direction. However, the center axis A of the radar 100 is determined by the dimensional accuracy and the mounting accuracy of the mounting portion of the radar 100 on the vehicle 102.
An angle (offset) in the azimuth direction corresponding to θo occurs between r and the vehicle front-rear axis Am.

As will be described later, when setting the reference azimuth of the radar, a corner reflector 101 is installed on the axis of the vehicle front-rear axis Am at a position separated from the radar 100 by a predetermined distance. For example, the corner reflector 101 is installed in advance at a position where the vehicle front-rear axis passes while the vehicle is stopped at a predetermined position where the vehicle stops. As a result, the above θo is used as the reference azimuth.

FIG. 2 is a block diagram showing the configuration of the radar 100 shown in FIG. In this example, a radar that detects the relative distance and relative speed of the target by the FM-CW method is shown. Here, 10 is a radar sensor, and 20 is a signal processing unit. The radar sensor 10 transmits and receives radio waves for radar measurement, and outputs beat signals of a transmitted wave and a received wave to the signal processing unit 20. The modulation counter 21 of the signal processing unit 20 is controlled by the microprocessor 26.
It is a counter that changes the count value into a triangular wave. D
The A / A converter 22 converts the output value from the modulation counter 21 into an analog signal and outputs the VCO of the radar sensor 10.
Give to 11. As a result, the VCO 11 FM-modulates the oscillation signal in a triangular wave shape including an up modulation section and a down modulation section.

The oscillation signal of the VCO 11 is transmitted to the isolator 1
2, it is supplied to the primary radiator 15 via the coupler 13 and the circulator 14. The primary radiator 15 is located at or near the focal plane of the dielectric lens 16, and the dielectric lens 16 transmits the millimeter wave signal emitted from the primary radiator 15 as a sharp beam. When a reflected wave from a target such as a vehicle is incident on the primary radiator 15 via the dielectric lens 16, the received signal is guided to the mixer 17 via the circulator 14. The mixer 17 inputs the received signal and a local signal that is a part of the transmitted signal from the coupler 13, and uses a beat signal that is a frequency signal of a difference between the received signal and the local signal as an intermediate frequency signal. D converter 2
Output to 3.

The A / D converter 23 converts this into digital data. DSP (Digital Signal Processor) 2
4 is a data string input from the A / D converter 23
FT (Fast Fourier Transform) processing is performed to obtain the power spectrum of the beat signal. In addition, the DSP 24 extracts a protruding portion of power (hereinafter simply referred to as a “projection portion”) included in the power spectrum due to the reflection of the target, and the peak of the protrusion portion in the up-modulation section and the down-modulation section. The relative position and relative velocity of the target are detected from the frequency pair. The communication interface 25 transmits the detected result to the host device. This communication interface 2
5 corresponds to the communication means according to the present invention.

The portion indicated by 18 in the radar sensor 10 is
It is a scanning unit that translates the primary radiator 15 in a focal plane of the dielectric lens 16 or in a plane parallel to the focal plane. The movable part provided with the primary radiator 15 and the fixed part constitute a 0 dB coupler. The portion indicated by M is its driving motor. The microprocessor 26 drives and controls the motor M to scan the beam.

The beam scanning is performed in this manner, and
By detecting the target by the DSP 24, the relative position and relative velocity of each target for each direction are obtained. The scan unit 18, the microprocessor 26 for controlling the scan unit 18, and the DSP 24 for detecting the target correspond to the target direction detecting means according to the present invention.

The host device 31 reads the relative position and relative speed of the target from the radar 100 and outputs a vehicle control command to the vehicle control unit 32 as necessary. The vehicle control unit 32 controls the vehicle according to the command.

FIG. 3 is a flowchart showing a processing procedure executed by the microprocessor 26 of the signal processing unit 20 when setting the reference azimuth. First, a command is received from the host device (s1). If the command is a command for switching to the reference azimuth setting mode, the following reference azimuth setting processing is performed in order. That is, the azimuth of the beam is directed to the initial position by the control of the scan unit 18 shown in FIG. 2 (s2 → s3). For example, the beam is directed to the leftmost direction of the beam scanning angle range. Then, A /
The digital data of the beat signal converted by the D converter 23 is acquired by a predetermined number of samplings, and FFT processing is performed on it (s4 → s5).

After that, the protrusion is detected (s6). That is, a portion in which the signal intensity of the frequency spectrum projects in a mountain shape is detected. If the protrusion exists, the peak frequency and the signal strength at the peak frequency are extracted.

After that, the beam azimuth is deviated by one beam and the same processing is repeated (s7 → s8 → s4 →.
・ ・).

By repeating the above processing until the final beam (the right end of the scanning angle range), the data required for detection within the predetermined scanning angle range is collected. After that, the peak frequency at the center of the protrusion extending in the azimuth direction and the frequency axis direction is extracted as the representative frequency, and the signal strength thereof is extracted as the representative signal strength. Then, from the plurality of representative signals in the up-modulation section and the down-modulation section, pairs in which the azimuth angles are substantially the same and the signal intensities are substantially the same are extracted as a pair.

At the time of this reference azimuth setting process, as shown in FIG. 1, since the corner reflector 101 is installed, the azimuth θo of the corner reflector, the distance to the corner reflector 101, and the speed are calculated (s
9). However, in the process of setting the reference azimuth, the distance and speed to the corner reflector 101 are not directly used. The orientation θo of the corner reflector 101 thus obtained is stored as a reference orientation in the memory in the microprocessor 26 (s10). The microprocessor 26 corresponds to the reference azimuth storage means according to the present invention.

In addition to the corner reflector 101,
The reflected waves of walls and targets existing farther than the radar 10
In an environment where it returns to 0, walls and corner reflectors 1
Targets other than 01 are also detected. However, if the calculated distance is out of the predetermined range or the relative speed is not substantially 0, it is not a corner reflector. Therefore, the azimuth of the reflection signal from the corner reflector 101 is used by using the calculation result of the distance and the speed. Only need extract.

In FIG. 3, if the command received from the host device is a command for switching to the normal mode, the normal operation shown in FIG. 4 is executed. First, initial setting is performed (s11). This initialization includes initialization of the beam azimuth similar to that shown in step s3 in FIG. After that, by scanning the beam once within a predetermined scanning angle range, the target existing within the scanning angle range is detected (s12). In this step s12, the azimuth / distance / speed of the existing target is calculated by the same processing as the processing shown in steps s4 to s9 shown in FIG.

Reference azimuth θ obtained by installing the corner reflector 101 on the axis of the vehicle front-rear axis which is the reference azimuth of the vehicle
o corresponds to the offset in the azimuth direction of the radar center axis Ar with respect to the vehicle front-rear axis Am. Therefore, in this example, the reference azimuth θo is subtracted from the azimuth θ of the target to correct the offset to correct the azimuth data (s13).
Then, the detection result obtained by correcting the azimuth data is output to the host device (s14). The target is continuously detected by repeating the processes of steps s12 to s14.
Microprocessor 2 for performing the processing in step s13
Reference numeral 6 corresponds to the azimuth data correcting means according to the present invention.

In this example, the radar sets the reference azimuth in response to a command from the host device, but a command to switch from the device connected to the radar to the reference azimuth setting mode only at the time of factory adjustment. You may receive it.

Next, the processing contents of the host device in the radar system according to the second embodiment will be explained based on FIG. FIG. 5 is a flowchart showing the processing procedure on the host device side. In this embodiment, the radar uses the reference azimuth θ.
A means for outputting o to the host device is provided, and the detection result is output to the host device as it is without correction by θo on the radar side.

In the host device, as shown in FIG. 5, first, the azimuth data input from the radar in the reference azimuth setting mode is stored in the memory as the reference azimuth θo (s21).
After that, the normal mode is entered, and the data of the target detection result (azimuth / distance / speed) is input from the radar (s2).
2). Then, the azimuth data θ is corrected by θo (s
23). As a result, the direction of the target is correctly detected. After that, the vehicle is controlled as necessary (s2
4). For example, when the distance to another vehicle traveling in front of the vehicle is within a predetermined distance and is approaching at a predetermined relative speed or more, the speed is restricted by reducing the accelerator opening.

By repeating the above steps s22 to s24, the correction of the detection result from the radar and the vehicle control are repeated. The means for performing the process of step s21 corresponds to the reference azimuth storage means according to the present invention. The means for performing the process of step s23 corresponds to the azimuth data correction means according to the present invention.

In the embodiment described above, a corner reflector is installed on the longitudinal axis of the vehicle to set the reference azimuth θo.
However, the orientation of the corner reflector may be detected by installing the corner reflector at a position deviated by a predetermined angle from the orientation that should be the reference. In that case, (corner reflector azimuth + above predetermined angle) may be treated as the reference azimuth. In any case, the reference azimuth is obtained based on the detected azimuth of the corner reflector.

[0031]

According to the present invention, since it is not necessary to control the scanning angle range of the scanning means, the structure of the scanning means can be simplified and the control thereof becomes easy. As a result, the reference direction of the radar can be easily set without increasing the scale of the device.

Further, according to the present invention, the reference azimuth can be easily set only by installing the reflector at a position of a predetermined azimuth with respect to the direction of the mounted body with the radar mounted on the mounted body such as a vehicle. Like Therefore, the time for adjusting the beam axis after mounting the radar becomes unnecessary, and the manufacturing efficiency is significantly improved.

Further, according to the present invention, if the host device is provided with means for correcting the deviation of the reference azimuth of the radar, the radar only needs to output the data concerning the reference azimuth to the host device. The configuration can be further simplified, and the size and cost can be reduced.

Further, according to the present invention, since the reference azimuth is stored in response to the instruction from the host device or other device, the radar side performs a special operation for setting the reference azimuth and It is not necessary to set, and the reference azimuth can be set in the final product state or in the state of being mounted on the mounted body such as a vehicle. Therefore, the work of setting the reference azimuth becomes easy.

[Brief description of drawings]

FIG. 1 is a diagram showing a mounting state of a radar according to a first embodiment on a vehicle, a beam scanning angle range, and the like.

FIG. 2 is a block diagram showing the configuration of the radar.

FIG. 3 is a flowchart showing a processing procedure of a radar microprocessor.

FIG. 4 is a flowchart showing a procedure of normal operation of the microprocessor.

FIG. 5 is a flowchart showing a processing procedure on the host device side to which the radar according to the second embodiment is connected.

[Explanation of symbols]

100-radar 101-corner reflector 102-vehicle (attached body) Am-vehicle front-rear axis Ar-Radar center axis θr, radar scanning angle range θm-Detection angle range required by the host device θo-reference direction (offset)

Claims (4)

[Claims] 1. A target azimuth detecting means for scanning a beam within a predetermined scanning angle range, receiving a reflected wave from the target within the scanning angle range, and detecting the azimuth of the target, and a reference. In the azimuth setting mode, a means for obtaining a reference azimuth based on the azimuth data detected by the target azimuth detecting means in a state where a reflector is installed at a predetermined position within the scanning angle range; and the reference azimuth is stored. A radar provided with reference azimuth storage means and azimuth data correction means for correcting the azimuth data detected by the target azimuth detection means in normal mode to azimuth data based on the reference azimuth. 2. A communication device for communicating with a host device or another device, the reference direction storage device storing the reference direction in response to an instruction from the communication device. The radar according to 1. 3. A target azimuth for scanning a beam within a predetermined scanning angle range, receiving a reflected wave from the target within the scanning angle range to detect the azimuth of the target, and outputting azimuth data. A radar having a detecting means, a means for obtaining a reference azimuth based on the azimuth data input from the radar in the reference azimuth setting mode with the reflector installed, and a reference azimuth storage for storing the reference azimuth And a azimuth data correction means for correcting the azimuth data input from the radar into azimuth data based on the reference azimuth in a normal mode. 4. The radar according to claim 1, 2 or 3 is mounted on a body to be mounted, a reflector is installed at a predetermined relative position to the direction of the body to be mounted, and the mode is set to the reference azimuth setting mode. A reference azimuth setting method for a radar, characterized in that the reference azimuth is switched to store the reference azimuth in the reference azimuth storage means.