JP3150511B2 - Radar equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar device for detecting a two-dimensional relative position of an object.

[0002]

2. Description of the Related Art In recent years, for example, in an automobile, a radar in which the relative distance or two-dimensional relative position of an object such as another vehicle existing in front of or behind the own vehicle with respect to the own vehicle is mounted on the own vehicle. A system has been developed in which detection is performed using a device, and in accordance with this, automatic cruise control such as holding the inter-vehicle distance and braking is performed, and various warnings are performed. The FM-CW radar device is generally used because it is possible to detect the target object and to easily make the system configuration relatively simple. In addition, as a technique for detecting the relative distance or the like of the target object using the radar technology, a pulse radar method, a laser radar method, and the like are known in addition to the FM-CW radar method.

[0003] Detection of the relative distance of an object by the FM-CW radar apparatus is performed, for example, as described below.

[0004] That is, as shown in FIG. 3, a signal comprising temporally modulated in triangular waveform frequency between the frequency f _X and f _Y as transmitting signals, having said transmission wave signal having the same frequency An electromagnetic wave beam is transmitted from an antenna mounted on the vehicle to an object, and a reflected wave reflected by the object is received by the antenna. At this time, the received wave signal of the reflected wave is frequency-modulated in a triangular wave shape like the transmitted signal, but the time required to reciprocate between the antenna transmitting and receiving the electromagnetic wave and the object. A delay (time difference) of τ is generated with respect to the transmitted signal. Therefore, when the transmitted and received signals are compared on the same time axis, a frequency difference f _B proportional to the delay time τ is obtained between the two signals.
Is generated. In this case, since the delay time τ is proportional to the relative distance of the object, the frequency difference f _B is also proportional to the relative distance of the object, and if the relative distance of the object is D, the following equation (1)
Holds.

D = k · f _B (1) In the equation (1), k is the propagation speed (light speed) of the electromagnetic wave;
This is a constant determined by the temporal change rate of the frequency of the transmitted / received signal.

[0006] Based on such a basic principle, FM-C
W radar apparatus, by mixing the transmit signal and the received signal to generate a beat signal having a frequency of the frequency difference f _B of the two signals, detects the frequency f _B of the beat signal was detected determining the relative distance D of the object by the formula from the frequency f _B of the beat signal (1).

When detecting not only the relative distance of the object but also the two-dimensional relative position including the azimuth, for example, as shown in FIG. B _X, B _Y and to transmit at different times (e.g., JP-a filed by the present applicant 4-259874
JP-A-5-87914). At this time, the ratio between the reception levels of the reflected waves of the electromagnetic wave beams _BX and _{BY from} the object A, or the ratio between the sum and the difference of the reception levels is constant with the azimuth angle θ of the object A. There is a correlation. Therefore, when detecting the two-dimensional relative position of the object A, the above-described correlation is determined and set in advance, and the correlation and the reception of the reflected waves corresponding to the electromagnetic wave beams B _X and _BY are detected. The azimuth of the target A is detected based on the level. Further, according to the principle of the FM-CW radar system, the relative distance of the object A is determined from the frequency of the beat signal generated corresponding to each of the electromagnetic wave beams _BX and _BY. The two-dimensional relative position of the object A is detected. Hereinafter, such a method of detecting the relative position of the object is referred to as a two-beam method.

The following method is also known as a method for detecting a two-dimensional relative position of an object.

That is, referring to FIG.
A pair of antennas a spaced apart in the direction₁, A_Two
Electromagnetic beam from each of the
B_P, B _QFrom the object A existing in the above area.
The reflected wave of each antenna a₁, A_TwoTo receive. Soshi
For example, according to the principle of the FM-CW radar system,
Each electromagnetic wave beam B_P, B_QGenerate a beat signal for each
Each antenna a of the object A depends on the frequency of each beat signal.
₁, A_TwoRelative distance D from₁, D_TwoAnd furthermore,
According to the principle of triangulation of knowledge, antenna a₁, A_TwoTo
Relative distance D as the center of each₁, D_TwoA pair with a radius of
Arc c₁, C_TwoThe intersection point P of the object A
And a two-dimensional relative position of the object A is detected.
You. Hereinafter, a method for detecting the relative position of an object in this manner
Is referred to as triangulation.

The relative distance of the object detected by the FM-CW radar method includes the detection accuracy of the frequency of the beat signal and the Doppler shift (frequency shift) of the received signal accompanying the movement of the object. Error (FIG. 8)
(A) and (b)). In the two-beam method, the level of the received signal for obtaining the azimuth of the object generally tends to fluctuate, and the azimuth angle θ of the detected object is relatively large as described above. (See FIG. 8A).

For this reason, in the two-beam method, even if the relative position of the object A is detected as described above, the object A is actually located in the hatched area in FIG. It is only known that the object A exists, and such an existing area of the object A spreads in the azimuth angle direction particularly when the detection error of the azimuth angle θ of the object A is relatively large. The position detection error also increases.

In the triangulation method, even if the relative position of the object A is detected as described above,
Due to the detection errors of the relative distances D ₁ and D ₂ of the object A detected corresponding to the electromagnetic wave beams B _P and B _Q , the object A is located in the hatched area in FIG. It is only known that the object A exists, and such an area where the object A exists is particularly large when the distance between the antennas a ₁ and a ₂ is smaller than the relative distances D ₁ and D ₂ of the object A. , Antenna a ₁ ,
spread at intervals direction of a _2, therefore, the detection error of the relative position of the object A is also increased. Such inconvenience is particularly caused by the antenna a in the case of a radar device for an automobile.
_1, the mounting position of a ₂ is limited, tends to occur can not be sufficiently increased their spacing.

[0013]

SUMMARY OF THE INVENTION In view of this background, the present invention can specify and detect a small range of an object in consideration of a detection error, and can accurately detect a two-dimensional relative position of the object. It is an object of the present invention to provide a radar device that can detect well.

[0014]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, a plurality of electromagnetic wave beams adjacent to each other from a pair of horizontally spaced antennas toward a common predetermined area. Transmitting and receiving means for receiving by each antenna a reflected wave from an object present in the transmitting direction of each electromagnetic wave beam, and a receiving means obtained by the transmitting and receiving means corresponding to each electromagnetic wave beam. Distance detecting means for detecting the relative distance of the object based on the time difference between the wave signal and the transmitted signal, and a pair of adjacent electromagnetic wave beams transmitted from the same antenna among the plurality of electromagnetic wave beams. Azimuth detecting means for detecting the azimuth of the object based on the reception level of the reflected wave corresponding thereto,
A first step of obtaining an existence range of the object from a relative distance detected by the distance detecting means and an azimuth detected by the azimuth detecting means in correspondence with at least one electromagnetic wave beam of the plurality of electromagnetic wave beams; An existence range detecting means and a triangulation method from a set of relative distances detected by the distance detecting means corresponding to each of a set of electromagnetic wave beams transmitted from different antennas among the plurality of electromagnetic wave beams. Position detecting means for detecting the position of the target object, second position range detecting means for obtaining the target range of the target object from the position of the target object detected by the position detecting means, And existence range specifying means for specifying an overlapping range of the existence range obtained by the second existence range detection means as the existence range of the object. The features.

Further, there is provided an existence position specifying means for specifying a center position of the existence range of the object specified by the existence range specifying means as an existing position of the object.

Also, by mixing the received signal and the transmitted signal obtained by the transmitting and receiving means corresponding to each of the electromagnetic wave beams, a beat signal having a frequency corresponding to the relative distance of the object can be obtained. A beat signal generating means for generating each electromagnetic wave beam is provided, and the distance detecting means detects a relative distance of the object based on a frequency of a beat signal generated by the beat signal generating means.

[0017]

According to the present invention, the relative distance of the object detected by the distance detecting means corresponding to at least one of the plurality of electromagnetic wave beams, and the relative distance of the plurality of electromagnetic wave beams From the azimuth of the object detected by the azimuth detecting means based on the reception level of the reflected wave corresponding to each of a pair of adjacent electromagnetic wave beams transmitted from the same antenna, their relative An existence range of an object in consideration of a detection error of a distance and an orientation is detected by the first existence range detection means, and a set of electromagnetic waves transmitted from different ones of the plurality of electromagnetic wave beams is used. From a set of relative distances of the object detected by the distance detecting means corresponding to each of the beams, the second existence range detecting means uses a triangulation method. Existence range of elephants object is detected. That is, a set of target object existence ranges is detected separately by different methods. Then, by specifying the overlapping range of the existence range detected by the first and second existence range detecting means as the existence range of the object, the existence range of the finally obtained object is narrowed.

Then, for example, by specifying the center of the existence range of the object narrowed as described above as the existence position of the object, it is possible to improve the detection accuracy of the existence position of the object.

In detecting the relative distance of the object by the distance detecting means, an FM-CW radar system, a pulse radar system, or the like can be used.
When the W radar system is used, the received signal and the transmitted signal corresponding to each electromagnetic wave beam are mixed by the beat signal generating means to generate a beat signal having a frequency corresponding to the relative distance of the object. Then, the relative distance of the target object is detected based on the frequency of the beat signal.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One example of the present invention will be described with reference to FIGS. FIG. 1 is an overall system configuration diagram of the radar apparatus of the present embodiment, FIG. 2 is a system configuration diagram of a main part of FIG. 1, and FIG.
FIG. 4 is a flowchart for explaining the operation of the radar device of FIG. 1, and FIGS. 5 to 7 are explanatory diagrams for explaining the operation of the radar device of FIG. It is.

Referring to FIG. 1, the radar device of the present embodiment is, for example, an FM-CW radar device mounted on an automobile, and 1 and 2 transmit and receive electromagnetic waves toward the front of vehicle 3 respectively. An antenna 4 attached to the front of the vehicle 3 with an interval in the vehicle width direction generates a transmission signal of an electromagnetic wave to be applied to the antennas 1 and 2, and receives the transmission signal and the antenna 1 and 2 to receive the transmission signal. A transmission / reception device (transmission / reception means) for generating and outputting a beat signal having a frequency corresponding to a relative distance of the object A existing in front of the vehicle 3 to the vehicle 3 from the received signal of the waved electromagnetic wave; Is a signal processing device that processes beat signal data output from the wave transmitting / receiving device 4 to detect a two-dimensional relative position of the object A with respect to the own vehicle 3 and the like, and 6 denotes an object A detected by the signal processing device 5. Relative position, etc. A planar image display device for displaying.

Each of the antennas 1 and 2, as shown in FIG.
A plurality (four in this embodiment) of electromagnetic wave beams Ba
i, Bbi, Bci, and Bdi (i is the code number of the antenna) can be transmitted in different directions adjacent to each other. Then, the antennas 1 and 2 have their respective electromagnetic wave beams B
ai, Bbi, Bci, and Bdi are arranged so as to point to a common area in front of the vehicle 3.

As shown in FIG. 2, the transmission / reception device 4 includes an oscillator 7 for generating an electromagnetic wave transmission signal, and a modulation control circuit 8 for temporally modulating and controlling the frequency of the transmission signal generated by the oscillator 7. A transmission signal output from the oscillator 7 via the isolator 9, the directional coupler 10, and the circulator 11 is selectively switched to each of the antennas 1 and 2, and each of the antennas 1 and 2 is provided in accordance with the transmission signal. A beam switching device 12 for selectively switching the electromagnetic wave beams Bai, Bbi, Bci, and Bdi transmitted by the electromagnetic wave beams Bai, Bbi, and Bdi.
Bci and Bdi are transmitted and distributed via the directional coupler 10 at the time of transmission.
A part of the input transmission signal and a reception signal of a reflected wave from the object A input from each of the antennas 1 and 2 via the circulator 11 are mixed to correspond to a temporal frequency difference between the two signals. A mixer 13 (beat signal generating means) for generating a beat signal having a frequency, an amplifier 14 for amplifying the beat signal generated by the mixer 13, and an A / D conversion of the beat signal amplified by the amplifier 14 for signal processing And an A / D converter 15 for outputting to the device 5. In this case, the beam switching device 12 switches between the antennas 1 and 2 that transmit and receive electromagnetic waves according to the timing instructed by the timing instructing unit 16 (see FIG. The switching of the electromagnetic wave beams Bai, Bbi, Bci, and Bdi is performed.

The signal processing device 5 is constituted by an electronic circuit including a microcomputer and the like, and has a functional configuration as a distance detecting means 17, an azimuth detecting means 18, a first existence range detecting means 19. , Position detecting means 2
0, second existence range detecting means 21, existence range specifying means 2
2 and an existence position specifying means 23. Details of these means 17 to 23 will be described later.

Next, the operation of the radar apparatus according to the present embodiment will be described together with the detailed description of each part thereof.

Referring to FIGS. 1 to 3, in the radar device of the present embodiment, the frequency of the transmission signal generated by the oscillator 7 of the transmission / reception device 4 is controlled by the modulation control circuit 8.
As shown by the solid line in FIG. 3, the signal is modulated into a triangular waveform, and the modulation control is repeated periodically at the timing specified by the timing specifying unit 16 of the signal processing device 5. And the transmission signal thus frequency-modulated is
Isolator 9, directional coupler 10, circulator 1
1 and each of the antennas 1 and 2 via the beam switching device 12. At this time, the beam switching device 12 first gives a transmission signal to the antenna 1 at the timing synchronized with the modulation of the transmission signal and issues an electromagnetic beam Ba1, B
b1, Bc1, and Bd1 are sequentially transmitted to the antenna 1.
Then, a transmission signal is applied to the antenna 2 and the electromagnetic wave beams Ba2, Bb2, Bc2,
The antenna 2 is controlled so as to sequentially transmit Bd2,
Thereafter, such switching and control are repeated. This allows
Electromagnetic wave beams Ba1, Bb1, Bc1, Bd frequency-modulated in the form of a triangular wave at the same frequency as the transmission signal from antennas 1 and 2.
1, Ba2, Bb2, Bc2, and Bd2 are sequentially transmitted to the front of the vehicle 3 at timing synchronized with the modulation of the transmission signal. At this time, a beam group consisting of the electromagnetic wave beams Ba1 to Bd1 of the antenna 1 and the electromagnetic wave beams Ba2 to Bd2 of the antenna 2
Are directed to a common area in front of the vehicle 3.

When transmitting such electromagnetic wave beams Bai to Bdi (hereinafter, simply referred to as an electromagnetic wave beam B when there is no need to distinguish these beams), the object is moved in the transmission direction of each electromagnetic wave beam B. When A exists, the electromagnetic wave beam B is reflected by the object A, and the reflected wave is received by the antenna 1 or 2 that transmitted the electromagnetic wave beam B. The received signal of the reflected wave (see FIG. 3)
The signal is input to the mixer 13 via the beam switching device 12 and the circulator 11 of the wave transmitting / receiving device 4. At this time, a part of the transmission signal output from the oscillator 7 is distributed and input to the mixer 13 via the directional coupler 10, and the mixer 13 converts these transmission signal and reception signal. Mixing. Thereby, every transmission of each electromagnetic wave beam B,
As described above, the beat signal having a frequency corresponding to the relative distance of the object A is generated by the mixer 13.
The beat signal sequentially generated by the mixer 13 in correspondence with each electromagnetic wave beam B is amplified by the amplifier 14 into a beat signal of a required amplitude level, and then, by the A / D converter 15, every predetermined sampling time. A / D converted and digitized beat signal data are output to the signal processing device 5.

The beat signal data sequentially generated corresponding to each electromagnetic wave beam B is processed by the signal processing device 5 as follows.

That is, referring to FIG. 4, the beat signal data output from the A / D converter 15 of the transmission / reception device 4 for each transmission of the electromagnetic wave beam B is first supplied to the distance detection means of the signal processing device 5. 4 (STEP 1 in FIG. 4), the distance detecting means 17 analyzes the frequency of the received beat signal data using an FFT (Fast Fourier Transform method) which is an arithmetic processing method of frequency analysis, and The spectrum distribution is obtained (STEP 2 in FIG. 4).

At this time, as shown in FIG. 1, for example, if the object A exists in the transmission direction of the electromagnetic wave beams Bb1 and Bc1 transmitted from the antenna 1, these electromagnetic wave beams Bb
The spectral distribution of the beat signal as conceptually shown in FIGS. 5A and 5B is obtained corresponding to 1 and Bc1, respectively. That is, the spectrum distribution is basically such a distribution that the spectrum level has a maximum value (peak) at a frequency f _P corresponding to the relative distance D _{1 of the} object A from the antenna ₁ (see FIG. 7). Become. In the spectrum distribution, a spectrum level at a frequency f _P (hereinafter, referred to as a peak frequency f _P ) corresponds to a reception level of a reflected wave reflected by the object A and directly received by the antenna 1. Things. In addition, when the object A exists in the transmission direction of the electromagnetic wave beam Ba2 as shown in FIG. 1, the electromagnetic wave beam Ba2 transmitted from the antenna 2 also
A spectrum distribution similar to the above is obtained, and the spectrum distribution is such that the spectrum level has a maximum value at a frequency corresponding to the relative distance D ₂ of the target A from the antenna ₂ (see FIG. 7).

Next, the distance detecting means 17 calculates, for each of the spectral distributions of the beat signals obtained corresponding to the electromagnetic wave beams B of the antennas 1 and 2 as described above,
The peak frequency f _{P at} which the spectrum level is equal to or higher than a threshold value (see FIG. 5) set in advance to eliminate noise components and the like and has a maximum value is determined by the antennas 1 and 2 of the object A.
The frequency is detected as a frequency corresponding to the relative distance from 2 (STEP 3 in FIG. 4). Then, relative distances D ₁ and D ₂ of the object A from each of the antennas 1 and 2 are obtained from the detected peak frequency f _{P in} accordance with the equation (1) for each of the antennas 1 and ₂ (STEP 4 in FIG. 4). ).

At this time, when the object A exists as shown in FIG. 1, the two electromagnetic wave beams B
From the spectral distributions corresponding to b1 and Bc1, the peak frequency f
_P is obtained, these peak frequency f _P may be a frequency slightly different due to the transmitting direction of the electromagnetic wave beam Bb1, Bc1 different, when determining the relative distance D ₁ of the from the antenna 1 For example, the relative distance D ₁ is obtained by using the peak frequency f _P having the larger spectrum level or by using the average value of the peak frequencies f _P. This is the same when peak frequencies are obtained for three or more electromagnetic wave beams B of the antenna 1,
The same applies to the antenna 2.

The relative distances D ₁ and D ₂ obtained for the antennas ₁ and ₂ are output to the first existence range detecting means 19 and the position detecting means 20 of the signal processing device 5.

The distance detecting means 17 includes the antenna 1,
2, the peak frequency f obtained corresponding to each of a pair of electromagnetic wave beams B adjacent to each other.
The spectrum level of _P (the reception level of the reflected wave) is detected from the spectrum distribution corresponding to each electromagnetic wave beam B, and the spectrum level is output to the azimuth detecting means 18. In this case, for each of the antennas 1 and 2, if there is a pair of electromagnetic wave beams B adjacent to each other at which a peak frequency is obtained, for example, the peak obtained for one of the predetermined antennas of the antennas 1 and 2 is obtained. The set of frequency spectrum levels is output to the azimuth detecting means 18. When a peak frequency is obtained for one of the antennas 1 and 2 corresponding to three or more electromagnetic wave beams B adjacent to each other, for example, one of the spectral levels of those peak frequencies having a higher level is used. The set of spectrum levels is output to the azimuth detecting means 18. FIG.
In the case of the spectral level of the electromagnetic wave beam Bb1, peak frequency f _P corresponding to Bc1 S _P1, S _P2 (see FIG. 5)
Is output to the azimuth detecting means 18.

Next, the azimuth detecting means 18 uses the set of peak levels f _{P and} the spectrum levels S _P1 and S _P2 provided from the distance detecting means 17 as described above, and performs the object A by the two-beam method. Direction is detected, and this is
Is output to the existence range detecting means 19 (STEP in FIG. 4).
5).

In this embodiment, as shown in FIG.
The ratio of the sum and difference of the spectral levels S _P1 and S _P2 (S _P1 −S
The correlation between _P2 ) / ( _SP1 + _SP2 ) and the azimuth angle θ (see FIG. 7) is set in the azimuth detecting means 18 by a map or the like. Spectral levels S _P1 , S given by the detecting means 17
_{From P2} , the azimuth angle θ of the object A is detected. At this time,
When the target A exists as shown in FIG. 1, the azimuth angle θ of the electromagnetic wave beams Bb1 and Bc1 with respect to the center direction is detected as shown in FIG.

Next, the azimuth angle θ of the object A obtained for one of the antennas 1 and 2 by the two-beam method as described above, and the object A from the one antenna 1 or 2
From the relative distance D ₁ or D ₂ Prefecture, existence range of their orientation angles and the object A in consideration of the detection error of the relative distance is determined by the first existence range detection means 19 (STEP6 in FIG. 4). In this case, the first existence range detecting means 19
, A detection error range of the azimuth angle and the relative distance is set in advance, and the existence range detection means 19 is, for example, on a two-dimensional plane determined by the azimuth angle and the relative distance of the object A obtained by the two-beam method. A range formed by superimposing the detection error ranges of the azimuth angle and the relative distance around the point is determined as the existence range of the target A by the two-beam method. Specifically, when the object A exists as shown in FIG.
, The azimuth angle θ obtained for the antenna 1
A point determined by the relative distance D ₁ of the from the antenna 1 P ₁
, A range S in which the detection error ranges of the azimuth angle and the relative distance are superimposed is determined as the existence range of the target A by the two-beam method.

On the other hand, while the existence range S of the object A is obtained by the two-beam method as described above, each of the antennas 1 and 2 obtained by the distance detecting means 17 as described above is used.
Based on the relative distances D ₁ and D ₂ of the object A from the position ₂ , the position of the object A is determined by the position detection means 20 using the triangulation method (STEP 7 in FIG. 4). The existence range of the object A is obtained by the second existence range detection means 21 by triangulation (ST in FIG. 4).
EP8).

More specifically, when the object A is present as shown in FIG. 1, referring to FIG. 7, the position detecting means 20 determines the circular arc c ₁ having the relative distance D ₁ as a radius around the antenna _1.
When obtains the intersection P ₂ of the arc c ₂ that the relative distance D ₂ and the radius around the antenna 2 as a location of the object A by triangulation. Then, the second existence range detecting means 2
1. A triangulation method is used to set a range W obtained by superimposing a predetermined detection error range of relative distances D ₁ and D ₂ around the position P ₂ of the object A obtained by the position detection means 20. It is determined as the existence range of the object A.

Next, the existence range specifying means 22 of the signal processing device 5 determines the overlapping range Z of the existence ranges S and W of the object A detected as described above by the two-beam method and the triangulation method (FIG. 7). Reference), and this is specified as the actual existence range of the object A (STEP 9 in FIG. 4). When the target A exists as shown in FIG. 1, the triangular range Z is specified as the actual existence range of the target A as shown in FIG. Thereby, the existence range of the object A is obtained by the existence ranges S and W obtained by the two-beam method and the triangulation method, respectively.
, And the existence range of the target object A is specified in a small range.

Next, the existence position specifying means 22 of the signal processing device 5 determines the center position of the existence range Z of the object A (point P in FIG. 7) obtained by the existence range specifying means 22 as described above.
₃ ) is obtained, and the obtained position is specified as the position of the target A (STEP 10 in FIG. 4). Center position P of existence range Z
₃ is obtained, for example, as follows.

That is, as shown in FIG. 7, for example, the position of the antenna 2 is taken as the origin O, the X axis is taken in the direction of the interval between the antennas 1 and 2, and the Y axis is taken in the direction perpendicular thereto. The XY coordinates of the corner points Q ₁ , Q ₂ , and Q ₃ at Z are (x ₁ , y ₁ ), (x ₂ , y ₂ ),
(X ₃ , y ₃ ), the center position P of the existence range Z
_{3 The} XY coordinates (x, y) of (the location of the object A)
It is determined by the following equations (2) and (3).

[0043]

(Equation 1)

The existence position specifying means 22 determines the existence position P ₃ of the object A, and further calculates the error range Δx of the existence position P ₃ of the object A in the vehicle width direction (X-axis direction) and the traveling direction. An error range Δy in the (Y-axis direction) is obtained by the following equations (4) and (5), respectively (STEP 11 in FIG. 4).

[0045]

(Equation 2)

Then, the presence position specifying means 22
Position P of the object A obtained as described above _ThreeAnd vehicle width direction (X axis
Direction) error range Δx and the traveling direction (Y axis direction) error range.
Is output to the planar image display device 6 and the
It is visually displayed on the display device 6 (STEP 1 in FIG. 4).
2).

[0047] In the radar apparatus of this embodiment is repeated actuation described above, the location P _3, etc. of the object A is detected every moment.

As described above, in the radar apparatus according to the present embodiment, the overlapping range of the existence ranges X and Y of the object A obtained using the two-beam method and the triangulation method, respectively, is used as the actual range of the object A. By specifying the existence range Z, the existence range Z can be reduced, and the existence range Z of the object A can be detected with high accuracy. Further, the center position of the existence range Z can be detected as the existence position of the object A. By specifying as, the detection accuracy of the two-dimensional relative position of the object A can be improved.

In this embodiment, the radar apparatus using the FM-CW radar system has been described. However, even if a radar system such as a pulse radar system is used, the existence range of the object and the like can be obtained in the same manner as in this embodiment. Can be detected.

[0050]

As is apparent from the above description, according to the present invention, a plurality of electromagnetic wave beams are respectively transmitted and received from a pair of antennas arranged at intervals in the horizontal direction.
The existence range of the object is detected by a two-beam method using a pair of electromagnetic wave beams adjacent to each other on one antenna, and the existence range of the object is detected by a triangulation method using a pair of electromagnetic wave beams of both antennas. By detecting and identifying the overlapping range of the detected existence ranges as the actual existence range of the object, the existence range of the object in consideration of the detection error can be identified and detected as a small one, The existence range can be accurately detected.

Then, the two-dimensional relative position of the object can be accurately detected by specifying the center position of the existence range of the object specified as described above as the position of the object.

[Brief description of the drawings]

FIG. 1 is an overall system configuration diagram of an example of a radar apparatus according to the present invention.

FIG. 2 is a system configuration diagram of a main part of the radar device of FIG. 1;

FIG. 3 is an explanatory diagram for explaining the operation of the radar device of FIG. 1;

FIG. 4 is a flowchart for explaining the operation of the radar device of FIG. 1;

FIG. 5 is an explanatory diagram for explaining the operation of the radar device of FIG. 1;

FIG. 6 is an explanatory diagram for explaining the operation of the radar device of FIG. 1;

FIG. 7 is an explanatory diagram for explaining the operation of the radar device of FIG. 1;

FIG. 8 is an explanatory diagram for explaining a method of detecting an object by a conventional radar device.

[Explanation of symbols]

4 ... Transmission / reception device, 13 ... Mixer (beat signal generation means), 17 ... Distance detection means, 18 ... Direction detection means, 19
... First existence range detecting means, 20 ... Position detecting means, 21
... second existence range detecting means, 22 ... existence range specifying means,
23 ... existence position specifying means.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI G01S 13/34 G01S 13/34 (56) References JP-A-4-348294 (JP, A) JP-A-4-270981 (JP , A) JP-A-5-256941 (JP, A) JP-A-5-297123 (JP, A) JP-A-4-118684 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB G01S 7/00-7/42 G01S 13/00-13/95

Claims (3)

(57) [Claims] A pair of antennas arranged at intervals in the horizontal direction transmit a plurality of electromagnetic wave beams adjacent to each other toward a common predetermined region, and a plurality of electromagnetic wave beams are present in a direction in which the electromagnetic wave beams are transmitted. Transmitting and receiving means for receiving a reflected wave from an object to be received by each antenna, and the object based on a time difference between a received signal and a transmitted signal obtained corresponding to each electromagnetic wave beam by the transmitting and receiving means. Distance detecting means for detecting a relative distance, and based on the reception level of the reflected wave corresponding to each of a pair of adjacent electromagnetic wave beams transmitted from the same antenna among the plurality of electromagnetic wave beams, Azimuth detecting means for detecting the azimuth of the object; and a relative distance detected by the distance detecting means corresponding to at least one of the plurality of electromagnetic wave beams and the azimuth detection. First existence range detection means for obtaining the existence range of the object from the direction detected by the means, and a plurality of electromagnetic wave beams corresponding to a pair of electromagnetic wave beams transmitted from different antennas among the plurality of electromagnetic wave beams, respectively. Position detecting means for detecting the position of the object by triangulation from a set of relative distances detected by the distance detecting means, and the position of the object detected by the position detecting means, Second existence range detection means for finding the existence range of the target object, and existence range identification for specifying the overlapping range of the existence range obtained by the first and second existence range detection means as the existence range of the target object And a radar device. 2. The apparatus according to claim 1, further comprising: an existence position specifying unit that specifies a center position of the existence range of the target object specified by the existence range specification unit as the existence position of the target object. Radar equipment. 3. A beat signal having a frequency corresponding to a relative distance of the object is obtained by mixing a reception signal and a transmission signal obtained by the transmission / reception means corresponding to each of the electromagnetic wave beams. The apparatus according to claim 1, further comprising: a beat signal generating unit configured to generate a beat signal for each electromagnetic wave beam, wherein the distance detecting unit detects a relative distance of the object based on a frequency of the beat signal generated by the beat signal generating unit. 2. The radar device according to 1.