WO2005066656A1 - Vehicle mounted radar system and its signal processing method - Google Patents

Vehicle mounted radar system and its signal processing method Download PDF

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Publication number
WO2005066656A1
WO2005066656A1 PCT/JP2003/016969 JP0316969W WO2005066656A1 WO 2005066656 A1 WO2005066656 A1 WO 2005066656A1 JP 0316969 W JP0316969 W JP 0316969W WO 2005066656 A1 WO2005066656 A1 WO 2005066656A1
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WO
WIPO (PCT)
Prior art keywords
radar
target
detection
composite
vehicle
Prior art date
Application number
PCT/JP2003/016969
Other languages
French (fr)
Japanese (ja)
Inventor
Jie Bai
Original Assignee
Hitachi, Ltd.
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Publication date
Application filed by Hitachi, Ltd. filed Critical Hitachi, Ltd.
Priority to PCT/JP2003/016969 priority Critical patent/WO2005066656A1/en
Publication of WO2005066656A1 publication Critical patent/WO2005066656A1/en

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/88Radar or analogous systems specially adapted for specific applications
    • G01S13/93Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/02Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06Systems determining position data of a target
    • G01S13/08Systems for measuring distance only
    • G01S13/32Systems for measuring distance only using transmission of continuous unmodulated waves, amplitude-, frequency- or phase-modulated waves
    • G01S13/34Systems for measuring distance only using transmission of continuous unmodulated waves, amplitude-, frequency- or phase-modulated waves using transmission of frequency-modulated waves and the received signal, or a signal derived therefrom, being heterodyned with a locally-generated signal related to the contemporaneous transmitted signal to give a beat-frequency signal
    • G01S13/345Systems for measuring distance only using transmission of continuous unmodulated waves, amplitude-, frequency- or phase-modulated waves using transmission of frequency-modulated waves and the received signal, or a signal derived therefrom, being heterodyned with a locally-generated signal related to the contemporaneous transmitted signal to give a beat-frequency signal using triangular modulation
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/02Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06Systems determining position data of a target
    • G01S13/08Systems for measuring distance only
    • G01S13/32Systems for measuring distance only using transmission of continuous unmodulated waves, amplitude-, frequency- or phase-modulated waves
    • G01S13/34Systems for measuring distance only using transmission of continuous unmodulated waves, amplitude-, frequency- or phase-modulated waves using transmission of frequency-modulated waves and the received signal, or a signal derived therefrom, being heterodyned with a locally-generated signal related to the contemporaneous transmitted signal to give a beat-frequency signal
    • G01S13/348Systems for measuring distance only using transmission of continuous unmodulated waves, amplitude-, frequency- or phase-modulated waves using transmission of frequency-modulated waves and the received signal, or a signal derived therefrom, being heterodyned with a locally-generated signal related to the contemporaneous transmitted signal to give a beat-frequency signal using square or rectangular modulation, e.g. diplex radar for ranging over short distances
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/88Radar or analogous systems specially adapted for specific applications
    • G01S13/93Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G01S2013/932Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles using own vehicle data, e.g. ground speed, steering wheel direction
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/88Radar or analogous systems specially adapted for specific applications
    • G01S13/93Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G01S2013/9327Sensor installation details
    • G01S2013/93271Sensor installation details in the front of the vehicles
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/88Radar or analogous systems specially adapted for specific applications
    • G01S13/93Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G01S2013/9327Sensor installation details
    • G01S2013/93275Sensor installation details in the bumper area

Abstract

Since a simultaneously detectable range is limited to one when a plurality of antennas are switched, a short distance detection range becomes small when a long distance antenna is used and, conversely, maximum detection distance decreases when a short distance antenna is used. When a radar is combined with an image sensor, the image sensor may exhibit a detection performance similar to that of a single radar due to bad weather or light beam conditions (backlight, forward light, and the like). The vehicle mounted radar system comprises a first radar for detecting at least the relative speed to a target or the position of the target by radiating a radio wave forward and receiving the reflected wave, and a second radar having a detection range different from that of the first radar, wherein both radars detect the target constantly. When the target deviates from the detection range of the first radar, information of the target detected immediately before it is transferred from the first radar to the second radar.

Description

 Specification

 TECHNICAL FIELD OF THE INVENTION

 The present invention relates to an on-vehicle radar device and a signal processing method thereof.

Background art

Electromagnetic radar is known as a sensor used in a driving support device such as an inter-vehicle distance control device (also called ACC: Adaptive Cruise Control) or an inter-vehicle distance alarm.

 Here, the detection range required for the sensor varies depending on the type of driving assistance device.However, when the transmission power is constant, the detection range becomes narrower by increasing the maximum detection distance when the transmission power is constant. Conversely, if a wide detection width (detection angle) is to be obtained, the maximum detection distance will be short, and it is difficult to configure a detection range that simultaneously satisfies the requirements of various driving support devices. In addition, it is possible in principle to satisfy the desired detection range by increasing the transmission power. However, the increase in the transmission power is not possible due to the increase in the size and cost of the radar and the effect of radio waves on the human body. In reality, it is difficult because of the limitations. As a conventional technique for solving this problem, there is known a millimeter wave radar apparatus in which a plurality of detection ranges are formed by switching a plurality of antennas (Japanese Patent Application Laid-Open No. 2001-116830). There is also known a technique in which a distance sensor and an image sensor are combined and a range in which the distance sensor cannot be detected is complemented by using detection information of the image sensor (Japanese Patent Application Laid-Open No. 2002-99907).

In the case of switching multiple antennas above, the detection range that can be detected simultaneously is one, so if an antenna for long distance is used However, there is a problem in that the detection range for short distances becomes narrower, and conversely, when an antenna for short distances is used, the maximum detection distance decreases.

 In the case of a combination of a radar and an image sensor, the detection accuracy of the image sensor may be drastically reduced due to bad weather or light conditions (backlight, normal light, etc.). There is a problem of performance. Disclosure of the invention

 An object of the present invention is to provide a radar apparatus having a plurality of different detection ranges without substantially increasing transmission power and without using antenna switching or an image sensor. The first radar detects at least the relative speed with respect to the target or the position of the evening target by irradiating the radio wave in front and receiving the reflected wave, and the second radar having a detection range different from that of the first radar. A radar is provided, and the first radar and the second radar are mounted so as to face in the same direction.

 Further, in the radar device as described above, the first radar forms a detection range in front of the vehicle, the second radar forms a detection range different from that of the first radar, and the target detects the first radar. When the target goes out of the range, the detection information of the target immediately before the target is transferred from the first radar to the second radar. Brief Description of Drawings

 FIG. 1 is a diagram showing an embodiment of a composite radar.

 FIG. 2 is a diagram showing an embodiment of the integrated vehicle-mounted composite radar.

FIG. 3 is a diagram showing an embodiment of an independently mounted composite radar. Fig. 4 is a diagram showing the principle of the dual frequency CW system and the FMCW system of a millimeter wave radar.

 Fig. 5 is a diagram showing the image of the tracker fil.

 FIG. 6 is a diagram showing an embodiment of improving the re-acquisition responsiveness in the embodiment of FIG. FIG. 7 is a diagram showing an implementation flowchart of FIG.

 FIG. 8 is a diagram showing an embodiment of improving the responsiveness of the interrupted vehicle detection in the embodiment of FIG.

 FIG. 9 is a diagram showing an implementation flowchart of FIG.

 FIG. 10 is a diagram showing an embodiment in which overlapping detection areas are collated. FIG. 11 is a diagram showing an implementation flowchart of FIG.

 FIG. 12 is a diagram showing another embodiment of the present invention.

 FIG. 13 is a diagram showing a configuration of an inter-vehicle distance automatic control, a warning and a rear-end collision reduction control. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Before describing the specific structure of the composite radar device and the embodiment of the signal processing, first, the performance required for the driving support device and the radar will be described with reference to FIG. Specific examples of driving assistance include an inter-vehicle distance alarm that detects the inter-vehicle distance to a vehicle (preceding vehicle) running ahead of the vehicle and sounds an alarm, or sets the inter-vehicle distance or inter-vehicle time to the preceding vehicle to a predetermined value Inter-vehicle distance control that controls the acceleration and deceleration of the vehicle so that it keeps it, or a collision warning that issues an alarm by detecting an obstacle ahead, or when there is a high possibility of a collision or when it is predicted that a collision cannot be avoided At the same time, the vehicle generates braking force, assists the driver's steering, and adjusts auxiliary equipment such as seat belts and airbags in preparation for a collision. For example, collision reduction control can be considered.

 Information on the preceding vehicle and obstacles ahead is indispensable for such a driving assistance device as described above. As shown in Fig. 13, the radar device mounted on the host vehicle (vehicle with radar) 1 Detects the relative speed with respect to 2, azimuth angle, distance 4 between vehicles, and controls brakes, power trains, alarms, etc. Specifically, for example, in the case of the inter-vehicle distance control, the relative speed or the inter-vehicle distance with the evening target 2 in front of the own vehicle 1 is measured, and the relative speed or the inter-vehicle distance is set to a target value. Next, the speed of the own vehicle 1 is controlled by controlling the brakes and power train of the own vehicle 1 (engines and mechanisms that transmit the output of the prime mover to the wheels, such as engines and transmissions).

 For example, in the case of the collision reduction control, the presence or absence of an obstacle in front of the own vehicle and the danger of a collision are determined, and the alarm device 7 is operated to urge the driver to avoid the collision. Furthermore, if it is determined that a collision with Target 2 is inevitable even after a sudden deceleration, emergency braking and seat belt winding will be performed to reduce damage in the event of a collision. In addition, by steering control of the steering system, it is possible to avoid an adjacent lane on the safe side without obstacles.

 As described above, there are various driving assistance functions that can be realized by the driving assistance device, but the detection ranges required by the driving assistance devices for the radar are different from each other.

For example, in the case of inter-vehicle distance control, a vehicle existing in the lane in which the own vehicle 1 is traveling, that is, a preceding vehicle, among vehicles existing in front of the own vehicle 1, that is, a preceding vehicle may be detected. Although the direction may be narrow, the maximum detection distance (longitudinal distance) must be long because it is assumed to be used on expressways. Therefore, a detection range such as a maximum detection distance of 150 Cm] and a detection angle (beam angle) of 16 ° is required. On the other hand, in the case of collision reduction control, for example, not only a head-on collision but also an oblique collision such as a collision at an intersection, the radar detection range is relatively wide in the lateral direction. However, the maximum detection distance is not required as much as inter-vehicle distance control. For this reason, for example, a detection range such as a maximum detection distance of 50 [m] and a beam angle of 60 ° is required.

 Next, an embodiment of the composite radar device of the present invention will be described with reference to FIGS. 1, 2, 5, and 6. FIG.

 As shown in FIG. 2 (b), the composite radar 3 includes a first radar 3a and at least one second radar 3b having a different detection range from the first radar 3a. ing. The first radar 3a and the second radar 3b are directed in the same direction, and both of them always detect the target. “Always” means that the two radars operate at the same time, and does not mean that they are not stopped at all.

 Here, in a case where the inter-vehicle distance control and the collision reduction control are realized, the detection range 51 of the first radar 3a and the detection range 52 of the second radar 3b are shown in FIG. 2 (a). Such a configuration is often used. That is, the first radar 3a realizes a detection range (for example, a maximum detection distance of 150 [m] and a beam angle of 16 degrees) for inter-vehicle distance control, and the second radar 3b realizes a detection range for collision reduction control. It realizes a detection range (for example, a maximum detection distance of 50 [m] and a beam angle of 60 degrees).

 With this configuration, it is possible to achieve both the relatively long-distance detection performance required for inter-vehicle distance control and the like and the wide-angle detection performance required for interrupt alarms and collision reduction control.

In such a case, the first radar that sets the maximum detection distance longer 3a has a large influence of the mounting angle, so it is necessary to precisely adjust the optical axis.However, the second radar 3b, which forms a short-range wide-angle detection range, has the same detection accuracy as the first radar 3a. , Since no mounting accuracy is required, the second radar 3b can have a small and simple configuration. Specifically, it is conceivable to form the second radar 3b as an integrated circuit on a part of the substrate of the first radar, or to adopt a one-chip radar.

 Fig. 1 shows a configuration example of the first radar 3a. Here, 2 frequency CW

 (Continuous Wave) method will be described as an example. The dual-frequency CW method is a radar device that measures the relative speed with respect to the vehicle ahead using Doppler shift, transmits two frequencies by switching, and uses the phase information of the received signal at each frequency. This method measures the distance to the vehicle ahead.

 The first radar 3a includes a transmitter 18 that outputs a transmission signal based on the modulated signal input from the modulator 17 and a transmitter 11 that emits a transmission signal output from the transmitter 18. As shown in Fig. 4 (a), two frequencies Fl and F2 are transmitted while switching over time.

 Also, the first radar 3a receives the transmission signal reflected by the target. The reception antenna 12 receives the transmission signal.

 Mixer section 14 for generating (IF signal), analog circuit section 15 for amplifying this IF signal, A / D section 16 for converting the amplified analog signal to digital signal (AZD conversion), and digital FFT processing of the converted received signal for each time frame to calculate the distance to the target, relative speed, etc. based on the radar principle, and an FFT waveform analyzer 20; and a timing controller that controls the operation of each of the above units 1 9

Here, the first radar 3a transmits the distance obtained by the FFT waveform analyzer 20. A tracker that reduces the effects of measurement noise and variations on detection data such as distance and relative speed, instead of using the detection data such as separation and relative speed (so-called raw data) directly as radar output. It is desirable to have a configuration including the arithmetic unit 21.

 Specific examples of the processing performed by the tracker calculation unit 21 include a method of performing a mathematical smoothing process by applying some kind of filtering to the detected data on the time axis to eliminate variations in measurement, Estimated values that reflect the smooth movement of the target are calculated by the fill-in process, and multi-target detection judgment is performed. Responsiveness such as tracking of moving targets (speed of detection for appearance and disappearance of targets) ) And eliminating false detections. The following describes an example of the configuration of the tracker filter 21 for the purpose of measuring variation and responsiveness, or eliminating false detections.

 As shown in FIG. 5, the tracker filter 21 of the composite radar 3 of the present embodiment transmits the detected data (distance, relative speed, azimuth (or lateral position = distance X azimuth)) to the raw data. The predicted value 42 is predicted from the previous value 40 estimated in the previous time frame, and the estimated value 40 is determined from the predicted value 42 and the actual raw data 41. According to such a configuration, it is possible to obtain a continuous fill estimated value 40 using the tracker fill.

 Also, in order to eliminate false detections, in each time frame, it is determined whether the raw data 41 is valid or invalid depending on whether or not it falls within the distance range 45. When the cumulative number of valid times reaches a certain value (for example, 80%) at a certain time interval T (for example, 1 second) 46, the filter estimation value 40 is output to the outside of the radar as detection data.

Next, the configuration of the second radar 3b will be described. The second radar 3b is a radar device having a detection range different from at least the first radar 3a. When the collision reduction control and the inter-vehicle distance control are compatible as described above, the first radar 3a is used. The one with a wider detection range angle is selected. As the second radar system, the same two-frequency CW radio wave radar as the first radar 3a may be used, but an FMCW (Frequency Modulated Continuous Wave) radio wave radar described below may be used.

 The FMCW method is an FMCW method (Frequency) that measures the distance and speed to the vehicle ahead by modulating the frequency of the transmission signal with a triangular wave and transmitting it.

An example of applying the Modulated CONTINUOUS WAV E) method will be described with reference to FIGS. 4 (b) and 3 (b).

 FIG. 3 (b) is a schematic diagram of the second radar 3b of the FM CW system. In FIG. 3 (b), a transmission signal subjected to a triangular modulation signal as shown in FIG. 4 (b) is transmitted from the transmission / reception MMIC 105. The transmitted radio wave is reflected by the target and received by the transmitting and receiving MMIC 105.

 The beat signal obtained by multiplying the received signal and the transmitted signal by the MMIC internal mixer is converted to obtain a beat frequency as shown in FIG. 4 (b).

 Subsequently, the obtained beat frequency is amplified by a signal processing IC 60, sampled by a built-in AZD converter, converted into digital data, and subjected to high-speed Fourier transform processing by a signal processing IC 60 processor, thereby obtaining a beat. Get the frequency spectrum of the signal. The signal processing is performed on the frequency spectrum of the beat signal acquired last to detect the evening signal.

In this embodiment, the second radar 3b is formed integrally with the first radar 3a. However, as shown in FIG. 3, the second radar 3b is separated from the first radar 3a and is separately provided. May be attached to.

 In this case, when the composite radar 3 is integrally formed as in the present embodiment, there is an effect that the mounting of the composite radar 3 on the radar-equipped vehicle 1 and the axis adjustment become easy, and the composite radar 3 is formed separately as shown in FIG. In this case, the relative relationship between the detection range 51 of the first radar 3a and the detection range 52 of the second radar 3b can be set in accordance with the requirements of driving support control such as inter-vehicle distance control and collision reduction control. That is, there is an effect that the degree of freedom of the mounting position is secured.

 Next, an embodiment of a target detection system using the composite radar of the present invention will be described with reference to FIGS. 6 to 11. FIG. In the present invention, since the required detection range is realized by using a plurality of radars, when the target moves from the detection range of one radar to the detection range of the other radar, the radar detection after the movement is performed. There is a delay due to tracker filter processing, etc., until an evening get is detected in the range, but this filter processing is inevitable due to noise reduction and erroneous detection elimination. Hereinafter, an embodiment of a target detection system using the composite radar according to the present invention will be described.

 First, an example of detecting a target traveling in the oncoming lane will be described with reference to FIGS. 6 and 7. FIG.

 In FIG. 6, since the target 71 traveling in the oncoming lane approaches from a long distance, the composite radar device first detects the evening target 71 in the detection range 51 of the first radar 3a. At this time, the first radar 3a uses the tracker calculation unit 21 to determine the detected raw data and the detected raw data is not a false detection but a true evening get. The detected data is output as radar output to the outside of the radar every time frame.

Here, for a predetermined time after the target 71 enters the detection range 51 of the first radar 3a, since the tracker operation unit 21 performs the filtering process, No radar output is obtained. That is, the data when the target 71 is at the position of the star in FIG. 6 does not appear in the radar output. This delay time is referred to as filter determination delay 72.

 Next, when the target 71 moves before the point A, the target 71 goes out of the detection range of the first radar 3a, and is not detected by the first radar 3a (lost).

 At this time, in the composite radar according to the present embodiment, target detection information (for example, distance, relative speed, and relative acceleration) near the boundary A of the detection range of the first radar 3a is transferred to the second radar 3b. The second radar 3b calculates a predicted trajectory 74 of the evening radar using the evening target information received from the first radar 3a, and the target is located in the detection range 52 of the second radar 3b. Predict where to enter. At this time, the output to the outside of the radar can be suspended. Thereafter, when the target 71 moves again to the detection boundary range B of the second radar 3b, the composite radar 3 detects the target 71 in the detection range 52 of the second radar 3b. At this time, if the detected raw data matches the position predicted from the evening target information received from the first radar 3a, the second radar 3b detects the raw data as an erroneous detection. The detected raw data (or trajectory 76) is immediately output to the outside of the second radar 3b without judging whether or not it exists. Here, whether or not the predicted position matches the actual detection position can be determined by a method such as matching when the distance between the two points is equal to or less than a predetermined value.

 By the above processing, when the target enters the detection range 52 of the second radar 3b, it is possible to reduce the filter determination delay 72 as in the first radar 3a to a minimum of zero.

FIG. 7 shows a flowchart of this embodiment. In FIG. First 1 It is determined whether or not the target is detected by the radar 3a (S1). If the target is detected here, it is determined whether or not the position is at the boundary point A of the first radar detection range 51 (S2). If the target position is at the boundary point A of the first radar detection range, the target information is transferred to the second radar (S3). Conversely, if the target is not detected or the target is not at the boundary point A, the processing routine is stopped (S7).

 Next, the second radar estimates a predicted position B when the target enters the detection range 52 of the second radar from the received target information.

(S4).

 Subsequently, the second radar determines whether or not the raw data of the target has been detected around the predicted position B (S5). If detected, the second radar immediately outputs the raw data to the outside of the radar as the true position of the target (S6). On the other hand, if no detection is made, this processing routine is stopped (S7).

 In the above processing, in addition to the target information passed from the first radar, own vehicle information such as own vehicle speed, yaw rate, and brakes are also needed, so that the composite radar 3 obtains such information from the outside of the radar. It is desirable to have an information input unit 25.

 Next, an example of the case where the interruption vehicle 81 is detected will be described with reference to FIGS. 8 and 9. FIG.

In Fig. 8, the interrupting vehicle 81 appears from behind the host vehicle in the adjacent lane and breaks in front of the host vehicle, so the composite radar system first starts the interrupting vehicle in the detection range 52 of the second radar 3b. 8 1 is detected. At this time, the second radar 3b detects the interrupted vehicle 81 after elapse of the filter determination delay 72 in order to determine that the detected raw data is not a false detection but a true target. Thereafter, when the interruption vehicle 81 comes to the detection boundary point C of the first radar 3a, the detection result is transferred to the first radar 3a. Then, when the first radar 3a detects the raw data around the detected detection point C, the first radar 3a immediately determines that it is a night target and continues to detect continuously. According to the present embodiment, the receiving radar reduces the fill time judgment delay 72 from the constant time interval shown in Fig. 5 to a minimum of 0 by passing information such as the distance between radars, relative speed, and relative acceleration. Therefore, the target can be detected earlier.

 FIG. 9 shows a flowchart of this embodiment. First, it is determined whether the second radar 3b has detected the evening target (S122). When the evening target is detected, it is determined whether or not the position is at the boundary point A of the first radar detection range (S122). When the target position is at the boundary point A of the first radar detection range, the target information is transferred from the second radar 3b to the first radar 3a (S123). Conversely, if the target has not been detected or the target position is not at the boundary point A, the processing routine is stopped (S127). Next, the first radar 3a estimates the predicted position of the target from the received target information (S124).

 Subsequently, it is determined whether or not the first radar 3a detects the raw data of the evening target around the predicted position B (S125). If detected, the first radar 3a immediately outputs the estimated value of the raw data to the outside of the radar as the true position of the evening get (S126). If no detection is made, this processing routine is stopped (S127).

 By performing the signal processing as described above, it is possible to reduce the time of the target loss (loss) that occurs when the evening target moves from the detection range of one radar to the detection range of the other radar. .

Therefore, the composite radar that performs the above signal processing is When applied to a driving support device, the time during which the target is lost can be shortened, so that the control accuracy is improved.

 In addition, radar usually detects multiple targets, but in inter-vehicle distance control, one target is selected as a tracking target. Here, in the conventional radar system, when an interrupting vehicle is detected by radar, it is necessary to determine which target is ahead of the other detected evening targets. Therefore, in addition to the above-mentioned fill-in processing, there is a delay in selecting the preceding vehicle.

 On the other hand, if the composite radar device that performs the processing as shown in FIGS. 8 and 9 is applied, the interrupted vehicle will enter the lane where the host vehicle 1 is still traveling before the interrupted vehicle enters the lane. (2) An interrupted vehicle can be detected by the radar 3b and the information can be transferred to the first radar 3a.When the interrupted vehicle actually enters the own lane and is detected by the first radar 3a, the detection is performed. It is possible to perform the following distance control by selecting the obtained evening target as the tracking target. FIG. 10 shows an embodiment of a composite radar composed of the first radar 3a and the fine beam radar 3c. The fine beam radar 3c is a second radar having a dielectric lens (not shown), and converges the radio wave beam to, for example, 2 ° or less, and irradiates the radio beam to a distance corresponding to the first radar 3a. This forms a narrow beam 9 1.

It is known that the dual-frequency CW method first radar 3a is difficult to separate and detect targets 92 and 93 stopped at the same distance because of the Doppler method. In addition, the detected target position may be erroneously detected as being between the same distance between the targets 92 and 93 in the evening. In this case, since the narrow beam radar 3c has a narrow beam detection range, there is no evening between the targets 92 and 93, and thus the beam is not detected. Detection results of 1st radar 3a and fine beam radar 3c By comparing with, the false detection of the first radar 3a can be canceled. According to this embodiment, it is possible to eliminate erroneous detection by performing detection data collation between composite radars in different radio systems.

 FIG. 11 shows a flowchart of this embodiment. First, it is determined whether the first radar 3a has detected the target (s131). Here, when the target is detected, it is determined whether or not the position is in front of the own lane (S132). If the target position is in front of the own lane, the target information is passed from the first radar 3a to the fine beam radar 3c (S133). Conversely, if no evening is detected or the evening is not at the front of the own lane, the processing routine is stopped (S137).

 Next, the fine beam radar 3c estimates a predicted position of the evening target from the received target information (S134). In addition, it is determined whether or not the fine beam radar 3c can detect the evening target around the predicted position (S135).

 If no target is detected here, the target detected by the first radar 3a and located in front of the own lane is canceled as an erroneous detection (S136). On the other hand, if it is detected, the data detected by the first radar 3a is output to the outside as it is (S137).

As shown in Fig. 11, when vehicles stop side by side in the lane on both sides of own vehicle 1 as in Fig. 11, only the first radar detects that two vehicles are connected to block the own lane. On the other hand, according to this embodiment, the narrow beam radar 3c can detect that there is no obstacle ahead of the own lane. Regardless, deceleration does not occur and the collision reduction control is not activated, and it is possible to pass between the left and right vehicles. Five

FIG. 12 shows an embodiment of a composite radar having a plurality of second radars. In this embodiment as well, information (distance, relative speed) between the detection ranges 51, 52, 53, 54, 55 of the radars, as in the embodiment shown in FIGS. , Relative acceleration, etc.), the target will leave the detection range of one radar and reduce the delay in determining the fill time when entering the detection range of the next radar to a minimum of 0. This allows early detection.

 Finally, examples of the present invention will be listed.

 In a composite radar system that can detect at least one of the vertical distance, horizontal position, azimuth angle, and relative speed with the target, at least the first radar (in this case, a long-range or medium-range millimeter-wave radar) ) And a second radar (here, an integrated short-range radar), and irradiates the first radar and the second radar simultaneously in the same direction to detect an obstacle. In the above, when the distance to the detection target is out of the capture range of the first radar, at least one of the distance or the relative speed to the target detected by the radar is assigned to the plurality of second radars. The second radar is able to process it so that there is an approaching object near the predicted position of the target object, and the second radar captures it in preference to other target objects.

 Further, when the distance to the detection target is within the capture range from outside the capture range of the first radar, at least one of the distance or the relative speed to the target detected by the second radar is set to the first radar. It can be passed to one radar, and the first radar can treat it as if there is an approaching object around the target object and preferentially catch it over other objects.

The second radar may be configured to transmit and receive signals using a different radio wave method than the first radar and detect obstacles. It is also possible to adopt a configuration in which transmission / reception is performed in the communication. Industrial applicability

 According to the composite radar of the present invention, a plurality of detection ranges can be used simultaneously, and the influence of weather on detection performance is reduced. Further, according to the signal processing method of the present invention, detection responsiveness and detection accuracy when a target moves between a plurality of detection ranges are improved.

Claims

7 Scope of Claim
 1. The first radar, which detects at least the relative speed with respect to the evening target or the position of the evening target by irradiating the radio wave forward and receiving the reflected wave, has a different detection range from the first radar. With a second radar,
 A composite radar apparatus, wherein the first radar and the second radar are mounted in the same direction, and the first and second radars always detect an overnight get.
2. In Claim 1,
 The composite radar device, wherein the second radar has a wider detection angle than the first radar.
3. In Claim 2,
 The composite radar device, wherein the second radar has a shorter maximum detection distance than the first radar.
 4. In claim 1,
 A composite radar device, wherein the second radar is provided integrally on a substrate of the first radar.
 5. In Claim 1,
 Means for determining whether the detected information is erroneous detection, the first radar and the second radar,
 Means for delivering target detection information between the first radar and the second radar.
 6. In Claim 5,
 In the situation where the first radar is detecting the evening target,
When the target goes out of the detection range of the first radar, the detection information of the target immediately before the target is transferred to the second radar. A composite radar device characterized by the following.
 7. In Claim 5,
 Equipped with a vehicle information input unit that captures at least vehicle information including the vehicle speed from outside the radar,
 The composite radar device, characterized in that the second radar includes means for predicting a movement route of the target based on the delivered detection information and the vehicle information.
 8. In Claim 5,
 The composite radar device, wherein the second radar includes means for comparing the detected position of the target with the predicted entry position of the evening target.
 9. In claim 1,
 The composite radar device, wherein the second radar has a maximum detection distance substantially equal to that of the first radar, and a detection angle is smaller than that of the first radar.
 10. In claim 1,
 The second radar includes a dielectric lens,
 A composite radar device which converges and radiates a transmission signal.
 1 1. In claim 1,
 The composite radar device, wherein the first radar is a dual-frequency CW millimeter-wave radar, and the second radar is an FMCW millimeter-wave radar.
1 2. The first radar that detects at least the relative speed with respect to the evening target or the position of the evening gate by irradiating the radio wave in front and receiving the reflected wave, and the maximum radar distance is the first radar. And a composite radar including a second radar having a detection angle smaller than the first radar, A driving assistance device that controls a vehicle based on a distance or a relative speed to a target detected by the composite radar,
 If the first radar detects a target on its own lane and the second radar does not detect a target at the position where the first radar detects the target, A driving assistance device that controls a vehicle as if no evening target was detected on the lane.
 1 3. A detection range is formed in front of the vehicle by the first radar,
 The second radar forms a detection range different from that of the first radar, and the first and second radars always perform a one-night detection, and
 When the target goes out of the detection range of the first radar, the detection information of the target immediately before the target is delivered from the first radar to the second radar. A signal processing method for a radar device.
 1 4. In claim 13,
 When the target goes out of the detection range of the first radar, the detection information of the target immediately before the target is delivered from the first radar to the second radar,
 A signal processing method for a radar device, wherein a movement trajectory of a target is predicted based on the passed-in evening detection information.
 1 5. In claim 13,
 When the target goes out of the detection range of the first radar, the detection information of the target immediately before the target is transmitted from the first radar to the second radar.
Hand over to radar 2
Vehicle information including at least the own vehicle speed is taken in from outside the radar, and a position at which the target enters the detection range of the second radar is predicted based on the delivered detection information and the vehicle information. Features to do A signal processing method for a radar device.
1 6. In claim 15,
 When the second radar detects the evening target,
 A signal of the composite radar, wherein the detected position of the evening target is compared with the predicted entrance position of the evening target, and when they match, the detection result is output to the outside of the radar. Processing method.
PCT/JP2003/016969 2003-12-26 2003-12-26 Vehicle mounted radar system and its signal processing method WO2005066656A1 (en)

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