JPH0798376A - On-vehicle radar device - Google Patents

Abstract

PURPOSE:To detect that a preceding vehicle enters a curve by judging its travel state based on the continuous detection period of a stationary body when a radar device detects both a moving body and the stationary body. CONSTITUTION:A radar means 1 recognizes a preceding vehicle as an object when a travel road is a straight road. When a new object is detected in front of a vehicle in addition to the preceding vehicle, the change is detected by a multi-object discriminating means 2. When the radar means 1 detects a stationary body, the relative speed of the vehicle against the stationary body is equal to the vehicle speed detected by a vehicle speed sensor 3. An object characteristic judging means 4 judges whether each object is a moving body or a stationary body. When the counts by a stationary body counting means 5 are continued for a prescribed period, a travel state judging means 6 judges the detection of both the moving body and the stationary body by the radar means 1 as the entering of the preceding vehicle into a curve. The vehicle is judged to approach the curve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle radar device, and more particularly to an on-vehicle radar device for monitoring the front of a vehicle and detecting the distance and relative speed to a preceding vehicle.

[0002]

2. Description of the Related Art Conventionally, there is known an on-vehicle radar device which detects an object existing in front of a vehicle as an object and detects a distance and a relative speed to the object. In a vehicle that monitors the running state of a preceding vehicle using such an on-vehicle radar device, a function to automatically activate the brake when an improper approach is made to prevent a rear-end collision, and to maintain an appropriate inter-vehicle distance, automatically It is possible to realize the function of following and traveling.

By the way, in order to realize the above-mentioned function by using the on-vehicle radar device, it is necessary that the radar device has the ability to constantly monitor the preceding vehicle regardless of the traveling state of the vehicle. In this case, a particular problem is when traveling on a curve where the relative positional relationship between the preceding vehicle and the subject vehicle is displaced. That is, in order to maintain an appropriate monitoring state when traveling on a curve, it is necessary to change the monitoring range of the radar device according to the movement of the preceding vehicle.

[0004] Japanese Laid-Open Patent Publication No. 5-126947 discloses an on-vehicle radar device in which the monitoring range of the radar device is linked to the steering angle of the steering wheel, paying attention to such a point. According to this device, when the host vehicle approaches the curve and the steering operation is performed, the monitoring range of the radar device is directed toward the preceding vehicle along with the operation, and the possibility of losing the preceding vehicle is reduced. .

[0005]

However, in the above-mentioned conventional device, the monitoring range of the radar device is changed toward the preceding vehicle only after the vehicle approaches the curve. On the other hand, the relative positional relationship between the preceding vehicle and the following vehicle starts to change when the preceding vehicle approaches the curve, and the relative position is already large when the following vehicle actually approaches the curve. It may fluctuate.

In other words, in the conventional radar apparatus, when the subject vehicle approaches the curve and the steering is actually operated, the monitoring range of the radar apparatus changes to the direction of the preceding vehicle. There was a problem that the preceding vehicle could be lost by the time the vehicle approaches the curve after the approach.

The present invention has been made in view of the above points, and when a stationary body starts to be detected in addition to the preceding vehicle within the monitoring range of the radar device, the stationary body is continuously detected. If it is not continuously detected, it is judged that a stationary object on the road has started to be detected as a result of the preceding vehicle approaching the curve, and the processing to be executed during the curve traveling is standby An object of the present invention is to provide an in-vehicle radar device that solves the above problems by setting the state.

[0008]

FIG. 1 is a diagram showing the principle configuration of an on-vehicle radar device that achieves the above object. That is, the above-mentioned object is, in an in-vehicle radar device provided with radar means 1 for detecting a distance and a relative speed to an object existing in front as shown in FIG. 1, a plurality of objects within the radar monitoring range of the radar means 1. A plurality of object discriminating means 2 for detecting the existence of an object, a vehicle speed sensor 3 for detecting a vehicle speed of a vehicle equipped with the in-vehicle radar device, and the plural object discriminating means 2 for detecting a plurality of object objects. When the presence is detected, the relative speed detected by the radar device 1 with respect to the plurality of objects is compared with the vehicle speed detected by the vehicle speed sensor 3, and the relative speed and the vehicle speed are determined to be substantially the same. It is determined that the object is a stationary body that is stopped on the road,
An object characteristic determining unit 4 that determines that an object whose relative speed and a vehicle speed are not substantially the same is a moving object that is moving on the road, and the object characteristic determining unit 4 includes a moving object and a stationary object. When both and are detected, the stationary body timing means 5 for counting the duration of the stationary body detection, and when the time counted by the stationary body timing means 5 exceeds a predetermined time, the vehicle approaches a curve. It is achieved by an in-vehicle radar device having a traveling state determination means 6 for determining that

[0009]

In the on-vehicle radar device according to the present invention, the radar means 1 individually detects the distance and the relative speed with the object existing within the predetermined monitoring range as the object. Here, the monitoring range of the radar means 1 is set toward the front of the vehicle, and when the traveling road is a straight road, the preceding vehicle is recognized as an object. When a new object is detected in front of the vehicle in addition to the preceding vehicle, the change is detected by the plural object discriminating means 2.

By the way, when the radar means 1 detects a stationary object that is stopped on the road, the relative speed of the vehicle with respect to the stationary object is substantially the same as the vehicle speed detected by the vehicle speed sensor 3. When the radar means 1 detects a plurality of objects by paying attention to this point, the object characteristic determination means 4 determines whether each object is a moving body or a stationary body.

In this case, the radar means 1 detects both a moving body and a stationary body because the preceding vehicle, which is a moving body, approaches a curve and is partially out of the monitoring range of the radar means 1. Instead, it may occur when a stationary object on the road is detected as an object, or when a preceding vehicle temporarily changes the traveling lane while traveling on a straight road.

Here, when traveling on a straight road, even if a stationary body on the roadside is detected, the relative positional relationship between the vehicle and the stationary body on the roadside fluctuates as the vehicle travels, and the stationary body is maintained for a long period of time. It will never be detected.

Paying attention to such a point, the traveling state judging means 6 detects that the radar means 1 detects a stationary body together with a moving body when the count in the stationary body timing means 5 continues for a predetermined time. It is determined that the result is that the preceding vehicle is approaching the curve, and it is determined that the vehicle is traveling in front of the curve.

[0014]

2 is a block diagram of an on-vehicle radar device according to an embodiment of the present invention. As shown in the figure, the in-vehicle radar device according to the present embodiment includes a spectrum processing circuit 10, a vehicle speed sensor 20, and an FM-CW radar 30.

The spectrum processing circuit is a main part of an in-vehicle radar device which realizes the plural object discriminating means 2, the object characteristic discriminating means 4, the stationary body timing means 5 and the traveling state discriminating means 6, and the vehicle speed sensor 20. Is a sensor that detects the vehicle speed of the vehicle in which the on-vehicle radar device is mounted and supplies the detection result to the spectrum processing circuit.

The FM-CW radar 30 corresponds to the above-mentioned radar means 1, emits a predetermined modulated wave toward the front of the vehicle, and detects the distance and the relative speed with an object existing in front of the vehicle as an object. It is a known device for

In the following, the spectrum processing circuit 10, which is the main part of this embodiment, realizes the above-mentioned plural object discriminating means 2, object characteristic discriminating means 4, stationary body timing means 5, and running state discriminating means 6. I will explain the processing contents to be executed,
Prior to that, the configuration of the FM-CW radar 30 and F
The principle of detecting the distance and the relative speed by the M-CW radar 30 will be described.

In FIG. 2, the carrier wave generation circuit 31, the frequency modulation circuit 32, the modulation voltage generation circuit 33, the circulator 34, and the transmission antenna 35 are the FM-CW radar 3.
0 constitutes the transmitting side circuit.

That is, the modulating voltage generating circuit 33 outputs a triangular wave whose amplitude changes in a triangular shape and supplies it to the frequency modulating circuit 32 as a modulating wave. As a result, the carrier wave from the carrier wave generating circuit 31 is frequency-modulated, and as shown by the solid line in FIG. 3A, the frequency is triangular with a predetermined fluctuation width Δf and a modulation frequency fm (= 1 / T) over time. A modulated wave signal that modulates the shape is output.

Then, the modulated wave signal is supplied to the transmitting antenna 35 via the circulator 34 to be emitted toward the obstacle as the object to be detected, and is also supplied to the mixer 37 of the receiving side circuit which will be described later.

Further, the receiving antenna 36, the mixer 37, the amplifier circuit 38, the anti-aliasing filter 39, and the fast Fourier transform processing circuit (FFT signal processing circuit) 40.
Constitute a receiving circuit of the FM-CW radar 40.

That is, when the modulated wave transmitted from the transmitting antenna 35 is reflected by an obstacle existing within the monitoring range of the FM-CW radar 30, the receiving antenna 36 receives the reflected wave and the mixer 37 receives it. Supply. Then, the reflected wave is analyzed by the circuits after the mixer 37.

The waveforms shown by the broken line and the alternate long and short dash line in FIG. 3A show how the frequency of the reflected wave received by the receiving antenna 36 changes. In the mixer 37, the signal representing the state of the reflected wave and the signal representing the state of the transmitted wave supplied from the circulator 34 are combined by a difference calculation to generate a beat signal that fluctuates at a frequency according to the frequency difference between the two. It

FIG. 3B shows the frequency fluctuation state of the beat signal, which is shown in FIG. 3A, where fup is the frequency in the frequency rising section of the triangular modulation wave and fdown is the frequency in the frequency falling section. The beat signal corresponding to the reflected wave is represented by a broken line and a dashed line. In this case fup is
It corresponds to the difference between the frequency of the transmitted wave and the frequency of the received wave while the modulated wave is in the frequency rising section, and fdown is the frequency of the transmitted wave and the frequency of the received wave while the modulated wave is in the frequency falling section. Is equivalent to the difference between.

The beat signal from the mixer 37 is amplified by the amplifier circuit 38 and supplied to the anti-aliasing filter 39. The beat signal supplied to the anti-aliasing filter 39 is separated into a beat signal in the rising section and a beat signal in the falling section here, and then supplied to the FFT signal processing circuit 40, respectively. Then, the FFT signal processing circuit 40 performs FFT processing on the beat signal in each section and calculates the power spectrums for fup and fdown.

FIG. 4 shows the power spectrum of the FFT signal processing circuit 40 in the case where two obstacles are present in front of the vehicle, showing the rising section (FIG. 4A) and the falling section (FIG. 4).
(B)).

That is, when there are two obstacles in front of the vehicle, the receiving antenna 36 receives the reflected waves of the respective obstacles. Therefore, the beat signals representing the frequency difference between the transmitted wave and the received wave are formed by the number corresponding to each obstacle, and as a result, the FFT signal processing circuit 40 detects the power spectrum having two peaks. become.

By the way, assuming that there is no relative velocity between the vehicle and the obstacle ahead, the modulated wave transmitted from the transmitting antenna 35 is required for the modulated wave to reach the obstacle and then be reflected and returned. After the time passes, the receiving antenna 36
To reach. In this case, the Doppler shift is not superimposed on the frequency of the reflected wave, and the waveform showing the frequency fluctuation of the reflected wave is obtained by simply translating the transmitted wave in parallel in time as shown by the alternate long and short dash line in FIG. It should be wavy.

Then, the frequency of the beat signal in the rising section is fup, and the frequency of the beat signal in the falling section is fup.
If it is down, as shown by the alternate long and short dash line in FIG.
fup = fdown is established. And fup = f
The size of down indicates a value according to the distance between the vehicle and the obstacle.

On the other hand, when the relative velocity v exists between the vehicle and the obstacle, the reflected wave is superposed with the Doppler shift corresponding to the relative velocity. If, for example, the two tend to approach each other, the frequency of the reflected wave shifts to the high frequency side as a whole, and the waveform representing the frequency fluctuation of the reflected wave is as shown in FIG.
As indicated by a broken line in (A), a waveform that is temporally translated according to the distance (a waveform that is indicated by a one-dot chain line in the figure) is further translated to a high frequency side.

That is, as compared with the case where the relative speed v is "0", fup is small and fdown is large, and each changes according to the relative speed v. Therefore, if the concept of fr = (fup + fdown) / 2 (1) is introduced, the Doppler shift components superposed on fup and fdown are canceled each other, and the value is the same between the vehicle and the front obstacle. When the concept of fd = (fdown−fup) / 2 (2) is introduced, the distance components superimposed on fup and fdown cancel each other out, leaving only the Doppler shift component. , That value represents the relative speed of the vehicle and the obstacle ahead.

If the center frequency of the modulated wave is f ₀ , the modulation frequency is fm, the modulation width is Δf, the relative velocity is v, and the distance is L, the theoretical values of fr and fd with respect to the speed of light c are It becomes like the following formula.

Fr = 4fm · Δf · L / c (3) fd = 2v · f ₀ / c (4) Therefore, when two spectral peaks are obtained as shown in FIG. Pairs FMu1 and FMd1 with
Further, FMu2 and FMd2 are paired and, for example, fr = (F
If the calculation of Mu1 + FMd1) / 2, fd = (FMd1-FMu1) / 2 is performed, the distance L and the relative speed v to the obstacle that has caused the spectrum peak of the former pair can be obtained, and the same applies to the latter pair. By carrying out the processing of (1), the distance L and the relative velocity v that give rise to the spectrum peak can be obtained.

As described above, the FM-CW radar 30 has fup and f for each object existing in front of it.
Down is detected as a spectrum peak, and the distance L and the relative velocity v for each object are detected. Therefore, if the front of the vehicle is monitored by the FM-CW radar 30 while the vehicle is running, the behavior of an object existing within the monitoring range can be reliably detected, and the application to, for example, an automatic braking system or It is possible to realize advanced vehicle control by applying it to an inter-vehicle distance warning device.

By the way, in order to realize such an in-vehicle radar device using the FM-CW radar 30, the FM-
The CW radar 30 must be capable of monitoring the preceding vehicle regardless of the traveling state of the vehicle. This is because the possibility that the preceding vehicle may be lost while the vehicle is running makes it virtually impossible to apply it to a system that requires high safety, such as an automatic braking system.

In this case, it is highly likely that the preceding vehicle will be lost when traveling on a curve. That is, FIG.
As shown in (A) and (B), the straight-ahead direction of the vehicle (a) is the monitoring range of the FM-CW radar 30 (hatched area in the figure).
In the in-vehicle radar device set as
As shown in, at time t ₀ , the preceding vehicle (b) and the own vehicle (a)
If both are traveling on a straight road, the monitoring range of the FM-CW radar 30 is occupied by the preceding vehicle, and the possibility that the preceding vehicle is lost is extremely low.

On the other hand, assuming that the monitoring range of the FM-CW radar 30 does not change thereafter, when the preceding vehicle (b) approaches the curve at time t ₁ as shown in FIG. 5 (B), the preceding vehicle (b) The relative position between the vehicle and the vehicle (a) in the lateral direction changes, and the preceding vehicle (b) gradually moves out of the monitoring range of the FM-CW radar 30, and instead the guard rail pole (c) remains stationary. The body will enter.

FIG. 6 shows the FM-CW in such a situation.
6 shows the results of the distance L with respect to the object in front of the vehicle and the relative velocity v calculated according to the above equations (1) to (4) based on the power spectrum detected by the radar 30, and FIG. 6A and 6B show the distance L and the relative speed v with respect to the preceding vehicle (B), respectively.
(C) and (D) are guardrail poles (C), respectively.
The distance L and the relative speed v are represented.

That is, after the time t ₁ , FIG.
Guardrail pole (c) as shown in (C) and (D)
While the distance L to the vehicle and the relative speed v are intermittently detected, the power spectrum intensity of the preceding vehicle (b) decreases, so that as shown in FIGS. 6 (A) and 6 (B), the preceding vehicle ( Regarding the distance L and the relative speed v with respect to (b), the data is missing or undetectable.

In order to prevent the occurrence of such a situation and realize an in-vehicle radar device applicable to an automatic braking system or the like, the preceding vehicle (c) approaches a curve and moves side by side with the own vehicle (a). When the relative position in the direction starts to change, it is a necessary condition to follow the change and change the monitoring range of the FM-CW radar 30.

In the on-vehicle radar device of this embodiment, the spectrum processing circuit 10 executes the process described below so as to satisfy such a condition, thereby determining that the vehicle (a) is traveling in front of the curve. It is characterized in that it can be done.

FIG. 7 shows the FM-
3 is a flowchart of a spectrum processing routine executed by the spectrum processing circuit 10 based on the power spectrum detected by the CW radar 30 and the vehicle speed detected by the vehicle speed sensor 20.

By the way, when the preceding vehicle (b) exists ahead of the own vehicle (a) and the preceding vehicle (b) approaches the curve, the states shown in FIGS. 6 (A) to 6 (D). Is detected, the FM-CW radar 30 has a power spectrum corresponding to the preceding vehicle (b), that is, a power spectrum of the moving body, and a power spectrum corresponding to the guardrail pole (c), that is, a power spectrum of the stationary body. Should be detected.

On the other hand, when there is no preceding vehicle (C) or when the preceding vehicle (C) is traveling straight ahead in the traveling direction of the own vehicle (B), the power spectrum of the stationary body or the movement Only the power spectrum of the body will be detected.

That is, it is necessary to change the monitoring range of the on-vehicle radar device because the FFT signal processing circuit 40 of the FM-CW radar 30 detects both the power spectrum of the moving body and the power spectrum of the stationary body. It is limited to the case. This routine determines the traveling state of the host vehicle (a) by paying attention to such characteristics.

That is, in the routine shown in FIG. 7, first, at step 100, it waits until a plurality of objects can be recognized based on the power spectrum detected by the FFT signal processing circuit 40. This is because a moving body and a stationary body are not detected together unless a plurality of objects can be recognized. In this sense, this step 100 corresponds to the plural object discriminating means 2 described above.

When a plurality of objects are recognized in step 100, the process proceeds to step 110, which is the main part of this routine, to see whether the recognized objects include both a moving body and a stationary body. To determine. in this case,
This step 110 is performed by the object characteristic determining means 4 described above.
This is realized by executing the object characteristic determination routine shown in FIG.

The contents of the object characteristic determination routine shown in FIG. 8 will be described below with reference to the power spectrum state diagram shown in FIG. The spectra shown in FIGS. 9A to 9E will be referred to as spectra A to spectra E below.
Called.

When executing the routine shown in FIG. 8, the spectrum processing circuit 10 first executes a process of reading the power spectrum detected by the FFT signal processing circuit 40 (step 111). That is, the FFT signal processing circuit 4
Of the detected power spectrum of 0, the rising section spectrum shown in FIG.
The falling section spectrum shown in (B) is read as spectrum B.

After the above processing is completed, spectra A and B
In order to identify the peak spectrum relating to the stationary body from the spectrum peak of, the processing of steps 112 to 113 is executed.

By the way, when the FM-CW radar 30 detects a spectrum peak of a stationary object existing within the monitoring range, the relative speed v equal to the vehicle speed of the own vehicle should be detected from the spectrum peak. .

Here, when the relative velocity is calculated from the spectrum A and the spectrum B detected by the FFT signal processing circuit 40, "fd = (fdown-
fup) / 2 "is calculated, and the relative speed v is obtained from the relationship between the result and the above equation (4)" fd = 2vf ₀ / c ".

[0053] In other words, if if the relative velocity v is equal to the vehicle speed V, the it should _{fd = 2V · f 0 / c} ··· (5) is satisfied, therefore _{2V · f 0 / c = (} fdo
wn−fup) / 2, that is, fdown−fup = 4V · f ₀ / c (6) should be established.

That is, in the spectra A and B shown in FIG. 9, if there is a pair of spectral peaks satisfying the relation of the above expression (6) "fdown-fup = 4Vf ₀ / c", the spectral peaks are It can be determined that the object is a stationary body.

In accordance with this principle, in this embodiment,
In detecting the spectrum peak of a stationary body, first, the vehicle speed V of the host vehicle is detected by the vehicle speed sensor 20, and the spectrum B is shifted to the low frequency side by the frequency difference (4 V · f ₀ / c) caused by the vehicle speed V. A process of shifting and storing the shifted spectrum as the spectrum C is performed (step 1
12).

Then, as shown in FIG. 9, a process of subtracting the spectrum C from the spectrum A is performed, and the spectrum consisting of the spectrum peaks remaining as a result is stored as the spectrum D (step 113).

In this case, for example, when the spectrum peak (c) shown in FIG. 9 is a spectrum peak related to a stationary body, the spectrum peak in spectrum C obtained by shifting spectrum B to the low frequency side by the amount corresponding to the vehicle speed. (C) is
The peak waveform is the same as the spectrum peak (c) in the spectrum A detected as the ascending section spectrum, and the spectrum D obtained by performing the process of the above step 113 is within the monitoring range of the FM-CW radar 30. Only the spectral peak (b) formed due to the moving body existing in the above remains in the positive / negative object.

Therefore, if a spectrum peak exists in the spectrum D, it means that a moving body, that is, a preceding vehicle (b) exists within the monitoring range of the FM-CW radar 30.
Further, if there is no spectrum peak in the spectrum D, it means that there is no suitable preceding vehicle in front of the host vehicle (a).

Therefore, in this routine, after performing the process for obtaining the spectrum D in step 113, it is checked whether or not there is an appropriate spectrum peak in the spectrum D (step 114). Only in this case, it is decided to perform the process of determining the presence or absence of a stationary body.

That is, if it is determined in step 114 that the spectrum D has a spectrum peak, then the spectrum peak of the positive portion of the spectrum D is subtracted from the spectrum A, and the result is stored as the spectrum E. Perform (step 115).

In this case, as described above, the spectrum peak (b) remaining in the spectrum D is guaranteed to be related to the moving body, and if this is subtracted from the spectrum A, the result is The obtained spectrum E is
It is ensured that the FM-CW radar 30 is composed of only the spectrum peaks of the stationary body existing within the monitoring range.

Therefore, if a spectrum peak exists in the spectrum E, it can be determined that a stationary object exists within the monitoring range of the FM-CW radar 30. Therefore, in this routine, after the process of obtaining the spectrum E is completed, it is determined whether or not there is an appropriate spectrum peak in the spectrum E (step 116), and the presence or absence of a stationary body is determined. .

If the condition is not satisfied in either step 114 or step 116, the process proceeds to step 117, and it is determined that the condition of step 110 in FIG. 7 is not satisfied, and the steps 114 and 116 are executed. If it is determined that both conditions are satisfied in step 1, the process proceeds to step 118 and it is determined that the condition of step 110 in FIG. 7 is satisfied, and the routine ends.

In the spectrum processing circuit 10 of this embodiment, the FM-CW radar 30 has the spectrum peak related to the moving body and the spectrum peak related to the stationary body in this way.
It is to determine whether or not it is detected within the monitoring range.

By the way, the fact that the moving body and the stationary body are both detected by the FM-CW radar 30 is inevitably within the monitoring range of the FM-CW radar 30 when the preceding vehicle (B) approaches the curve. In addition to the case where a stationary body comes in, it may occur when the relative position between the preceding vehicle (b) and the own vehicle (a) fluctuates temporarily when traveling on a straight road.

Therefore, in order to recognize that the preceding vehicle (c) is approaching the curve without erroneous detection, when both the moving body and the stationary body are detected, the situation is surely confirmed by the preceding vehicle. It is necessary to confirm that it is the result of the approach.

Therefore, in the on-vehicle radar device of this embodiment, when it is determined that the condition of step 110 in FIG. 7 is satisfied, it is determined whether or not the state continues for a predetermined time (step 120). Then, only when this situation continues for a predetermined time, it is determined that the preceding vehicle (b) is approaching the curve (step 130), and the processing of this time is ended.

As described above, in this routine, this step 120 corresponds to the stationary body timing means 5 described above,
Further, step 130 corresponds to the traveling state determination means 6 described above. In the vehicle-mounted radar device of this embodiment, the predetermined time used for the determination in step 120 is set to 1 sec.

As described above, according to the on-vehicle radar device of the present embodiment, the preceding vehicle (B) approaches the curve, and then F
The situation in which the preceding vehicle (B) is predicted to be out of the monitoring range of the M-CW radar 30 can be quickly detected, and the FM-CW radar 30 can be prevented in order to prevent the preceding vehicle from being lost.
It is possible to appropriately execute measures such as following the monitoring range of the preceding vehicle.

As a method of adjusting the monitoring range of the FM-CW radar 30 in the direction of the preceding vehicle (B), FM-CW
The left and right are searched by the radar 30, and F is detected in the direction in which the spectrum peak of the preceding vehicle (b) is detected at a higher level.
A method for adjusting the orientation of the M-CW radar 30 is known, and the above method can be applied to the in-vehicle radar device of this embodiment.

Further, in the above embodiment, the FM-CW radar 30 is used as a mechanism for realizing the above-mentioned radar means 1.
However, the radar means 1 only needs to be capable of detecting the distance and the relative speed with respect to the target object, for example, a known pulse Doppler radar or intermittent FM-CW.
It may be realized by radar or the like.

[0072]

As described above, according to the present invention, when a preceding vehicle approaches a curve and the lateral relative position between the preceding vehicle and the subject vehicle fluctuates, the change situation is reliably detected. can do. Therefore, unlike a device that cannot detect that the traveling path curves until the vehicle actually reaches the curve, it is possible to detect that the traveling path curves as soon as the vehicle reaches the front of the curve.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of an in-vehicle radar device according to the present invention.

FIG. 2 is a block configuration diagram of an in-vehicle radar device that is an embodiment of the present invention.

FIG. 3 is a diagram for explaining a principle of detecting a distance and a relative speed by an FM-CW radar.

FIG. 4 is an example of a power spectrum detected by an FM-CW radar. It is the device of this embodiment.

FIG. 5 is a diagram for explaining the necessity of adjusting the monitoring range of the FM-CW radar.

FIG. 6 is an example of a distance and a relative speed detected when a preceding vehicle approaches a curve.

FIG. 7 is a flowchart showing the contents of spectrum processing executed by a spectrum processing circuit which is a main part of the in-vehicle radar device according to the present embodiment.

FIG. 8 is a flowchart showing the contents of an object characteristic determination process executed by a spectrum processing circuit that is a main part of the in-vehicle radar device according to the present embodiment.

FIG. 9 is a power spectrum state diagram for explaining the operation of the on-vehicle radar device according to the present embodiment.

[Explanation of symbols]

 1,30 FM-CW radar 2 Multiple object discrimination means 3,20 Vehicle speed sensor 4 Object characteristic determination means 5 Stationary body timing means 6 Running state determination means 10 Spectrum processing circuit

Claims (1)

[Claims] 1. An in-vehicle radar device comprising radar means for detecting a distance and a relative speed to an object existing in front, wherein a plurality of objects exist within a radar monitoring range of the radar means. A plurality of object discriminating means for detecting, a vehicle speed sensor for detecting a vehicle speed of a vehicle equipped with the in-vehicle radar device, and the radar device when the plural object discriminating means detects the presence of a plurality of objects. The relative speed detected with respect to these plural objects is compared with the vehicle speed detected by the vehicle speed sensor, and an object whose relative speed and vehicle speed are substantially the same is a stationary object that is stopped on the road. If there is an object whose relative speed and vehicle speed are not substantially the same, it is judged that the object characteristic judgment means is a moving object moving on the road, and the object characteristic judgment means When both a moving body and a stationary body are detected, the stationary body timing means for counting the duration of detection of the stationary body, and when the time counted by the stationary body timing means is a predetermined time or more, the vehicle turns into a curve. An on-vehicle radar device, comprising: a traveling state determination unit that determines that a vehicle is approaching.