JP5065611B2 - Radar equipment - Google Patents

Description

  The present invention relates to a radar apparatus that detects an object using radio waves, and more particularly to a radar apparatus that detects an object using a beamforming technique.

  An in-vehicle radar device that is installed in front of a vehicle and measures the distance to the object and the relative speed between the vehicle and the object has been proposed. By measuring the distance to the object and the relative speed, it is possible to operate an alarm device that warns in advance of a collision with the object, or to operate a brake to avoid a collision with the object.

  The conventional in-vehicle radar system transmits a beam of radio waves in the millimeter wave region, receives the reflected waves reflected by the object with multiple receiving antennas, and determines the direction of the object from the phase difference of the received waves. There is an on-vehicle radar device.

  FIG. 1 is an example of reception of reflected waves in a phase monopulse type on-vehicle radar device. Here, θ is an angle indicating the direction of the object, and the front direction of the vehicle is 0 °. The distance D is the interval between the two receiving antennas, and the phase difference φ is the phase difference between the two received waves. The two receiving antennas 9a and 9b receive the reflected wave reflected by the object in the direction of the angle θ. The angle θ indicating the direction of the object that reflects the reflected wave received by the two receiving antennas is obtained by the following equation.

Here, λ is the wavelength of the received wave.

  Similarly, a radar apparatus using a beam forming technique for detecting the direction of an object using a phase difference of received waves has been proposed.

  FIG. 2 is a configuration diagram of a receiving unit of a conventional radar apparatus using digital beam forming. In FIG. 2, an object reflects a transmission wave transmitted by a transmission unit (not shown), and the receiving antennas 31a to 31z receive the reflected wave. The reception antennas 31a to 31z supply the reception signals generated by reception to the A / D converters 32a to 32z. Thereafter, the A / D converters 32a to 32z convert the supplied reception signals into digital signals. The converted digital signals are stored in the memories 33a to 33z, respectively. Based on the stored digital data, the signal processing unit 34 performs an operation to obtain the direction of the object.

  Here, a method used for determining the direction of the object will be described.

  FIG. 3 is a diagram showing a memory of a conventional radar apparatus. In FIG. 3, the digital signals supplied from the A / D converters 32a to 32c are stored in the memories 33a to 33c, respectively. A0 to A5, B0 to B5, and C0 to C5 in the memories 33a to 33c indicate memory addresses, respectively. The supplied digital signal is first stored at addresses A5 to C5. After a certain time, digital signals supplied from the A / D converters 32a to 32c again are stored at addresses A4 to C4. Similarly, digital signals are stored in the addresses A3 to C3, A2 to C2, A1 to C1, and A0 to C0. The signal processing unit 34 calculates the direction of the object using these stored digital data.

  FIG. 4 is a diagram for calculating the reception intensity of radio waves from the front direction of the receiving antenna. The radio wave from the front direction of the receiving antenna reaches the same phase at the same time in any receiving antenna. If there is an object in front of the receiving antenna and the object reflects a transmitted wave from a transmitter (not shown), the intensity of the reflected wave is obtained by adding digital data stored in addresses A0 to C0. Can do.

  Similarly, the intensity of the reflected wave from other directions can be obtained.

  FIG. 5 is a diagram for calculating the reception intensity of radio waves from the direction of the angle φ1. In FIG. 5, the object exists in the direction of the angle φ1, the plane PA1 represents the plane of the same phase of the reflected wave from the object, and the plane PB2 is a plane parallel to the plane. Here, for easy understanding, it is assumed that ΔdX / ΔDX = tanφ1 when the interval between memory addresses, for example, the interval between A1 and A0 is ΔdX, and the interval between A0 and B0 is ΔDX. . In order to facilitate understanding, it is assumed that digital data is stored in the memories 33a to 33c every (ΔDXcos φ1) / c (c is the speed of light) seconds. If an object in the direction of angle φ1 reflects a transmission wave from a transmission unit (not shown), the digital data stored in addresses A0, B1, and C2 all have the same phase, and the addition of the intensity of the reflection wave Can be sought.

  In such direction estimation using digital beamforming, the problem of side lobe described below occurs.

  FIG. 6 is a diagram for explaining the side lobes. In FIG. 6, radio waves arrive from the front direction of the antennas 31a to 31d. At this time, when the reception signals are added along the plane PD1 parallel to the plane formed by the antennas 31a to 31d, it can be seen that the object exists in the front direction. However, even if the received signals are added along the plane PD3 whose phases are shifted by 3 / 4π, the addition result is similarly maximized.

  FIG. 7 is an angle spectrum of the reflected wave intensity obtained as a result of the observation in FIG. In this observation, the maximum value of the reflected wave intensity is observed in the front direction and in the direction of the angle P1 corresponding to the plane PD1 in FIG. 6 (this is called a main lobe). Further, the maximum value of the reflected wave intensity is also observed in the direction of the angle P3 corresponding to the plane PD3 in FIG. 6 (this is called a side lobe). Then, the reflected wave intensity becomes zero in the direction of the angle P2 corresponding to the plane PD2 in FIG. This is because radio waves of opposite phases are received alternately on the plane PD2 in FIG.

In this way, the maximum value of the reflected wave intensity that exists beside the real object is called a side lobe, and this side lobe becomes an obstacle to the direction determination in the observation of the object.
In a radar device mounted on a vehicle, when the side lobe is high, a roadside sign, a crossover, or the like is erroneously detected, which causes a problem.

Conventionally, the problem of the side lobe has been dealt with by increasing the size of the antenna. It is known that side lobes can be reduced by increasing the size of the antenna. Similarly, the side lobes can be reduced by increasing the width of the beam to be formed. In this way, the side lobes can be reduced, a predetermined threshold value can be set for the angle spectrum of the reflected wave intensity, and the main lobe can be separated by the difference in peak level from the side lobe. Further, as shown in Patent Document 1, a method of suppressing side lobes by a side lobe canceller technique using an auxiliary antenna has been devised.
JP 2002-43822 A

  However, in a radar device mounted on a vehicle, it is difficult to reduce the antenna because the space for installation is narrow. Further, in a radar device mounted on a vehicle, it is necessary to distinguish between a forward vehicle in a traveling lane and a forward vehicle traveling in an adjacent lane, so that the beam width needs to be kept narrow. For this reason, it is difficult to reduce the reception intensity of the side lobe by the conventional method.

  Also, when distinguishing between the main lobe and side lobe peak levels, it is difficult to observe an object having a large reflection area.

  Accordingly, an object of the present invention is to provide a radar apparatus that reduces side lobes without increasing the size of a receiving antenna.

  Another object of the present invention is to provide a radar apparatus capable of discriminating side lobes and main lobes even when observing an object having a large reflection area.

  Furthermore, another object of the present invention is to provide a radar apparatus that reduces side lobes without increasing the azimuth resolution by widening the beam width.

  In order to solve the above-described problem, according to a first aspect of the present invention, a transmission unit that transmits a transmission wave, a plurality of antennas that receive reflected waves from an object that has received the transmission wave, and each of the antennas A signal processing unit that calculates an angular spectrum of the intensity of the reflected wave using digital beam forming according to the phase difference of the received signal and determines the direction in which the object exists. The signal processing unit multiplies each of the reception signals by a first coefficient group corresponding to each of the antennas, calculates a first angular spectrum, and calculates a second coefficient corresponding to each of the antennas. Multiply each of the received signals by a group to calculate a second angular spectrum and exceed a predetermined threshold set in the first and second angular spectrum in both angular spectra The degree range, and determines that the object is present.

  In a preferred embodiment, the signal processing unit determines that the object is present at both ends of an angle range that exceeds a predetermined threshold set in the first and second angular spectra in both angular spectra. It is characterized by that.

  Furthermore, in a preferred embodiment, the signal processing unit sets an angle having a maximum value of the spectrum within an angle range that exceeds a predetermined threshold set in the first and second angular spectrums in both angular spectra. It is determined that the object exists.

  Further, in a preferred embodiment, the first angular spectrum is an angular spectrum obtained by reducing a side lobe appearing on the left side of the object, and the second angular spectrum is a side lobe appearing on the right side of the object. It is characterized by a reduced angular spectrum.

  Furthermore, in a preferred embodiment, the signal processing unit calculates an angular spectrum without using the first and second coefficient groups, confirms the presence of an object, and then calculates the first and second angular spectrums. The calculation is performed.

  The radar apparatus of the present invention makes it possible to reduce the influence of side lobes by forming and combining an angle spectrum of asymmetric reflected wave intensity.

  Embodiments of the present invention will be described below with reference to the drawings. However, the technical scope of the present invention is not limited to these embodiments, but extends to the matters described in the claims and equivalents thereof.

  FIG. 8 is a configuration diagram of the radar apparatus according to the embodiment of the present invention. FIG. 9 is a diagram showing how the radar apparatus 1 observes the preceding vehicle. In FIG. 9, the radar device 1 is installed in front of the vehicle 2, transmits a radio wave in the millimeter wave region over the detection range 3, and detects the vehicle 4 ahead. At the same time, surrounding obstacles are detected.

  The transmission system of the radar apparatus 1 installed in the vehicle 2 includes a modulator 11, an oscillator 12, and a transmission antenna 13. The modulator 11 generates a modulation signal for transmitting a frequency-modulated millimeter wave. The oscillator 12 of the radar apparatus 1 generates a transmission signal based on this modulation signal and transmits it to the front of the vehicle 2 via the transmission antenna 13.

  FIG. 10 is a diagram illustrating the frequencies of the transmission wave and the reception wave. The transmission frequency SF of the transmission wave transmitted based on the modulation signal generated by the modulator 11 rises at a constant rate over a certain time, then falls at the same rate, and returns to the original frequency. The transmission frequency SF repeats this. The reception frequency RF obtained by reflecting the transmission wave on the object is delayed by a time difference ΔT compared to the transmission frequency SF. Based on this time difference ΔT, the position to the object reflecting the transmission wave is calculated. Further, the reception frequency RF is subjected to Doppler displacement DS based on the relative velocity of the object that reflects the transmission wave. Based on the Doppler displacement DS, the relative speed between the object and the vehicle 2 is obtained.

  Returning to FIG. 8, the transmitted transmission wave is reflected by an object existing in front and is received by a plurality of reception antennas 14a, 14b,. In the present embodiment, 16 receiving antennas are mounted. The receiving system of the radar apparatus 1 includes a receiving antenna 14, an amplifier 15, a mixer 16, a filter 17, an analog / digital converter (hereinafter referred to as A / D converter) 18, memories 19 and 21, a calculation unit 20, and a signal processing unit. Consists of 22. Here, the same number of amplifiers 15, mixers 16, filters 17, A / D converters 18, memories 19 and 21, and arithmetic units 20 as the reception antennas 14 are arranged.

  The reflected wave reflected by the object is received by the plurality of receiving antennas 14a to 14p. Each of the plurality of receiving antennas 14a to 14p receives a reflected wave from the object, and determines the direction of the object causing the reflected wave based on the phase difference of the received reflected wave.

  Received signals generated by the receiving antennas 14a to 14p are amplified by the amplifiers 15a to 15p, respectively. The amplified signals are mixed with the transmission signal generated by the oscillator 12 by the mixers 16a to 16p, respectively. The mixers 16a to 16p generate and output a beat signal obtained by mixing the reception signal and the transmission signal. The distance and relative speed are calculated in the signal processing unit 22 as described later, using the beat signal in the section where both the reception signal and the transmission signal rise and the beat signal in the section where both the reception signal and the transmission signal fall. The beat signals are input to the filters 17a to 17p, respectively. The signals band-limited by the filters 17a to 17p are input to the A / D converters 18a to 18p and converted into digital signals, respectively. Each digital signal is input to and stored in the memories 19a to 19p.

  The digital data stored in the memories 19a to 19p is Fourier transformed by the arithmetic units 20a to 20p installed at the subsequent stage. The converted digital data is further stored in time series in memories 21a to 21p provided in the subsequent stage. The signal processing unit 22 estimates the direction of the object reflecting the transmission wave using the digital data stored in the memories 21a to 21p.

  As will be described in detail later, the signal processing unit 22 calculates the direction of the object that reflects the transmission wave using DBF (digital beamforming). Thereafter, the distance to the object and the relative speed with the object are calculated. The calculated direction, distance, and relative speed of the object are output from the signal processing unit 22 and supplied to an ECU (Electric Control Unit) 5 installed outside the radar apparatus 1. Various information such as a vehicle speed signal SG1, steering angle information SG2, and yaw rate signal SG3 is supplied to the ECU 5 from each part of the vehicle 2. Based on these information and the determined direction, distance, and relative speed of the object, the ECU 5 warns the driver who is driving the vehicle via the warning signal SG5 and the display signal SG6. The ECU 5 can also weaken the accelerator via the throttle signal SG4.

  Here, the processing in the signal processor 22 will be described in detail.

  FIG. 11 is a process flowchart in the signal processing unit 22. First, the signal processing unit 22 forms a symmetric pattern, which is an angle spectrum of the reflected wave intensity symmetrical to the left and right, by DBF (step S1).

  Formation of the symmetrical pattern is performed as follows.

  FIG. 12 is a diagram for explaining pattern formation in DBF. Radio waves indicated by A1exp (jωt), A2exp (j [ωt + Δ / 2πλ]), and A3exp (j [ωt + 2Δ / 2πλ]) are incident on the receiving antennas 14a to 14c, respectively. Here, A1 to A3 of the reflected wave are amplitudes, ω is the angular frequency of the reflected wave, λ is the wavelength of the reflected wave, j is an imaginary unit, Δ is d · sin θ, and d is an antenna interval. Here, when these incident waves are added for all 16 receiving antennas, the following equation is obtained.

  FIG. 13 is an example of a symmetrical pattern formed in step S1. A main lobe exists at the point of the angle θ0, indicating the angular direction in which the object exists. Side lobes are formed at angles θ1, θ2, θ-1, and θ-2 on both sides of the main lobe.

  Returning to FIG. 11, after step S1, it is confirmed whether or not there is a portion where the reflected wave intensity is higher than a predetermined threshold in the formed symmetrical pattern (step S2). If the reflected wave intensity does not exceed the predetermined threshold value, the process returns to the start of the process flow of FIG. If the reflected wave intensity exceeds a predetermined threshold value, an asymmetric pattern that is an angle spectrum of reflected wave intensity that is asymmetrical on the left and right is formed by DBF (step S3).

  Here, in order to form the asymmetric pattern, a modified expression of Expression 2 is used. An asymmetric pattern is obtained by multiplying the amplitude and phase of the input signal with respect to the equation (2) by a coefficient. The following equation is an equation multiplied by a coefficient to obtain an asymmetric pattern.

  In order to obtain an asymmetric pattern in which the side lobe appearing on the left side of the object is reduced, first, the value shown in FIG. Then, the value of FIG. 15 is substituted for Φi in Equation 4. When the value of φ is changed with respect to the number 4 in which these values are substituted, an asymmetric pattern with reduced side lobes appearing on the left side of the object is generated.

  Similarly, in order to reduce the side lobe appearing on the right side of the object, first, the value shown in FIG. Then, the value of FIG. 16 is substituted for Φi in Equation 4. When the value of φ is changed with respect to the number 4 in which these values are substituted, an asymmetric pattern with reduced side lobes appearing on the right side of the object is generated.

  17 and 18 are examples of asymmetric patterns generated in step S3. The asymmetric pattern of FIG. 17 is generated using the values of FIG. 15, and the asymmetric pattern of FIG. 18 is generated using the values of FIG. The left side lobe is suppressed in the asymmetric pattern in FIG. 17, and the right side lobe is suppressed in the asymmetric pattern in FIG.

  Next, a predetermined threshold value is given to the asymmetric pattern of FIG. 17 and FIG. 18 obtained in step S3, and the side lobe on the reduced side is excluded (step S4). For example, if the threshold value is set to −25 dB in FIG. 17, detection by the left side lobe is not performed. In FIG. 18, if the threshold is set to −25 dB, detection by the right side lobe is not performed. As a result, only the detection by the central main lobe is detected in both asymmetric patterns, and the influence of the side lobe can be eliminated.

  Thereafter, in step S5, the distance and relative velocity of the object detected in step S4 are obtained from the frequency of the reflected wave, and the angle of the object that is the angle of the main lobe is calculated.

  In this way, by detecting an object using two asymmetric patterns, it is possible to reduce the influence of side lobes without increasing the size of the receiving antenna. Further, it is possible to reduce the influence of side lobes without reducing the azimuth resolution by widening the beam width.

  So far, the case of detecting one object has been described, but the technique using two asymmetric patterns is also effective when detecting a plurality of objects.

  Hereinafter, a case where two objects are detected will be described.

  FIG. 19 shows an example in which two objects are observed and a conventional symmetrical pattern is formed by DBF. Here, it is assumed that the two objects are located at angles θ0 and θ1 in FIG. In this way, it is very difficult to specify the number of objects, and the angle at which the peak of the reflected wave from the object exists, only by forming a symmetrical pattern.

  Therefore, an asymmetric pattern is generated to reduce the influence of side lobes.

  FIG. 20 is an example of an angle spectrum of the reflected wave intensity when two objects are detected using the values shown in FIG. FIG. 21 shows an example of the angle spectrum of the reflected wave intensity when two objects are detected using the values shown in FIG. Here, it is assumed that the two objects are located at angles θ0 and θ1 in FIGS. 20 and 21. Further, the distribution TA0 in FIGS. 20 and 21 is a distribution due to the influence of the object located at the angle θ0, and the distribution TA1 in FIGS. 20 and 21 is a distribution due to the influence of the object located at the angle θ1.

  When the values in FIG. 15 are used, the side lobe located on the left side of the position where the object is considered to be present is reduced. Further, when the values in FIG. 16 are used, the side lobe located on the right side of the position where the object is considered to be present is reduced.

  At this time, a predetermined threshold is set for the angle spectrum of the reflected wave intensity in FIGS. In FIG. 20, the portion exceeding the threshold is on the right side from the angle θ0, whereas in FIG. 21, the portion exceeding the threshold is on the left side from the angle θ1. In both FIG. 20 and FIG. 21, the portion exceeding the threshold is a region between the angle θ0 and the angle θ1.

  FIG. 22 is an angle spectrum of reflected wave intensity obtained by extracting a portion exceeding a predetermined threshold in both of the two asymmetric patterns. FIG. 23 is a diagram in which an envelope is applied to the distribution of FIG. The envelope can be obtained by connecting individual peak values.

  In both of the two asymmetric patterns, if a portion exceeding a predetermined threshold (here, angles θ0 to θ1) exceeds a predetermined width, an object is present at both ends (here, angles θ0 and θ1). Recognize. In addition, there is no other object if there is no maximum value in the envelope in a portion where the predetermined threshold is exceeded in both of the two asymmetric patterns. In other words, in this case, two objects are observed, and it can be seen that the directions in which the objects exist are the angles θ0 and θ1.

  In this way, by detecting an object using two asymmetric patterns, it is possible to reduce the influence of side lobes without increasing the size of the receiving antenna. Further, it is possible to reduce the influence of side lobes without reducing the azimuth resolution by widening the beam width. In addition, the side lobe and the main lobe can be distinguished even in the observation of an object having a large reflection area.

  So far, the case where two objects are detected has been described. However, a technique using two asymmetric patterns is also effective in detecting more objects.

  Hereinafter, a case where three objects are detected will be described.

  FIG. 24 shows an example in which three objects are observed and a conventional symmetrical pattern is formed by DBF. Here, it is assumed that the three objects are located at angles θ0, θ1, and θ2 in FIG. In this way, it is very difficult to specify the number of objects, and the angle at which the peak of the reflected wave from the object exists, only by forming a symmetrical pattern.

  Therefore, an asymmetric pattern is generated to reduce the influence of side lobes.

  FIG. 25 is an example of an angle spectrum of reflected wave intensity when three objects are detected using the values of FIG. FIG. 26 is an example of an angle spectrum of reflected wave intensity when three objects are detected using the values shown in FIG. Here, it is assumed that the three objects are located at angles θ0, θ1, and θ2 in FIGS. 25 and 26 is a distribution due to the influence of the object located at the angle θ0, and the distribution TA1 in FIGS. 25 and 26 is a distribution due to the influence of the object located at the angle θ1. The distribution TA2 in FIG. 26 is a distribution due to the influence of the object located at the angle θ2.

  When the values in FIG. 15 are used, the side lobe located on the left side of the position where the object is considered to be present is reduced. Further, when the values in FIG. 16 are used, the side lobe located on the right side of the position where the object is considered to be present is reduced.

  At this time, a predetermined threshold is set for the angle spectrum of the reflected wave intensity in FIGS. In FIG. 25, the portion exceeding the threshold is on the right side from the angle θ0, whereas in FIG. 26, the portion exceeding the threshold is on the left from the angle θ2. In both FIG. 25 and FIG. 26, the portion exceeding the threshold is a region between the angle θ0 and the angle θ2.

  FIG. 27 is an angle spectrum of reflected wave intensity obtained by extracting a portion exceeding a predetermined threshold in both of the two asymmetric patterns. FIG. 28 is a diagram in which an envelope is applied to the distribution of FIG. The envelope can be obtained by connecting individual peak values.

  In both of the two asymmetric patterns, if a portion exceeding a predetermined threshold (here, angles θ0 to θ2) exceeds a predetermined range, an object may exist at both ends (here, angles θ0 and θ2). Recognize. In addition, it can be understood that another object exists if the envelope has a maximum value in a portion exceeding a predetermined threshold value in both of the two asymmetric patterns. That is, in this case, since only one maximum value is observed in the direction of the angle θ1, three objects are observed, and it can be seen that the directions of the objects are angles θ0, θ1, and θ2.

  In this way, by detecting an object using two asymmetric patterns, it is possible to reduce the influence of side lobes without increasing the size of the receiving antenna. Further, it is possible to reduce the influence of side lobes without reducing the azimuth resolution by widening the beam width. In addition, the side lobe and the main lobe can be distinguished even in the observation of an object having a large reflection area.

It is an example of reception of the reflected wave in the vehicle-mounted radar apparatus of a phase monopulse system. It is a block diagram of the receiving part of the conventional radar apparatus using digital beam forming. It is a figure which shows the memory of the conventional radar apparatus. It is a figure which calculates the receiving intensity of the electromagnetic wave from the front direction of a receiving antenna. It is a figure which calculates the reception intensity | strength of the electromagnetic wave from the direction of angle (phi) 1. It is a figure for demonstrating a side lobe. It is an angle spectrum of the reflected wave intensity obtained as a result of observation in FIG. It is a block diagram of the radar apparatus in 1st embodiment of this invention. FIG. 3 is a diagram illustrating a state of observation of a forward vehicle in the radar apparatus 1. It is a figure which shows the frequency of a transmission wave and a reception wave. 3 is a processing flowchart in a signal processing unit 22. It is a figure for demonstrating the pattern formation in DBF. It is an example of a symmetrical pattern formed in step S1. It is an example of the coefficient Ci. It is an example of the offset value of a phase. It is an example of the offset value of a phase. It is an example of an asymmetric pattern generated in step S3. It is an example of an asymmetric pattern generated in step S3. This is an example of observing two objects and forming a conventional symmetrical pattern by DBF. FIG. 16 is an example of an angle spectrum of reflected wave intensity when two objects are detected using the values of FIG. FIG. 17 is an example of an angle spectrum of reflected wave intensity when two objects are detected using the values of FIG. It is an angle spectrum of reflected wave intensity obtained by extracting a portion exceeding a predetermined threshold in both of the two asymmetric patterns. It is the figure which applied an envelope with respect to the distribution of FIG. This is an example of observing three objects and forming a conventional symmetrical pattern by DBF. FIG. 16 is an example of an angle spectrum of reflected wave intensity when three objects are detected using the values of FIG. FIG. 17 is an example of an angle spectrum of reflected wave intensity when three objects are detected using the values of FIG. It is an angle spectrum of reflected wave intensity obtained by extracting a portion exceeding a predetermined threshold in both of the two asymmetric patterns. It is the figure which applied the envelope to the distribution of FIG.

Explanation of symbols

1 Radar device 2 Vehicle 3 Detection range 5 ECU
DESCRIPTION OF SYMBOLS 11 Modulator 12 Oscillator 13 Transmission antenna 14 Reception antenna 15 Amplifier 16 Mixer 17 Filter 18 A / D converter 19 Memory 20 Calculation part 21 Memory 22 Signal processing part

Claims (5)

A transmission unit for transmitting a transmission wave;
A plurality of antennas for receiving reflected waves from an object that has received the transmitted wave;
A signal processing unit that calculates an angle spectrum of the intensity of the reflected wave using digital beam forming according to a phase difference between reception signals received by each of the antennas and determines a direction in which the object exists. And
The signal processing unit multiplies each of the reception signals by a first coefficient group corresponding to each of the antennas, calculates a first angle spectrum, and calculates a second coefficient group corresponding to each of the antennas. Each of the received signals is multiplied to calculate a second angular spectrum, and the object exists in an angular range that exceeds a predetermined threshold set in the first and second angular spectrums in both angular spectra. A radar apparatus characterized in that it is determined. In claim 1,
The signal processing unit determines that the object is present at both ends of an angular range that exceeds a predetermined threshold set in the first and second angular spectrums in both angular spectra. . In claim 1,
Wherein the signal processing unit, a predetermined threshold value set in the first and second angular spectrum, determine the envelope by connecting the peak values of the individual angular spectrum definitive within an angular range exceeding in both angular spectrum, If there is a maximum value in the envelope, it is determined that an object is also present in the angular direction of the maximum value . In claim 1,
The first angular spectrum is an angular spectrum with reduced side lobes appearing on the left side of the object, and the second angular spectrum is an angular spectrum with reduced side lobes appearing on the right side of the object. A radar device characterized by the above. In claim 1,
The signal processing unit calculates the angle spectrum without using the first and second coefficient groups, confirms the presence of an object, and then calculates the first and second angle spectra. Radar device.

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