JP2015175659A - Radar system, control method of radar system, and control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radar system, a control method of the radar system, and a control program capable of performing abnormality determination even when the ambient reflection is extremely small.SOLUTION: The radar system includes: a transmission unit for transmitting a transmission signal; a receiving unit for receiving a reflection signal coming from a target of the transmission signal transmitted by the transmission unit; a peak detection unit for detecting a peak of the signal received by the receiving unit and counting the number of detected peaks; and a failure diagnosis unit for diagnosing a failure on the basis of a signal level of the signal received by the receiving unit, a count number counted by the peak detection unit, and information indicating supplementary to the target.

Description

  The present invention relates to a radar apparatus, a radar apparatus control method, and a control program.

  In recent years, radar that detects a target by using a radar such as a millimeter wave to measure the distance, relative speed, and direction from the target based on the reflected wave from another object (also referred to as a reflector, target, or target). The device has been put into practical use. For example, radar devices using systems such as FMCW (Frequency Modulated Continuous Wave) radar, multi-frequency CW (Continuous Wave) radar, and pulse radar are known as in-vehicle radars.

In such a radar apparatus, when dirt such as mud, snow, and dust adheres to a transmission antenna that transmits a transmission wave and a reception antenna that receives a reception wave, the detection sensitivity of the radar apparatus decreases.
For this reason, in such a radar apparatus, it is proposed to determine an abnormal state in which the detection sensitivity decreases based on the difference between the maximum value and the minimum value of the reception level that is received when the transmission wave is reflected by another object. (For example, refer to Patent Document 1).

  Further, in such a radar apparatus, it has been proposed to determine an abnormal state in which the detection sensitivity decreases when the level of the reflected wave signal decreases when the target detection state is in a predetermined condition. The predetermined condition of the detection status is that the width of the target is a specified value or more, or the number of detection beams reflected from the target is a specified number or more (for example, refer to Patent Document 2).

JP 2006-258598 A JP 2006-250793 A

  However, the techniques described in Patent Documents 1 and 2 erroneously detect that the radar apparatus is dirty because a reflected wave cannot be obtained in a situation where there are extremely few targets that can reflect radio waves around the radar apparatus. There was a problem. The situation in which the number of targets that can reflect radio waves around the radar device is extremely small is, for example, an environment in which roads without guardrails or signals are continuous.

  The present invention has been made in view of such circumstances, and provides a radar apparatus, a radar apparatus control method, and a control program capable of determining an abnormality even in a situation where ambient reflection is extremely small.

  In order to solve the above-described problem, a radar apparatus according to the present invention includes a transmission unit that transmits a transmission signal, a reception unit that receives a reflected signal from a target with respect to the transmission signal transmitted by the transmission unit, and the reception Based on the peak detection unit that detects the peak of the signal received by the unit and counts the number of detected peaks, the signal level of the signal received by the reception unit, and information indicating that the target is supplemented A failure diagnosis unit that performs failure diagnosis.

  In the radar apparatus according to the present invention, the information indicating that the target is supplemented may be lock-on information for the target.

  In the radar apparatus according to the present invention, the information indicating that the target is supplemented may be a count number counted by the peak detection unit.

  Further, in the radar apparatus according to the present invention, the failure diagnosis unit is based on a signal level of the signal received by the reception unit at the first time and a signal level received at the second time before the first time. A determination level may be generated, and failure diagnosis may be performed using the generated determination level.

  Further, in the radar apparatus according to the present invention, the failure diagnosis unit is based on a signal level of the signal received by the reception unit at the first time and a signal level received at the second time before the first time. A determination level may be generated, and failure diagnosis may be performed using the generated determination level.

  In the radar apparatus according to the present invention, the failure diagnosis unit determines whether or not the target to be tracked exists, and does not perform the failure diagnosis when the target to be tracked exists. May be.

  In the radar apparatus according to the present invention, the peak detector may count the number of peaks in the first region or the second region in the third signal included in the signal received by the receiver.

  Further, in the radar apparatus according to the present invention, the failure diagnosis unit, for the second signal included in the signal received by the reception unit, at a first time, the first maximum signal in the first region in the second signal. A level is extracted, a second maximum level of the signal is extracted in the first region of the second signal at a second time prior to the first time, and the extracted first maximum level and the second maximum level are It may be used to generate the first determination level.

  Further, in the radar apparatus according to the present invention, the failure diagnosis unit may be configured to output a third signal of the first signal included in the signal received by the reception unit in the first region of the first signal at the first time. A maximum level is extracted, a fourth maximum level of the signal is extracted in the first region of the first signal at the second time, and the second maximum level is extracted using the extracted third maximum level and the fourth maximum level. A determination level may be generated.

  In the radar apparatus according to the present invention, the failure diagnosis unit may have the first determination level less than a first predetermined level, the second determination level less than a second predetermined level, and the peak detection unit. When the counted number satisfies the condition of 0, the first predetermined distance is added to the travel distance after the failure diagnosis is initialized, the first determination level is less than the first predetermined level, and the first When the determination level of 2 is less than the second predetermined level and the count number counted by the peak detection unit does not satisfy the condition of 0, the travel distance after initializing the failure diagnosis may be initialized. Good.

  Further, in the radar apparatus according to the present invention, the failure diagnosis unit, when the first determination level exceeds a third predetermined level and the second determination level exceeds a fourth predetermined level, It may be detected that no failure has occurred and the travel distance after the failure diagnosis is started may be initialized.

  In the radar apparatus according to the present invention, the first signal is an unmodulated CW wave, the second signal is a modulated sub-wave, and the third signal is a main wave. The first region is a downstream region, the second region is an upstream region, the first determination level is a determination level for the sub-wave, and the second determination level is the CW The peak detection unit counts the number of peaks in the downstream region in the main wave included in the signal received by the reception unit, and the failure diagnosis unit performs the first time at the first time A first maximum level of a signal is extracted in the downlink region of the subwave, a second maximum level of the signal is extracted in the downlink region of the subwave at the second time, and the extracted first maximum level and The second maximum level is used to generate a first determination level, a third maximum level of the signal is extracted in the downstream region in the CW wave at the first time, and the CW wave at the second time is extracted. A fourth maximum level of the signal is extracted in the downlink region, a second determination level is generated using the extracted third maximum level and the fourth maximum level, and the first determination level is a first predetermined level. And the second determination level is less than a second predetermined level, and the count number counted by the peak detection unit satisfies a condition of 0, the first travel distance from the start of failure diagnosis is A predetermined distance is added, the first determination level is less than the first predetermined level, the second determination level is less than the second predetermined level, and the count number counted by the peak detection unit is 0. Is not satisfied, the mileage after the failure diagnosis is initialized is initialized, the first determination level exceeds a third predetermined level, and the second determination level exceeds a fourth predetermined level. When it is, it may be detected that no failure has occurred, and the mileage from the start of failure diagnosis may be initialized.

  In order to solve the above-described problem, a method of controlling a radar apparatus according to the present invention includes a transmission procedure in which a transmission unit transmits a transmission signal, and a reception unit from a target for the transmission signal transmitted by the transmission procedure. A reception procedure for receiving a reflected signal, a peak detection unit for detecting a peak of the signal received by the reception procedure, and a peak detection procedure for counting the number of detected peaks, and a failure diagnosis unit by the reception procedure A failure diagnosis procedure for performing a failure diagnosis based on a signal level of the received signal, a count number counted by the peak detection procedure, and information indicating that the target is supplemented.

  In order to solve the above-described problem, a control program according to the present invention receives a transmission procedure to be transmitted as a transmission signal to a computer of a radar apparatus and a reflection signal from a target with respect to the transmission signal transmitted by the transmission procedure. A reception procedure, a peak detection procedure for detecting a peak of the signal received by the reception procedure, and counting the number of detected peaks; a signal level of the signal received by the reception procedure; and a count by the peak detection procedure And a failure diagnosis procedure for performing failure diagnosis based on the counted number and information indicating that the target is supplemented.

  According to the present invention, an abnormality can be determined even in a situation where ambient reflection is extremely small.

It is a block diagram which shows the structure of the vehicle-mounted radar apparatus which concerns on this embodiment. It is a figure which shows the state into which the transmission signal and the received signal reflected by the target were input. It is a flowchart for demonstrating operation | movement of the radar apparatus which concerns on this embodiment. It is a flowchart of a processing procedure of radar contamination determination according to the present embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of an in-vehicle radar device 1 according to this embodiment.
In the present embodiment, an electronic scanning radar device (FMCW millimeter wave radar device) is shown as an example of an on-vehicle radar device. The on-vehicle radar device according to the present embodiment relates to an object (target) that is transmitted in front of a vehicle (in the present embodiment, as an example, an automobile) and is present in front of the vehicle. In order to detect information, it is provided in the front part of the vehicle.

  As shown in FIG. 1, the radar apparatus 1 includes n (n is an integer of 1 or more) receiving antennas 2 (2-2 to 2-n), n mixers 3-1 to 3-n, and n. Filters 4-1 to 4-n, SW (switch) 5, ADC (A / D converter) 6, control unit 7, triangular wave generation unit 8, voltage controlled oscillator (VCO) 9, distributor 10 , A transmission antenna 11, a signal processing unit 20, and a failure diagnosis unit 40. The radar apparatus 1 includes n amplifiers 12-1 to 12-n, an amplifier 13, an amplifier 14, an amplifier 15, and n amplifiers 16-1 to 16-n.

  The radar apparatus 1 has a reception system of n channels (Ch) that constitute a reception array antenna. The reception system includes reception antennas 2-1 to 2-n, amplifiers 12-1 to 12-n, mixers 3-1 to 3-n, filters 4-1 to 4-n, and amplifiers for each channel. 16-1 to 16-n.

The triangular wave generation unit 8 generates a triangular wave signal under the control of the control unit 7 and outputs the generated triangular wave signal to the amplifier 14.
The amplifier 14 amplifies the triangular wave signal input from the triangular wave generator 8 and outputs it to the VCO 9.
The VCO 9 outputs a signal including a modulated wave obtained by frequency-modulating the triangular wave signal based on the triangular wave signal input from the amplifier 14 to the distributor 10 as a transmission signal.

The distributor 10 distributes the transmission signal input from the VCO 9 and outputs the distributed signal to the amplifier 15 and the amplifiers 16-1 to 16-n.
The amplifier 15 amplifies the signal input from the distributor 10 and outputs the amplified signal to the transmission antenna 11.
The transmission antenna 11 wirelessly transmits the signal input from the amplifier 15 as a transmission wave. This transmitted wave is reflected by the object.

Each of the receiving antennas 2-1 to 2-n receives a reflected wave (that is, a received wave) that is received by reflecting a transmitted wave transmitted from the transmitting antenna 11 by an object, and an amplifier corresponding to the received received wave Output to 12-1 to 12-n. This received wave is a reflected wave of a transmitted wave including a modulated wave.
Each of the amplifiers 12-1 to 12-n-1 amplifies the reception wave input from the corresponding reception antenna 2-1 to 2-n and outputs the amplified signal to the corresponding mixer 3-1 to 3-n.

Each of the amplifiers 16-1 to 16-n amplifies the signal input from the distributor 10 and outputs the amplified signal to the corresponding mixers 3-1 to 3-n.
Each of the mixers 3-1 to 3-n mixes the received wave signals input from the corresponding amplifiers 16-1 to 16-n and the signals input from the corresponding amplifiers 12-1 to 12-n ( Mixing) to generate beat signals corresponding to the respective frequency differences, and output the generated beat signals to the corresponding filters 4-1 to 4-n.

Each of the filters 4-1 to 4-n performs band limitation on the beat signals input from the corresponding mixers 3-1 to 3-n, and outputs the band-limited beat signal to SW5.
SW5 sequentially switches the beat signals input from the filters 4-1 to 4-n in response to the sampling signal input from the control unit 7 and outputs the beat signals to the amplifier 13.
The amplifier 13 amplifies the beat signal input from the SW 5 and outputs it to the ADC 6.

  The ADC 6 corresponds to the sampling signal input from the control unit 7 and beat signals input from the SW 5 in synchronization with the sampling signal (for each channel 2 to n corresponding to each receiving antenna 2-1 to 2-n). The beat signal is converted from an analog signal to a digital signal by A / D conversion in synchronization with the sampling signal. The ADC 6 sequentially stores the digital signal obtained by the conversion in the waveform storage area of the memory 21 in the signal processing unit 20.

  The control unit 7 is configured using, for example, a microcomputer. The control unit 7 performs overall control in the radar apparatus based on a control program stored in a ROM (Read Only Memory) (not shown) or the like. As a specific example, the control unit 7 controls processing for generating a triangular wave signal by the triangular wave generation unit 8, generates a predetermined sampling signal, and outputs the sampling signal to the SW 5 and the ADC 6.

Here, an outline of the principle of detecting the distance, relative speed, and angle (azimuth) between the radar apparatus 1 and the target used in the signal processing unit 20 in the present embodiment will be described.
FIG. 2 is a diagram illustrating a state in which a transmission signal and a reception signal reflected by a target are input. FIG. 2A is a diagram illustrating a relationship between transmission signal versus time and reception signal versus time. FIG. 2B is a diagram illustrating the relationship between the received signal and the frequency in the ascending region and the descending region. In FIG. 2A, the horizontal axis represents time and the vertical axis represents frequency. Moreover, in FIG.2 (b), a horizontal horizontal axis shows a frequency and a vertical axis | shaft shows intensity | strength.
The signal shown in this figure includes a transmission signal (first triangular wave) obtained by frequency-modulating the signal generated in the triangular wave generation unit 8 of FIG. 1 by the VCO 9, and a reception signal received by reflecting the transmission signal by the target. (Second triangular wave). In the example of this figure, the case where there is one target is shown. In FIG. 2A, a solid line indicates a transmission signal (first triangular wave), and a chain line indicates a reception signal (second triangular wave).

  As shown in FIG. 2A, in the radar apparatus 1, the received signal that is a reflected wave from the target is delayed in the right direction (time delay direction) in proportion to the distance to the target with respect to the signal to be transmitted. Received. Furthermore, it varies in the vertical direction (frequency direction) with respect to the transmission signal in proportion to the relative speed with the target. Then, after the DBF (Digital Beam Forming) processing of the beat signal obtained in FIG. 2A, as shown in FIG. ) And the descending region (downward) each have one peak value.

  The signal processing unit 20 will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the signal processing unit 20 includes a memory 21, a DBF processing unit 22, a peak detection unit 23, a peak combination unit 24, a distance detection unit 25, a speed detection unit 26, a pair determination unit 27, an azimuth detection unit 28, A return target determination unit 29 and a target determination unit 30 are provided.

  The memory 21 stores the reception signal A / D converted by the ADC 6 in the waveform storage area as time-series data (ascending portion and descending portion) corresponding to each of the receiving antennas 2-1 to 2-n. . For example, if 256 samples are taken in each of the rising portion (upward and second region) and the falling portion (downward and second region) of the triangular wave, data of 2 × 256 × number of antennas is stored in the waveform storage region. Is done.

  The DBF processing unit 22 performs Fourier transform on the data corresponding to each of the receiving antennas 2-1 to 2-n from the sampled data of the beat signal stored in the memory 21, that is, the spatial axis Fourier. Perform the conversion. Further, the DBF processing unit 22 calculates spatial complex data for each angle channel depending on the angle, that is, corresponding to the angular resolution, and the calculated spatial complex data for each angle channel and the peak detection unit 23 and the azimuth for each beat frequency. The data is output to the detection unit 28.

  For example, if each of the ascending part and the descending part has 256 sampled data for each antenna, it is converted into a beat frequency as complex frequency domain data for each antenna, and 128 pieces of data are obtained for each of the ascending part and the descending part. Complex data (2 × 128 × number of antenna data). The beat frequency is indicated by a frequency point.

  Based on the information input from the DBF processing unit 22, the peak detection unit 23 has a peak value (for example, a peak value of complex data exceeding a preset numerical value at the rising and falling portions of the triangular wave shown in FIG. 2B). By detecting a beat frequency having a peak value such as reception intensity or amplitude, the presence of an object is detected for each beat frequency, and a beat frequency corresponding to the detected object is selected as a target frequency. The peak detection unit 23 outputs the detection result of the target frequency (the beat frequency of the target frequency and its peak value) to the peak combination unit 24. The information input from the DBF processing unit 22 includes information on the main wave and the SUB (sub) wave. A SUB wave is a sub FMCW wave, and a CW (Continuous Wave) wave is an unmodulated signal.

  The peak detector 23 detects the peak of the main wave going down, and counts and holds the number of detected peaks. The peak detection unit 23 outputs the counted number of peaks to the failure diagnosis unit 40. Note that the peak detector 23 may detect and count the peak of the main wave ascending. The reason for detecting the peak on the downside is that when the vehicle is running, the main wave down is shifted farther than the actual distance due to the Doppler shift, and the main wave ascent is the actual distance due to the Doppler shift. Shift forward. In the peak detection, since the possibility that the shorter distance cannot be detected increases, in the present embodiment, it is preferable to count the number of peaks at the down of the main wave. Further, the peak detection unit 23 may count and hold the number of peaks in the downstream or upstream of the SUB wave. The reason why the main wave is used for peak detection in the present embodiment is that the main wave has a longer detectable distance than the SUB wave. For this reason, when the distance which can detect a SUB wave is longer than a main wave, the peak detection part 23 may detect the peak in the downward direction of a SUB wave.

  In the peak detector 23, for example, complex data related to any of the receiving antennas 2-1 to 2-n is converted into a frequency spectrum, or complex data related to all the receiving antennas 2-1 to 2-n is added. The beat frequency corresponding to each peak value in the frequency spectrum can be detected as the target frequency based on the value converted into a frequency spectrum. Here, when using the addition value of the complex number data of all the receiving antennas 2-1 to 2-n, the noise components are averaged and the S / N ratio (signal-to-noise ratio) is improved.

The peak combination unit 24 uses the first and second modulation waves among the triangular waves based on the first to third modulation waves for the information (the beat frequency of the target frequency and its peak value) input from the peak detection unit 23. The beat frequency and its peak value in each of the rising and falling parts of the triangular wave based on the above are combined in a brute force manner in a matrix. As a result, all the beat frequencies in each of the rising portion and the falling portion are combined, and the result of the combination is sequentially output to the distance detection unit 25 and the speed detection unit 26.
The peak combination unit 24 adds the beat frequencies and peak values of the rising and falling portions of the triangular wave based on the second and third modulated waves in a matrix for the information input from the peak detection unit 23. Combine at the hit. As a result, all the beat frequencies in each of the rising portion and the falling portion are combined, and the result of the combination is sequentially output to the distance detection unit 25 and the speed detection unit 26.

The distance detection unit 25 calculates a distance r to the object based on a numerical value obtained by adding beat frequencies (target frequencies) in a combination of an ascending portion and a descending portion sequentially input from the peak combination unit 24, and the result ( In this example, a peak value is included) to the pair determination unit 27.
The distance r is expressed by the following equation (1).

r = {C × T / (2 × Δf)} × {(f _u + f _d ) / 2} (1)

Further, the speed detection unit 26 calculates a relative speed from the target frequency f _u of the rising portion output from the peak combination unit 24 and the target frequency f _d of the lowering portion by the following equation (2).

v = {C / (2 × f ₀ )} × {(f _u −f _d ) / 2} (2)

In the expression for calculating the distance r and the relative speed v in Expression (1) and Expression (2), C is the speed of light, Δf is the frequency modulation width of the triangular wave, f ₀ is the center frequency of the triangular wave, and T is the modulation time ( (Rising portion / falling portion), f _u is the target frequency in the rising portion, and f _d is the target frequency in the falling portion.

  Based on the information input from the distance detection unit 25 and the information input from the speed detection unit 26, the pair determination unit 27 determines an appropriate combination of the peaks of the ascending portion and the descending portion corresponding to each object. Then, the pair of peaks of the ascending portion and the descending portion is confirmed, and the target group number indicating the confirmed pair (distance r, relative speed v, frequency point) is output to the azimuth detecting unit 28.

  Here, since the azimuth of each target group is not determined, the arrangement of the reception antennas 2-1 to 2-n with respect to the vertical axis with respect to the arrangement direction of the reception antenna array in the radar apparatus according to the present embodiment. The lateral position parallel to the direction has not been determined.

  The azimuth detection unit 28 detects the azimuth (azimuth angle) of the object (hereinafter also referred to as azimuth detection) based on the information input from the DBF processing unit 22 and the information input from the pair determination unit 27 and outputs the detected azimuth. To do.

Here, as a method (for example, an algorithm) used for detecting the azimuth of the object by the azimuth detecting unit 28, except for a characteristic point in the radar apparatus 1 according to the present embodiment related to the azimuth detection described later, Various techniques may be used including known ones.
As a specific example, the azimuth detection unit 28 performs a spectrum estimation process using an AR spectrum estimation method, a MUSIC method, a modified covariance method (MCOV method), which is a high resolution algorithm, and based on the result of the spectrum estimation process, The orientation of the object can be detected.

The return target determination unit 29 receives the direction information detected by the direction detection unit 28, the target group, and the reception signal based on the first triangular wave and the reception signal based on the second triangular wave, which are beat signals. The return target determination unit 29 determines the magnitude of the background noise of the received signal by the second triangular wave. The folding target determination unit 29 compares the received signal levels of the first triangular wave and the second triangular wave when the background noise is equal to or lower than a predetermined threshold, and detects the object outside the detection range. It is determined whether it is a return.
The return target determination unit 29 determines whether there is a second triangular wave corresponding to a pair obtained from the received signal of the first triangular wave. When there is a second triangular wave reflected wave corresponding to the pair obtained from the first triangular wave received signal, the folding target determining unit 29 reflects the second triangular wave reflected wave corresponding to the pair obtained from the first triangular wave received signal. It is determined whether the signal level is lower than the reception signal level of the first triangular wave. When the signal level of the reflected wave of the second triangular wave corresponding to the pair obtained from the received signal of the first triangular wave is smaller than the received signal level of the first triangular wave, the folding target determination unit 29 obtained from the received signal of the first triangular wave The target group number indicating the distance r and the relative velocity v in which the pair is determined is removed from the input target group. On the other hand, when the signal level of the reflected wave of the second triangular wave corresponding to the pair obtained from the received signal of the first triangular wave is higher than the received signal level of the first triangular wave, the folding target determination unit 29 obtains from the first triangular wave received signal. The target group number indicating the determined distance r and the relative speed v is output to the target determination unit 30. That is, the information based on the return target is a target group number indicating a distance r and a relative velocity v in which a pair obtained from the first triangular wave reception signal is determined.

  The target determination unit 30 determines the distance between the target orientation and the target based on the distance r determined by the return target determination unit 29 and the target group number indicating the relative speed v. The target determination unit 30 outputs the determined target orientation and the distance between the targets to the failure diagnosis unit 40. In addition, when the tracking can be continued a predetermined number of times, the target determination unit 30 sets information indicating the lock-on state, and outputs the lock-on information to the sensitivity decrease detection unit 42.

The failure diagnosis unit 40 includes a speed acquisition unit 41 and a sensitivity decrease detection unit 42. The fault diagnosis unit 40 converts the digital signal into a digital signal by the ADC 6 and samples the signal, and then performs signal processing by the signal processing unit 20 on the basis of the state in the peak detection process performed at the beginning of the target recognition process. Detects malfunctions such as dirt.
If internal parameters in processing after peak detection are used, the criteria for determining dirt are complicated. For example, after the combination processing, it is necessary to obtain both upward and downward triangular waves as described above, and when the final output target is used, the lateral position is accurately calculated in the positional information calculation processing. There is a need to.
On the other hand, according to the present embodiment, since failure detection such as dirt is detected based on the state in the peak detection process performed at the beginning of the target recognition process, the process can be reduced, and the triangular wave to be used is also downloaded as described later. It is possible to detect dirt by using only.

  The speed acquisition unit 41 acquires information about the moving speed of the vehicle on which the radar device 1 is mounted (hereinafter referred to as speed information), and outputs the acquired speed information to the sensitivity decrease detection unit 42.

Based on the speed information input from the speed acquisition unit 41, the sensitivity decrease detection unit 42 performs sensitivity decrease detection when the vehicle is traveling at a predetermined speed or higher. The sensitivity reduction detection unit 42 extracts the maximum level from the FFT spectrum in the downstream of the current SUB wave. The sensitivity decrease detection unit 42 calculates a SUB determination level used for determining a sensitivity decrease of the SUB wave. The sensitivity decrease detection unit 42 detects the maximum level in the FFT spectrum in the downstream of the CW wave. The sensitivity decrease detection unit 42 calculates a CW determination level used for determining sensitivity decrease of the CW wave. When the radar apparatus 1 is not locked on the target at a determination distance equal to or greater than a predetermined distance, the sensitivity decrease detection unit 42 determines the number of peaks output by the peak detection unit 23, the calculated SUB determination level, and the CW determination level. Based on this, it is detected that the sensitivity is reduced. Note that when the distance is equal to or longer than a predetermined distance, there is no continuous object around the vehicle and no reflected wave can be obtained on a farm road in Japan or a desert in the United States. This predetermined distance may differ depending on the country or region.
Note that the lock-on state is a state in which, for example, the peak is continuously detected a predetermined number of times in the up and down directions of the main wave and the sub wave, and the position of the target such as another vehicle is stably detected. It is.

  The failure diagnosis unit 40 may display the result detected by the sensitivity decrease detection unit 42 on the display unit of the radar apparatus 1 or the display unit of the dashboard of the vehicle. For example, the failure diagnosing unit 40 may perform control so as to display a message that prompts the user of the vehicle to clean the antenna when a decrease in sensitivity is detected.

Next, the operation of the radar apparatus 1 will be described.
FIG. 3 is a flowchart for explaining the operation of the radar apparatus 1 according to the present embodiment.
(Step S1) The first triangular wave and the second triangular wave are transmitted from the transmitting antenna 11, and the respective reflected waves are received by the receiving antennas 2-1 to 2-n. Next, the ADC 6 performs AD sampling on the reflected wave received via the mixers 3-1 to 3-n, the filters 4-1 to 4-n, and the SW5.

(Step S <b> 2) The signal processing unit 20 performs signal processing of the AD signal sampled by AD sampling.
(Step S3) The peak detector 23 performs peak detection.

(Step S <b> 4) The peak detector 23 counts the number of peaks in the downward direction of the main signal, and holds the counted number of peaks.
(Step S5) The peak combination unit 24 combines all beat frequencies of the ascending region and the descending region for the beat frequency output from the peak detection unit 23 and its peak value, and sequentially detects the distance detection unit 25 and the speed detection unit 26. Output to.

(Step S6) The distance detection unit 25 calculates the distance r to the target from a numerical value obtained by adding the target frequency of the rising portion and the target frequency of the falling portion that are sequentially input from the peak combination unit 24. Next, the speed detection unit 26 calculates the relative speed v of the target from the difference between the target frequency of the rising portion and the target frequency of the falling portion input from the peak combination unit 24.
Next, based on the information input from the distance detection unit 25 and the information input from the speed detection unit 26, the pair determination unit 27 appropriately sets the peaks of the ascending portion and the descending portion corresponding to each object. The combination is determined to determine each peak pair of the rising and falling portions.
Next, the direction detection unit 28 performs spectrum estimation processing using the MCOV method based on the information input from the DBF processing unit 22 and the information input from the pair determination unit 27. Next, the return target determination unit 29 determines whether the peak signal is the object or the return based on the information output from the azimuth detection unit 28, and based on the determination result, Exclude the effect of wrapping.

(Step S7) The target determination unit 30 performs tracking processing on the object whose orientation is detected in Step S6. When tracking can be continued a predetermined number of times, the target determination unit 30 sets information indicating that the lock-on state is set, and outputs the lock-on information to the sensitivity decrease detection unit 42.
(Step S <b> 8) The sensitivity decrease detection unit 42 performs radar dirt determination processing based on the vehicle speed information output from the speed acquisition unit 41 and the peak information output from the peak detection unit 23. The radar dirt determination process will be described later.

Next, the radar dirt determination process performed in step S8 (FIG. 3) will be described.
FIG. 4 is a flowchart of a processing procedure for radar contamination determination according to the present embodiment. In FIG. 4, the processes in steps S <b> 101 to S <b> 108 are sensitivity reduction detection processes, and the processes in steps S <b> 109 to S <b> 110 are sensitivity recovery processes.
(Step S101) The sensitivity decrease detection unit 42 determines whether or not the vehicle speed information output from the speed acquisition unit 41 is equal to or higher than a predetermined speed. When it is determined that the vehicle speed information output from the speed acquisition unit 41 is equal to or higher than a predetermined speed (step S101; YES), the sensitivity decrease detection unit 42 proceeds to step S102, and the speed information is equal to or higher than the predetermined speed. If it is determined that it is not (step S101; NO), the process is terminated. The predetermined speed is, for example, 20 km / h.

(Step S102) The sensitivity decrease detection unit 42 initializes (resets) the determination distance to 0, and sets the determination flag to 0. Next, the sensitivity decrease detection unit 42 detects the maximum level in the FFT spectrum in the downstream of the current SUB wave. Next, the sensitivity decrease detection unit 42 sets the time average value of 50% of the maximum level of the current SUB wave and 50% of the maximum level of the previous SUB wave as the SUB determination level used for determining the sensitivity decrease of the SUB wave. Is calculated.
When the determination flag is 0, the detection sensitivity is in a normal state, and when the determination flag is 1, the detection sensitivity is decreased to indicate an abnormal state due to dirt or a failure.
The reason why the signal level of the current SUB wave is not used but is averaged with the previous signal level is to suppress variation in the determination level. Further, the ratio of the signal level of the SUB wave is not limited to 50% each for the current time and the previous time. The ratio may be obtained by experiment, for example, or a plurality of ratios may be switched according to the environment (temperature, time, season, etc.). Further, in this embodiment, the example of calculating the time average of the maximum signal level between the current time and the previous time has been described, but the maximum value of three or more signals such as the current time and the previous time may be used as the time average. Good.

(Step S103) The sensitivity decrease detection unit 42 detects the maximum level in the FFT spectrum in the downstream of the CW wave. Next, the sensitivity decrease detection unit 42 calculates a time average value of 50% of the maximum level of the current CW wave and 50% of the maximum level of the previous CW wave as the CW determination level used for determining the sensitivity decrease of the CW wave. Is calculated.
Note that the reason for averaging the signal level of the previous CW wave instead of using the signal level of the current CW wave is to suppress variation in the determination level as in step S102. Similarly to the SUB wave, the ratio of the signal level of the CW wave may be obtained by experiment, for example, and a plurality of ratios may be switched according to the environment (temperature, time, season, etc.).

(Step S104) The sensitivity decrease detection unit 42 is a condition in which the SUB determination level is equal to or lower than the first predetermined level, the CW determination level is equal to or lower than the second predetermined level, and the number of downstream peaks of the main wave DBF is zero. It is determined whether or not the above is satisfied. The sensitivity decrease detection unit 42 satisfies a condition that the SUB determination level is equal to or lower than the first predetermined level, the CW determination level is equal to or lower than the second predetermined level, and the number of downward peaks of the main wave DBF is 0. When it determines (step S104; YES), it progresses to step S105. If the sensitivity decrease detection unit 42 determines that the condition is not satisfied (step S104; NO), the process proceeds to step S106.
The first predetermined level is greater than the second predetermined level. The condition may be that the SUB determination level is lower than the first predetermined level, the CW determination level is lower than the second predetermined level, and the number of downward peaks of the main wave DBF is zero.

(Step S105) The sensitivity decrease detection unit 42 calculates the travel distance that the vehicle has traveled at a predetermined time based on the acquired speed information, and adds the calculated travel distance to the determination distance. After the addition, the sensitivity decrease detection unit 42 advances the process to step S107. Note that the predetermined time may be one period of time during which the sensitivity decrease detection unit 42 performs detection.
(Step S106) The sensitivity decrease detection unit 42 clears the determination distance to zero. The sensitivity decrease detection unit 42 proceeds with the process to step S107.

(Step S107) The sensitivity decrease detection unit 42 determines whether or not the determination distance is greater than or equal to a predetermined distance. If the sensitivity decrease detection unit 42 determines that the determination distance is equal to or greater than the predetermined distance and that the current radar lock-on condition is not satisfied (step S107; YES), the process proceeds to step S108. If the sensitivity decrease detection unit 42 determines that the condition is not satisfied (step S107; NO), the process proceeds to step S109.
(Step S <b> 108) The sensitivity decrease detection unit 42 determines that the sensitivity has decreased, and sets the determination flag to 1.

(Step S109) The sensitivity decrease detection unit 42 determines whether or not a condition that the determination flag is 1, the SUB determination level is equal to or higher than the third predetermined level, and the CW determination level is equal to or higher than the fourth predetermined level is satisfied. Determine. The sensitivity decrease detection unit 42 determines that the condition that the determination flag is 1, the SUB determination level is equal to or higher than the third predetermined level, and the CW determination level is equal to or higher than the fourth predetermined level is satisfied (step S109; YES), the process proceeds to step S110. If the sensitivity decrease detection unit 42 determines that the condition is not satisfied (step S109; NO), the process ends.
The third predetermined level is greater than the first predetermined level and greater than the fourth predetermined level.

(Step S110) The sensitivity decrease detection unit 42 determines that the sensitivity has been recovered, and sets the determination flag to 0. Next, the sensitivity decrease detection unit 42 clears the determination distance to zero. The sensitivity decrease detection unit 42 ends the process after clearing.
This is the end of the radar contamination determination process.

  As described above, the radar apparatus 1 according to the present embodiment transmits the transmission unit as a transmission signal (the transmission antenna 11, the amplifier 15, the distributor 10, the VCO 9, the amplifier 14, and the triangular wave generation unit 8) and the transmission unit. Receiving units (receiving antennas 2-1 to 2-n, amplifiers 12-1 to 12-n, mixers 3-1 to 3-n, filters 4-1 to 4-4) that receive reflected signals from the target with respect to the transmitted signals that have been transmitted -N, SW5, amplifier 13, and ADC 6), the peak of the signal received by the receiver, and the peak detector 23 for counting the number of detected peaks, and the signal level of the signal received by the receiver, And a failure diagnosis unit 40 that performs failure diagnosis based on information indicating that the target is supplemented (lock-on information or the count number counted by the peak detection unit).

  With this configuration, the radar apparatus 1 according to the present embodiment can continue to detect other vehicles even when the signal level decreases while the other vehicle running in front of the host vehicle is locked on. The radar apparatus 1 according to the present embodiment determines that the sensitivity reduction has occurred when the state where the other vehicle cannot be locked on continues for a predetermined detection distance and when the signal level further decreases. Even when there is an extremely small amount of noise, it is possible to determine whether the reception antenna 2 and the transmission antenna 11 are dirty or the radar device 1 is broken. For this reason, in the radar apparatus 1 of the present embodiment, as long as a predetermined distance can be exceeded and the other vehicle can be locked on as in step S107, the other vehicle continues to follow even if the signal level decreases. To do. After that, when it becomes impossible to lock on the other vehicle that is following, it can be determined that the sensitivity is lowered. For this reason, even if the condition of step S104 is satisfied, there can be a locked-on state. Even in such a state, it is possible to both follow the other vehicle and detect dirt and failure. it can.

  In addition, in order to prevent erroneous determination, the radar apparatus 1 according to the present embodiment is not capable of detecting a target by extracting features of the radar front and ambient reflection by counting the number of peaks in addition to checking the ambient reflection level. It can be determined whether or not.

  In the above-described embodiment, a program for realizing each function in the signal processing unit 20 and the failure diagnosis unit 40 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is stored in a computer system. The encoding process and the decoding process may be performed by reading and executing. Here, the “computer system” may include an OS and hardware such as peripheral devices. Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used. The “computer-readable recording medium” means a flexible disk, a magneto-optical disk, a ROM, a writable nonvolatile memory such as a flash memory, a portable medium such as a CD-ROM, a hard disk built in a computer system, etc. This is a storage device.

  Further, the “computer-readable recording medium” refers to a volatile memory (for example, DRAM (DYNAMIC) inside a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. RANDOM ACCESS MEMORY)) and the like that hold a program for a certain period of time. The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

DESCRIPTION OF SYMBOLS 1 ... Radar apparatus, 2, 2-2 to 2-n ... Reception antenna, 3, 3-1 to 3-n ... Mixer, 4, 4-1 to 4-n ... Filter, 5 ... SW (switch), 6 DESCRIPTION OF SYMBOLS ... ADC, 7 ... Control part, 8 ... Triangle wave generation part, 9 ... VCO, 10 ... Distributor, 11 ... Transmission antenna, 12, 12-1 to 12-n ... Amplifier, 13 ... Amplifier, 14 ... Amplifier, 15 ... Amplifiers 16, 16-1 to 16-n ... Amplifiers, 20 ... Signal processing unit, 21 ... Memory, 22 ... DBF processing unit, 23 ... Peak detection unit, 24 ... Peak combination unit, 25 ... Distance detection unit, 26 ... Speed detection unit, 27 ... Pair determination unit, 28 ... Direction detection unit, 29 ... Return target determination unit, 30 ... Target determination unit, 40 ... Failure diagnosis unit, 41 ... Speed acquisition unit, 42 ... Sensitivity decrease detection unit

Claims (14)

A transmission unit for transmitting a transmission signal;
A receiving unit that receives a reflected signal from a target with respect to a transmission signal transmitted by the transmitting unit;
Detecting a peak of the signal received by the receiving unit, and counting the detected number of peaks; and
A failure diagnosis unit that performs a failure diagnosis based on the signal level of the signal received by the reception unit and information indicating that the target is supplemented;
A radar apparatus comprising: Information indicating that the target is supplemented is:
The radar apparatus according to claim 1, wherein the radar apparatus is lock-on information for the target. Information indicating that the target is supplemented is:
The radar device according to claim 1, wherein the radar device counts the number counted by the peak detection unit. The failure diagnosis unit
A determination level is generated based on the signal level of the signal received by the receiving unit at the first time and the signal level received at the second time before the first time, and a failure diagnosis is performed using the generated determination level. The radar device according to any one of claims 1 to 3, wherein The failure diagnosis unit
The radar apparatus according to any one of claims 1 to 4, wherein the failure diagnosis is performed when a travel distance after the failure diagnosis is initialized is equal to or longer than a first predetermined distance. The failure diagnosis unit
The radar apparatus according to any one of claims 1 to 5, wherein it is determined whether or not the target to be followed exists, and the failure diagnosis is not performed when the target to be followed exists. The peak detector is
The radar apparatus according to claim 1, wherein the number of peaks in the first region or the second region is counted in a third signal included in the signal received by the receiving unit. The failure diagnosis unit
For the second signal included in the signal received by the receiving unit, the first maximum level of the signal is extracted in the first region of the second signal at the first time, and the second time before the first time is extracted. The second maximum level of the signal is extracted in the first region of the second signal, and a first determination level is generated using the extracted first maximum level and the second maximum level. Radar device. The failure diagnosis unit
For the first signal included in the signal received by the receiving unit, the third maximum level of the signal is extracted in the first region of the first signal at the first time, and the first signal at the second time is extracted. The radar apparatus according to claim 8, wherein a fourth maximum level of a signal is extracted in the first region, and a second determination level is generated using the extracted third maximum level and the fourth maximum level. The failure diagnosis unit
When the first determination level is less than a first predetermined level, the second determination level is less than a second predetermined level, and the count number counted by the peak detection unit satisfies a condition of 0, failure diagnosis is performed. Add the first predetermined distance to the distance traveled since initialization,
A failure occurs when the first determination level is less than a first predetermined level, the second determination level is less than a second predetermined level, and the count number counted by the peak detection unit does not satisfy a condition of 0. The radar apparatus according to claim 9, wherein the travel distance after the diagnosis is initialized is initialized. The failure diagnosis unit
When the first determination level exceeds a third predetermined level and the second determination level exceeds a fourth predetermined level, it is detected that no failure has occurred, and a failure diagnosis is started. The radar apparatus according to claim 9, wherein a traveling distance from the vehicle is initialized. The first signal is an unmodulated CW wave;
The second signal is a modulated sub-wave;
The third signal is a main wave;
The first region is a downstream region;
The second region is an upstream region;
The first determination level is a determination level for the sub-wave,
The second determination level is a determination level for the CW wave,
The peak detector is
In the main wave included in the signal received by the receiver, the number of peaks in the downlink region is counted,
The failure diagnosis unit
The first maximum level of the signal is extracted in the downlink region in the subwave at the first time, the second maximum level of the signal is extracted in the downlink region in the subwave at the second time, and the extracted first Generating a first determination level using one maximum level and the second maximum level;
The third maximum level of the signal is extracted in the downstream region of the CW wave at the first time, and the fourth maximum level of the signal is extracted and extracted in the downstream region of the CW wave at the second time. A second determination level is generated using 3 maximum levels and the 4th maximum level,
Failure diagnosis when the first determination level is less than a first predetermined level, the second determination level is less than a second predetermined level, and the count number counted by the peak detector is 0 The first predetermined distance is added to the travel distance after starting
A failure occurs when the first determination level is less than a first predetermined level, the second determination level is less than a second predetermined level, and the count number counted by the peak detection unit does not satisfy a condition of 0. Initialize the mileage since the diagnosis was initialized,
When the first determination level exceeds a third predetermined level and the second determination level exceeds a fourth predetermined level, it is detected that no failure has occurred, and a failure diagnosis is started. The radar apparatus according to claim 10, wherein a traveling distance from the vehicle is initialized. A transmission procedure in which the transmission unit transmits a transmission signal;
A receiving unit that receives a reflected signal from a target with respect to a transmission signal transmitted by the transmission procedure;
A peak detection unit detects a peak of the signal received by the reception procedure, and counts the number of detected peaks,
A fault diagnosis procedure in which a fault diagnosis unit performs fault diagnosis based on the signal level of the signal received by the reception procedure and information indicating that the target is supplemented;
A method for controlling a radar apparatus including: To the radar computer,
A transmission procedure for transmitting as a transmission signal;
A receiving procedure for receiving a reflected signal from a target with respect to a transmission signal transmitted by the transmitting procedure;
A peak detection procedure for detecting a peak of the signal received by the reception procedure and counting the number of detected peaks;
A failure diagnosis procedure for performing a failure diagnosis based on the signal level of the signal received by the reception procedure and information indicating that the target is supplemented;
Control program to execute

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