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WO2009084159A1 - Appareil de radar - Google Patents

Appareil de radar Download PDF

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Publication number
WO2009084159A1
WO2009084159A1 PCT/JP2008/003692 JP2008003692W WO2009084159A1 WO 2009084159 A1 WO2009084159 A1 WO 2009084159A1 JP 2008003692 W JP2008003692 W JP 2008003692W WO 2009084159 A1 WO2009084159 A1 WO 2009084159A1
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WO
WIPO (PCT)
Prior art keywords
signal
frequency
transmission
radar
switch
Prior art date
Application number
PCT/JP2008/003692
Other languages
English (en)
Japanese (ja)
Inventor
Yoshihide Uesato
Tomohiro Shinomiya
Katsuyuki Ohguchi
Kunihiro Tanaka
Original Assignee
Fujitsu Ten Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fujitsu Ten Limited filed Critical Fujitsu Ten Limited
Publication of WO2009084159A1 publication Critical patent/WO2009084159A1/fr

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Classifications

    • 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
    • G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
    • G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
    • G01S3/14—Systems for determining direction or deviation from predetermined direction
    • G01S3/46—Systems for determining direction or deviation from predetermined direction using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
    • G01S3/48—Systems for determining direction or deviation from predetermined direction using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured
    • 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
    • G01S7/35—Details of non-pulse systems
    • 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
    • G01S13/345—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 using triangular modulation
    • 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
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • 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
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G01S2013/9319—Controlling the accelerator
    • 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
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G01S2013/9321—Velocity regulation, e.g. cruise control
    • 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
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G01S2013/9325—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles for inter-vehicle distance regulation, e.g. navigating in platoons
    • 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
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G01S2013/9327—Sensor installation details
    • G01S2013/93271—Sensor installation details in the front of the vehicles
    • 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
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G01S2013/9327—Sensor installation details
    • G01S2013/93275—Sensor installation details in the bumper area

Definitions

  • the present invention includes a transmission antenna pair that transmits a radar signal having a predetermined frequency and a reception antenna group that receives the radar signal reflected by a target as a reception signal.
  • the present invention relates to a radar apparatus that detects an azimuth angle at which a target is located by processing a received signal from a group of receiving antennas obtained when performing the operation.
  • An electronic scanning method is known as a scanning method for an on-vehicle radar device.
  • the radar apparatus transmits a radar signal from a transmission antenna, and receives the radar signal reflected on the target as a reception signal by a plurality of reception antennas arranged at predetermined intervals. . Then, the radar apparatus detects the azimuth angle at which the target is located using a plurality of received signals having different phases and amplitudes depending on the direction of arrival.
  • FIG. 1 shows a configuration example of a conventional electronic scan type radar apparatus.
  • the voltage controlled oscillator (VCO) 8 outputs a radar signal frequency-modulated by an FM-CW (Frequency Modulated-Continuous Wave) system in accordance with the modulation signal output from the control unit 6.
  • Distributor 1 0 is a radar signal for transmission (hereinafter referred to as a transmission signal) ST, and a radar signal (hereinafter simply referred to as a local signal) SL as a local signal used for processing the received signal.
  • Power distribution to The transmission signal ST is amplified by the amplifier 12_1 and transmitted from the transmission antenna AT_1.
  • reception signals SR_1, SR_2, SR_3, SR_4 When this signal is reflected by the target, it is received as reception signals SR_1, SR_2, SR_3, SR_4 by reception antennas AR_1, AR_2, AR_3, AR_4 arranged at regular intervals.
  • the received signal SR_n (hereinafter, when referring to the plurality of components described above, the subscript is represented by “_n”) is amplified by the amplifiers 14_1, 14_2, 14_3, and 14_4, respectively, and the mixers 16_1, 16_2, 16_3, 16_4.
  • the local signal SL distributed by the distributor 10 is amplified by the amplifier 12_2 and input to the mixer 16_n.
  • the mixer 16_n mixes the local signal SL and the reception signal SR_n, respectively, and a frequency difference between the local signal SL and the reception signal SR_n, that is, a frequency difference between the transmission signal ST and the reception signal SR_n.
  • Difference signals (hereinafter referred to as beat signals) SB_1, SB_2, SB_3, and SB_4 are output.
  • the bit signal SB_n is sampled by the A / D converters 18_1, 18_2, 18_3, and 18_4 and converted into digital data, and then taken into the control unit 6.
  • the control unit 6 is mainly composed of a well-known microcomputer having a CPU, a ROM, and a RAM. Further, the controller 6 performs high-speed Fourier transform (FFT) on the data taken in via the A / D converter 18_n. : An arithmetic processing unit (for example, DSP: Digital Signal) for executing Fast Fourier Transform (Fast Fourier Transform) processing Processor).
  • FFT high-speed Fourier transform
  • An arithmetic processing unit for example, DSP: Digital Signal
  • DBF Digital Beam Forming
  • the control unit 6 obtains the combined amplitude of the beat signal SB_n generated from the received signal SR_n as a function of the azimuth, and calculates the azimuth corresponding to the maximum value of the combined amplitude.
  • the change curve of the combined amplitude becomes steeper, so the azimuth corresponding to the maximum value of the combined amplitude is more accurate. I can find it well. For this purpose, it is desirable to arrange a large number of receiving antennas.
  • the radar apparatus 2 shown in FIG. 2 further distributes the power of the transmission signal ST distributed by the distributor 10 and amplifiers 22_1 and 22_2 that amplify the transmission signal ST distributed by the distributor 20, respectively. 1 in that it has a pair of transmission antennas AT_1 and AT_2 that transmit the amplified transmission signal ST.
  • the transmission antennas AT_1 and AT_2 are spaced apart from each other by being positioned at both ends of the array of the reception antennas AR_n. Therefore, a difference occurs in the path length from both transmitting antennas to the target according to the interval and the azimuth angle at which the target is located. Therefore, the round trip path length when the transmission signal from the transmission antenna AT_1 is reflected by the target and received by the reception antenna AR_n, and the transmission signal from the transmission antenna AT_2 is reflected by the target and is received by the reception antenna AR_n. Each of the round trip path lengths when received is different. Therefore, in each combination of the transmission antennas AT_1 and AT_2 and the reception antenna AR_n, a plurality of reception signals SR_n having different amplitudes and phases are obtained.
  • a configuration equivalent to the configuration in which a double number of receiving antennas are arranged as shown in FIG. can get. That is, a configuration equivalent to a configuration including one transmission antenna and eight reception antennas can be realized by two transmission antennas and four reception antennas.
  • the amplifiers 22_1 and 22_2 use the intensity of the distributed transmission signal ST as the expected power. Amplify until. However, in order to compensate for the decrease in strength due to power distribution, a certain degree of amplification is required. Then, noise is also amplified at the same time, and a transmission signal ST having a good S / N ratio cannot be obtained. Therefore, a method for avoiding such a situation by using a switch that alternately outputs the transmission signal ST to the transmission antenna pair AT_1 and AT_2 instead of the distributor 20 has been proposed.
  • FIG. 4 shows the configuration of the radar apparatus in an example of such a method.
  • This radar apparatus 2 has a switch SW_1 that alternately outputs the transmission signal ST to the transmission paths P_1 and P_2 corresponding to the transmission antennas AT_1 and AT_2, instead of the distributor 20 that distributes the transmission signal ST.
  • the switch SW_1 is switch-controlled by the control unit 6.
  • FIG. 5 shows a configuration of a radar apparatus in still another example.
  • the radar apparatus 2 further includes a switch SW_2 that sequentially switches the reception signal SR_n from the reception antenna AR_n and inputs the signal to one mixer 16, and the beat signal SB output from the mixer 16 is one A / D conversion. 4 is different from the configuration of FIG.
  • the switch SW_2 is switch-controlled by the control unit 6. In this configuration, the number of mixers and A / D converters is reduced by providing the switch SW_2, and the circuit scale of the radar apparatus 2 is further reduced.
  • Patent Document 1 Still another example is described in Patent Document 1.
  • the radar apparatus described in Patent Document 1 has a configuration in which a pair of transmission antennas are provided at both ends of a plurality of arranged reception antenna groups, and a radar signal is transmitted from each of them in a time division manner.
  • JP 2004-198312 A JP 2004-198312 A
  • the transmission paths P_1 and P_2 for transmitting the distributed transmission signals are indispensable for a plurality of transmission antennas spaced apart by a fixed interval.
  • the frequency band of radio waves that can be used is limited to a high frequency band of 76.0 to 77.0 GHz, which is included in the millimeter wave band, due to legal restrictions.
  • the conductor resistance of the transmission path that is, the sum of the surface resistance of the transmission path due to the skin effect and the internal inductance is the frequency of the transmission signal. It grows according to.
  • the transmission paths P_1 and P_2 are formed on a dielectric like a microstrip line, dielectric loss also occurs. Therefore, when the transmission signal ST is transmitted to the transmission antenna pair, the strength of the transmission signal ST is reduced due to transmission loss.
  • the switch SW_1 that distributes the transmission signal ST output from the VCO 8 to the transmission paths P_1 and P_2 has a large insertion loss according to the frequency of the signal passing through, the switch SW_1 also passes through the switch SW1. The intensity of the transmission signal ST decreases.
  • an object of the present invention is to reduce the detection performance even in a configuration including a transmission path pair that transmits a transmission signal to a pair of transmission antennas spaced apart by a predetermined interval and a switch that distributes the transmission signal to the transmission path pair. It is an object of the present invention to provide a radar device that can be prevented.
  • a radar apparatus includes a pair of transmitting antennas that transmit a radar signal of a predetermined frequency and a radar that is reflected by a target.
  • a radar that receives a signal as a received signal, and detects a azimuth angle at which the target is located using a received signal obtained by alternately transmitting the radar signal from the transmitting antenna pair.
  • An oscillator that outputs a radar signal having a frequency lower than the predetermined frequency; a radar signal that is output from the oscillator; a first transmission path to the first transmitting antenna; A switch that distributes to a second transmission path to the transmission antenna and a first transmission antenna that is connected to the first transmission path and converts the frequency of the radar signal to the predetermined frequency. Output to the first And a second multiplier that is connected to the second transmission path and converts the frequency of the radar signal to the predetermined frequency and then outputs the second signal to the second transmission antenna. And
  • the predetermined frequency is a millimeter wave band
  • the frequency of the radar signal output from the oscillator is a microwave band lower than the millimeter wave band.
  • the millimeter wave band is a band of 30 GHz to 300 GHz
  • the microwave band is a band of 1 GHz to 1000 GHz.
  • a band lower than the millimeter wave band of 30 GHz to 300 GHz that is, It means a band of 1 GHz to 30 GHz.
  • the radar device includes an oscillator that outputs a radar signal having a frequency (microwave band) lower than the predetermined frequency (millimeter wave band), and a first transmission path to the first transmitting antenna.
  • a switch that distributes the second transmission path to the second transmission antenna, and a switch that is connected to the first transmission path and converts the frequency of the radar signal to the predetermined frequency and then the first transmission path.
  • a first multiplier that outputs to the second transmission antenna, and a second multiplier that is connected to the second transmission path, converts the frequency of the radar signal to the predetermined frequency, and then outputs the second signal to the second transmission antenna. And a multiplier.
  • the switch is used as a radar signal having a frequency (microwave band) lower than a predetermined frequency (millimeter wave band).
  • a predetermined frequency millimeter wave band.
  • the insertion loss can be suppressed smaller than when passing through the switch with the radar signal having a predetermined frequency.
  • the transmission loss increases according to the frequency.
  • the frequency of the transmission signal is lowered to reduce the first and second transmission paths. By transmitting, transmission loss can be suppressed small.
  • it is possible to prevent a decrease in the intensity of the radar signal transmitted to the transmission antenna via the switch and the transmission path it is possible to prevent a decrease in the detection accuracy of the radar apparatus.
  • FIG. 3 is a diagram illustrating a configuration example of a conventional electronic scanning radar apparatus different from FIG. 2.
  • FIG. 5 is a diagram showing a configuration example of a conventional electronic scanning radar apparatus different from FIG. 4. It is a figure explaining the 1st structural example of the radar apparatus in this embodiment. It is a figure explaining the insertion loss of a switch, and the transmission loss of a transmission path. It is a figure which shows the change of the frequency with respect to the time of a transmission / reception signal.
  • DBF processing It is a figure explaining the modification of the 1st example of composition. It is a figure explaining the 2nd structural example of the radar apparatus in this embodiment. It is a figure explaining the modification of the 2nd example of composition. It is a figure explaining the use condition in which a radar apparatus is used as a vehicle-mounted radar apparatus.
  • FIG. 6 is a diagram for explaining a first configuration example of the radar apparatus according to the present embodiment. This radar device 2 is different from the conventional configuration shown in FIG. 4 in the following points.
  • multipliers 30_1 and 30_2 that multiply the frequency of the transmission signal ST distributed by the switch SW_1 by N and output to the transmission antennas AT_1 and AT_2 are connected to the ends of the transmission paths P_1 and P_2.
  • a multiplier 30_3 that similarly multiplies the frequency of the local signal SL by N and outputs it to the mixer 16_n is connected to the transmission path P_4 of the local signal SL.
  • the VCO 8, the divider 10, the amplifier 12_n, the switch SW_1, the multiplier 30_n, and the amplifier 22_n are modularized to transmit MMIC (Microwave Monolithic IC).
  • the amplifier 14_n, the mixer 16_n, and the A / D converter 18_n are modularized and configured by a receiving MMIC.
  • Each module is composed of a combination of a high power material (GaAs, SiGe, etc.) and a low power material (Si).
  • the switch SW_1 is configured by a switch circuit using a diode, and is controlled to be switched by the control unit 6.
  • the switch SW_1 has one input terminal and three output terminals. One of the output terminals is connected to the transmission path P_1, the other is connected to the transmission path P_2, and the other is connected to the transmission path P_3.
  • the output to the transmission path P_3 is located in the middle of the outputs to the transmission paths P_1 and P_2, and is output to the transmission path P_1 (or P_2) by connecting the transmission path P_3 to the resistor R.
  • the isolation of the switch SW_1 can be improved. Further, when the insertion loss with respect to the frequency of the signal passing through the switch SW_1 is shown using FIG. 7A, the frequency of the passing signal (horizontal axis) increases, whereas the insertion loss of the passing signal (vertical axis) ) Will increase.
  • the transmission signal ST in the microwave band passes through the switch SW_1 instead of the transmission signal ST in the millimeter wave band, so that the strength of the transmission signal ST is reduced due to the insertion loss of the switch SW_1. Can be kept smaller than in the millimeter wave band.
  • the transmission signal ST is transmitted from the transmission antennas AT_1 and AT_2.
  • a predetermined frequency for example, 76.5 GHz
  • the switch SW_1 and alternately output the strength of the transmission signal ST can be prevented from decreasing and the transmission signal ST having a desired frequency can be transmitted.
  • FIG. 7 shows that the transmission loss (vertical axis) of different types of transmission paths increases as the frequency (horizontal axis) of the transmitted signal increases.
  • the transmission signal ST in the microwave band is transmitted instead of the transmission signal ST in the millimeter wave band, and this is multiplied to the millimeter wave band just before being transmitted, and then transmitted to the transmission antenna AT_1.
  • transmission loss in the transmission paths P_1 and P_2 can be suppressed to be smaller than that in the millimeter wave band. Therefore, since the transmission antennas AT_1 and AT_2 are spaced apart from each other by a certain distance, the strength of the transmission signal ST transmitted through the transmission paths P_1 and P_2 is reduced even when the transmission paths P_1 and P_2 are of a certain length.
  • the transmission antennas AT_1 and AT_2 are arranged at both ends of the reception antenna AR_n arranged, which is equivalent to the case where the reception antennas are doubled as shown in FIG.
  • the configuration can be realized.
  • the interval between the transmitting antennas AT_1 and AT_2 may not be limited to this.
  • the round-trip path length until the radar signals transmitted from the transmitting antennas AT_1 and AT_2 are reflected by the target and received by the receiving antenna AR_n is different, and therefore, the received signals having different phases and amplitudes are received by all the transmitting antennas.
  • the VCO 8 When the FM-CW type triangular wave modulation signal is input from the control unit 6, the VCO 8 has a lower band than the millimeter wave band modulated so that the frequency linearly increases and decreases with time.
  • a microwave band radar signal is generated.
  • the oscillation frequency of the VCO 8 is set so that the center frequency of the radar signal is 76.5 GHz and the frequency fluctuation width is 100 MHz
  • the transmission signal ST is amplified by the amplifier 12_1 and input to the switch SW_1.
  • the switch SW_1 switches the output destination of the transmission signal ST alternately to the transmission paths P_1 and P_2 in time division in response to the control signal from the control unit 6.
  • the transmission signal ST output alternately from the switch SW_1 is input to the multipliers 30_1 and 30_2 via the transmission paths P_1 and P_2.
  • the multiplier 30_n multiplies the frequency of the input transmission signal ST to a predetermined frequency of 76.5 GHz in the millimeter wave band and outputs the result. Then, the frequency-multiplied transmission signal ST is amplified by the amplifiers 22_1 and 22_2 and transmitted from the transmission antennas AT_1 and AT_2.
  • control unit 6 alternately switches the output destination of the switch SW_1, so that the transmission signal ST having a predetermined frequency in the millimeter wave band is alternately transmitted from the transmission antennas AT_1 and AT_2.
  • the local signal SL distributed by the distributor 10 is transmitted through the transmission path P_4, is amplified by the amplifier 12_2, and is input to the multiplier 30_3. Then, the multiplier 30_3 multiplies the frequency of the input local signal ST to the same frequency 76.5 GHz as that of the transmission signal ST, and outputs the result to the mixer 16_n.
  • the radar signal transmitted as the transmission signal is reflected by the target, it is received by the reception antenna AR_n as the reception signal SR_n.
  • the received signal SR_n is amplified by the amplifier 14_n and input to the mixer 16_n.
  • the mixer 16_n mixes the local signal SL having the same frequency as the transmission signal ST and the reception signal SR_n to generate a frequency difference signal (bit signal) SB_n between the transmission signal ST and the reception signal SR_n. .
  • FIG. 8 shows changes in frequency (vertical axis) with respect to time (horizontal axis) of each signal.
  • the transmission signal ST is frequency-modulated according to a triangular wave-like modulation signal. Therefore, as indicated by a solid line in FIG. 8A, the frequency of the transmission signal ST gradually increases or decreases linearly with respect to time.
  • the received signal SR_n is delayed by a time ⁇ T in which the radar signal reciprocates the distance from the target as shown by a dotted line in FIG. 8A, and only by a frequency ⁇ D corresponding to the relative speed with the target. Doppler shift.
  • a beat signal SB_n having a frequency corresponding to the frequency difference between the two is generated as shown in FIG. 8B.
  • the frequency increase period the frequency of the beat signal (hereinafter referred to as “upbeat frequency”) fu and when the frequency of the transmission signal ST decreases (hereinafter referred to as the frequency)
  • the relative distance Rd of the target is obtained by the following equation (1) and the relative velocity Rv is obtained by the equation (2) from the frequency (hereinafter referred to as “downbeat frequency”) fd of the beat signal during the descent period). It is done.
  • C is a radio wave propagation speed (light speed)
  • fm is a modulation frequency of the transmission signal ST
  • ⁇ F is a frequency fluctuation range of the transmission signal ST
  • fo is a center frequency of the transmission signal ST.
  • the control unit 6 performs an FFT process on the beat signal SB_n for each modulation period of the transmission signal ST. Then, the phase and amplitude are detected from each of the beat signals SB_n for each up / down beat frequency. Then, the control unit 6 performs DBF processing using the beat signal SB_n for each up / down beat frequency.
  • a reception signal SR_n arriving from a target that is sufficiently far away from the interval (d) of the reception antenna AR_n is considered to be incident on the reception antenna AR_n in parallel.
  • the antenna interval d is between the received signals SR_n between the adjacent receiving antennas AR_n.
  • Phase difference ⁇ ( 2 ⁇ ⁇ d ⁇ sin ( ⁇ ) / ⁇ , where ⁇ is the wavelength of the received signal SR_n).
  • the reception surface H1 since the reception signal SR_n has a phase difference ⁇ , there is a portion where the amplitudes of the reception signals SR_n cancel each other.
  • the plane H2 is referred to as the same phase plane
  • the reception signals SR_n intensify each other and the combined amplitude becomes maximum.
  • the angle ⁇ of the in-phase surface H2 corresponds to the azimuth angle at which the reception gain of the receiving antenna AR_n is maximized (that is, the directivity is the same), and the angle ⁇ of the in-phase surface is calculated.
  • the arrival direction of the received signal SR_n that is, the azimuth angle at which the target is located is obtained.
  • the control unit 6 first obtains the combined amplitude of the beat signal SB_n of the upbeat frequency obtained from the received signal SR_n during the frequency rise period.
  • the amplitude of the beat signal SB_n at each receiving antenna AR_n E_n
  • the control unit 6 performs the same processing for the beat signal SB_n having the downbeat frequency in the frequency falling period. Then, the azimuth angle at which the target is located during the frequency drop period is obtained.
  • Such processing is performed for each frequency increase period and frequency decrease period. Then, the intensity distribution of the beat signal SB_n in the azimuth angle direction and the frequency direction is obtained for each frequency increase period and frequency decrease period.
  • control unit 6 detects the frequency at which the intensity distribution in the azimuth direction forms a peak as the up / down beat frequency. At this time, the azimuth angles of the two peaks associated with each other are detected as the azimuth angle at which the target is located.
  • control unit 6 specifies the up / down beat frequency by associating peaks having the same intensity or azimuth angle between the frequency increase period and the frequency decrease period, and the above-described equation (1)
  • the relative distance and relative speed of the target are calculated according to (2).
  • the radar apparatus 2 includes a switch SW_3 that alternately outputs a local signal SL transmitted through the transmission path P_4 to a plurality of transmission paths T_1, T_2, T_3, and T_4, and a switch Multipliers 32_1, 32_2, 32_3, and 32_4 that multiply the frequency of the local signal SL that has passed through SW_3 and then input to the mixer may be provided.
  • the output timing from the switch SW_3 is controlled by the control unit 6, and the local signal SL is input to the multiplier 32_n in a time division manner.
  • the frequency is multiplied to a predetermined frequency in the millimeter wave band by the multiplier 32_n. Therefore, the insertion loss due to the switch SW_3 is suppressed to be smaller than when the local signal SL passes in the millimeter wave band. Also, the loss in the transmission paths P_4 and T_n is suppressed to be smaller than when the local signal SL passes in the millimeter wave band. Therefore, the mixer 16_n can generate the beat signal SB_n using the local signal SL with sufficient strength.
  • FIG. 11 is a diagram for explaining a second configuration example of the radar apparatus 2 in the present embodiment.
  • the radar apparatus 2 is different from the radar apparatus 2 in the first configuration example shown in FIG. 6 in the following points.
  • the radar apparatus 2 receives one A / D converter 18 instead of the plurality of A / D converters 18_n and the beat signal SB_n output from the mixer 16_n according to an instruction from the control unit 6. It has switch SW_2 which inputs into A / D converter 18 by turns. With such a configuration, the circuit scale can be reduced as compared with the first configuration example having the plurality of A / D converters 18_n. Therefore, the cost can be reduced.
  • the frequency of the beat signal SB_n output from the mixer 16_n is a frequency band that is somewhat low because it is the frequency difference between the transmission signal ST and the reception signal SR_n in the millimeter wave band. For this reason, the insertion loss when the beat signal SB_n passes through the switch SW_2 is kept small, and the signal strength of the beat signal SB_n is secured to such an extent that the signal processing in the control unit 6 is not hindered.
  • the radar apparatus 2 uses the switch SW_3 that alternately outputs the local signal SL to a plurality of transmission paths T_n, and the frequency of the local signal SL that has passed through the switch SW_3.
  • a multiplier 32_n that multiplies and then inputs to the mixer may be provided.
  • the input / output timing of the switch SW_3 is controlled by the control unit 6, and the local signal SL is input to the mixer in a time division manner.
  • the frequency is increased to a predetermined frequency in the millimeter wave band by the multiplier 32_n. Since the frequency is multiplied, the insertion loss due to the switch SW_3 is suppressed to be smaller than when the local signal SL passes in the millimeter wave band. Further, the loss due to the transmission paths P_4 and T_n is also suppressed to be smaller than when the local signal SL passes in the millimeter wave band. Therefore, the mixer 16_n can generate the beat signal SB_n using the local signal SL with sufficient strength.
  • FIG. 13 is a diagram for explaining a usage situation in which the radar device according to the present embodiment is used as a vehicle-mounted radar device.
  • the radar device 2 is mounted in the front front grill of the vehicle 100, and transmits and receives a transmission signal ST and a reception signal SR_n through a bump provided on the bumper or the front grill of the vehicle 100. Then, an azimuth angle at which a target such as a preceding vehicle or an obstacle in front of the vehicle 100 (arrow F) is located, a relative speed with respect to the target, and a relative distance are detected.
  • the target information such as the azimuth angle at which the target detected by the control unit 6 is located as described above, the relative distance to the target, and the relative speed is the vehicle control device (ECU: Electronic Control Unit) 200 of the vehicle 100. Is output.
  • ECU Electronic Control Unit
  • the vehicle ECU 200 controls the actuator such as the throttle and brake of the vehicle 100 to adjust the speed of the vehicle so as to follow the preceding vehicle and perform follow-up running control.
  • the vehicle ECU 200 outputs a notification to the driver or activates a safety device such as an airbag when the distance from the preceding vehicle or an obstacle approaches a certain distance or more and the probability of a collision increases. Then, the collision handling operation is performed.
  • the radar device 2 may be installed not only on the front side of the vehicle 100 but also on the side surface and the rear side of the vehicle 100 as a radar device for monitoring the side and the rear.
  • the radar apparatus 2 including four reception antennas AR_1, AR_2, AR_3, and AR_4 is taken as an example, but the number of reception antennas is not limited to this.
  • the frequency band of the radar signal output from the VCO 8 is not limited to the above-described example, and may not necessarily be the microwave band.
  • the rate of multiplication by the multiplier 32_n is not limited to the above example, and it is not always necessary to multiply to the millimeter wave band. If the configuration is such that the frequency of the signal passing through the switch or transmission path is lowered and then multiplied, it prevents the transmission signal strength from being reduced due to the insertion loss of the switch or the transmission signal from being reduced due to the transmission loss. It is possible to achieve the operational effects.
  • the radar apparatus of the present embodiment even if a transmission path for transmitting a transmission signal to a pair of transmission antennas separated by a predetermined interval or a switch for distributing the transmission signal to the transmission path is used, the detection performance can be improved. Decline can be prevented.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

L'invention porte sur un appareil de radar dans lequel, bien qu'une paire de trajets de propagation soient prévus pour propager des signaux de transport à une paire d'antennes de transmission espacées d'une distance donnée, et bien qu'un commutateur soit prévu pour distribuer le signal de transport à la paire de trajets de propagation, l'efficacité de recherche ne peut cependant pas se dégrader. L'appareil de radar possède un oscillateur qui émet un signal radar dont la fréquence est inférieure à la fréquence prédéterminée ; un commutateur qui distribue le signal radar émis par l'oscillateur à la paire de trajets de propagation conduisant à la paire d'antennes de transmission, et une paire de multiplicateurs qui sont connectés à la paire de trajets de propagation, respectivement, et qui convertissent les fréquences des signaux radar en la fréquence prédéterminée pour l'émission vers la paire d'antennes de transmission. Ainsi, les fréquences des signaux de transport passant à travers le commutateur et le long des trajets de propagation sont réduites, ce par quoi la perte d'insertion du commutateur et la perte de propagation des trajets de propagation peuvent être supprimées, empêchant ainsi que l'efficacité de recherche ne se dégrade en raison d'une intensité diminuée des signaux de transport.
PCT/JP2008/003692 2007-12-28 2008-12-10 Appareil de radar WO2009084159A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2007-339712 2007-12-28
JP2007339712A JP2009162521A (ja) 2007-12-28 2007-12-28 レ−ダ装置

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WO2009084159A1 true WO2009084159A1 (fr) 2009-07-09

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Publication number Priority date Publication date Assignee Title
JP2011033498A (ja) * 2009-08-03 2011-02-17 Fujitsu Ten Ltd レーダ装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0354494A (ja) * 1989-07-21 1991-03-08 Honda Motor Co Ltd 高周波送信機
JPH075252A (ja) * 1993-06-17 1995-01-10 Honda Motor Co Ltd 時分割型ｆｍレーダシステム
JPH08338871A (ja) * 1996-07-08 1996-12-24 Honda Motor Co Ltd Ｆｍレーダ装置
JP2000028711A (ja) * 1998-07-09 2000-01-28 Mitsui Eng & Shipbuild Co Ltd アレイアンテナの送受信方法および周波数逓倍方式ミリ波二次元映像装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0354494A (ja) * 1989-07-21 1991-03-08 Honda Motor Co Ltd 高周波送信機
JPH075252A (ja) * 1993-06-17 1995-01-10 Honda Motor Co Ltd 時分割型ｆｍレーダシステム
JPH08338871A (ja) * 1996-07-08 1996-12-24 Honda Motor Co Ltd Ｆｍレーダ装置
JP2000028711A (ja) * 1998-07-09 2000-01-28 Mitsui Eng & Shipbuild Co Ltd アレイアンテナの送受信方法および周波数逓倍方式ミリ波二次元映像装置

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