WO2011136281A1 - In-vehicle radar device and in-vehicle radar system - Google Patents

In-vehicle radar device and in-vehicle radar system Download PDF

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Publication number
WO2011136281A1
WO2011136281A1 PCT/JP2011/060287 JP2011060287W WO2011136281A1 WO 2011136281 A1 WO2011136281 A1 WO 2011136281A1 JP 2011060287 W JP2011060287 W JP 2011060287W WO 2011136281 A1 WO2011136281 A1 WO 2011136281A1
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Prior art keywords
modulation
frequency
vehicle radar
distance calculation
unit
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PCT/JP2011/060287
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French (fr)
Japanese (ja)
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善之 武藤
浩司 黒田
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日立オートモティブシステムズ株式会社
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Publication of WO2011136281A1 publication Critical patent/WO2011136281A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/34—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/36—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated with phase comparison between the received signal and the contemporaneously transmitted signal
    • G01S13/38—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated with phase comparison between the received signal and the contemporaneously transmitted signal wherein more than one modulation frequency is used
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/40—Means for monitoring or calibrating
    • G01S7/4004—Means for monitoring or calibrating of parts of a radar system
    • G01S7/4021—Means for monitoring or calibrating of parts of a radar system of receivers

Definitions

  • the present invention relates to an in-vehicle radar device and an in-vehicle radar system mounted on a vehicle.
  • Examples of safe driving support systems for vehicles include an inter-vehicle distance warning system, an adaptive cruise control system, a pre-crash system, and the like.
  • a device that measures a distance to a target on a preceding road, a relative speed, and the like In constructing the above system, a device that measures a distance to a target on a preceding road, a relative speed, and the like.
  • the 2-frequency CW system is a modulation system that alternately transmits two frequencies.
  • a phase difference occurs between the IF signals of the respective frequencies. Since this phase difference is a unique value according to the distance to the target, the distance to the target can be calculated by detecting the phase difference.
  • FM modulation methods such as FM-CW (Frequency-Modulated-Continuous Wave) method (Patent Document 2) and StepFM (Step Frequency-Modulated) method.
  • FM modulation method modulation is performed on a signal to linearly increase or decrease the frequency on the time axis, and the signal is transmitted.
  • a frequency shift occurs on the time axis between the transmission and reception signals. Since this frequency shift amount corresponds to the propagation round trip time, it is a value that is uniquely determined with respect to the distance to the target. Therefore, in the FM modulation method, the distance from the frequency shift amount to the target can be calculated.
  • the phase difference in the IF signal is not generated, and thus the distance to the target cannot be calculated.
  • a safe driving support system such as an inter-vehicle distance warning system
  • control is performed based on information on the distance to the target and relative speed, it is difficult to maintain the reliability of the system when the abnormality occurs.
  • the present invention provides an on-vehicle radar measurement device that accurately detects a state in which an abnormality has occurred in a frequency switching processing unit that switches a plurality of frequency modulation methods.
  • the in-vehicle radar device is switched based on the modulation switching processing unit that switches the modulation schemes of the plurality of transmission frequencies and the modulation switching processing unit, and the modulation schemes of the plurality of transmission frequencies are changed.
  • a plurality of modulation processing units each processing, an oscillation unit that generates a transmission frequency that is frequency-modulated based on a modulation voltage output from the modulation processing unit switched by the modulation switching processing unit, and generated by the oscillation unit
  • a transmission unit that transmits a transmission signal
  • a reception unit that receives a reception signal generated by reflecting the transmission signal to a measurement object
  • a beat signal generation unit that generates a beat signal by mixing the transmission signal and the reception signal
  • a distance calculation unit that calculates a distance to the measurement object based on a distance calculation method corresponding to the modulation method of the beat signal, and a distance calculation unit.
  • an abnormality determination processing unit for modulating abnormality determination based on a plurality of difference of distance calculated in a different distance calculation methods.
  • the different distance calculation methods include a first distance calculation method for calculating a distance to the measurement object using a phase difference, and a frequency. It is preferable to have a second distance calculation method for calculating the distance to the measurement object using the difference.
  • the plurality of modulation processing units process the transmission frequency of the first modulation scheme that calculates the distance by the first distance calculation method.
  • the distance calculation unit performs a Fourier transform process on the beat signal to obtain a Fourier transform spectrum, and based on the beat signal.
  • the distance calculation unit includes the first distance calculation unit that calculates the distance to the measurement object using the phase difference, and the frequency difference. And a second distance calculation unit that calculates a distance to the measurement object using the error determination processing unit, and the abnormality determination processing unit calculates the distance calculated by the first distance calculation unit and the second distance calculation unit. It is preferable to perform modulation abnormality determination based on a difference from the measured distance.
  • the abnormality determination processing unit when the difference between the plurality of distances calculated by different distance calculation methods is greater than or equal to a predetermined value, It is preferable to determine that there is a modulation abnormality.
  • the abnormality determination processing unit includes an error determination unit that outputs an abnormality occurrence warning signal when it is determined that the modulation is abnormal. Is preferred.
  • the beat signal generation unit mixes the transmission signal and the reception signal to generate a beat signal, and demodulates the beat signal. It is preferable to include a demodulation processing unit that performs the conversion and an A / D conversion unit that converts the demodulated beat signal of the analog signal into a digital signal.
  • the multi-frequency CW method that is the first modulation method is a two-frequency CW method that alternately transmits two frequencies. preferable.
  • the modulation schemes for the plurality of transmission frequencies are the multi-frequency CW scheme which is the first modulation scheme and the second modulation scheme.
  • a StepFM modulation scheme in which the frequency is decreased or increased stepwise according to time.
  • the modulation schemes of the plurality of transmission frequencies are the first modulation scheme, and the frequency is decreased stepwise according to time. It is preferable to have the StepFM modulation method to be increased and the CW modulation method which is the second modulation method.
  • an in-vehicle radar system includes an in-vehicle radar device and a processing device, and the in-vehicle radar device includes a modulation switching processing unit that switches a modulation scheme of a plurality of transmission frequencies, and a modulation Switching based on the switching processing unit, the modulation method of the plurality of transmission frequencies, the frequency based on the modulation processing unit respectively processed by the modulation processing unit switched by the modulation switching processing unit
  • An oscillation unit that generates a transmission signal having a modulated transmission frequency, a transmission unit that transmits the transmission signal generated by the oscillation unit, and a reception unit that receives a reception signal generated by reflecting the transmission signal on the measurement object
  • a beat signal generation unit that generates a beat signal by mixing a transmission signal and a reception signal, and a distance calculation method that varies depending on the modulation method, and calculates a distance corresponding to the modulation method of the beat signal
  • a distance calculation unit that calculates the distance to the measurement object
  • an abnormality determination processing unit for outputting modulation abnormality occurrence information when it is determined as abnormal as a result of the modulation abnormality determination.
  • the different distance calculation methods include the first distance calculation method for calculating the distance to the measurement object using the phase difference, and the frequency It is preferable to have a second distance calculation method for calculating the distance to the measurement object using the difference.
  • the plurality of modulation processing units process the transmission frequency of the first modulation scheme that calculates the distance by the first distance calculation method.
  • the modulation schemes for the plurality of transmission frequencies are the multi-frequency CW scheme that is the first modulation scheme and the second modulation scheme. It is preferable to have an FM modulation system.
  • the abnormality determination processing unit is configured such that the difference between a plurality of distances calculated by different distance calculation methods is equal to or greater than a predetermined value.
  • the abnormality determination processing unit includes an error determination unit that outputs an abnormality occurrence warning signal when it is determined that the modulation is abnormal. Is preferred.
  • the on-vehicle radar device 1 of the present invention is characterized by detecting an abnormality in the frequency switching processing unit by having a plurality of means for calculating the distance to the target.
  • a representative one of the on-vehicle radar devices 1 for realizing the present invention includes a two-frequency CW method and a FM modulation method in which the frequency increases or decreases with the passage of time as a radio wave modulation method.
  • the two-frequency CW method it has means for calculating the distance to the target from the phase difference obtained from the IF signal of each frequency of the transmission / reception signal.
  • the FM modulation method from the amount of shift of the Doppler frequency according to the target distance, It has a means for calculating the distance to the target.
  • the two-frequency CW system is a modulation system that alternately transmits two frequencies as shown in FIG.
  • the IF signal obtained from the received signal becomes as shown in FIG.
  • the IF signal is generated from a reception signal in which two frequencies are mixed, a phase difference is generated between the IF signals of the respective frequencies. Since this phase difference is a unique value according to the distance to the target, the distance to the target can be calculated by detecting the phase difference.
  • the IF signal between the two frequencies becomes the same phase, so that no phase difference occurs, and as a result, the distance cannot be calculated.
  • the frequency to the beat signal generated by the frequency difference between the transmission signal and the reception signal is changed according to the propagation round-trip time between transmission and reception, thereby reducing the distance to the target. Can be calculated.
  • a modulation method in which a fixed frequency is switched like the two-frequency CW method the frequency of the beat signal is generated at a frequency corresponding to the relative speed of the target.
  • An example of an FM modulation signal waveform is shown in FIG.
  • the signal is subjected to modulation that linearly increases or decreases the frequency on the time axis, and the signal is transmitted.
  • the frequency is swept at a certain period, so that the frequency shift amount between the transmission and reception signals also changes when the propagation round-trip time between transmission and reception changes. To do. Since the propagation round-trip time can be converted into a distance, the amount of frequency shift and the distance can be correlated.
  • the shift amount of the frequency can be calculated from the difference between the Doppler frequency of the two-frequency CW method without the shift amount and the beat frequency of the FM modulation method that generates the shift amount.
  • the distance can be calculated from the difference between the frequencies of the two modulation methods.
  • the calculated distance due to the phase difference is an abnormal value due to the two-frequency modulation abnormality
  • the calculated distance from the frequency difference can be calculated regardless of the two-frequency modulation abnormality.
  • FIG. 1 is a block diagram of an in-vehicle radar device 1 according to an embodiment of the present invention.
  • the two-frequency CW scheme is used as the first modulation scheme
  • the FM modulation scheme is used as the second modulation scheme. That is, as shown in FIG. 2, frequency modulation is used in which the two-frequency CW method and the FM modulation method are alternately repeated. Note that these modulation methods differ in the method of calculating the distance to the target that is the measurement object.
  • the two-frequency CW method calculates the distance from the phase difference as the first distance calculation method
  • the FM modulation method calculates the distance from the frequency difference as the second distance calculation method.
  • the on-vehicle radar device 1 includes a modulation switching processing unit 100 that switches a modulation method of a plurality of transmission frequencies, and a plurality of modulation processing units (first devices) that respectively process a plurality of modulation methods switched by the modulation switching processing unit 100.
  • a modulation switching processing unit 100 that switches a modulation method of a plurality of transmission frequencies
  • a plurality of modulation processing units (first devices) that respectively process a plurality of modulation methods switched by the modulation switching processing unit 100.
  • 2 frequency CW modulation processing unit 101 which is a modulation processing unit of the above
  • FM modulation processing unit 102 which is a second modulation processing unit
  • a voltage-controlled oscillator 103 that generates a frequency-modulated transmission frequency
  • a transmission antenna 104 that is a transmission unit that transmits a transmission signal generated by the voltage-controlled oscillator 103, and a target whose transmission signal is a measurement object
  • the receiving antenna 105 which is a receiving unit that receives the reception signal generated by reflection on the signal, and the transmission signal and the reception signal are mixed, that is, mixed, and beat
  • the two-frequency CW modulation processing unit 101 When the two-frequency CW modulation is selected by the modulation switching processing unit 100, the two-frequency CW modulation processing unit 101 generates a modulation voltage and outputs it to the voltage-controlled oscillator 103.
  • the voltage-controlled oscillator 103 FIG.
  • a transmission signal Tx that is alternately modulated at the frequency f1 or the frequency f2 is generated at regular time intervals.
  • the transmission signal input to the transmission antenna 104 is radiated into the space as a transmission radio wave and reflected by the target, so that it is received by the reception antenna 105 as a reception radio wave, and the reception signal Rx in FIG. 3A is obtained. .
  • the transmission signal Tx and the reception signal Rx are mixed to generate a beat signal.
  • the generated beat signal is demodulated by the demodulation processing unit 107 and converted into a digital signal by the A / D conversion unit 108.
  • the converted digital signal is input to the signal processing unit 109.
  • the signal processing unit 109 performs arithmetic processing according to the flow described later, and obtains the distance to the target, the relative speed, the azimuth angle, the Doppler frequency of the beat signal, and the like.
  • the FM modulation processing unit 102 When the FM switching method is selected by the modulation switching processing unit 100, the FM modulation processing unit 102 generates a modulation voltage and outputs the modulation voltage to the voltage controlled oscillator 103.
  • the voltage controlled oscillator 103 FIG.
  • the transmission signal Tx whose frequency is gradually decreased is generated while switching between two frequency bands having a difference of ⁇ F for each FM modulation period TFM.
  • the transmission signal Tx is radiated by the transmission antenna 104, and the reflected signal from the target is received by the reception antenna 105, and then the mixer 106, the demodulation processing unit 107, and the A / D conversion unit.
  • the signal processing unit 109 obtains the distance to the target, the relative speed, the azimuth angle, the frequency of the beat signal, and the like.
  • the distance to the target calculated by the two-frequency CW modulated wave, the Doppler frequency of the beat signal, and the distance to the target calculated by the FM modulated wave, and the Doppler frequency of the beat signal Information is input to the abnormality determination processing unit 110, and it is determined whether there is an abnormality in modulation according to a flow described later.
  • the abnormality determination processing unit 110 outputs modulation abnormality occurrence information to the notification device 111.
  • warning methods include display indications such as LEDs and warning sounds such as beep sounds.
  • the abnormality determination processing unit 110 is provided in the in-vehicle laser device 1, but the abnormality determination processing unit 110 is, for example, an ECU that is a processing device 300 on the vehicle side, as shown in FIG. It is good also as a structure of the vehicle-mounted laser system mounted in.
  • the IF signal generated by the demodulation processing unit 107 when receiving a reception wave of two-frequency CW modulation shows a waveform as shown in FIG.
  • the IF signal when a transmission signal is generated by switching between two frequencies f1 and f2 as shown in FIG. 3A, the IF signal has two frequencies as shown in FIG. 3B. A phase difference corresponding to the distance occurs between them. By measuring this phase difference, the distance to the target can be calculated by Equation 1.
  • R CW is the target distance
  • c is the speed of light
  • ⁇ f is the frequency difference between f1 and f2
  • ⁇ is the phase difference due to ⁇ f.
  • the FM modulation method a transmission signal Tx as shown in FIG. 5 is generated, and when a reflected wave from the target is received, a reception signal Rx is obtained.
  • the frequency is gradually changed according to time. Therefore, if the distance to the target changes, the propagation round-trip time between the transmission and reception signals also changes.
  • the frequency difference between the transmitted and received signals includes not only the Doppler shift f d but also the frequency variation ⁇ f R due to the propagation round-trip time ⁇ .
  • FIG. 6 shows an FFT spectrum obtained by performing FFT (Fast Fourier Transform) processing in the signal processing unit 109.
  • FFT Fast Fourier Transform
  • ⁇ f R is uniquely determined by the distance to the target, the distance to the target can be calculated from ⁇ f R.
  • ⁇ f R can be expressed by Equation 2.
  • T FM is an FM modulation period in which the frequency changes according to time
  • ⁇ Ramp is a frequency change amount during T FM
  • ⁇ is a propagation round-trip time from transmission of a transmission signal to reception of a reception signal.
  • Equation 3 the propagation round-trip time ⁇ is as shown in Equation 3.
  • c means the speed of light and R means the distance to the target.
  • the distance R to the target can be expressed as Equation 4 from Equation 2 and Equation 3.
  • ⁇ f R can be derived by taking the difference between the Doppler frequency at the time of two-frequency CW modulation and the beat frequency at the time of FM modulation, the distance to the target can be calculated by Equation 4.
  • FFT processing which is Fourier transform means in step 200 is executed on the beat signal. That is, a Fourier transform process is performed on the beat signal to obtain a Fourier transform spectrum.
  • a modulation method determination process as modulation method determination means in step 201, it is determined whether the input beat signal is a two-frequency CW modulation wave or an FM modulation wave. Specifically, since modulation scheme information indicating which modulation scheme is implemented in the modulation switching processing unit 100 in FIG. 1 is stored, the modulation scheme is determined based on the modulation scheme information.
  • the distance calculation means calculates the distance from the Fourier transform spectrum to the measurement object using the determined distance calculation method of the modulation method.
  • the FFT spectrum obtained by the FFT process is converted into a physical value of target information.
  • the FM modulation physical value conversion process in step 203 the FFT spectrum obtained by the FFT process is converted into a physical value of the target information.
  • the 2-frequency modulation abnormality determination is performed using the physical values calculated above.
  • the physical values include the distance to the target, the relative speed, the azimuth angle, the Doppler frequency of the beat signal, and the like.
  • step 204 calculates the frequency difference ⁇ f R between the beat signals in the two-frequency CW modulated wave and FM modulated wave obtained from signal processing section 109.
  • the target distance is calculated in step 205 from Equation 4.
  • the target distance is calculated using the phase difference in the physical value conversion process of the signal processing unit 109
  • the difference between the distance calculated from the phase difference and the distance calculated from the frequency difference in step 205 is calculated in step 206. In the calculation.
  • the distance calculated from the phase difference is obtained correctly, so the distance difference calculated in step 206 is small.
  • the distance value calculated from the phase difference fluctuates, and thus the distance difference value in step 206 increases.
  • this distance difference it is possible to determine a two-frequency modulation abnormality. That is, if the difference between the distance calculated from the phase difference and the distance calculated from the frequency difference is greater than or equal to a predetermined value in step 207, it is determined that the two-frequency modulation is abnormal, and error determination processing is performed in step 208. If the difference in distance is less than or equal to a predetermined value, it is determined to be normal and the error determination process is not executed.
  • the predetermined value in step 207 is a value derived in advance in consideration of the calculation accuracy of the distance calculated from the phase difference and the distance calculated from the frequency difference, and differs depending on the hardware specifications of the radar. It is assumed that 19.8 [m].
  • an abnormality occurrence warning signal is output to the notification device 111, and the notification device 111 notifies the driver that an abnormality has occurred.
  • the abnormality occurrence warning signal is not output.
  • the abnormality can be detected even when abnormality occurs in the FM modulation.
  • the frequency fluctuation amount ⁇ f R due to the propagation round-trip time ⁇ varies, and an error occurs in the distance calculated from the frequency difference calculated in step 205.
  • the difference between the distance calculated from the phase difference in step 207 and the distance calculated from the frequency difference becomes equal to or greater than a predetermined value, and an error determination is made in step 208. Therefore, it is possible to detect even FM modulation abnormality.
  • the present invention is not limited to the above-described embodiment, and can be realized even when the two-frequency CW method and the StepFM method are used as the modulation method, or when the StepFM method and the CW method are used.
  • the StepFM method is a modulation method that decreases or increases the frequency stepwise according to time, like the frequency waveform of StepFM modulation in FIG.
  • the same technique as in the above-described embodiment can be realized by providing a Step FM modulation processing unit instead of the FM modulation processing unit 102.
  • a frequency waveform as shown in FIG. 9 is given as an example.
  • the same technique as that of the above-described embodiment is provided by providing the Step FM modulation processing unit and the CW modulation processing unit instead of the two-frequency CW modulation processing unit 101 and the FM modulation processing unit 102. Can be realized.

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Abstract

An in-vehicle radar device comprises: a modulation switching processing unit which performs switching between a plurality of transmission frequency modulation methods; a plurality of modulation processing units between which switching is performed on the basis of the modulation switching processing unit and which respectively process the plurality of transmission frequency modulation methods; an oscillation unit which generates a transmission frequency frequency-modulated on the basis of modulation voltage outputted from the modulation processing unit, switching to which is performed by the modulation switching processing unit; a transmission unit which transmits a transmission signal generated by the oscillation unit; a reception unit which receives a reception signal generated by the reflection of the transmission signal by an object to be measured, a beat signal generation unit which generates a beat signal by mixing the transmission signal and the reception signal; a distance calculation unit which has different distance calculation methods depending on the modulation methods and calculates the distance to the object to be measured on the basis of a distance calculation method corresponding to the modulation method of the beat signal; and an abnormality determination processing unit which determines modulation abnormality on the basis of the difference between a plurality of distances calculated by the different distance calculation methods by the distance calculation unit.

Description

車載用レーダ装置及び車載用レーダシステムIn-vehicle radar device and in-vehicle radar system
　本発明は、車両に搭載する車載用レーダ装置及び車載用レーダシステムに関する。 The present invention relates to an in-vehicle radar device and an in-vehicle radar system mounted on a vehicle.
　自動車の安全運転支援システムとして、車間距離警報システム，アダプティブクルーズコントロールシステム，プリクラッシュシステム等が挙げられるが、上記システムを構築する際に、先行路上のターゲットまでの距離や相対速度等を計測する装置として、車載用レーダ装置がある。 Examples of safe driving support systems for vehicles include an inter-vehicle distance warning system, an adaptive cruise control system, a pre-crash system, and the like. In constructing the above system, a device that measures a distance to a target on a preceding road, a relative speed, and the like. As an example, there is an in-vehicle radar device.
　この車載用レーダ装置に用いられる変調方式には様々なものがあるが、その一つに２周波ＣＷ（Continuous Wave）方式がある（特許文献１）。２周波ＣＷ方式は、２つの周波数を交互に送信する変調方式である。これによって、受信信号から得られるＩＦ信号は、２つの周波数が混在する受信信号より生成されるので、各周波数によるＩＦ信号の間に位相差が発生する。この位相差は、ターゲットまでの距離に応じて一義的な値になっているので、位相差を検出することで、ターゲットまでの距離を算出することができる。 There are various modulation methods used in this on-vehicle radar device, and one of them is a two-frequency CW (Continuous Wave) method (Patent Document 1). The 2-frequency CW system is a modulation system that alternately transmits two frequencies. Thereby, since the IF signal obtained from the received signal is generated from the received signal in which two frequencies are mixed, a phase difference occurs between the IF signals of the respective frequencies. Since this phase difference is a unique value according to the distance to the target, the distance to the target can be calculated by detecting the phase difference.
　また、車載用レーダ装置で用いられる別の変調方式として、ＦＭ－ＣＷ（Frequency Modulated Continuous Wave）方式（特許文献２）や、ＳｔｅｐＦＭ（Step Frequency Modulated）方式等のＦＭ変調方式がある。ＦＭ変調方式では、周波数を時間軸上で直線的に増減させるような変調を信号にかけて、同信号を送信させている。ここで、送信信号がターゲットで反射し、その反射信号を受信するまでの間に伝播往復時間がある。これにより、送受信信号の間には時間軸上で周波数シフトが発生する。この周波数シフト量は伝播往復時間に対応するので、ターゲットまでの距離に対しても一義的に決まる値になる。よって、ＦＭ変調方式では、周波数シフト量からターゲットまでの距離を算出することができる。 Further, as another modulation method used in the on-vehicle radar device, there are FM modulation methods such as FM-CW (Frequency-Modulated-Continuous Wave) method (Patent Document 2) and StepFM (Step Frequency-Modulated) method. In the FM modulation method, modulation is performed on a signal to linearly increase or decrease the frequency on the time axis, and the signal is transmitted. Here, there is a propagation round-trip time between the transmission signal reflected by the target and the reception of the reflected signal. As a result, a frequency shift occurs on the time axis between the transmission and reception signals. Since this frequency shift amount corresponds to the propagation round trip time, it is a value that is uniquely determined with respect to the distance to the target. Therefore, in the FM modulation method, the distance from the frequency shift amount to the target can be calculated.
特開２０００－２９２５３０号公報JP 2000-292530 A 特開２００６－２９２５７６号公報JP 2006-292576 A
　２周波ＣＷ方式において、２つの周波数を切り替える機構に異常が発生し、周波数切り替えが実行されなくなった場合、ＩＦ信号における位相差が発生されなくなるため、ターゲットまでの距離を演算することができなくなる。 In the two-frequency CW method, when an abnormality occurs in the mechanism for switching two frequencies and the frequency switching is not performed, the phase difference in the IF signal is not generated, and thus the distance to the target cannot be calculated.
　車間距離警報システム等の安全運転支援システムでは、ターゲットまでの距離や相対速度の情報を元に制御しているので、その異常が発生すると、システムの信頼性を維持することが困難となる。 In a safe driving support system such as an inter-vehicle distance warning system, since control is performed based on information on the distance to the target and relative speed, it is difficult to maintain the reliability of the system when the abnormality occurs.
　本発明は、複数の周波数変調方式を切り替える周波数切替処理部に異常が発生している状態を、精度良く検知する車載用レーダ計測装置を提供する。 The present invention provides an on-vehicle radar measurement device that accurately detects a state in which an abnormality has occurred in a frequency switching processing unit that switches a plurality of frequency modulation methods.
　本発明の第１の態様によると、車載用レーダ装置は、複数の送信周波数の変調方式を切り替える変調切替処理部と、変調切替処理部に基づいて切り替えられ、複数の送信周波数の変調方式を、それぞれ処理する複数の変調処理部と、変調切替処理部にて切り替えられた変調処理部から出力される変調電圧に基づいて周波数変調された送信周波数を生成する発振部と、発振部で生成された送信信号を送信する送信部と、送信信号が測定対象物に反射して生成された受信信号を受信する受信部と、送信信号と受信信号とを混合してビート信号を生成するビート信号生成部と、変調方式によって異なる距離算出方法を有し、ビート信号の変調方式に対応する距離算出方法に基づいて測定対象物までの距離を算出する距離算出部と、距離算出部によって異なる距離算出方法で算出された複数の距離の差分に基づいて変調異常判定を行う異常判定処理部と、を有する。
　本発明の第２の態様によると、第１の態様の車載用レーダ装置において、異なる距離算出方法は、位相差を用いて測定対象物までの距離を算出する第１の距離算出方法と、周波数差を用いて測定対象物までの距離を算出する第２の距離算出方法と、を有するのが好ましい。
　本発明の第３の態様によると、第２の態様の車載用レーダ装置において、複数の変調処理部は、第１の距離算出方法で距離を算出する第１の変調方式の送信周波数を処理する第１の変調処理部と、第２の距離算出方法で距離を算出する第２の変調方式の送信周波数を処理する第２の変調処理部と、を有するのが好ましい。
　本発明の第４の態様によると、第３の態様の車載用レーダ装置において、複数の送信周波数の変調方式は、第１の変調方式である多周波ＣＷ方式と、第２の変調方式であるＦＭ変調方式と、を有するのが好ましい。
　本発明の第５の態様によると、第１の態様の車載用レーダ装置において、距離算出部は、ビート信号にフーリエ変換処理を行い、フーリエ変換スペクトラムを得るフーリエ変換部と、ビート信号に基づいて変調方式を判断する変調方式判断部と、変調方式判断部で判断された変調方式の距離計算方法にて、フーリエ変換スペクトラムから測定対象物までの距離を算出する距離算出部と、を有するのが好ましい。
　本発明の第６の態様によると、第５の態様の車載用レーダ装置において、距離算出部は、位相差を用いて測定対象物までの距離を算出する第１の距離算出部と、周波数差を用いて測定対象物までの距離を算出する第２の距離算出部と、を有し、異常判定処理部は、第１の距離算出部で算出された距離と第２の距離算出部で算出された距離との差に基づいて変調異常判定を行うのが好ましい。
　本発明の第７の態様によると、第１の態様の車載用レーダ装置において、異常判定処理部は、異なる距離算出方法で算出された複数の距離の差が予め定めた所定値以上の場合、変調異常であると判定を行うのが好ましい。
　本発明の第８の態様によると、第７の態様の車載用レーダ装置において、異常判定処理部は、変調異常であると判定された場合、異常発生警告信号を出力するエラー判定部を有するのが好ましい。
　本発明の第９の態様によると、第１の態様の車載用レーダ装置において、ビート信号生成部は、送信信号と受信信号とを混合してビート信号を生成する混合部と、ビート信号を復調する復調処理部と、復調されたアナログ信号のビート信号をデジタル信号に変換するＡ／Ｄ変換部と、を有するのが好ましい。
　本発明の第１０の態様によると、第４の態様の車載用レーダ装置において、第１の変調方式である多周波ＣＷ方式は、２つの周波数を交互に送信する２周波ＣＷ方式であるのが好ましい。
　本発明の第１１の態様によると、第３の態様の車載用レーダ装置において、複数の送信周波数の変調方式は、第１の変調方式である多周波ＣＷ方式と、第２の変調方式であって、時間に応じて段階的に周波数を減少又は増加させるＳｔｅｐＦＭ変調方式と、を有するのが好ましい。
　本発明の第１２の態様によると、第３の態様の車載用レーダ装置において、複数の送信周波数の変調方式は、第１の変調方式であって、時間に応じて段階的に周波数を減少又は増加させるＳｔｅｐＦＭ変調方式と、第２の変調方式であるＣＷ変調方式と、を有するのが好ましい。
　本発明の第１３の態様によると、車載用レーダシステムは、車載用レーダ装置と、処理装置とを備え、車載用レーダ装置は、複数の送信周波数の変調方式を切り替える変調切替処理部と、変調切替処理部に基づいて切り替えられ、複数の送信周波数の変調方式を、それぞれ処理する複数の変調処理部と、変調切替処理部にて切り替えられた変調処理部から出力される変調電圧に基づいて周波数変調された送信周波数の送信信号を生成する発振部と、発振部で生成された送信信号を送信する送信部と、送信信号が測定対象物に反射して生成された受信信号を受信する受信部と、送信信号と受信信号とを混合してビート信号を生成するビート信号生成部と、変調方式によって異なる距離算出方法を有し、ビート信号の変調方式に対応する距離算出方法に基づいて測定対象物までの距離を算出する距離算出部と、を有し、処理装置は、距離算出部によって異なる距離算出方法で算出された複数の距離の差分に基づいて変調異常判定を行い、変調異常判定の結果、異常と判定された場合は変調異常発生情報を出力する異常判定処理部を有する。
　本発明の第１４の態様によると、第１３の態様の車載用レーダシステムにおいて、異なる距離算出方法は、位相差を用いて測定対象物までの距離を算出する第１の距離算出方法と、周波数差を用いて測定対象物までの距離を算出する第２の距離算出方法と、を有するのが好ましい。
　本発明の第１５の態様によると、第１４の態様の車載用レーダシステムにおいて、複数の変調処理部は、第１の距離算出方法で距離を算出する第１の変調方式の送信周波数を処理する第１の変調処理部と、第２の距離算出方法で距離を算出する第２の変調方式の送信周波数を処理する第２の変調処理部と、を有するのが好ましい。
　本発明の第１６の態様によると、第１５の態様の車載用レーダシステムにおいて、複数の送信周波数の変調方式は、第１の変調方式である多周波ＣＷ方式と、第２の変調方式であるＦＭ変調方式と、を有するのが好ましい。
　本発明の第１７の態様によると、第１３の態様の車載用レーダシステムにおいて、異常判定処理部は、異なる距離算出方法で算出された複数の距離の差が予め定めた所定値以上の場合、変調異常であると判定を行うのが好ましい。
　本発明の第１８の態様によると、第１７の態様の車載用レーダシステムにおいて、異常判定処理部は、変調異常であると判定された場合、異常発生警告信号を出力するエラー判定部を有するのが好ましい。 According to the first aspect of the present invention, the in-vehicle radar device is switched based on the modulation switching processing unit that switches the modulation schemes of the plurality of transmission frequencies and the modulation switching processing unit, and the modulation schemes of the plurality of transmission frequencies are changed. A plurality of modulation processing units each processing, an oscillation unit that generates a transmission frequency that is frequency-modulated based on a modulation voltage output from the modulation processing unit switched by the modulation switching processing unit, and generated by the oscillation unit A transmission unit that transmits a transmission signal, a reception unit that receives a reception signal generated by reflecting the transmission signal to a measurement object, and a beat signal generation unit that generates a beat signal by mixing the transmission signal and the reception signal And a distance calculation unit that calculates a distance to the measurement object based on a distance calculation method corresponding to the modulation method of the beat signal, and a distance calculation unit. Having, an abnormality determination processing unit for modulating abnormality determination based on a plurality of difference of distance calculated in a different distance calculation methods.
According to the second aspect of the present invention, in the in-vehicle radar device according to the first aspect, the different distance calculation methods include a first distance calculation method for calculating a distance to the measurement object using a phase difference, and a frequency. It is preferable to have a second distance calculation method for calculating the distance to the measurement object using the difference.
According to the third aspect of the present invention, in the in-vehicle radar device according to the second aspect, the plurality of modulation processing units process the transmission frequency of the first modulation scheme that calculates the distance by the first distance calculation method. It is preferable to include a first modulation processing unit and a second modulation processing unit that processes the transmission frequency of the second modulation scheme that calculates the distance by the second distance calculation method.
According to the fourth aspect of the present invention, in the on-vehicle radar device according to the third aspect, the modulation schemes of the plurality of transmission frequencies are the multi-frequency CW scheme which is the first modulation scheme and the second modulation scheme. It is preferable to have an FM modulation system.
According to the fifth aspect of the present invention, in the in-vehicle radar device according to the first aspect, the distance calculation unit performs a Fourier transform process on the beat signal to obtain a Fourier transform spectrum, and based on the beat signal. A modulation method determination unit that determines a modulation method, and a distance calculation unit that calculates a distance from a Fourier transform spectrum to a measurement object by the distance calculation method of the modulation method determined by the modulation method determination unit. preferable.
According to the sixth aspect of the present invention, in the in-vehicle radar device according to the fifth aspect, the distance calculation unit includes the first distance calculation unit that calculates the distance to the measurement object using the phase difference, and the frequency difference. And a second distance calculation unit that calculates a distance to the measurement object using the error determination processing unit, and the abnormality determination processing unit calculates the distance calculated by the first distance calculation unit and the second distance calculation unit. It is preferable to perform modulation abnormality determination based on a difference from the measured distance.
According to the seventh aspect of the present invention, in the in-vehicle radar device according to the first aspect, the abnormality determination processing unit, when the difference between the plurality of distances calculated by different distance calculation methods is greater than or equal to a predetermined value, It is preferable to determine that there is a modulation abnormality.
According to the eighth aspect of the present invention, in the on-vehicle radar device according to the seventh aspect, the abnormality determination processing unit includes an error determination unit that outputs an abnormality occurrence warning signal when it is determined that the modulation is abnormal. Is preferred.
According to a ninth aspect of the present invention, in the in-vehicle radar device according to the first aspect, the beat signal generation unit mixes the transmission signal and the reception signal to generate a beat signal, and demodulates the beat signal. It is preferable to include a demodulation processing unit that performs the conversion and an A / D conversion unit that converts the demodulated beat signal of the analog signal into a digital signal.
According to the tenth aspect of the present invention, in the on-vehicle radar device according to the fourth aspect, the multi-frequency CW method that is the first modulation method is a two-frequency CW method that alternately transmits two frequencies. preferable.
According to the eleventh aspect of the present invention, in the on-vehicle radar device according to the third aspect, the modulation schemes for the plurality of transmission frequencies are the multi-frequency CW scheme which is the first modulation scheme and the second modulation scheme. Thus, it is preferable to have a StepFM modulation scheme in which the frequency is decreased or increased stepwise according to time.
According to the twelfth aspect of the present invention, in the in-vehicle radar device according to the third aspect, the modulation schemes of the plurality of transmission frequencies are the first modulation scheme, and the frequency is decreased stepwise according to time. It is preferable to have the StepFM modulation method to be increased and the CW modulation method which is the second modulation method.
According to a thirteenth aspect of the present invention, an in-vehicle radar system includes an in-vehicle radar device and a processing device, and the in-vehicle radar device includes a modulation switching processing unit that switches a modulation scheme of a plurality of transmission frequencies, and a modulation Switching based on the switching processing unit, the modulation method of the plurality of transmission frequencies, the frequency based on the modulation processing unit respectively processed by the modulation processing unit switched by the modulation switching processing unit An oscillation unit that generates a transmission signal having a modulated transmission frequency, a transmission unit that transmits the transmission signal generated by the oscillation unit, and a reception unit that receives a reception signal generated by reflecting the transmission signal on the measurement object And a beat signal generation unit that generates a beat signal by mixing a transmission signal and a reception signal, and a distance calculation method that varies depending on the modulation method, and calculates a distance corresponding to the modulation method of the beat signal A distance calculation unit that calculates the distance to the measurement object based on the method, and the processing device performs modulation abnormality determination based on a difference between a plurality of distances calculated by different distance calculation methods by the distance calculation unit. And an abnormality determination processing unit for outputting modulation abnormality occurrence information when it is determined as abnormal as a result of the modulation abnormality determination.
According to the fourteenth aspect of the present invention, in the in-vehicle radar system according to the thirteenth aspect, the different distance calculation methods include the first distance calculation method for calculating the distance to the measurement object using the phase difference, and the frequency It is preferable to have a second distance calculation method for calculating the distance to the measurement object using the difference.
According to the fifteenth aspect of the present invention, in the on-vehicle radar system according to the fourteenth aspect, the plurality of modulation processing units process the transmission frequency of the first modulation scheme that calculates the distance by the first distance calculation method. It is preferable to include a first modulation processing unit and a second modulation processing unit that processes the transmission frequency of the second modulation scheme that calculates the distance by the second distance calculation method.
According to the sixteenth aspect of the present invention, in the on-vehicle radar system according to the fifteenth aspect, the modulation schemes for the plurality of transmission frequencies are the multi-frequency CW scheme that is the first modulation scheme and the second modulation scheme. It is preferable to have an FM modulation system.
According to the seventeenth aspect of the present invention, in the in-vehicle radar system according to the thirteenth aspect, the abnormality determination processing unit is configured such that the difference between a plurality of distances calculated by different distance calculation methods is equal to or greater than a predetermined value. It is preferable to determine that there is a modulation abnormality.
According to an eighteenth aspect of the present invention, in the on-vehicle radar system according to the seventeenth aspect, the abnormality determination processing unit includes an error determination unit that outputs an abnormality occurrence warning signal when it is determined that the modulation is abnormal. Is preferred.
　複数の周波数変調方式を切り替える周波数切替処理部に異常が発生している状態を、精度良く検知する車載用レーダ計測装置を提供できる。 It is possible to provide an in-vehicle radar measurement device that accurately detects a state where an abnormality has occurred in a frequency switching processing unit that switches a plurality of frequency modulation methods.
本発明に係る車載用レーダ装置のブロック構成を示す図である。It is a figure which shows the block configuration of the vehicle-mounted radar apparatus which concerns on this invention. 本発明の車載用レーダ装置の２周波ＣＷ方式とＦＭ変調方式を使用した場合の周波数変調波形を示す図である。It is a figure which shows the frequency modulation waveform at the time of using the 2 frequency CW system and FM modulation system of the vehicle-mounted radar apparatus of this invention. ２周波ＣＷ方式における送受信信号の周波数変調波形及び位相波形を示す図である。It is a figure which shows the frequency modulation waveform and phase waveform of the transmission / reception signal in a 2 frequency CW system. ２周波ＣＷ方式において２周波変調が異常になった場合の送受信信号の周波数波形及び位相波形を示す図である。It is a figure which shows the frequency waveform and phase waveform of a transmission / reception signal when 2 frequency modulation becomes abnormal in 2 frequency CW system. ＦＭ変調方式における波形を示す図である。It is a figure which shows the waveform in FM modulation system. ２周波ＣＷ方式及びＦＭ変調方式におけるＦＦＴスペクトラムを示す図である。It is a figure which shows the FFT spectrum in a 2 frequency CW system and FM modulation system. 本発明に係る車載用レーダ装置の信号処理部及び異常判定処理部のフローチャートを示す図である。It is a figure which shows the flowchart of the signal processing part and abnormality determination processing part of the vehicle-mounted radar apparatus which concerns on this invention. 本発明の車載用レーダ装置の変調方式として、２周波ＣＷ方式とＳｔｅｐＦＭ方式を使用した場合の一例の周波数波形を示す図である。It is a figure which shows an example of a frequency waveform at the time of using 2 frequency CW system and StepFM system as a modulation system of the vehicle-mounted radar apparatus of this invention. 本発明の車載用レーダ装置の変調方式として、ＳｔｅｐＦＭ方式とＣＷ方式を使用した場合の一例の周波数波形を示す図である。It is a figure which shows an example of a frequency waveform at the time of using a StepFM system and a CW system as a modulation system of the vehicle-mounted radar apparatus of this invention. 本発明に係る車載用レーダシステムのブロック構成を示す図である。It is a figure which shows the block configuration of the vehicle-mounted radar system which concerns on this invention.
　以下、本発明に関する実施例を、添付の図面を参照しながら詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
　本発明の車載用レーダ装置１は、ターゲットまでの距離算出手段を複数持つことで、周波数切替処理部の異常を検出することを特徴とする。 The on-vehicle radar device 1 of the present invention is characterized by detecting an abnormality in the frequency switching processing unit by having a plurality of means for calculating the distance to the target.
　本発明を実現する車載用レーダ装置１のうち代表的な一つは、電波変調の方式として、２周波ＣＷ方式と、時間経過とともに周波数が増加または減少するＦＭ変調方式と、がある。２周波ＣＷ方式では、送受信信号の各周波数のＩＦ信号から得られる位相差よりターゲットまでの距離を算出する手段を有し、ＦＭ変調方式では、ターゲットの距離に応じたドップラ周波数のシフト量から、ターゲットまでの距離を算出する手段を有していることを特徴とする。 A representative one of the on-vehicle radar devices 1 for realizing the present invention includes a two-frequency CW method and a FM modulation method in which the frequency increases or decreases with the passage of time as a radio wave modulation method. In the two-frequency CW method, it has means for calculating the distance to the target from the phase difference obtained from the IF signal of each frequency of the transmission / reception signal. In the FM modulation method, from the amount of shift of the Doppler frequency according to the target distance, It has a means for calculating the distance to the target.
　２周波ＣＷ方式におけるＩＦ信号の位相差は、ターゲットまでの距離に応じて変化するので、位相差を検出することで距離に換算することが可能となる。２周波ＣＷ方式は、図３（ａ）のように、２つの周波数を交互に送信する変調方式である。これによって、受信信号から得られるＩＦ信号は図３（ｂ）のようになる。ここでＩＦ信号は、２つの周波数が混在する受信信号より生成されるので、各周波数によるＩＦ信号の間に位相差が発生する。この位相差は、ターゲットまでの距離に応じて一義的な値になっているので、位相差を検出することで、ターゲットまでの距離を算出することができる。 Since the phase difference of the IF signal in the two-frequency CW system changes according to the distance to the target, it can be converted into a distance by detecting the phase difference. The two-frequency CW system is a modulation system that alternately transmits two frequencies as shown in FIG. Thereby, the IF signal obtained from the received signal becomes as shown in FIG. Here, since the IF signal is generated from a reception signal in which two frequencies are mixed, a phase difference is generated between the IF signals of the respective frequencies. Since this phase difference is a unique value according to the distance to the target, the distance to the target can be calculated by detecting the phase difference.
　しかし、２周波変調の切り替えがされない異常が発生した場合、２周波の各周波数間のＩＦ信号が同位相になるので位相差が発生しなくなり、その結果、距離を算出できなくなる。 However, if an abnormality occurs in which the 2-frequency modulation cannot be switched, the IF signal between the two frequencies becomes the same phase, so that no phase difference occurs, and as a result, the distance cannot be calculated.
　その一方で、ＦＭ変調方式では、送信信号と受信信号の周波数差によって生成されるビート信号の周波数が、送受信間の伝播往復時間に応じて変化する特性を利用することで、ターゲットまでの距離を算出することができる。２周波ＣＷ方式のように、固定の周波数を切り替えるような変調方式では、ビート信号の周波数は、ターゲットの相対速度に応じた周波数に発生する。ＦＭ変調方式の信号波形の一例を図５に示す。図５のようにＦＭ変調方式では、周波数を時間軸上で直線的に増減させるような変調を信号にかけて、同信号を送信させている。ここで、送信信号がターゲットで反射し、その反射信号を受信するまでの間に伝播往復時間がある。これにより、送受信信号の間には時間軸上で周波数シフトが発生する。この周波数シフト量は伝播往復時間に対応するので、ターゲットまでの距離に対しても一義的に決まる値になる。よって、ＦＭ変調方式では、周波数シフト量からターゲットまでの距離を算出することができる。 On the other hand, in the FM modulation method, the frequency to the beat signal generated by the frequency difference between the transmission signal and the reception signal is changed according to the propagation round-trip time between transmission and reception, thereby reducing the distance to the target. Can be calculated. In a modulation method in which a fixed frequency is switched like the two-frequency CW method, the frequency of the beat signal is generated at a frequency corresponding to the relative speed of the target. An example of an FM modulation signal waveform is shown in FIG. As shown in FIG. 5, in the FM modulation method, the signal is subjected to modulation that linearly increases or decreases the frequency on the time axis, and the signal is transmitted. Here, there is a propagation round-trip time between the transmission signal reflected by the target and the reception of the reflected signal. As a result, a frequency shift occurs on the time axis between the transmission and reception signals. Since this frequency shift amount corresponds to the propagation round trip time, it is a value that is uniquely determined with respect to the distance to the target. Therefore, in the FM modulation method, the distance from the frequency shift amount to the target can be calculated.
　しかし、ＦＭ－ＣＷ方式やＳｔｅｐＦＭ方式のようなＦＭ変調方式では、ある一定の周期で周波数が掃引されているので、送受信間の伝播往復時間が変化すると、送受信信号間の周波数のシフト量も変化する。伝播往復時間は距離に換算できるので、周波数のシフト量と距離を相関付けることができる。 However, in the FM modulation method such as the FM-CW method or the StepFM method, the frequency is swept at a certain period, so that the frequency shift amount between the transmission and reception signals also changes when the propagation round-trip time between transmission and reception changes. To do. Since the propagation round-trip time can be converted into a distance, the amount of frequency shift and the distance can be correlated.
　ここで周波数のシフト量は、シフト量が無い２周波ＣＷ方式のドップラ周波数と、シフト量が発生するＦＭ変調方式のビート周波数の差分から算出することが可能である。これより、２つ変調方式の周波数の差分から、距離を算出することができる。 Here, the shift amount of the frequency can be calculated from the difference between the Doppler frequency of the two-frequency CW method without the shift amount and the beat frequency of the FM modulation method that generates the shift amount. Thus, the distance can be calculated from the difference between the frequencies of the two modulation methods.
　ここで、２周波変調異常で位相差による算出距離が異常値になっている一方、周波数の差分からの算出距離は、２周波変調異常によらず算出可能であるので、両者の算出距離の差分を確認することで、２周波変調異常の有無を検出することが可能となる。 Here, while the calculated distance due to the phase difference is an abnormal value due to the two-frequency modulation abnormality, the calculated distance from the frequency difference can be calculated regardless of the two-frequency modulation abnormality. By confirming the above, it is possible to detect the presence or absence of two-frequency modulation abnormality.
　図１は、本発明の一実施例に関する車載用レーダ装置１のブロック構成図である。なお、本実施例では、複数の送信周波数の変調方式のうち、第１の変調方式として２周波ＣＷ方式を使用し、第２の変調方式としてＦＭ変調方式を使用する。即ち、図２のように、２周波ＣＷ方式とＦＭ変調方式を交互に繰り返すような周波数変調を使用する。なお、これらの変調方式は、測定対象物であるターゲットまでの距離算出方法が異なる。本実施例では、２周波ＣＷ方式は、第１の距離算出方法として位相差から距離を算出し、ＦＭ変調方式は、第２の距離算出方法として、周波数差から距離を算出する。 FIG. 1 is a block diagram of an in-vehicle radar device 1 according to an embodiment of the present invention. In this embodiment, among the plurality of transmission frequency modulation schemes, the two-frequency CW scheme is used as the first modulation scheme, and the FM modulation scheme is used as the second modulation scheme. That is, as shown in FIG. 2, frequency modulation is used in which the two-frequency CW method and the FM modulation method are alternately repeated. Note that these modulation methods differ in the method of calculating the distance to the target that is the measurement object. In this embodiment, the two-frequency CW method calculates the distance from the phase difference as the first distance calculation method, and the FM modulation method calculates the distance from the frequency difference as the second distance calculation method.
　車載用レーダ装置１は、複数の送信周波数の変調方式を切り替える変調切替処理部１００と、変調切替処理部１００で切り替えられた、複数の変調方式を、それぞれ処理する複数の変調処理部（第１の変調処理部である２周波ＣＷ変調処理部１０１、第２の変調処理部であるＦＭ変調処理部１０２）と、２周波ＣＷ変調処理部１０１又はＦＭ変調処理部１０２から出力される変調電圧に基づいて周波数変調された送信周波数を生成する電圧制御型発振器１０３と、電圧制御型発振器１０３で生成された送信信号を送信する送信部である送信アンテナ１０４と、送信信号が測定対象物であるターゲットに反射して生成された受信信号を受信する受信部である受信アンテナ１０５と、送信信号と受信信号を混合、つまりミキシングされ、ビート信号を生成するミキサ１０６と、復調処理部１０７と、Ａ／Ｄ変換部１０８と、信号処理部１０９と、異常判定処理部１１０と、を備え、更に外に報知装置１１１を備えている。 The on-vehicle radar device 1 includes a modulation switching processing unit 100 that switches a modulation method of a plurality of transmission frequencies, and a plurality of modulation processing units (first devices) that respectively process a plurality of modulation methods switched by the modulation switching processing unit 100. 2 frequency CW modulation processing unit 101, which is a modulation processing unit of the above, and FM modulation processing unit 102, which is a second modulation processing unit), and the modulation voltage output from the two frequency CW modulation processing unit 101 or the FM modulation processing unit 102. A voltage-controlled oscillator 103 that generates a frequency-modulated transmission frequency, a transmission antenna 104 that is a transmission unit that transmits a transmission signal generated by the voltage-controlled oscillator 103, and a target whose transmission signal is a measurement object The receiving antenna 105, which is a receiving unit that receives the reception signal generated by reflection on the signal, and the transmission signal and the reception signal are mixed, that is, mixed, and beat A mixer 106 for generating a No., a demodulation processing unit 107, an A / D converter 108, a signal processing unit 109, an abnormality judgment processing unit 110 includes a, and a notification device 111 further out.
　変調切替処理部１００によって、２周波ＣＷ変調が選択された場合、２周波ＣＷ変調処理部１０１は、変調電圧を生成して電圧制御型発振器１０３に出力し、電圧制御型発振器１０３では、図３（ａ）のように、一定時間間隔で、周波数ｆ１または周波数ｆ２に交互に変調された送信信号Ｔｘを生成する。送信アンテナ１０４に入力された送信信号は、送信電波として空間中に放射され、ターゲットに反射することで、受信電波として受信アンテナ１０５にて受信され、図３（ａ）の受信信号Ｒｘが得られる。 When the two-frequency CW modulation is selected by the modulation switching processing unit 100, the two-frequency CW modulation processing unit 101 generates a modulation voltage and outputs it to the voltage-controlled oscillator 103. In the voltage-controlled oscillator 103, FIG. As shown in (a), a transmission signal Tx that is alternately modulated at the frequency f1 or the frequency f2 is generated at regular time intervals. The transmission signal input to the transmission antenna 104 is radiated into the space as a transmission radio wave and reflected by the target, so that it is received by the reception antenna 105 as a reception radio wave, and the reception signal Rx in FIG. 3A is obtained. .
　ミキサ１０６において、送信信号Ｔｘと受信信号Ｒｘとがミキシングされ、ビート信号が生成される。 In the mixer 106, the transmission signal Tx and the reception signal Rx are mixed to generate a beat signal.
　生成されたビート信号は、復調処理部１０７にて復調処理をされ、Ａ／Ｄ変換部１０８にてデジタル信号に変換される。 The generated beat signal is demodulated by the demodulation processing unit 107 and converted into a digital signal by the A / D conversion unit 108.
　変換されたデジタル信号は、信号処理部１０９に入力される。信号処理部１０９では、後述の流れで演算処理がなされ、ターゲットまでの距離，相対速度，方位角，ビート信号のドップラ周波数、等が求まる。 The converted digital signal is input to the signal processing unit 109. The signal processing unit 109 performs arithmetic processing according to the flow described later, and obtains the distance to the target, the relative speed, the azimuth angle, the Doppler frequency of the beat signal, and the like.
　また、変調切替処理部１００によって、ＦＭ変調方式が選択された場合、ＦＭ変調処理部１０２は、変調電圧を生成して電圧制御型発振器１０３に出力し、電圧制御型発振器１０３では、図５のように、ＦＭ変調周期ＴＦＭ毎にΔＦの差分がある２つの周波数帯を切り替えつつ、徐々に周波数が減少していくような送信信号Ｔｘを生成する。 When the FM switching method is selected by the modulation switching processing unit 100, the FM modulation processing unit 102 generates a modulation voltage and outputs the modulation voltage to the voltage controlled oscillator 103. In the voltage controlled oscillator 103, FIG. As described above, the transmission signal Tx whose frequency is gradually decreased is generated while switching between two frequency bands having a difference of ΔF for each FM modulation period TFM.
　その後、２周波ＣＷ変調の場合と同様に、送信信号Ｔｘは送信アンテナ１０４で放射し、ターゲットからの反射信号を受信アンテナ１０５で受信した後、ミキサ１０６，復調処理部１０７，Ａ／Ｄ変換部１０８を経て、信号処理部１０９においてターゲットまでの距
離，相対速度，方位角，ビート信号の周波数、等が求まる。 Thereafter, as in the case of the two-frequency CW modulation, the transmission signal Tx is radiated by the transmission antenna 104, and the reflected signal from the target is received by the reception antenna 105, and then the mixer 106, the demodulation processing unit 107, and the A / D conversion unit. Through 108, the signal processing unit 109 obtains the distance to the target, the relative speed, the azimuth angle, the frequency of the beat signal, and the like.
　以上処理を経て、２周波ＣＷ変調波によって算出された、ターゲットまでの距離と、ビート信号のドップラ周波数、およびＦＭ変調波によって算出された、ターゲットまでの距離と、ビート信号のドップラ周波数と、の情報を異常判定処理部１１０に入力し、後述の流れで、変調に異常があるか判断する。変調に異常があると判断された場合、異常判定処理部１１０は報知装置１１１に変調異常発生情報を出力する。 Through the above processing, the distance to the target calculated by the two-frequency CW modulated wave, the Doppler frequency of the beat signal, and the distance to the target calculated by the FM modulated wave, and the Doppler frequency of the beat signal Information is input to the abnormality determination processing unit 110, and it is determined whether there is an abnormality in modulation according to a flow described later. When it is determined that there is an abnormality in modulation, the abnormality determination processing unit 110 outputs modulation abnormality occurrence information to the notification device 111.
　報知装置１１１に変調異常発生情報が入力された場合、運転者に異常が発生している旨を警告する。警告方法として、ＬＥＤ等のディスプレイ表示や、ビープ音などの警告音が挙げられる。 When the abnormal modulation occurrence information is input to the notification device 111, the driver is warned that an abnormality has occurred. Examples of warning methods include display indications such as LEDs and warning sounds such as beep sounds.
　なお、上記は、車載用レーザ装置１に異常判定処理部１１０を設けた構成としたが、この異常判定処理部１１０を例えば、図１０に示すように、車両側の処理装置３００であるＥＣＵ等に搭載した車載用レーザシステムの構成としても良い。 In the above description, the abnormality determination processing unit 110 is provided in the in-vehicle laser device 1, but the abnormality determination processing unit 110 is, for example, an ECU that is a processing device 300 on the vehicle side, as shown in FIG. It is good also as a structure of the vehicle-mounted laser system mounted in.
　次に、２周波ＣＷ変調処理における２周波変調に異常が発生した場合の影響について説明する。 Next, the influence when abnormality occurs in the two-frequency modulation in the two-frequency CW modulation processing will be described.
　２周波ＣＷ変調の受信波を受信した時に、復調処理部１０７によって生成されるＩＦ信号は、図３（ｂ）のような波形を示す。２周波ＣＷ変調において、図３（ａ）のように、ｆ１，ｆ２という２つの周波数を切り替えて送信信号が生成された場合、そのＩＦ信号は図３（ｂ）のように、２つの周波数の間には、距離に応じた位相差が発生する。この位相差を計測することで、ターゲットまでの距離を数式１で算出することができる。 The IF signal generated by the demodulation processing unit 107 when receiving a reception wave of two-frequency CW modulation shows a waveform as shown in FIG. In the two-frequency CW modulation, when a transmission signal is generated by switching between two frequencies f1 and f2 as shown in FIG. 3A, the IF signal has two frequencies as shown in FIG. 3B. A phase difference corresponding to the distance occurs between them. By measuring this phase difference, the distance to the target can be calculated by Equation 1.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　ＲCWはターゲット距離、ｃは光速、Δｆはｆ１とｆ２の周波数差、φはΔｆに起因する位相差を表す。 R CW is the target distance, c is the speed of light, Δf is the frequency difference between f1 and f2, and φ is the phase difference due to Δf.
　ここで、２周波ＣＷ変調処理において異常が発生し、ｆ１，ｆ２の２つの周波数の切り替えが実行されなくなった場合、送信信号Ｔｘ、および受信信号Ｒｘは、図４（ａ）のように、周波数変調がされていない信号となってしまう。その結果、図４（ｂ）のように、ＩＦ信号において位相差が発生しない状態となり、ターゲットまでの距離を数式１から算出できなくなる。 Here, when an abnormality occurs in the two-frequency CW modulation processing and switching between the two frequencies f1 and f2 is not performed, the transmission signal Tx and the reception signal Rx are shown in FIG. This results in an unmodulated signal. As a result, as shown in FIG. 4B, no phase difference occurs in the IF signal, and the distance to the target cannot be calculated from Equation 1.
　次に、ビート信号の周波数の差分から、ターゲット距離を算出方法について説明する。 Next, a method for calculating the target distance from the difference in the frequency of the beat signal will be described.
　ＦＭ変調方式では、図５のような送信信号Ｔｘが生成され、ターゲットからの反射波を受信すると、受信信号Ｒｘが得られる。ＦＭ変調方式は、時間に応じて周波数を徐々に変化させているので、ターゲットまでの距離が変われば、送受信信号間の伝播往復時間も変動する。これにより、送受信信号間の周波数差は、ドップラシフトｆdのみでなく、伝播往復時間τによる周波数変動量ΔｆRも加味される。 In the FM modulation method, a transmission signal Tx as shown in FIG. 5 is generated, and when a reflected wave from the target is received, a reception signal Rx is obtained. In the FM modulation method, the frequency is gradually changed according to time. Therefore, if the distance to the target changes, the propagation round-trip time between the transmission and reception signals also changes. As a result, the frequency difference between the transmitted and received signals includes not only the Doppler shift f d but also the frequency variation Δf R due to the propagation round-trip time τ.
　ここで、信号処理部１０９においてＦＦＴ（Fast Fourier Transform：高速フーリエ変換）処理されて得られるＦＦＴスペクトラムを表すと、図６のようになる。２周波ＣＷ変調のように、時間に応じて徐々に周波数が変化しない場合、ＦＦＴスペクトラムは図６（ａ）のように、周波数ｆdにピーク信号が発生する。しかし、ＦＭ変調のように、時間に応じて周波数が変化している場合、送受信信号間の周波数差は図５のようにΔｆR＋ｆdだけあるので、ＦＦＴスペクトラムのピーク信号は、図６（ｂ）のように、周波数：ΔｆR＋ｆdに発生する。つまり、ＦＭ変調時のＦＦＴスペクトラムのピーク信号は、２周波ＣＷ変調時のピーク信号よりΔｆRだけシフトされた周波数に発生する。 Here, FIG. 6 shows an FFT spectrum obtained by performing FFT (Fast Fourier Transform) processing in the signal processing unit 109. When the frequency does not gradually change with time as in the case of two-frequency CW modulation, a peak signal is generated at the frequency f d in the FFT spectrum as shown in FIG. However, when the frequency changes with time as in FM modulation, the frequency difference between the transmission and reception signals is Δf R + f d as shown in FIG. 5, and the peak signal of the FFT spectrum is shown in FIG. As shown in b), the frequency is generated at Δf R + f d . That is, the peak signal of the FFT spectrum at the time of FM modulation is generated at a frequency shifted by Δf R from the peak signal at the time of two-frequency CW modulation.
　このΔｆRは、ターゲットまでの距離によって一義的に決まるものなので、ターゲットまでの距離は、ΔｆRより算出することができる。ここで、ΔｆRは数式２で表すことができる。 Since Δf R is uniquely determined by the distance to the target, the distance to the target can be calculated from Δf R. Here, Δf R can be expressed by Equation 2.
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　ここで、ＴFMは時間に応じて周波数が変化するＦＭ変調周期、ΔＲampはＴFMの間の周波数変化量、τは送信信号を送信してから、受信信号を受信するまでの伝播往復時間を意味する。 Here, T FM is an FM modulation period in which the frequency changes according to time, ΔRamp is a frequency change amount during T FM , and τ is a propagation round-trip time from transmission of a transmission signal to reception of a reception signal. means.
　また、伝播往復時間τは、数式３のようになる。 Also, the propagation round-trip time τ is as shown in Equation 3.
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　ここで、ｃは光速、Ｒはターゲットまでの距離を意味する。 Here, c means the speed of light and R means the distance to the target.
　よって、数式２，数式３より、ターゲットまでの距離Ｒは、数式４のように表すことができる。 Therefore, the distance R to the target can be expressed as Equation 4 from Equation 2 and Equation 3.
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000004
　ΔｆRは、２周波ＣＷ変調時のドップラ周波数と、ＦＭ変調時のビート周波数の差分を取ることで導出できるので、数式４でターゲットまでの距離を算出可能となる。 Since Δf R can be derived by taking the difference between the Doppler frequency at the time of two-frequency CW modulation and the beat frequency at the time of FM modulation, the distance to the target can be calculated by Equation 4.
　以上のような距離算出方式から、２周波ＣＷ変調異常を判定する処理手順について、図７のフローチャートを用いて説明する。 A processing procedure for determining a two-frequency CW modulation abnormality from the above distance calculation method will be described with reference to the flowchart of FIG.
　信号処理部１０９では、まずビート信号に対してステップ２００のフーリエ変換手段であるＦＦＴ処理を実行する。つまりビート信号にフーリエ変換処理を行い、フーリエ変換スペクトラムを得る。次にステップ２０１の変調方式判断手段である変調方式判断処理において、入力されたビート信号が２周波ＣＷ変調波かＦＭ変調波か、変調方式を判断する。具体的には、図１の変調切替処理部１００においてどちらの変調方式を実施したかという変調方式情報が格納されているため、その変調方式情報に基づいて変調方式を判断する。次に、距離算出手段によって、判断された変調方式の距離計算方法にて、フーリエ変換スペクトラムから測定対象物までの距離を算出する。具体的には、２周波ＣＷ変調波と判断された場合は、ステップ２０２の２周波ＣＷ物理値変換処理において、ＦＦＴ処理で得られるＦＦＴスペクトラムからターゲット情報の物理値に変換する。ＦＭ変調波と判断された場合は、ステップ２０３のＦＭ変調物理値変換処理において、ＦＦＴ処理で得られるＦＦＴスペクトラムからターゲット情報の物理値に変換する。以上で算出された物理値をもって、２周波変調異常判定を行う。なお、ここでの物理値とは、上述したターゲットまでの距離，相対速度，方位角，ビート信号のドップラ周波数、等である。 In the signal processing unit 109, first, FFT processing which is Fourier transform means in step 200 is executed on the beat signal. That is, a Fourier transform process is performed on the beat signal to obtain a Fourier transform spectrum. Next, in a modulation method determination process as modulation method determination means in step 201, it is determined whether the input beat signal is a two-frequency CW modulation wave or an FM modulation wave. Specifically, since modulation scheme information indicating which modulation scheme is implemented in the modulation switching processing unit 100 in FIG. 1 is stored, the modulation scheme is determined based on the modulation scheme information. Next, the distance calculation means calculates the distance from the Fourier transform spectrum to the measurement object using the determined distance calculation method of the modulation method. Specifically, when it is determined that the frequency is a two-frequency CW modulated wave, in the two-frequency CW physical value conversion process in step 202, the FFT spectrum obtained by the FFT process is converted into a physical value of target information. If it is determined as an FM modulated wave, in the FM modulation physical value conversion process in step 203, the FFT spectrum obtained by the FFT process is converted into a physical value of the target information. The 2-frequency modulation abnormality determination is performed using the physical values calculated above. Here, the physical values include the distance to the target, the relative speed, the azimuth angle, the Doppler frequency of the beat signal, and the like.
　異常判定処理部１１０では、信号処理部１０９から得られる、２周波ＣＷ変調波およびＦＭ変調波における、それぞれのビート信号の周波数の差分ΔｆRをステップ２０４で算出する。 In abnormality determination processing section 110, step 204 calculates the frequency difference Δf R between the beat signals in the two-frequency CW modulated wave and FM modulated wave obtained from signal processing section 109.
　ステップ２０４で算出されたΔｆRを用いて、数式４より、ターゲット距離をステップ２０５で算出する。 Using Δf R calculated in step 204, the target distance is calculated in step 205 from Equation 4.
　一方、信号処理部１０９の物理値変換処理において、位相差を用いてターゲット距離が算出されるので、その位相差から算出した距離と、ステップ２０５における、周波数差から算出した距離の差分をステップ２０６において算出する。 On the other hand, since the target distance is calculated using the phase difference in the physical value conversion process of the signal processing unit 109, the difference between the distance calculated from the phase difference and the distance calculated from the frequency difference in step 205 is calculated in step 206. In the calculation.
　ここで、２周波変調に異常がなかった場合、位相差から算出される距離は正しく求められるので、ステップ２０６で算出される距離差は小さくなる。しかし、２周波変調に異常が発生して位相差が異常値になった場合、位相差から算出される距離値は変動してしまうので、ステップ２０６の距離差の値は大きくなる。 Here, when there is no abnormality in the two-frequency modulation, the distance calculated from the phase difference is obtained correctly, so the distance difference calculated in step 206 is small. However, when an abnormality occurs in the two-frequency modulation and the phase difference becomes an abnormal value, the distance value calculated from the phase difference fluctuates, and thus the distance difference value in step 206 increases.
　よって、この距離差の値を確認することで、２周波変調異常を判定することができる。すなわち、ステップ２０７において、位相差から算出した距離と周波数差から算出した距離の差分が所定値以上だった場合、２周波変調異常と判断し、ステップ２０８においてエラー判定処理を行う。また、その距離の差分が所定値以下だった場合は正常と判断し、エラー判定処理を実行しない。 Therefore, by confirming the value of this distance difference, it is possible to determine a two-frequency modulation abnormality. That is, if the difference between the distance calculated from the phase difference and the distance calculated from the frequency difference is greater than or equal to a predetermined value in step 207, it is determined that the two-frequency modulation is abnormal, and error determination processing is performed in step 208. If the difference in distance is less than or equal to a predetermined value, it is determined to be normal and the error determination process is not executed.
　ここで、ステップ２０７における所定値は、位相差から算出した距離、および周波数差から算出した距離の算出精度を勘案して、予め導出される値であり、レーダのハード仕様によって異なるが、ここでは１９.８〔ｍ〕とする。 Here, the predetermined value in step 207 is a value derived in advance in consideration of the calculation accuracy of the distance calculated from the phase difference and the distance calculated from the frequency difference, and differs depending on the hardware specifications of the radar. It is assumed that 19.8 [m].
　ステップ２０８にてエラー判定処理が実行された場合、報知装置１１１に異常発生警告信号を出力し、報知装置１１１によって、運転者に異常発生状態にあることを報知する。なお、エラー判定処理が実行されない場合は、異常発生警告信号が出力されないようにする。 When the error determination process is executed in step 208, an abnormality occurrence warning signal is output to the notification device 111, and the notification device 111 notifies the driver that an abnormality has occurred. When the error determination process is not executed, the abnormality occurrence warning signal is not output.
　一方で、ＦＭ変調に異常が発生した場合においても、その異常を検出することができる。ＦＭ変調に異常が発生した場合、伝播往復時間τによる周波数変動量ΔｆRが変動し、ステップ２０５で演算される、周波数差から算出した距離に誤差が生じる。その結果、ステップ２０７における位相差から算出した距離と周波数差から算出した距離の差分が所定値以上となり、ステップ２０８においてエラー判定される。よって、ＦＭ変調異常においても、検出が可能となる。 On the other hand, even when an abnormality occurs in the FM modulation, the abnormality can be detected. When abnormality occurs in the FM modulation, the frequency fluctuation amount Δf R due to the propagation round-trip time τ varies, and an error occurs in the distance calculated from the frequency difference calculated in step 205. As a result, the difference between the distance calculated from the phase difference in step 207 and the distance calculated from the frequency difference becomes equal to or greater than a predetermined value, and an error determination is made in step 208. Therefore, it is possible to detect even FM modulation abnormality.
　このような構成により、複数の周波数を切り替える変調処理において異常が発生し、複数の周波数間の位相差を用いてターゲット距離を算出できなくなっている状態を精度良く検出し、より信頼性の高い安全運転システムを提供できる車載用レーダ装置を提供することができる。 With such a configuration, it is possible to accurately detect a state in which an abnormality has occurred in the modulation processing for switching a plurality of frequencies and the target distance cannot be calculated using a phase difference between the plurality of frequencies, and a more reliable safety An on-vehicle radar device that can provide an operation system can be provided.
　なお、本発明は上記実施例のみに限らず、変調方式として、２周波ＣＷ方式とＳｔｅｐＦＭ方式を使用した場合や、ＳｔｅｐＦＭ方式とＣＷ方式を使用した場合でも実現可能である。 Note that the present invention is not limited to the above-described embodiment, and can be realized even when the two-frequency CW method and the StepFM method are used as the modulation method, or when the StepFM method and the CW method are used.
　２周波ＣＷ方式とＳｔｅｐＦＭ方式を使用した場合、一例として図８のような周波数波形が挙げられる。ここで、ＳｔｅｐＦＭ方式とは、図８のＳｔｅｐＦＭ変調の周波数波形のように、時間に応じて段階的に周波数を減少または増加させる変調方式のことである。 When the 2-frequency CW method and the StepFM method are used, a frequency waveform as shown in FIG. 8 is given as an example. Here, the StepFM method is a modulation method that decreases or increases the frequency stepwise according to time, like the frequency waveform of StepFM modulation in FIG.
　図１の上記実施例のブロック構成において、ＦＭ変調処理部１０２の箇所に、ＳｔｅｐＦＭ変調処理部を代わりに設けることで、上記実施例と同じ手法を実現することができる。 In the block configuration of the above-described embodiment of FIG. 1, the same technique as in the above-described embodiment can be realized by providing a Step FM modulation processing unit instead of the FM modulation processing unit 102.
　また、ＳｔｅｐＦＭ方式とＣＷ方式を使用した場合、一例として図９のような周波数波形が挙げられる。 Further, when the StepFM method and the CW method are used, a frequency waveform as shown in FIG. 9 is given as an example.
　図１の上記実施例のブロック構成において、２周波ＣＷ変調処理部１０１およびＦＭ変調処理部１０２の箇所で、ＳｔｅｐＦＭ変調処理部およびＣＷ変調処理部を代わりに設けることで、上記実施例と同じ手法を実現することができる。 In the block configuration of the above-described embodiment of FIG. 1, the same technique as that of the above-described embodiment is provided by providing the Step FM modulation processing unit and the CW modulation processing unit instead of the two-frequency CW modulation processing unit 101 and the FM modulation processing unit 102. Can be realized.
　このように図８，図９のような変調方式の組み合わせでも、位相差から算出した距離と周波数差から算出した距離の差分が所定値以上だった場合、２周波変調異常やＦＭ変調異常と判断し、ステップ２０８においてエラー判定処理を行い、異常判定をすることができ、変調処理における周波数切替処理部に異常が発生している状態を、精度良く検知する車載用レーダ計測装置を提供することができる。 As described above, even in the combination of the modulation methods as shown in FIGS. 8 and 9, when the difference between the distance calculated from the phase difference and the distance calculated from the frequency difference is equal to or larger than a predetermined value, it is determined that the two-frequency modulation abnormality or the FM modulation abnormality. Then, it is possible to provide an on-vehicle radar measurement device that can perform error determination processing in step 208 to determine abnormality and accurately detect a state in which an abnormality has occurred in the frequency switching processing unit in the modulation processing. it can.
　上記では、２周波ＣＷ方式の例で説明をしたが、２周波以上の多周波ＣＷ方式であってもよい。 In the above description, the example of the two-frequency CW method has been described, but a multi-frequency CW method of two or more frequencies may be used.
　上記では、種々の実施の形態および変形例を説明したが、本発明はこれらの内容に限定されるものではない。本発明の技術的思想の範囲内で考えられるその他の態様も本発明の範囲内に含まれる。 Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other embodiments conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.
　次の優先権基礎出願の開示内容は引用文としてここに組み込まれる。
　日本国特許出願２０１０年第１０１５９９号（２０１０年４月２７日出願） The disclosure of the following priority application is hereby incorporated by reference.
Japanese patent application 2010 No. 101599 (filed April 27, 2010)

Claims (18)

  1. 　車載用レーダ装置であって、
    　複数の送信周波数の変調方式を切り替える変調切替処理部と、
    　前記変調切替処理部に基づいて切り替えられ、複数の送信周波数の変調方式を、それぞれ処理する複数の変調処理部と、
    　前記変調切替処理部にて切り替えられた変調処理部から出力される変調電圧に基づいて周波数変調された送信周波数の送信信号を生成する発振部と、
    　前記発振部で生成された前記送信信号を送信する送信部と、
    　前記送信信号が測定対象物に反射して生成された受信信号を受信する受信部と、
    　前記送信信号と前記受信信号とを混合してビート信号を生成するビート信号生成部と、
    　前記変調方式によって異なる距離算出方法を有し、前記ビート信号の変調方式に対応する前記距離算出方法に基づいて前記測定対象物までの距離を算出する距離算出部と、
    　前記距離算出部によって前記異なる距離算出方法で算出された複数の距離の差分に基づいて変調異常判定を行う異常判定処理部と、を有する車載用レーダ装置。     An on-vehicle radar device,
    A modulation switching processing unit that switches a modulation scheme of a plurality of transmission frequencies;
    A plurality of modulation processing units that are switched based on the modulation switching processing unit and that respectively process modulation schemes of a plurality of transmission frequencies;
    An oscillation unit that generates a transmission signal having a transmission frequency that is frequency-modulated based on a modulation voltage output from the modulation processing unit switched by the modulation switching processing unit;
    A transmission unit for transmitting the transmission signal generated by the oscillation unit;
    A receiving unit for receiving a reception signal generated by reflecting the transmission signal to an object to be measured;
    A beat signal generation unit that generates a beat signal by mixing the transmission signal and the reception signal;
    A distance calculation unit having a different distance calculation method depending on the modulation method, and calculating a distance to the measurement object based on the distance calculation method corresponding to the modulation method of the beat signal;
    An in-vehicle radar device comprising: an abnormality determination processing unit that performs modulation abnormality determination based on a difference between a plurality of distances calculated by the different distance calculation method by the distance calculation unit.
  2. 　請求項１記載の車載用レーダ装置において、
    　前記異なる距離算出方法は、位相差を用いて前記測定対象物までの距離を算出する第１の距離算出方法と、周波数差を用いて前記測定対象物までの距離を算出する第２の距離算出方法と、を有する車載用レーダ装置。     The on-vehicle radar device according to claim 1,
    The different distance calculation methods include a first distance calculation method that calculates a distance to the measurement object using a phase difference and a second distance calculation that calculates a distance to the measurement object using a frequency difference. And an on-vehicle radar device.
  3. 　請求項２記載の車載用レーダ装置において、
    　前記複数の変調処理部は、前記第１の距離算出方法で距離を算出する第１の変調方式の送信周波数を処理する第１の変調処理部と、前記第２の距離算出方法で距離を算出する第２の変調方式の送信周波数を処理する第２の変調処理部と、を有する車載用レーダ装置。     The on-vehicle radar device according to claim 2,
    The plurality of modulation processing units calculate a distance by the first modulation processing unit that processes the transmission frequency of the first modulation scheme that calculates the distance by the first distance calculation method, and the second distance calculation method. And a second modulation processing unit that processes the transmission frequency of the second modulation method.
  4. 　請求項３記載の車載用レーダ装置において、
    　前記複数の送信周波数の変調方式は、前記第１の変調方式である多周波ＣＷ方式と、前記第２の変調方式であるＦＭ変調方式と、を有する車載用レーダ装置。     The in-vehicle radar device according to claim 3,
    The plurality of transmission frequency modulation methods include a multi-frequency CW method that is the first modulation method and an FM modulation method that is the second modulation method.
  5. 　請求項１記載の車載用レーダ装置において、
    　前記距離算出部は、
    　前記ビート信号にフーリエ変換処理を行い、フーリエ変換スペクトラムを得るフーリエ変換部と、
    　前記ビート信号に基づいて変調方式を判断する変調方式判断部と、
    　前記変調方式判断部で判断された変調方式の距離計算方法にて、前記フーリエ変換スペクトラムから前記測定対象物までの距離を算出する距離算出部と、を有する車載用レーダ装置。     The on-vehicle radar device according to claim 1,
    The distance calculation unit
    Fourier transform processing is performed on the beat signal to obtain a Fourier transform spectrum; and
    A modulation scheme determination unit that determines a modulation scheme based on the beat signal;
    A vehicle-mounted radar device comprising: a distance calculation unit that calculates a distance from the Fourier transform spectrum to the measurement object by a modulation method distance calculation method determined by the modulation method determination unit.
  6. 　請求項５記載の車載用レーダ装置において、
    　前記距離算出部は、位相差を用いて前記測定対象物までの距離を算出する第１の距離算出部と、周波数差を用いて前記測定対象物までの距離を算出する第２の距離算出部と、を有し、
    　前記異常判定処理部は、前記第１の距離算出部で算出された前記距離と前記第２の距離算出部で算出された前記距離との差に基づいて変調異常判定を行う車載用レーダ装置。     The on-vehicle radar device according to claim 5,
    The distance calculation unit includes a first distance calculation unit that calculates a distance to the measurement object using a phase difference, and a second distance calculation unit that calculates a distance to the measurement object using a frequency difference. And having
    The in-vehicle radar device, wherein the abnormality determination processing unit performs modulation abnormality determination based on a difference between the distance calculated by the first distance calculation unit and the distance calculated by the second distance calculation unit.
  7. 　請求項１記載の車載用レーダ装置において、
    　前記異常判定処理部は、前記異なる距離算出方法で算出された複数の距離の差が予め定めた所定値以上の場合、変調異常であると判定を行う車載用レーダ装置。     The on-vehicle radar device according to claim 1,
    The on-vehicle radar device that determines that the abnormality is a modulation abnormality when a difference between a plurality of distances calculated by the different distance calculation methods is equal to or greater than a predetermined value.
  8. 　請求項７記載の車載用レーダ装置において、
    　前記異常判定処理部は、変調異常であると判定された場合、異常発生警告信号を出力するエラー判定部を有する車載用レーダ装置。     The on-vehicle radar device according to claim 7,
    The on-vehicle radar device having an error determination unit that outputs an abnormality occurrence warning signal when the abnormality determination processing unit is determined to have a modulation abnormality.
  9. 　請求項１記載の車載用レーダ装置において、
    　前記ビート信号生成部は、
    　前記送信信号と前記受信信号とを混合してビート信号を生成する混合部と、
    　前記ビート信号を復調する復調処理部と、
    　復調されたアナログ信号の前記ビート信号をデジタル信号に変換するＡ／Ｄ変換部と、を有する車載用レーダ装置。     The on-vehicle radar device according to claim 1,
    The beat signal generator
    A mixing unit that generates a beat signal by mixing the transmission signal and the reception signal;
    A demodulation processing unit for demodulating the beat signal;
    An on-vehicle radar device comprising: an A / D converter that converts the demodulated beat signal into a digital signal.
  10. 　請求項４記載の車載用レーダ装置において、
    　前記第１の変調方式である多周波ＣＷ方式は、２つの周波数を交互に送信する２周波ＣＷ方式である車載用レーダ装置。     The on-vehicle radar device according to claim 4,
    The multi-frequency CW method that is the first modulation method is a vehicle-mounted radar device that is a two-frequency CW method that alternately transmits two frequencies.
  11. 　請求項３記載の車載用レーダ装置において、
    　前記複数の送信周波数の変調方式は、前記第１の変調方式である多周波ＣＷ方式と、前記第２の変調方式であって、時間に応じて段階的に周波数を減少又は増加させるＳｔｅｐＦＭ変調方式と、を有する車載用レーダ装置。     The in-vehicle radar device according to claim 3,
    The modulation schemes of the plurality of transmission frequencies are a multi-frequency CW scheme that is the first modulation scheme and a second modulation scheme, and a StepFM modulation scheme that decreases or increases the frequency stepwise according to time. And an on-vehicle radar device.
  12. 　請求項３記載の車載用レーダ装置において、
    　前記複数の送信周波数の変調方式は、前記第１の変調方式であって、時間に応じて段階的に周波数を減少又は増加させるＳｔｅｐＦＭ変調方式と、前記第２の変調方式であるＣＷ変調方式と、を有する車載用レーダ装置。     The in-vehicle radar device according to claim 3,
    The modulation schemes of the plurality of transmission frequencies are the first modulation scheme, and a StepFM modulation scheme that decreases or increases the frequency stepwise according to time, and a CW modulation scheme that is the second modulation scheme, An on-vehicle radar device.
  13. 　車載用レーダシステムであって、
    　車載用レーダ装置と、
    　処理装置とを備え、
    　前記車載用レーダ装置は、
    　複数の送信周波数の変調方式を切り替える変調切替処理部と、
    　前記変調切替処理部に基づいて切り替えられ、複数の送信周波数の変調方式を、それぞれ処理する複数の変調処理部と、
    　前記変調切替処理部にて切り替えられた変調処理部から出力される変調電圧に基づいて周波数変調された送信周波数の送信信号を生成する発振部と、
    　前記発振部で生成された前記送信信号を送信する送信部と、
    　送信信号が測定対象物に反射して生成された受信信号を受信する受信部と、
    　前記送信信号と前記受信信号とを混合してビート信号を生成するビート信号生成部と、
    　前記変調方式によって異なる距離算出方法を有し、前記ビート信号の変調方式に対応する前記距離算出方法に基づいて前記測定対象物までの距離を算出する距離算出部と、を有し、
    　前記処理装置は、
    　前記距離算出部によって前記異なる距離算出方法で算出された複数の距離の差分に基づいて変調異常判定を行い、変調異常判定の結果、異常と判定された場合は変調異常発生情報を出力する異常判定処理部を有する車載用レーダシステム。     An in-vehicle radar system,
    An on-vehicle radar device;
    A processing device,
    The in-vehicle radar device is
    A modulation switching processing unit that switches a modulation scheme of a plurality of transmission frequencies;
    A plurality of modulation processing units that are switched based on the modulation switching processing unit and that respectively process modulation schemes of a plurality of transmission frequencies;
    An oscillation unit that generates a transmission signal having a transmission frequency that is frequency-modulated based on a modulation voltage output from the modulation processing unit switched by the modulation switching processing unit;
    A transmission unit for transmitting the transmission signal generated by the oscillation unit;
    A receiving unit for receiving a reception signal generated by reflecting a transmission signal to an object to be measured;
    A beat signal generation unit that generates a beat signal by mixing the transmission signal and the reception signal;
    A distance calculation unit that has a different distance calculation method depending on the modulation method, and a distance calculation unit that calculates a distance to the measurement object based on the distance calculation method corresponding to the modulation method of the beat signal,
    The processor is
    Abnormality determination that performs modulation abnormality determination based on the difference between a plurality of distances calculated by the different distance calculation method by the distance calculation unit, and outputs modulation abnormality occurrence information when it is determined as abnormal as a result of the modulation abnormality determination An in-vehicle radar system having a processing unit.
  14. 　請求項１３記載の車載用レーダシステムにおいて、
    　前記異なる距離算出方法は、位相差を用いて前記測定対象物までの距離を算出する第１の距離算出方法と、周波数差を用いて前記測定対象物までの距離を算出する第２の距離算出方法と、を有する車載用レーダシステム。     The in-vehicle radar system according to claim 13,
    The different distance calculation methods include a first distance calculation method that calculates a distance to the measurement object using a phase difference and a second distance calculation that calculates a distance to the measurement object using a frequency difference. And an on-vehicle radar system.
  15. 　請求項１４記載の車載用レーダシステムにおいて、
    　前記複数の変調処理部は、前記第１の距離算出方法で距離を算出する第１の変調方式の送信周波数を処理する第１の変調処理部と、前記第２の距離算出方法で距離を算出する第２の変調方式の送信周波数を処理する第２の変調処理部と、を有する車載用レーダシステム。     The in-vehicle radar system according to claim 14,
    The plurality of modulation processing units calculate a distance by the first modulation processing unit that processes the transmission frequency of the first modulation scheme that calculates the distance by the first distance calculation method, and the second distance calculation method. And a second modulation processing unit that processes the transmission frequency of the second modulation method.
  16. 　請求項１５記載の車載用レーダシステムにおいて、
    　前記複数の送信周波数の変調方式は、前記第１の変調方式である多周波ＣＷ方式と、前記第２の変調方式であるＦＭ変調方式と、を有する車載用レーダシステム。     The in-vehicle radar system according to claim 15,
    The plurality of transmission frequency modulation methods include a multi-frequency CW method that is the first modulation method and an FM modulation method that is the second modulation method.
  17. 　請求項１３記載の車載用レーダシステムにおいて、
    　前記異常判定処理部は、前記異なる距離算出方法で算出された複数の距離の差が予め定めた所定値以上の場合、変調異常であると判定を行う車載用レーダシステム。     The in-vehicle radar system according to claim 13,
    The on-vehicle radar system, wherein the abnormality determination processing unit determines that there is a modulation abnormality when a difference between a plurality of distances calculated by the different distance calculation methods is equal to or greater than a predetermined value.
  18. 　請求項１７記載の車載用レーダシステムにおいて、
    　前記異常判定処理部は、変調異常であると判定された場合、異常発生警告信号を出力するエラー判定部を有する車載用レーダシステム。     The in-vehicle radar system according to claim 17,
    The on-vehicle radar system including an error determination unit that outputs an abnormality occurrence warning signal when the abnormality determination processing unit is determined to have a modulation abnormality.
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JP2000028715A (en) * 1998-07-14 2000-01-28 Nippon Signal Co Ltd:The Composite-type radar sensor
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000028715A (en) * 1998-07-14 2000-01-28 Nippon Signal Co Ltd:The Composite-type radar sensor
JP2000292530A (en) * 1999-04-09 2000-10-20 Hino Motors Ltd Radar

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