JP3260948B2 - Radar device with self-diagnosis function and planar antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to output a wave transmitted from a transmitting antenna to a front space, receive a reflected wave formed by a target ahead through a receiving antenna, and identify the presence / absence and distance of the target. The present invention relates to a radar device having a self-diagnosis function.

[0002]

2. Description of the Related Art A radar device has been put to practical use which outputs a transmission wave from a transmission antenna to a front space, receives a reflection wave formed by a target ahead through a reception antenna, and identifies the presence / absence and distance of the target. ing. Radar devices can be broadly classified into a pulse system that outputs a transmitted wave in a pulsed form and a continuous wave system that continuously outputs a transmitted wave.One example of an application is to mount a vehicle on an automobile and determine the inter-vehicle distance to a preceding vehicle ahead. This is an application to measure.

[0003] A general radar device uses radio waves in the millimeter wave band, and a remarkable electronic circuit for signal generation, transmission path, reception path, and signal processing is required to operate with a high-frequency signal at the GHz level. You. Therefore, when the self-diagnosis function is added, a very special circuit design is required, and the number of signals that can be extracted from the transmission / reception circuit for the purpose of self-diagnosis is also limited.

FIG. 5 is an explanatory diagram of a conventional FM-CW radar device. In the figure, (a) shows an inter-vehicle distance measurement, (b) shows a circuit configuration, and (c) shows a transmission / reception signal. Here, the inter-vehicle distance is measured using the transmission wave that is regularly frequency-modulated.

[0005] In FIG. 5 (a), a transmitting antenna 54 and a receiving antenna 55 are arranged in front of a vehicle 51. A high-frequency signal supplied from a radar device mounted on the vehicle 51 is converted into a transmission wave by a transmission antenna 54.
The transmitted wave radiated into the front space reaches the preceding vehicle 52 and forms a reflected wave. Part of the reflected wave travels toward the vehicle 51 and is received by the receiving antenna 55. The received high-frequency signal is processed to determine whether or not the preceding vehicle 52 exists.
, And the relative speed between the own vehicle 51 and the preceding vehicle 52.

In FIG. 5B, a frequency modulation section 53A
Changes the oscillation frequency of the oscillator 53B regularly at a predetermined amplitude and period to form a high-frequency transmission signal in the GHz band. The high-frequency transmission signal is guided to the transmission antenna 54,
Converted to outgoing waves.

[0007] The reflected wave is received by the receiving antenna 55 and converted into a high-frequency received signal. After being amplified by the amplifier 56C, the high-frequency reception signal is input to the mixer 56B, and the high-frequency transmission signal extracted from the transmission side through the directional coupler 56A is integrated. The directional coupler 56A is an element that extracts only a part of the high-frequency signal propagating from the oscillator 53B.

The signal processing unit 57 performs signal processing, frequency analysis, frequency detection, calculation operation, and the like by using the beat signal obtained by integrating the high-frequency reception signal and the high-frequency transmission signal, and executes the own vehicle 51 and the preceding vehicle 52. Find the distance between vehicles. The relative distance is notified to the driving vehicle through the distance display unit 58A, and is also used to control the speed of the vehicle 51 through the vehicle speed control unit 58B.

The transmitting antenna 54 and the receiving antenna 5
5 can employ a waveguide array antenna, a waveguide parabolic antenna, or the like, in addition to a planar antenna such as a microstrip line antenna or a triplate antenna. However, a strong directivity is provided so that the detection area is within the same lane even several hundred meters ahead.

Referring to FIG. 5C, the oscillator 53 shown in FIG.
The high-frequency transmission signal generated at B changes its frequency up and down linearly with a constant period over a constant frequency width around the center frequency f _C. On the other hand, the antenna 55B
The high-frequency reception signal received through has a time delay caused by the time required to reciprocate in the distance from the own vehicle 51 to the preceding vehicle 52 and the Doppler effect due to the relative speed.

[0011]

In the radar apparatus shown in FIG. 5, the frequency modulator 53A, the oscillator 53B, the transmitting antenna 54, the receiving antenna 55, the amplifier 56C, the directional coupler 56A, and the path from the oscillator 53B to the transmitting antenna 54. If an abnormality occurs in any one of the paths from the receiving antenna 55 to the signal processing unit 57, the function of detecting the preceding vehicle 52 and measuring the inter-vehicle distance cannot be performed.

[0012] For example, the oscillator 53
When the output of B decreases, when the fixation of the waveguide forming the path from the oscillator 53B to the transmitting antenna 54 is loosened,
A case where the noise level of the amplifier 56C increases may be considered.

In such a case, even if the preceding vehicle 52 is running immediately in front of the own vehicle 51, a display indicating that the preceding vehicle 52 does not exist is displayed. In addition, the inter-vehicle distance output from the radar device is a meaningless numerical value. When the output distance between the vehicles becomes meaningless, the radar device for ensuring safety while driving may adversely affect the driver's judgment or hinder driving, which may cause danger during driving. May increase.

If an automatic driving function (cruise control) for controlling the speed of the vehicle 51 in accordance with the inter-vehicle distance output from the radar device to keep the inter-vehicle distance constant is introduced, the preceding vehicle 52 cannot be detected. In this case, the possibility of collision with the preceding vehicle 52 is increased as it is, and the reliability of speed control cannot be ensured.

By the way, a self-diagnosis system applied to a general device is a system in which an abnormality detection sensor is provided in each of the components, and when all the sensors show normality, it is determined that the entire function is normal. When such a self-diagnosis system is applied to the radar device shown in FIG. 5B, a frequency modulation unit 53A, an oscillator 53B, a transmission antenna 54, a reception antenna 55, an amplifier 56C, a directional coupler 56A, a transmission antenna It is necessary to provide an abnormality detection sensor on each of the path from the receiving antenna 55 to the signal processing unit 57, and to separately provide an arithmetic element and the like for judging the outputs of all the sensors at regular intervals.

In such a self-diagnosis system, parts are significantly added, and it is necessary to completely redesign and arrange parts and circuits in the conventional radar apparatus. This leads to an increase in the size and cost of the entire apparatus.

The present invention provides a radar apparatus with a self-diagnosis function which can identify the overall quality of the target detection function of the radar apparatus, can easily be diverted from the conventional radar apparatus, and can realize the self-diagnosis function at low cost. It is intended to provide.

[0018]

FIG. 1 is an explanatory diagram of a radar device according to a first embodiment. The radar device with a self-diagnosis function according to claim 1 will be described with reference to the symbols attached to the configuration in FIG. However, the radar device with a self-diagnosis function according to claim 1 is not limited to the mode described in FIG. 1 and the first embodiment.

In FIG. 1, a radar device with a self-diagnosis function according to claim 1 radiates a high-frequency signal propagating through a track to a space, and forms a transmission wave going forward, and a target object in front. A receiving antenna 15 for receiving a reflected wave formed by the transmission wave and converting the reflected wave into a high-frequency signal propagating through another line, and a part of the high-frequency signal propagating through the line of the transmitting antenna 14 Means 12A, 12
B, the switch means 19A, 1B, which can intermittently connect the line of the transmitting antenna 14 and the line of the receiving antenna 15 at a predetermined frequency.
9B and detecting means 17 for detecting a frequency component generated in relation to the predetermined frequency with respect to a high-frequency signal propagating through the line of the receiving antenna 15 during a period when the switching means 19A and 19B are intermittently connected. And identification means 17 for identifying a function abnormality based on the detection result of the frequency component.

A planar antenna according to a second aspect of the present invention is a planar antenna having two antenna patterns for transmission and reception arranged on the same plane, wherein at least one radiating part of the transmission antenna pattern and the reception antenna are provided. A switch element is provided between at least one receiving unit of the antenna pattern for use in communication with both according to an external signal.

According to a third aspect of the present invention, there is provided a radar apparatus with a self-diagnosis function, which radiates a high-frequency signal propagating on a track to a space and forms a forward-transmitted wave, and the forward target forms the transmitted wave. A receiving antenna that receives the reflected wave, and converts the reflected wave into a high-frequency signal that propagates through another line, and a modulation unit that performs amplitude modulation of a predetermined frequency on the high-frequency signal that propagates through the line of the receiving antenna. In a heterodyne type radar device having, a switch means capable of communicating the transmission antenna line and the reception antenna line, and a high-frequency signal propagating through the reception antenna line during a period in which the switch means is in contact, Detecting means for detecting a frequency component generated in relation to the predetermined frequency; and identifying a function abnormality based on the detection result of the frequency component. And identification means, in which the provided.

According to a fourth aspect of the present invention, there is provided a radar apparatus having a self-diagnosis function, wherein a transmission wave generating means for forming a high-frequency transmission signal which is regularly frequency-modulated with a predetermined amplitude and a predetermined period; A transmitting unit that outputs a transmitting wave to a space, a receiving unit that receives a reflected wave formed by a target ahead of the transmitting wave to form a high-frequency receiving signal, and converts a part of the high-frequency transmitting signal to the high-frequency receiving signal. An FM-CW type radar device having an integrating means for integrating, a switch means capable of communicating a line of the transmitting antenna and a line of the receiving antenna, and the receiving antenna during a period in which the switching means is connected. Detecting means for detecting a frequency component generated in connection with the regular modulation of the high-frequency transmission signal, for the high-frequency signal propagating through the line, Identifying means for identifying an abnormality of functions based on the detection result of the component, in which the provided.

[0023]

In FIG. 1, in the radar device with a self-diagnosis function according to the first aspect, a high-frequency signal for self-diagnosis irrelevant to the target ahead is generated on the line of the receiving antenna 15 using the switch means 19A and 19B. Let it. At this time, if the switch means 19B is simply communicated, the integration means 12
A and 12B result in integration of high-frequency signals of the same frequency, and the amplitude of the intermediate frequency signal (or beat signal) input to the detection means 17 becomes 0, and a signal for self-diagnosis reflecting the entire function is obtained. I can't.

Therefore, the switching means 19A and 19B intermittently communicate the transmitting antenna side and the receiving antenna side at a predetermined frequency. The amplitude of the frequency component generated due to the intermittent frequency reflects the state of the overall function of the radar device, and can be used as a signal for self-diagnosis. The identification unit 17 determines, for example, whether the amplitude of the frequency component is a normal value or not, and identifies whether the overall function is normal / abnormal.

The timing for performing the self-diagnosis by operating the switch means 19A and 19B may be a fixed time just after the power of the radar device is turned on. However, in the case where the radar apparatus is mounted on a car, the self-diagnosis may be performed every 0.1 seconds, for example, every 0.1 seconds in order to continuously maintain the reliability of the radar apparatus while traveling. At this time, the self-diagnosis may be performed during the duration of the pulse by outputting a long pulse in the pulse method or in a state in which the FM modulation is temporarily stopped in the FM-CW method.

When the switch 19B directly communicates between the receiving antenna 15 and the transmitting antenna 14, it is possible to discriminate whether the whole function including the receiving antenna 15 and the transmitting antenna 14 is normal or abnormal. However, since the receiving antenna 15, the transmitting antenna 14, and the route following these are usually fixed and hard to break down, the integrating means 12A, 12B
The switch means may be arranged on the side closer to. For example, the switch means can be incorporated in an integrated circuit including the amplifier 16.

The flat antenna according to the second aspect can be employed in the radar apparatus having the self-diagnosis function according to the first aspect. The switch element controls connection / disconnection between the transmitting antenna pattern and the receiving antenna pattern according to an external signal.

The radar device with a self-diagnosis function according to the third aspect is of a heterodyne type in which an intermediate frequency signal is formed from a received high-frequency signal using an output of a local oscillator that is unrelated to a high-frequency signal of a transmitted wave. Therefore, the problem caused by the above-described integrating means (12A, 12B) does not occur,
The intermediate frequency signal directly reflects the overall function of the radar device. Therefore, there is no need to intermittently contact the switch means at a predetermined frequency (see FIG. 4 (c)).

Further, not only in the case of performing the pure heterodyne signal processing, but also in the case of the so-called pseudo-heterodyne method, it is not necessary to intermittently connect the switch means at a predetermined frequency. In the process of forming an intermediate frequency signal from the received high-frequency signal,
In this method, after a predetermined amplitude modulation operation is applied to a received high-frequency signal, a part of the transmitted high-frequency signal is integrated (see FIG. 4A).

The application of the radar device with a self-diagnosis function according to the fourth aspect is limited to the FM-CW type radar device. In the FM-CW type radar device, a self-diagnosis signal reflecting the entire function is reflected by using the FM modulation frequency component included in the high-frequency transmission signal without intermittently communicating the switch means at a predetermined frequency. Can be secured.

However, in the FM-CW type radar device, it is also possible to configure the system of claim 1 in which the switch means is intermittently communicated at a predetermined frequency to secure a signal for self-diagnosis.

In the FM-CW radar device, the FM
Due to the modulation frequency, the output of the integrating means includes FM-AM conversion noise. FM- when contacting the switch means
Since the AM conversion noise has an amplitude that reflects the entire function of the radar device, the amplitude of the FM-AM conversion noise can be detected to determine whether the entire function is normal or abnormal.

[0033]

FIG. 1 is an explanatory view of a radar device according to a first embodiment,
FIG. 2 is an explanatory diagram of a planar antenna, and FIG. 3 is an explanatory diagram of switching. In FIG. 1, (a) shows the configuration, and (b) shows the signal processing program. In FIG. 2, (a) shows the arrangement, and (b) shows the structure. 3A shows no switching, FIG. 3B shows switching, and FIG. 3C shows a determination circuit.

Here, a self-diagnosis function that can be used for a pulse type or FM-CW type radar device will be described.
In the pulse method, when a long pulse is output, the FM-C
In the W system, the switching elements are intermittently connected at a constant frequency while the FM modulation is temporarily stopped. As a result, an intermediate frequency signal (or beat signal) for self-diagnosis reflecting the overall function is formed on the line on the receiving antenna side.

In FIG. 1 (a), the transmission wave generator 11
A high frequency signal in the GHz band is generated. In the pulse method, pulse-shaped amplitude modulation is added, and in the FM-CW method, regular frequency modulation is added. Thereafter, the high-frequency signal is transmitted to the directional coupler 1.
It is supplied from the output side circuit including 2A to the transmission antenna 14 through the waveguide 13A, and is radiated to the space to form a transmission wave.

A part of the reflected wave formed by the forward target by the transmitted wave enters the receiving antenna 14 and is converted into a high-frequency signal. The received high-frequency signal is input to the amplifier 16 through the waveguide 13B. The amplifier 16 is a front-end low-noise amplifier.
IC (Microwave Integrated Circuit) and MMIC (Mo
norisic MIC).

In the mixer 12B, the output of the amplifier 16 is supplied to the output wave generator 11 branched by the directional coupler 12A.
Are integrated. The output of the mixer 12B is input to the reception processing unit 17 as an intermediate frequency signal (or beat signal). High-frequency components in the GHz band remaining in the intermediate frequency signal are effectively removed by the filter effect of the line reaching the reception processing unit 17.

In the normal measurement mode, the reception processing unit 17 performs signal processing on the input intermediate frequency signal (or beat signal), executes necessary detection operations and arithmetic operations, and executes the necessary inter-vehicle distance to the preceding vehicle ahead. Ask for. The obtained inter-vehicle distance is numerically displayed to the driver through the inter-vehicle distance display section 18A.

On the other hand, the reception processing unit 17 shifts to the self-diagnosis mode for every t seconds at regular intervals. In the self-diagnosis mode, the switch element 19B is operated through the drive unit 19A, so that the transmission antenna 14 and the reception antenna 15 are intermittently connected at a constant frequency.

The reception processing unit 17 extracts a frequency component reflecting the entire function from the intermediate frequency signal (or beat signal) at this time to form a signal for self-diagnosis. The amplitude of the self-diagnosis signal is determined by the transmission wave generator 11, the directional coupler 12A, the waveguide 13A, the transmission antenna 14, the reception antenna 15, the waveguide 13B, the amplifier 16, the mixer 12B,
The amplitudes of the signals for self-diagnosis when all other waveguides are normal are compared.

In this manner, the normal / abnormal of the total function of the entire radar apparatus can be accurately identified without judging the normal / abnormal of each configuration at all. The identification result (normal / abnormal) is displayed to the driver through the diagnosis result display section 18B. If it is determined that there is an abnormality, the display of the inter-vehicle distance display section 18A is not performed.

In FIG. 1B, in the radar device of the first embodiment, the normal sequence 10A for measuring the following distance is repeated unless the reception processing unit 17 shifts to the self-diagnosis mode and instructs to start the diagnosis. However, the reception processing unit 1
7 shifts to the self-diagnosis mode and commands the start of diagnosis,
The self-diagnosis sequence 10B is selected.

In FIG. 2A, a planar antenna 22 is mounted on a grill in front of a vehicle body 21. The planar antenna 22 has the transmitting antenna 14 and the receiving antenna 15 arranged side by side. The area where the directivity of the transmitting antenna 14 and the directivity of the receiving antenna overlap constitutes the detection area 23. A part of the reflected wave formed by the target located in the detection area 23 is received through the receiving antenna 15.

In FIG. 2B, the transmitting antenna 14 and the receiving antenna 15 are formed on the surface of a common dielectric substrate 24 by a transmitting antenna pattern 14P and a receiving antenna pattern 1.
5P is formed. Antenna pattern 14P,
15P forms a microstrip line structure, forms a waveguide in cooperation with a ground electrode formed on the back surface of the dielectric substrate 24, and propagates a high frequency in a form in which radio waves are confined in the dielectric substrate 24.

The waveguide wavelength λ _g in the waveguide of the microstrip line can be changed by adjusting the dielectric constant, the thickness and the like of the dielectric substrate 24. In a microstrip line waveguide, the size and shape of the line are adjusted to form a waveguide for transmitting a high frequency wave, a reflecting portion for turning back, and a radiating portion for emitting radio waves into space.

The antenna pattern 14P is formed on the dielectric substrate 2
On the 4, a large number of radiating portion 1 by an integer multiple of the spacing of the waveguide wavelength lambda _g
4R is arranged. And the line 14 of an appropriate pattern
L, the radiating portions 14R are connected to each other, and the waveguide 1 of the feeding portion is connected.
Contact 3A. On the other hand, the antenna pattern 15P connects a large number of radiating portions 15R arranged in the same manner with a line 15L to communicate with the waveguide 13B. The lines 14 </ b> L and 15 </ b> L are designed in a pattern and a dimensional shape capable of forming a waveguide and confining a radio wave in the dielectric substrate 24. On the other hand, the radiating section 14
R and 15R are designed to have dimensions that radiate radio waves from the waveguides of the lines 14L and 15L to the space.

Many radiating portions 1 of the antenna pattern 14P
The radio waves radiated from the 4R advance in the vertical direction with the phases aligned, and form a highly directional transmission wave. On the other hand, the reflected waves taken in through the many radiating portions 14R of the antenna pattern 15P have the same phase in the waveguide of the line 15L to form a high-frequency signal.

The pin diode 19B is arranged below the center of the dielectric substrate 24. The pin diode 19B can ensure an efficient switching function even at a high frequency, and short-circuits the antenna pattern 14P and the antenna pattern 15B when an external signal is applied.

Incidentally, the triplate structure in which the upper and lower portions of the antenna pattern 14P and the antenna pattern 15P are sandwiched between dielectrics also propagates a high frequency by a mechanism similar to that of a microstrip line antenna, and radiates radio waves into space. Therefore, the structure of FIG. 2B can be applied to a triplate antenna as it is. In the triplate antenna, a radiation opening is provided at a position corresponding to each radiation part on the ground electrode on the front surface side.

In FIG. 3 (a), when the switch element 19B of FIG. 1 (a) continuously connects the transmitting antenna 14 and the receiving antenna 15, the output of the amplifier 16 is of it does not include a frequency component other than the oscillation frequency f _r.

In FIG. 3 (b), in the state where the switching element 19B of FIG. 1 (a) intermittently connects the transmitting antenna 14 and the receiving antenna 15 at a constant frequency, it is affected by the switching frequency f _L. , the output of the amplifier 16, in addition to the frequency component of the oscillation frequency f _r of the sending wave generating unit 11, f _r ± nf _L: contains the frequency components of the (n is a natural number). This additional frequency component is output from the mixer 12B to the output wave generator 11, the directional coupler 12
A, waveguide 13A, transmitting antenna 14, receiving antenna 1
5, having an amplitude that comprehensively reflects all functions of the waveguide 13B, the amplifier 16, the mixer 12B, and other signal lines.

Therefore, by extracting the additional frequency component from the output of the mixer 12B and detecting the amplitude, it is possible to easily determine whether the overall function is normal or abnormal. For example, through a band-pass filter characteristics illustrating the output of the mixer 12B, it examining the amplitude by extracting a frequency component of f _r + f _L.

Referring to FIG. 3 (c), another method for examining ancillary frequency components is to extract a frequency component of f _L from the output of the mixer 12B using a low-pass filter 27, and amplify the frequency component with an amplifier 28 having an appropriate gain. This is a method of counting pulses using a counter 29 that counts pulses having a certain amplitude or more. If the pulse count per unit time corresponds to f _L , it is determined that the entire function is normal.

FIG. 4 is an explanatory view of a radar device according to another embodiment. In the figure, (a) shows a pseudo heterodyne type, (b) shows an example using a directional coupler, and (c) shows a heterodyne type.
In the first embodiment, the amplitude modulation (ON-OFF) is performed by the switch element in order to secure a signal component for self-diagnosis reflecting the entire function in the output of the mixer. When the signal component can be secured, it is not necessary to cause the switch element to perform amplitude modulation.

In FIG. 4A, the quasi-heterodyne method refers to the transmission wave generator 41 branched by the directional coupler 42A.
In this method, the output of A is integrated with the received signal amplitude-modulated by the amplifier 46A to form an intermediate frequency signal. The high frequency in the GHz band used for the transmission wave cannot be used for signal processing as it is, the loss in a waveguide such as a microstrip line is large, and the line pattern design of the circuit is not easy. Therefore, in the front end including the mixer 42E and the amplifier 46A, the high frequency in the GHz band is converted into an intermediate frequency signal. The component in the GHz band included in the output of the mixer 42E is
It is removed by the line until it reaches the reception processing unit 47A.

The front end switching unit 31A is
A pulse having a predetermined frequency is output, and the output of the amplifier 46A is amplitude-modulated (ON-OFF). In this case, the amplifier 46
A shares the amplitude modulation in the first embodiment, and if the switch element 49E is continuously turned on for t seconds, the input signal of the mixer 46E is the same as that in the first embodiment.

The reception processing section 47A shifts to the self-diagnosis mode for every t seconds at a fixed time interval, and brings the switch element 49E into the communication state for t seconds through the driving section 49A. The output of the transmission wave generator 41A flows directly from the transmitting antenna 44A to the receiving antenna 45A through the switch element 49E. After being amplitude-modulated by the amplifier 46A, the branch output of the transmission wave generator 41A is integrated by the mixer 42E. The amplitude modulation in the amplifier 46A forms an intermediate frequency component at the output of the mixer 42E as described with reference to FIG.

In FIG. 4B, in the pseudo heterodyne system, the directional coupler 42B and the mixer 42
F, amplifier 46B, etc. to MMIC (Monorisic Microwave
IC). In this case, the same MMI
If the switch element 49F can be incorporated in C, (1) the apparent circuit configuration becomes the same as that without the self-diagnosis function, (2) the transmission antenna 44B and the reception antenna 45B may be the same as before. There are advantages.

Therefore, the directional coupler 3 is connected to the same MMIC.
2B and the switch element 49F, and the transmitting antenna 4
Instead of letting 4B communicate with the receiving antenna 45B, the MM
The transmitting side and the receiving side are communicated within the IC. MM
The functions from the IC to the transmitting antenna 44B and the functions from the receiving antenna 45B to the MMIC cannot be self-diagnosed, but usually, the abnormality of the function of the radar device is likely to occur in the transmission wave generating unit 41B or the MMIC. Therefore, a self-diagnosis function with practically sufficient reliability can be secured.

The reception processing unit 47B brings the switch element 49E into the communication state for t seconds at regular time intervals. The output of the transmission wave generator 41B flows into the amplifier 46B from the directional coupler 32B through the switch element 49F. The output of the amplifier 46B amplitude-modulated by the output of the front-end switching unit 31B is integrated in the mixer 42F into the output signal of the transmission wave generation unit 41A branched by the directional coupler 42B. The amplitude modulation in the amplifier 46B is shown in FIG.
As described in (b), an intermediate frequency component is formed at the output of the mixer 42F.

In FIG. 4C, in the heterodyne system, an intermediate frequency signal is formed from the received high-frequency signal by using an independent local oscillator 33C independent of the oscillation output of the transmission wave generator 41C. In this case, the output of the mixer 42G with the switch element 49G closed can be used as it is as a signal for self-diagnosis reflecting the entire function. Therefore, normal / abnormal of the overall function can be identified without performing amplitude modulation by the switch element 49G or the amplifier 46C.

The reception processing unit 47C brings the switch element 49G into the communication state for t seconds at regular time intervals. The output of the transmission wave generator 41C flows from the transmission antenna 44C to the amplifier 46C through the switch element 49G. Mixer 4
In 2G, the output of the local oscillator 33C is integrated with the output of the amplifier 46C to form an intermediate frequency component in the output of the mixer 42G. High-frequency components in the GHz band are removed by a line from the mixer 42G to the reception signal processing unit 47C.

[0063]

According to the radar device with the self-diagnosis function of the first aspect, it is not necessary to overlook the case where the entire function of the radar device becomes insufficient. If an abnormality has occurred in any part of the configuration of the radar device, safety is ensured through a warning, stoppage of the display of the output of the radar device, cancellation of automatic control using the output of the radar device, and a certain level of reliability. Quality can be guaranteed.

For example, in the system for measuring the following distance shown in FIG. 5B, the oscillator 53B, the transmitting antenna 54, the receiving antenna 55, the amplifier 56C, the directional coupler 56A, the path from the oscillator 53B to the transmitting antenna 54, the receiving When an abnormality occurs in any one of the routes from the antenna 55 to the signal processing unit 57, the driver is immediately notified of the abnormality and can be instructed not to rely on the radar device.

Therefore, the driver does not need to doubt the instruction of the radar device, and the instruction of the radar device does not mislead the driver's judgment or hinders the driving, and the driver is traveling due to the radar device. There is no need to worry about losing safety.
In addition, the automatic driving function (cruise control) that keeps the distance between vehicles constant according to the distance between vehicles output from the radar device also eliminates uncertainty caused by the radar device and always guarantees a certain level of control reliability. it can.

In addition, since the self-diagnosis function can be obtained by adding a small number of parts to the conventional radar device and modifying the processing program, the configuration of the conventional radar device can be used as it is, resulting in an increase in cost and size of the device. You don't have to. Further, since the degree of freedom in circuit design is not lost, it is easy to reduce the size and weight of the radar device, reduce the number of components, and the like.

According to the planar antenna of the second aspect, the transmitting antenna, the receiving antenna, and the switch are integrally formed, and the pattern design and the like can be shared, so that the planar antenna can be provided at low cost.

According to the radar device with the self-diagnosis function of the third aspect, the overall function of the radar device which forms the intermediate frequency signal from the received high-frequency signal by the heterodyne method or the pseudo heterodyne method becomes insufficient. Don't miss the case.

According to the radar device with the self-diagnosis function of the fourth aspect, in the FM-CW type radar device, the switch means capable of communicating the line of the transmitting antenna and the line of the receiving antenna, and the switch means With respect to the high-frequency signal propagating through the line of the receiving antenna during the communication period, it is not necessary to overlook the case where the entire function of the radar device becomes insufficient.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a radar device according to a first embodiment.

FIG. 2 is an explanatory diagram of a planar antenna.

FIG. 3 is an explanatory diagram of switching.

FIG. 4 is an explanatory diagram of a radar device of another embodiment.

FIG. 5 is an explanatory diagram of an FM-CW radar device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Sending wave generation part 14 Transmission antenna 15 Receiving antenna 16 Amplifier 17 Reception processing part 12A Directional coupler 12B Mixer 13A Waveguide 13B Waveguide 18A Inter-vehicle distance display part 18B Diagnosis result display part 19A Drive part 19B Switch element

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI H01Q 21/06 H01Q 21/06 Examiner Tetsunobu Miyagawa (56) References JP-A-5-341032 (JP, A) JP-A-5-264726 (JP, A) JP-A-64-59092 (JP, A) JP-A-54-37495 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01S 7/00-7 / 42 G01S 13/00-13/95 H01Q 13/08 H01Q 21/06

Claims (4)

(57) [Claims] A transmitting antenna (1) that radiates a high-frequency signal propagating through a line to a space to form a forward-transmitting wave.
4) and receiving the reflected wave formed by the transmitted wave at the target ahead,
A receiving antenna (15) for converting into a high-frequency signal propagating through another line; and a part of the high-frequency signal propagating through the line of the transmitting antenna (14) is integrated into a high-frequency signal propagating through the line of the receiving antenna (15). Integrating means (12A, 12B)
A switch unit (19A, 19B) capable of intermittently connecting a line of the transmitting antenna (14) and a line of the receiving antenna (15) at a predetermined frequency; and the switch unit. Detecting means (17) for detecting a frequency component generated in relation to said predetermined frequency with respect to a high-frequency signal propagating through a line of said receiving antenna (15) during a period when (19A, 19B) is intermittently connected; And an identification means (17) for identifying an abnormality in the function based on the detection result of the frequency component. 2. A planar antenna having two antenna patterns for transmission and reception arranged on the same plane, wherein at least one radiating portion of the transmission antenna pattern and at least one of the reception antenna patterns are provided. A planar antenna, comprising a switch element capable of communicating between the two receiving units in accordance with an external signal. 3. A transmitting antenna that radiates a high-frequency signal propagating through a line into a space to form a forward-transmitting wave, and receives a reflected wave formed by the transmitting wave at a target ahead,
In a heterodyne radar device having a receiving antenna that converts to a high-frequency signal propagating through another line, and a modulation unit that performs amplitude modulation of a predetermined frequency on a high-frequency signal propagating through the line of the receiving antenna, Switch means capable of communicating the line of the transmission antenna and the line of the reception antenna; and for a high-frequency signal propagating through the line of the reception antenna during a period in which the switch means is in communication, with respect to the predetermined frequency A radar device with a self-diagnosis function, comprising: detection means for detecting a generated frequency component; and identification means for identifying an abnormality in a function based on a detection result of the frequency component. 4. A transmission wave generating means for forming a high-frequency transmission signal which is regularly frequency-modulated at a predetermined amplitude and a predetermined period, and a transmission means for guiding the high-frequency signal to a transmission antenna and outputting a transmission wave to a front space. A receiving means for forming a high-frequency reception signal by receiving a reflected wave in which the transmitted wave is formed by a forward target; and an integrating means for integrating a part of the high-frequency transmission signal into the high-frequency reception signal. In the radar device of the CW system, switch means capable of communicating the transmission antenna line and the reception antenna line, and a high-frequency signal propagating through the reception antenna line during a period when the switch means is in communication, Detecting means for detecting a frequency component generated in association with the regular modulation of the high-frequency transmission signal; and detecting a functional abnormality based on the detection result of the frequency component. A radar device with a self-diagnosis function, comprising: identification means for identifying.