JP2011237322A - Onboard radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an onboard radar device that determines, when an adhering matter on a radome is detected by adhering matter detection means, whether the adhering matter is temporarily adhered on the radome or constantly adhered on the radome.SOLUTION: Adhering matter detection means 16 is provided with a radome reflection variation detection unit that detects temporal variation of reflection waves due to an adhering matter 7 on a radome 6 and when the adhering matter detection means 16 detects the adhering matter 7 on the radome 6, the radome reflection variation detection unit determines that the adhering matter 7 is temporarily adhered on the radome 6 upon detecting large temporal variation of the reflection waves due to the adhering matter 7 adhered on the radome 6, and that the adhering matter 7 is constantly adhered on the radome 6 upon detecting small variation of the reflection waves due to the adhering matter 7 on the radome 6.

Description

  The present invention relates to an on-vehicle radar device, and relates to an on-vehicle radar device having an adhering matter detecting means for detecting a performance deterioration due to an adhering radar object from a reflected wave reflected by an adhering object on a radome.

An in-vehicle radar device mounted on a vehicle or the like is used for an ACC (Adaptive Cruise Control), a collision mitigation / prevention device with a preceding vehicle, and the like by measuring a distance between vehicles and a relative speed with other vehicles. The on-vehicle radar device for the above-mentioned uses a lot of frequency-modulated continuous wave (FMCW). Such a conventional on-vehicle radar device is described in Non-Patent Document 1 and Non-Patent Document 2. In an on-vehicle radar system, if an object that absorbs or reflects radio waves such as rain, snow, or dirt adheres to the cover (hereinafter referred to as radome) installed in front of the radar, the radar performance deteriorates and the system operates normally. Can not be operated.

  An apparatus as disclosed in Patent Document 1 is known as an apparatus that detects that the radome has deteriorated due to adhesion of rain, snow, dirt, or the like to the radome. In this device, when rain, snow or dirt adheres to the radome, the reception level of the reflected wave by the radome increases, and when the reception level of the low frequency component exceeds a certain value, the deposit is detected. In such a case, the system operation such as ACC is stopped, and the user is notified to remove the dirt.

Japanese Patent Laid-Open No. 10-160836 JP 2009-250640 A

Introduction to Radar Systems M.I.SKOLNIK, McGRAW-HILL BOOKCOMPANY, INC. (1962) RADAR HANDBOOK M.I.SKOLNIK, McGRAW-HILL BOOK COMPANY, INC. (1970) ''

  However, if rain or snow continues, these deposits will temporarily adhere to the radome and the radar performance will deteriorate, but if it is rain, snow or dirt, If the rain or snow stops, these deposits will be blown away from the radome and the radar performance will be restored. Also, even if the user is notified to remove the dirt and the user removes the dirt, if the rain or snow continues to fall, the rain or snow will adhere to the radome, and the radar performance will deteriorate again. The user will be notified that the kimono will be dropped, and the user will feel troublesome.

In addition, when rain or snow has stopped, it is naturally blown off by the wind pressure, so that it is often unnecessary to remove deposits. In order to improve such annoyance, for example, as in Patent Document 2, whether or not to notify that the deposit is to be dropped is determined by the elapsed time from when the deposit is dropped until the deposit is detected again. Although there is a device that determines whether or not there is a device, the user needs to remove the deposit once. Moreover, in patent document 1, when the time when the reception level of the low-frequency component exceeds a certain value is equal to or longer than a predetermined determination time, the false detection due to various noises is prevented by detecting the adhering matter. It is possible. However, if the adhering material temporarily adheres to the radome and is immediately removed by wind or the like, the adhering material is adhering to the radome in order to prevent detection by the temporary adhering material. Although it is necessary to make it larger than the time, the adhesion time is indefinite. The longer the determination time is, the lower the probability of erroneous detection can be. However, even in the case of a deposit that should be truly detected, the time until this is detected becomes longer.

  The present invention has been made to solve such a problem, and it is possible to determine whether the deposits such as rain, snow or dirt are temporarily attached to the radome, so that the user can remove the deposits. It is an object of the present invention to provide an on-vehicle radar device having an adhering matter detection means that can determine whether or not a work to be dropped is necessary.

  The on-vehicle radar device according to the present invention detects a target object by radiating a transmission wave and receiving a reflected wave reflected by the target object, and detects the target object from the reflected wave reflected by the target object of the radome that protects the main body. In the on-vehicle radar device that detects a performance degradation due to radar deposits by a detection unit, the deposit detection unit includes a radome reflection fluctuation detection unit that detects temporal fluctuations of reflected waves due to the radome deposits. When the radome adhering matter is detected by the detecting means, and the radome reflection fluctuation detecting unit has a large temporal fluctuation of the reflected wave due to the radome adhering matter, the adhering matter is temporarily attached to the radome. If the fluctuation of the reflected wave due to the deposit on the radome is small, it is determined that the deposit is constantly attached to the radome.

  The on-vehicle radar device according to the present invention radiates a transmission wave, which is a modulated wave having a frequency that repeatedly rises and falls, receives a reflected wave reflected by an object, and transmits the frequency of the transmitted wave and the reflected wave. Calculate the distance and relative speed of the object from the beat signal that has a frequency difference from the frequency, and reduce the performance due to radar deposits by the deposit detection means from the reflected wave reflected by the deposit on the radome that protects the main body. In the on-vehicle radar device for detecting, the deposit detection means detects a temporal variation of a low-frequency component of a beat signal having a frequency difference between a frequency of a transmission wave and a frequency of a reflected wave due to the deposit on the radome. A detection unit, and when the deposit detection means detects the deposit on the radome, the radome reflection variation detection unit detects the temporal change of the low frequency component of the beat signal. When the value is large, it is determined that the deposit is temporarily attached to the radome, and when the temporal variation of the low frequency component of the beat signal is small, it is determined that the deposit is constantly attached to the radome. Is.

  According to the on-vehicle radar device of the present invention, when the adhering matter detection means detects the adhering matter on the radome, the adhering matter is temporarily adhering to the radome or steadily adhering to the radome. By determining whether or not the user is in a state, it is possible to determine whether or not the user really needs to drop the deposit.

It is a block diagram which shows the vehicle-mounted radar apparatus in Embodiment 1 of this invention. It is the figure which showed the FET result of the beat signal when the reflected wave by the deposit | attachment of a radome has a fluctuation | variation. It is the figure which showed the phase and phase difference of the low frequency component of a beat signal when there is no fluctuation | variation in the reflected wave by the deposit | attachment of a radome. It is the figure which showed the phase and phase difference of the low frequency component of a beat signal when there exists a fluctuation | variation in the reflected wave by the deposit | attachment of a radome. 4 is a flowchart for explaining signal processing of a deposit detection unit in the in-vehicle radar device according to the first embodiment.

6 is a flowchart for explaining signal processing of a deposit detection unit in the in-vehicle radar device according to the second embodiment. 12 is a flowchart for explaining signal processing of an adhering matter detection unit in the in-vehicle radar device according to the third embodiment. 10 is a first half flowchart for explaining signal processing of an adhering matter detection unit in the in-vehicle radar device according to the fourth embodiment. 10 is a latter half flowchart for explaining signal processing of an adhering matter detection unit in the in-vehicle radar device according to the fourth embodiment.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing an in-vehicle radar device according to Embodiment 1 of the present invention. In FIG. 1, 1 is an on-vehicle radar device, 2 is a CPU that controls the on-vehicle radar device, and performs signal processing, 3 is a VCO that controls the increase and decrease of the frequency of the transmission signal in response to a command from the CPU 2, and 4 is a VCO A distributor that distributes the generated transmission signal to the transmission antenna 5 and the mixer 10, 5 is a transmission antenna that radiates a transmission wave to the outside of the on-vehicle radar device 1, 6 is a radome that covers and protects the on-vehicle radar device, and 7 is a radome 6. Attached deposits such as raindrops, snow or dirt, 8 is an object to be detected by the in-vehicle radar device 1, and 9 is a receiving antenna for receiving a reflected wave reflected by the object 8, and here has two receiving antennas. .

  10 is a mixer that mixes the received signal (reflected wave) received by the receiving antenna 9 with the transmitted signal (transmitted wave) distributed by the distributor 4 and generates a beat signal according to the distance, speed, and direction of the object 8. , 11 is an amplifier that amplifies the beat signal generated by the mixer 10, 12 is a low-pass filter (LPF) that removes unnecessary high-frequency components, and 13 is an A / D converter that converts the output signal of the low-pass filter from an analog signal to a digital signal. 14 is an FFT processing unit that performs fast Fourier transform (FFT) on the digital signal output from the A / D converter 13 for each receiving antenna, and 15 is the distance of the object 8 from the FFT result output by the FFT processing unit 14. , An object calculation unit for calculating the speed and direction, 16 is an object detection means for performing an object detection process from the FFT result output from the FFT processing unit 14, and 17 is an object An ACC processing unit that calculates an ACC control signal based on the processing results of the calculation unit 15 and the adhering matter detection unit 16, a user interface device that notifies the user of information according to information from the in-vehicle radar device 1, and 19 An engine control ECU 20 that performs engine control based on the processing result calculated by the ACC processing unit 17, and a brake control ECU 20 that performs brake control based on the processing result calculated by the ACC processing unit 17. An in-vehicle LAN 21 communicates between the on-vehicle radar device 1 and each ECU.

  Next, the operation of the ACC system using this on-vehicle radar device will be described. In accordance with the control signal from the CPU 2, the VCO 3 repeats increasing and decreasing the transmission frequency at a predetermined cycle. The output signal of the VCO 3 is distributed by the distributor 4 and sent to the transmission antenna 5. A transmission wave is transmitted from the transmission antenna 5 and transmitted to the outside of the in-vehicle radar device 1 through the radome 6. The transmitted wave is reflected by the object 8, and the reflected wave passes through the radome 6 again and is received by the two receiving antennas 9 (receiving antennas I and II). Some of the transmission waves are reflected by the radome 6 and raindrops 7 and received by the two receiving antennas 9. The signal received by the receiving antenna 9 and the transmission signal distributed by the distributor 4 are mixed by the mixer 10 to obtain a beat signal. The beat signal is amplified by the amplifier 11, unnecessary frequencies are removed by the LPF 12, converted from an analog signal to a digital signal by the A / D converter 13, and input to the CPU 2.

  The FFT unit 14 in the CPU 2 performs FFT on the beat signal received by each receiving antenna. The object calculation unit 15 calculates the distance and speed of the object from the combination of the frequency components of the beat signal when the transmission frequency is increased and the beat signal when the transmission frequency is decreased. The azimuth is calculated from the phase difference between received signals or the sum and difference of received levels. The calculation method of distance, speed, and direction is described in Non-Patent Document 1, Non-Patent Document 2, Patent Document 1, and the like. The ACC processing unit 17 calculates a vehicle control signal based on the distance, speed and direction of the object output from the object calculation unit 15 and the speed and traveling direction of the host vehicle obtained via the in-vehicle LAN. Information is transmitted through the in-vehicle LAN, the engine control ECU 19 and the brake control ECU 20 operate, and acceleration / deceleration control is performed. At this time, the ACC control unit 17 interrupts the ACC control according to the output of the adhering matter detection means 16, sends a notification prompting the user to remove the adhering matter to the user interface unit 18, or the ACC control is interrupted. To notify the user. The above processing is repeated at regular intervals.

  Next, the adhering matter detection means 16 will be described. In order to determine the state in which a deposit such as snow or dirt containing rain or moisture is temporarily attached to the radome that protects the main body, in Embodiment 1, the reflected wave of the radio wave due to the deposit on the radome is Take advantage of changing over time.

In other words, the deposit adheres to the radome in a state where the deposit adheres securely and the user needs to remove the dirt. In this case, the reception level of the low frequency component of the beat signal having a frequency difference between the frequency of the transmission wave and the frequency of the reflected wave due to the radome deposit is high and the temporal variation is small. Alternatively, the temporal variation of the phase of the low frequency component of the beat signal is reduced. Or it has the 1st, 2nd receiving antennas I and II, and the low frequency of the beat signal which has the frequency difference of the frequency of a transmission wave and the frequency of the reflected wave by the deposit | attachment of the radome received by the 1st receiving antenna I Temporal phase difference between the phase of the component and the phase of the low frequency component of the beat signal having a frequency difference between the frequency of the transmitted wave and the frequency of the reflected wave due to the radome deposit received by the second receiving antenna II The fluctuation becomes smaller.

The phase of the low frequency component of the beat signal takes a stable value as shown in FIG. 3, and in the case of an in-vehicle radar device having first and second receiving antennas I and II, the reflected wave received by each receiving antenna The phase difference of each phase of the low frequency component of the beat signal due to each becomes a value depending on the arrival direction of the reflected wave, but the phase difference also takes a stable value as shown in FIG.

On the other hand, in the state where deposits such as snow or dirt that contains rain or moisture are temporarily attached to the radome, the adhesion of the deposits to the radome is unstable, and radio waves from the radome are The reflected wave also changes according to the degree of attachment of the attached matter on the radome. In this case, it appears as a low frequency component of the beat signal having a frequency difference between the frequency of the transmission wave and the frequency of the reflected wave due to the radome deposit, and the reception level of the low frequency component (frequency is near 0) as shown in FIG. Fluctuates and the temporal fluctuation increases. Alternatively, the temporal variation of the phase of the low frequency component of the beat signal becomes large. Alternatively, the low frequency component of the beat signal having the first and second receiving antennas I and II and having a frequency difference between the frequency of the transmitted wave and the frequency of the reflected wave due to the radome deposit received by the first receiving antenna I. Variation in phase difference between the phase of the beat signal and the phase of the low frequency component of the beat signal having a frequency difference between the frequency of the transmitted wave and the frequency of the reflected wave due to the radome deposit received by the second receiving antenna II Becomes larger.

The phase of the low frequency component of the beat signal takes an unstable value as shown in FIG. 4, and in the case of an on-vehicle radar device having first and second receiving antennas I and II, the reflected wave received by each receiving antenna. The phase difference of each phase of the low-frequency component of the beat signal due to each of the above becomes a value depending on the arrival direction of the reflected wave, but the phase difference also takes an unstable value as shown in FIG. .

Next, the adhering matter detection process performed by the adhering matter detection means 16 will be described with reference to the flowchart of FIG. First, in step S101, the reception level Amp [t] of the low frequency component (region) in the FFT result at time t is compared with a preset threshold value. When it is smaller than the threshold value, the adhering matter detection process at the time t ends. If it is equal to or greater than the threshold value (when a deposit on the radome is detected), the process proceeds to step S102.

Next, in step S102, the amount of change AmpDiff [t] of the reception level in the low frequency region at time t and time t-1 of the previous measurement cycle is calculated as in equation (1).
AmpDiff [t] = | Amp [t] ― Amp [t-1] | (1)
Next, in step S103, “average of the amount of change in the reception level in the low frequency region” AmpDiffAve [t] in the past n measurement cycles is calculated as shown in Equation (2).

  This “average of the amount of change in the reception level in the low frequency region” increases as the fluctuation of the reflected wave from the radome increases. At this time, it is presumed that deposits such as rain or moisture containing snow or dirt are temporarily attached to the radome.

  Next, in step S104, “average of reception level change in low frequency region” AmpDiffAve [t] is compared with a preset threshold value. If it is above the threshold value, such as snow or dirt containing rain or moisture. It is determined that the adhering matter is temporarily attached, and only the ACC system is stopped (the radar is disabled) in step S105.

  If it is determined in step S104 that “the average of the amount of change in the reception level in the low frequency region” AmpDiffAve [t] is smaller than the threshold value, it is determined that the adhering matter is steadily adhering to the radome. In step S106, the ACC system is stopped. In step S107, the user interface device 18 notifies the user to remove the deposits. The radome reflection fluctuation detection unit is configured by software in steps S102 to S104.

In addition, when the fluctuation of reflection due to the deposit on the radome is large, the fluctuation of the “average of the amount of change in the reception level in the low frequency region” AmpDiffAve [t] is considered to be large. Or it can become smaller. Even in such a case, in order to reliably detect the change in reflection, once the threshold value is exceeded, it may be considered that the change is large even if the predetermined time is smaller than the threshold value. Further, since the average of the amount of change in the reception level in the low frequency region is compared with the threshold value, it is strong against noise.

In the first embodiment, the FMCW method is adopted as the method of the in-vehicle radar device, but an FM pulse Doppler method or other methods may be adopted.
In the first embodiment, only one amplifier 11 is arranged. However, an amplifier may be further arranged between the VCO 3 and the transmitting antenna 5 or between the receiving antenna 9 and the A / D converter 13. . In the first embodiment, the ACC system using the in-vehicle radar device is described. However, the same method may be used for other vehicle control systems using the in-vehicle radar device.

As described above, in the in-vehicle radar device according to the first embodiment, when the deposit on the radome is detected, when the deposit on the radome is constantly adhered, the ACC control is surely stopped and the deposit is detected. To remove the deposits, and when deposits such as snow or dirt containing rain or moisture are temporarily attached, the system operation such as ACC is stopped and the deposits are removed. By not doing so, the user's troublesomeness can be reduced.

Embodiment 2. FIG.
FIG. 6 is a flowchart showing the adhering matter detection process of the adhering matter detection means 16 in the in-vehicle radar device of the second embodiment. The block configuration of the ACC system using the in-vehicle radar device of the second embodiment is the same as that of the first embodiment.

First, in step S201, the low frequency component (of the FFT result of the beat signal at time t (
Area) reception level Amp [t] is compared with a preset threshold value. When it is smaller than the threshold value, the adhering matter detection process at the time t ends. When larger than the threshold value (when a deposit on the radome is detected), the process proceeds to step S202.

Next, in step S202, the phase difference Δθ [t] of the low frequency region of the beat signal caused by the receiving antenna I and the receiving antenna II is obtained from Equation (3) for the low frequency region of the FFT result of the beat signal. Here, θ1 [t] is the phase of the low frequency component of the beat signal having a frequency difference between the frequency of the transmitted wave and the frequency of the reflected wave due to the radome deposit received by the receiving antenna I, and θ2 [t] Is the phase of the low frequency component of the beat signal having a frequency difference between the frequency of the transmitted wave and the frequency of the reflected wave due to the radome deposit received by the receiving antenna II.
Δθ [t] = θ1 [t] − θ2 [t] (3)

Next, in step S203, the phase difference change amount Δθdiff [t] is calculated from the phase difference in the low frequency region of the frequency component of the beat signal caused by the receiving antennas I and II at the time t and the time t-1 of the previous measurement cycle.
Is calculated as shown in Equation (4).
Δθdiff [t] = Δθ [t] − Δθ [t-1] (4)

  Next, in step S204, the average ΔθdiffAve [t] of the amount of change in phase difference in the past n measurement cycles is calculated as in equation (5).

This “average phase difference variation” ΔθdiffAve [t] increases as the fluctuation of the reflected wave from the radome deposit increases. At this time, it is presumed that deposits such as rain or moisture containing snow or dirt are temporarily attached to the radome.

  Next, in step S205, the “average difference in phase difference” ΔθdiffAve [t] is compared with a preset threshold value. If it is equal to or greater than the threshold value, deposits such as rain or moisture containing snow or dirt are temporarily present. In step S206, the ACC system is only stopped. If it is determined in step S205 that “average difference in phase difference” ΔθdiffAve [t] is smaller than the threshold value, it is determined that the deposit is constantly attached to the radome, and the ACC system is switched on in step S207. In step S208, the user interface device 18 notifies the user to remove the deposits. The radome reflection fluctuation detection unit is configured by software in steps S202 to S205.

In the second embodiment, when there are two or more receiving antennas, two receiving antennas I and II may be selected.
As described above, in the on-vehicle radar device according to the second embodiment, when the deposit on the radome is detected, when the deposit on the radome is constantly adhered, the ACC control is surely stopped and the deposit is detected. To remove the deposits, and when deposits such as snow or dirt containing rain or moisture are temporarily attached, the system operation such as ACC is stopped and the deposits are removed. By not doing so, the user's troublesomeness can be reduced.

Embodiment 3 FIG.
FIG. 7 is a flowchart showing the adhering matter detection process of the adhering matter detecting means 16 in the on-vehicle radar device of the third embodiment. The block configuration of the ACC system using the on-vehicle radar device of the third embodiment is the same as that of the first embodiment.

First, in step S401, the low frequency component (of the FFT result of the beat signal at time t (
Area) reception level Amp [t] is compared with a preset threshold value. When it is smaller than the threshold value, the adhering matter detection process at the time t ends. If it is larger than the threshold value (when a deposit on the radome is detected), the process proceeds to step S402.

Next, in step S402, a beat having a frequency difference between the frequency of the transmitted wave and the frequency of the reflected wave caused by the radome deposit received by the receiving antenna (I or II) at time t and time t-1 of the previous measurement cycle. The amount of phase change Δθdiff [t] of the low frequency component of the signal is calculated as in equation (6).
Δθdiff [t] = θ [t] − θ [t-1] (6)

  Next, in step S403, the average ΔθdiffAve [t] of the phase change amount in the past n measurement cycles is calculated as in Expression (7).

This “average phase change amount” ΔθdiffAve [t] increases as the fluctuation of the reflected wave from the deposit on the radome increases. At this time, it is presumed that deposits such as rain or moisture containing snow or dirt are temporarily attached to the radome.

  Next, in step S404, the “average phase change amount” ΔθdiffAve [t] is compared with a preset threshold value. If it is equal to or greater than the threshold value, deposits such as snow or dirt containing rain or moisture are temporarily present. In step S405, the ACC system is only stopped. If it is determined in step S404 that “average phase change amount” ΔθdiffAve [t] is smaller than the threshold value, it is determined that the adhering matter is constantly attached to the radome, and the ACC system is stopped in step S406. In step S407, the user interface device 18 notifies the user to remove the deposits. The radome reflection fluctuation detection unit is configured by software in steps S402 to S404.

In Embodiment 3, when there are two or more receiving antennas, one receiving antenna I or receiving antenna II may be selected.
As described above, in the on-vehicle radar device according to the third embodiment, when the deposit on the radome is detected, when the deposit on the radome is constantly attached, the ACC control is surely stopped and the deposit is detected. To remove the deposits, and when deposits such as snow or dirt containing rain or moisture are temporarily attached, the system operation such as ACC is stopped and the deposits are removed. By not doing so, the user's troublesomeness can be reduced.

Embodiment 4 FIG.
FIG. 8 is the first half of a flowchart showing the deposit detection process of the deposit detection means 16 in the on-vehicle radar device of the fourth embodiment, and FIG. 9 is the latter half. By connecting a in FIG. 8 and a in FIG. 9, a flowchart showing the whole is obtained. The block configuration of the ACC system using the in-vehicle radar device in the fourth embodiment is the same as that in the first embodiment.

First, in step S301, the position, speed, and direction of the detected object at this time, that is, time t, are predicted from the distance, speed, and direction of the detected object (target object) at time t-1 that is the previous measurement cycle.
Next, in step S302, the beat frequency at the time of frequency rise and fall is calculated backward from the predicted distance and speed. Next, in step S303, it is determined whether or not the predicted beat frequency when the frequency rises overlaps with the low frequency component (region). If they overlap, in step S304, the deposit fluctuation flag when the frequency is increased is set to OFF, and the deposit detection flag when the frequency is increased is set to OFF, and the process proceeds to step S321. Otherwise, the process proceeds to step S305.

  In step S305, the reception level Amp [t] in the low frequency region when the frequency is increased is compared with the threshold value. If the threshold level is exceeded, the process proceeds to step S306, and the adhering matter detection flag when the frequency is increased is set to ON. . When it is less than the threshold value, the process proceeds to step S307, and the adhering matter detection flag at the time of frequency increase is set to OFF.

  Next, in step S308, “average of phase difference variation” ΔθdiffAve [t] in the past n measurement periods is obtained and compared with a threshold value in the same manner as in the second embodiment. The adhering matter fluctuation flag at the time of frequency increase is set to ON, and if it is less than the threshold, the adhering matter fluctuation flag at the time of frequency increase is set to OFF.

  The same applies to when the frequency is lowered. In steps S321 to S328, processing similar to that performed when the frequency is increased is performed, and the attached matter detection flag when the frequency is lowered and the attached matter variation flag when the frequency is lowered are set.

  Next, in step S331, when the adhering matter variation flag at the time of frequency increase = OFF and the adhering matter variation flag at the time of frequency decrease = OFF, the processing ends. Otherwise, the processing proceeds to step S332. Next, in step S332, if the deposit fluctuation flag at the time of frequency increase = ON or the deposit fluctuation flag at the time of frequency decrease = ON, the process proceeds to step S335, and if not, the process proceeds to step S333.

  In step S333, assuming that regular dirt is attached to the radome, the ACC system is stopped, and in step S334, notification is made to prompt the user to remove dirt through the user interface device 18.

  In step S335, it is assumed that an adhering substance such as snow or dirt containing rain or moisture is temporarily attached, and the process is ended only by stopping the ACC system.

As described above, in the on-vehicle radar device according to the third embodiment, when the reflected wave other than the reflected wave due to the radome and the attached substance attached to the radome, that is, the reflected wave due to the object is mixed in the low frequency region of the beat signal. Therefore, it is impossible to accurately measure the reflected wave due to the deposit on the radome. In this case, by not performing the adhering matter detection process, malfunction of the adhering matter detection process can be prevented.

  Similarly, when the frequency of the transmitted wave rises and falls, the radome reflection fluctuation detector detects the frequency of the beat signal of the reflected wave from the roadside stop object and the reflected wave from the radome attachment from the speed of the host vehicle. Predicts whether the frequency of the beat signal substantially matches, and when the frequency of the transmitted wave increases or decreases, the frequency of the beat signal reflected by the roadside stop and the frequency of the reflected wave by the radome deposit When the frequency of the beat signal is expected to be almost the same, the radome reflection fluctuation detection unit is stopped, and the radome attachment is determined only by the determination of the radome reflection fluctuation detection unit on the other side when the transmission wave frequency is rising or falling. The fluctuation of the reflected wave due to the kimono is obtained, and the frequency of the beat signal of the reflected wave due to the roadside stop object and the reflection due to the radome deposit both when the frequency of the transmitted wave rises and falls. If the frequency of the beat signal is expected to substantially match the radome reflection variation detecting unit of the determination in both it may be to stop.

  In the above embodiment, a transmission wave, which is a modulated wave having a frequency that repeats ascending / descending, is radiated, a reflected wave reflected by an object is received, and a frequency between the frequency of the transmitted wave and the frequency of the reflected wave is received. On-vehicle radar device that calculates the distance and relative velocity of the object from the beat signal having a difference, and detects the performance degradation due to the radar deposit by the deposit detection means from the reflected wave reflected by the deposit on the radome that protects the main body In the above, the adhering matter detecting means includes a radome reflection fluctuation detecting unit that detects temporal fluctuations of low frequency components of the beat signal having a frequency difference between the frequency of the transmission wave and the frequency of the reflected wave due to the radome adhering substance. Applied.

  The present invention further detects an object by radiating a transmission wave and receiving a reflected wave reflected by the object, and detects the object from the reflected wave reflected by the object attached to the radome that protects the main body. In-vehicle radar devices that detect performance degradation due to radar deposits, the deposit detection means can be applied to those equipped with a radome reflection fluctuation detection unit that detects temporal fluctuations of reflected waves due to radome deposits. When the radome attachment is detected by the means, the radome reflection fluctuation detection unit determines that the attachment is temporarily attached to the radome when the temporal fluctuation of the reflected wave due to the radome attachment is large, When the fluctuation of the reflected wave due to the deposit on the radome is small, it may be determined that the deposit has constantly adhered to the radome.

The radome reflection fluctuation detection unit may detect the temporal fluctuation of the reflected wave due to the radome deposit on the basis of the temporal fluctuation of the reception level or phase of the reflected wave due to the radome deposit.
Furthermore, it has a 1st, 2nd receiving antenna, and a radome reflection fluctuation | variation detection part is the temporal fluctuation of the phase difference of each reflected wave by the deposit | attachment of the radome each received with the 1st, 2nd receiving antenna, It is preferable to detect the temporal variation of the reflected wave due to the radome deposit.

1 On-vehicle radar device 2 CPU
3 VCO 4 distributor 5 transmitting antenna 6 radome 7 deposit 8 object 9 receiving antenna 10 mixer 11 amplifier 12 low-pass filter 13 A / D converter 14 FFT processing unit 15 object calculation unit 16 deposit detection unit 17 ACC processing unit 18 User interface device 19 Engine control ECU 20 Brake control ECU
21 Car LAN

Claims (8)

Detects the object by radiating the transmitted wave and receiving the reflected wave reflected by the object, and the performance of the radar object by the object detection means from the reflected wave reflected by the object attached to the radome that protects the main body In the on-vehicle radar device that detects the drop,
The adhering matter detection means includes a radome reflection fluctuation detecting unit that detects temporal fluctuation of a reflected wave due to the radome adhering matter,
When the attached matter detection means detects the attached matter on the radome, the radome reflection fluctuation detection unit temporarily attaches the radome to the radome when the reflected wave due to the attached object on the radome has a large temporal fluctuation. An in-vehicle radar device characterized in that it is determined that a kimono has adhered, and when the fluctuation of the reflected wave due to the radome deposit is small, it is determined that the deposit has steadily adhered to the radome.   The radome reflection fluctuation detection unit is configured to detect a temporal fluctuation of a reflected wave due to the radome deposit based on a temporal fluctuation of a reception level or a phase of the reflected wave due to the radome deposit. The on-vehicle radar device according to claim 1. Having first and second receiving antennas;
The radome reflection fluctuation detection unit detects the time of the reflected wave due to the radome deposit by temporal variation of the phase difference of each reflected wave due to the radome deposit received by the first and second receiving antennas, respectively. 2. The on-vehicle radar device according to claim 1, wherein a dynamic fluctuation is detected. A transmission wave, which is a modulated wave having a frequency that repeats rising and falling, is radiated, a reflected wave reflected by an object is received, and the beat signal having a frequency difference between the frequency of the transmitted wave and the frequency of the reflected wave is In the on-vehicle radar device that calculates the distance and relative speed of the object and detects the performance degradation due to the radar deposit by the deposit detection means from the reflected wave reflected by the deposit on the radome protecting the main body,
The adhering matter detection means includes a radome reflection fluctuation detecting unit that detects temporal fluctuations of a low frequency component of a beat signal having a frequency difference between a frequency of a transmission wave and a frequency of a reflected wave by the radome adhering matter,
When the deposit detection means detects the deposit on the radome and the radome reflection variation detector detects a large temporal variation of the low frequency component of the beat signal, the deposit is temporarily deposited on the radome. An on-vehicle radar device characterized in that it is determined that an adhering matter has adhered to the radome when it is judged that the adhering material has adhered and the temporal variation of the low frequency component of the beat signal is small.   The radome reflection fluctuation detection unit detects a temporal fluctuation of the low frequency component of the beat signal due to a deposit on the radome based on a temporal fluctuation of the reception level or phase of the low frequency component of the beat signal. The on-vehicle radar device according to claim 4. The radome reflection variation detector has first and second receiving antennas,
The phase of the low frequency component of the beat signal having a frequency difference between the frequency of the transmitted wave and the frequency of the reflected wave by the radome deposit received by the first receiving antenna;
Due to the temporal variation of the phase difference between the frequency of the transmission wave and the phase of the low-frequency component of the beat signal having a frequency difference between the frequency of the reflected wave due to the deposit on the radome received by the second receiving antenna, 5. The on-vehicle radar device according to claim 4, wherein a temporal variation of a low frequency component of the beat signal due to a radome deposit is detected. The radome reflection fluctuation detection unit at each of the frequency rise and fall of the transmission wave,
Based on the distance and relative speed of the object calculated last time, it is predicted whether the frequency of the beat signal of the reflected wave from the object and the frequency of the beat signal of the reflected wave from the radome deposit will almost match at this time. If the frequency of the beat signal of the reflected wave from the object and the frequency of the beat signal of the reflected wave from the attached object of the radome are expected to be substantially the same when the frequency of the transmitted wave is increased or decreased. The radome reflection fluctuation detection unit is stopped, the fluctuation of the reflected wave due to the deposit on the radome is determined based on only the determination of the radome reflection fluctuation detection unit at the other time when the frequency of the transmission wave rises and falls, and the transmission frequency The frequency of the beat signal of the reflected wave due to the object and the frequency of the beat signal of the reflected wave due to the deposit on the radome are almost the same both when rising and falling. If the expected in-vehicle radar device according to any one of claims 4 to claim 6, characterized in that said radome reflection variations detector is determined at both was stopped.   When the frequency of the transmitted wave rises and falls, the radome reflection fluctuation detection unit detects the frequency of the beat signal of the reflected wave due to the roadside stop and the beat of the reflected wave due to the deposit on the radome from the speed of the host vehicle. Predicting whether the frequency of the signal is substantially the same, and when the frequency of the transmitted wave increases or decreases, the frequency of the beat signal reflected by the roadside stop and the frequency of the reflected wave by the radome deposit When it is expected that the frequency of the beat signal is substantially the same, the radome reflection fluctuation detection unit is stopped, and only the radome reflection fluctuation detection unit at the other of the increase and decrease of the frequency of the transmission wave determines the The fluctuation of the reflected wave due to the deposit on the radome is obtained, and the frequency of the beat signal of the reflected wave due to the roadside stop object and the redo both when the frequency of the transmitted wave rises and falls. The determination of the radome reflection fluctuation detection unit in both cases is stopped when it is expected that the frequency of the beat signal of the reflected wave due to the attached object is substantially the same. The on-vehicle radar device according to any one of items 6.

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