JP2011158401A - Radar system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radar system that covers a wide angle, and improves angle measurement precision by forming a narrow beam in a prescribed direction. <P>SOLUTION: The system includes: an antenna 10 including a plurality of elements, where the plurality of elements are successively divided into a plurality of first elements 12a, second elements 11a, and third elements 11a', and a plurality of fourth elements 12a'; a beam forming unit 34 that forms beams for covering an entire observation angle range using the second and third elements, forms beams for covering a prescribed range with a prescribed angle as a center using the plurality of first elements and the plurality of fourth elements, and forms beams in an optional direction within a prescribed range with a prescribed angle as a center using the whole of the plurality of elements; and an angle measurement unit 37 for performing a monopulse angle measurement based on beams formed by the beam forming unit. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a radar apparatus that can observe the direction (angle) of a vehicle or the like at a wide angle.

  When observing a vehicle traveling on a road with a radar device, a small antenna is used. FIG. 13 is a system diagram showing the configuration of a conventional radar apparatus, and FIG. 14 is a flowchart showing the operation of this radar apparatus. The radar apparatus includes an antenna 10, a transceiver 20 and a signal processor 30.

  The signal swept by the transmitter 21 inside the transceiver 20 is transmitted from the antenna transmission element 11. On the other hand, the signals received by the plurality of antenna receiving elements 12 are frequency-converted by the plurality of mixers 22 and sent to the signal processor 30. In the signal processor 30, the signal from the transceiver 20 is input (step S201), converted into a digital signal by the AD converter 31, and sent to the FFT unit 32 as an element signal.

  The FFT unit 32 performs a fast Fourier transform on the signal sent from the AD converter 31 to convert it into an element signal on the frequency axis, and sends it to a DBF (Digital Beam Forming) unit 34. The DBF unit 33 uses the element signal on the frequency axis sent from the FFT unit 32 to form a Σ beam and a Δ beam. The Σ beam formed by the DBF unit 33 is sent to the detecting unit 35, and the Δ beam is sent to the angle measuring unit 37. The detection unit 35 detects the target based on the Σ beam sent from the DBF unit 33 and sends the detection result to the distance measurement / speed measurement unit 36.

  Next, the distance and speed are calculated (step S202). That is, the distance measurement / speed measurement unit 36 measures the distance to the target and the speed of the target based on the detection result from the detection unit 35, transmits the target to the outside, and sends the Σ beam to the angle measurement unit 37.

  Next, an angle is calculated (step S203). That is, the angle measuring unit 37 performs angle measurement by the monopulse method as shown in FIG. 15 using the Σ beam sent from the distance measuring / speed measuring unit 36 and the Δ beam sent from the DBF unit 33. . The monopulse method is described in Non-Patent Document 1. The angle obtained by the angle measurement by the angle measuring unit 37 is sent to the outside.

  Next, correlation tracking is performed (step S204). That is, an external correlation tracking unit (not shown) performs correlation tracking processing based on the distance, speed, and angle sent from the signal processor 30 to calculate the target position and speed. Thereafter, it is checked whether or not the cycle is completed (step S205). If it is determined in step S205 that the cycle has not ended, processing for setting the next cycle as a processing target is performed (step S206). Then, it returns to step S201 and the process mentioned above is repeated. On the other hand, when it is determined in step S205 that the cycle has ended, the tracking processing of the radar apparatus ends.

Supervised by Takashi Yoshida, “Revised Radar Technology”, IEICE, pp. 260-264 (1996)

  However, when observing a vehicle traveling on a road with a radar, a small antenna is used, so it is possible to form a wide-angle beam and a narrow beam at the same time to ensure a wide-angle range and measure the angle with high accuracy. It was difficult.

  An object of the present invention is to provide a radar apparatus that can cover a wide angle and form a narrow beam in a predetermined direction to improve angle measurement accuracy even with a small antenna.

  In order to solve the above problems, the invention of claim 1 is directed to an antenna in which a plurality of elements are sequentially divided into a plurality of first elements, a second element, a third element, and a plurality of fourth elements, and an observation angle. A beam that covers the entire range with the second element and the third element is formed, and a beam that covers a predetermined range around the predetermined angle with the plurality of first elements and the plurality of fourth elements is formed. And a beam shaping unit that forms a beam in an arbitrary direction within a predetermined range centered on a predetermined angle, and an angle measuring unit that performs monopulse angle measurement based on the beam formed by the beam shaping unit. .

  In the invention of claim 2, the plurality of elements are sequentially divided into a plurality of first elements, a second element, a third element, and a plurality of fourth elements, and the plurality of first elements and the plurality of fourth elements are An antenna composed of a snake waveguide that performs frequency scanning, and a snake waveguide that forms a beam that covers the entire observation angle range with the second element and the third element, and that scans the predetermined range centered on the predetermined angle. A beam shaping unit that forms a beam that is covered by the plurality of first elements and the plurality of fourth elements, and that forms the beam in any direction within a predetermined range centered on a predetermined angle with the plurality of elements as a whole. And an angle measuring unit that performs monopulse angle measurement based on the beam formed by the beam shaping unit.

  According to a third aspect of the present invention, there is provided an antenna in which a plurality of elements are sequentially divided into one or more first elements, one or more second elements, one or more third elements, and one or more fourth elements, and an observation angle The entire range is covered with the second element and the third element, and the first predetermined range centered on the first predetermined angle and the second predetermined range centered on the second predetermined angle are the plurality of first elements and the plurality of fourth elements. A Σ beam that is covered with the element is formed, a Δ beam is formed by the difference between the second element and the third element, and a phase monopulse angle measurement based on the Δ beam and the Σ beam formed by the beam shaping part And an angle measuring unit for performing.

  In the invention of claim 4, the plurality of elements are sequentially divided into one or more first elements, one or more second elements, one or more third elements, and one or more fourth elements, and the plurality of first elements And a plurality of fourth elements that are formed of a snake waveguide for frequency scanning, and the entire observation angle range is covered with the second element and the third element, and the first predetermined range centered on the first predetermined angle And a beam shaping unit for forming a Σ beam that is covered with a plurality of first elements and a plurality of fourth elements composed of a snake waveguide that frequency scans a second predetermined range centered on a second predetermined angle, and a beam An angle measuring unit that performs phase monopulse angle measurement based on the Δ beam and the Σ beam formed by the shaping unit is provided.

  According to the present invention, it is possible to provide a radar apparatus that can improve the angle measurement accuracy by covering a wide angle and forming a narrow beam in a predetermined direction even with a small antenna mounted on a vehicle or the like.

  According to the first aspect of the present invention, even in a small antenna, the element spacing is small, the wide angle is covered by the second element and the third element having a small number of elements, and the plurality of first elements and the plurality of first elements having a large number of elements are covered. By covering the beam width of the four elements over a predetermined angle range and forming a narrow beam using the entire element in the angle range, angle measurement accuracy can be improved.

  According to the invention of claim 2, even in a small antenna, the element spacing is narrow, the wide angle is covered by the second element and the third element having a small number of elements, and the plurality of first elements and the plurality of first elements having a large number of elements are covered. By covering the beam width of the four elements over an angle range of a predetermined angle and further performing frequency scanning, a narrow beam is formed using the entire elements in the scannable angle range, thereby improving the angle measurement accuracy in a wide range.

  According to the invention of claim 3, even in a small antenna, the element spacing is narrow, the wide angle is covered by the second element and the third element having a small number of elements, and the plurality of first elements and the plurality of first elements having a large number of elements are covered. In order to cover the four elements of the beam in two predetermined directions, a target in a wide angle range is detected. Can be improved.

  According to the invention of claim 4, even in a small antenna, the element spacing is narrow, the wide angle is covered by the second element and the third element having a small number of elements, and the plurality of first elements and the plurality of first elements having a large number of elements are covered. Since the beam of four elements is covered in two predetermined directions, a target in a wide angle range is detected, and in two specific directions, angle measurement accuracy can be improved by using a Σ and Δ phase monopulse beam having a narrow beam width.

1 is a system diagram showing a configuration of a radar apparatus according to Embodiment 1 of the present invention. It is a figure which shows the antenna of the radar apparatus which concerns on Example 1 of this invention. It is a figure which shows the wide angle beam and narrow angle beam which are formed with the antenna of Example 1 of this invention. It is a figure which shows the antenna of the radar apparatus which concerns on Example 2 of this invention. It is a figure which shows the wide angle beam and narrow angle beam which are formed with the antenna of Example 2 of this invention. It is a specific block diagram of the antenna of Example 2 of the present invention. It is a figure which shows the antenna of the radar apparatus which concerns on Example 3 of this invention. It is a figure which shows the wide angle beam and narrow angle beam which are formed with the antenna of Example 3 of this invention. It is a figure which shows the antenna of the radar apparatus which concerns on Example 4 of this invention. It is a figure which shows the wide angle beam and narrow angle beam which are formed with the antenna of Example 4 of this invention. It is a figure which shows a mode that the directivity direction of a beam is changed by changing a frequency in the radar apparatus of Example 4 of this invention. It is a figure which shows a mode that the first half and the second half of a sweep signal are FFTed in the radar apparatus of Example 4 of this invention. It is a systematic diagram which shows the structure of the conventional radar apparatus. It is a flowchart which shows operation | movement of the conventional radar apparatus. It is a figure for demonstrating the angle measurement of the monopulse system performed with the conventional radar apparatus. It is a figure which shows the beam formed with the conventional radar apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a system diagram showing a configuration of a radar apparatus according to Embodiment 1 of the present invention. The radar apparatus includes an antenna 10, a transceiver 20 and a signal processor 30.

  The antenna 10 is composed of a plurality of subarray elements (hereinafter referred to as a plurality of elements), and the plurality of elements are in order a plurality of antenna reception arrays 12a, an antenna transmission / reception array 11a, an antenna transmission / reception array 11a ', and a plurality of antennas. It is divided into a receiving array 12a '.

  The antenna transmission / reception arrays 11a and 11a ′ convert a transmission signal sent as an electric signal from the transmitter / receiver 20 into a radio wave and send it out. The plurality of antenna reception arrays 12a and 12a ′ receive external radio waves, convert them into electrical signals, and send them to the transceiver 20 as reception signals.

  The transceiver 20 includes a transmitter 21 and a plurality of mixers 22, and the transmitter 21 generates a transmission signal and sends it to the antenna transmission / reception arrays 11 a and 11 a ′ and the plurality of mixers 22. The plurality of mixers 22 frequency-converts the received signals received from the plurality of antenna receiving elements 12 a and 12 ′ according to the signal from the transmitter 21, and sends it to the signal processor 30.

  The signal processor 30 includes an AD converter 31, an FFT unit 32, a DBF unit 33, a beam shaping unit 34, a detection unit 35, a distance measurement / speed measurement unit 36, and an angle measurement unit 37.

  The AD converter 31 converts the analog signal sent from the transceiver 20 into a digital signal, and sends it to the FFT unit 32 as an element signal. The FFT unit 32 converts the element signal sent from the AD converter 31 into an element signal on the frequency axis by fast Fourier transform, and sends it to the DBF unit 33.

  The DBF unit 33 uses the element signal on the frequency axis sent from the FFT unit 32 to form a Σ beam and a Δ beam. The Σ beam formed by the DBF unit 33 is sent to the beam shaping unit 34, and the Δ beam is sent to the angle measuring unit 37.

  The beam shaping unit 34 combines the Σ beams sent from the DBF unit 33 and sends them to the detection unit 35. The detection unit 35 detects the target based on the combined Σ beam sent from the beam shaping unit 34 and sends the detection result to the distance measurement / speed measurement unit 36.

  The distance measurement / speed measurement unit 36 performs distance measurement and speed measurement based on the detection result sent from the detection unit 35. The distance and speed obtained by the distance measurement and speed measurement in the distance measurement / speed measurement unit 36 are output to the outside.

  The angle measuring unit 37 measures the angle based on the Σ beam sent from the DBF unit 33 via the beam shaping unit 34, the detecting unit 35 and the distance measuring / speed measuring unit 36 and the Δ beam sent from the DBF unit 33. I do. The angle obtained by the angle measurement in the angle measuring unit 37 is output to the outside.

  Next, the operation of the radar apparatus according to Embodiment 1 of the present invention configured as described above will be described.

  When the cycle is started, first, a fast Fourier transform (FFT) is performed. That is, a sweep signal whose frequency changes continuously (FM-modulated) is transmitted from the antenna transmission element 11, and the transmitted signals are received by the plurality of antenna reception elements 12. The received signal is frequency-converted by the transmitter / receiver 20 and sent to the AD converter 31 of the signal processor 30.

  The AD converter 31 converts the analog signal sent from the transceiver 20 into a digital signal, and sends it to the FFT unit 32 as an element signal. The FFT unit 32 performs a fast Fourier transform on the element signal sent from the AD converter 31. Thereby, an element signal on the frequency axis is obtained. The element signal on the frequency axis obtained by the FFT unit 32 is sent to the DBF unit 33.

  Next, DBF processing is performed. That is, the DBF unit 33 forms the Σ beam and the Δ beam using the element signal on the frequency axis sent from the FFT unit 32. The Σ beam formed by the DBF unit 33 is sent to the beam shaping unit 34, and the Δ beam is sent to the angle measuring unit 37.

  Next, the Σ absolute value calculation is performed. That is, the beam shaping unit 34 calculates the absolute value of the Σ beam sent from the DBF unit 33. Next, it is checked whether or not the sweep is completed. That is, it is checked whether or not the processing for all sweeps has been completed. If it is determined that the sweep is not finished, the above-described processing is repeated for the next sweep signal.

  On the other hand, if it is determined that the sweep is completed, beam synthesis is performed. In other words, the beam shaping unit 34 forms (synthesizes) the beam by multiplying the calculated absolute value of the Σ beam by a predetermined coefficient and adds it, and sends the beam to the detection unit 35.

  Next, a detection process is performed. That is, the detection unit 35 detects a target based on the combined Σ beam sent from the beam shaping unit 34 and sends the detection result to the distance measurement / speed measurement unit 36. The distance measurement / speed measurement section 36 performs distance measurement and speed measurement based on the detection result sent from the detection section 35, and outputs the distance and speed obtained by the distance measurement and speed measurement to the outside.

  Next, monopulse angle measurement is performed. That is, the angle measuring unit 37 is based on the Σ beam sent from the DBF unit 33 via the beam shaping unit 34, the detecting unit 35 and the distance measuring / speed measuring unit 36 and the Δ beam sent from the DBF unit 33. Monopulse angle measurement (amplitude monopulse angle measurement, phase monopulse angle measurement, squint monopulse angle measurement, etc.) is performed, and the angle obtained by this angle measurement is output to the outside.

  The radar apparatus described above will be further described. Here, an antenna with a small number of channels is considered. In order to form a wide-angle beam, an antenna having a small aperture length is required. On the other hand, an antenna having a large antenna aperture length is necessary to improve the angle measurement accuracy due to the narrow beam width. However, if the number of channels is small, it is difficult to construct an antenna that satisfies both.

  As a countermeasure, the radar apparatus according to the first embodiment of the present invention covers a wide angle by a sub-array having a small number of elements, and covers the beam width of a sub-array having a large number of elements in an angular range of a predetermined angle. The angle measurement accuracy is improved by forming a narrow beam using the entire sub-array.

  As shown in FIG. 2, in a phased array composed of antennas of a plurality of elements (subarrays), a plurality of elements are arranged in order, a plurality of first elements 12a (corresponding to a plurality of antenna reception arrays 12a) and second elements. 11a (corresponding to the antenna transmission / reception array 11a), a third element 11a ′ (corresponding to the antenna transmission / reception array 11a ′), and a plurality of first elements 12a ′ (corresponding to the plurality of antenna reception arrays 12a ′).

  A subarray output obtained by synthesizing a plurality of antenna reception arrays 12a with a power feeding circuit is denoted by e1, a subarray output obtained by synthesizing the antenna transmission / reception array 11a by a power feeding circuit is denoted by e2, and a subarray output obtained by synthesizing the antenna transmission / reception array 11a ′ by a power feeding circuit is denoted by e3. A sub-array output obtained by synthesizing the plurality of antenna reception arrays 12a ′ with a power feeding circuit is denoted by e4.

  First, it is assumed that the observation angle range is θst to θed, and the entire angle range of the observation angle range is covered with the subarray output e2 and the subarray output e3. When the observation angle range is wide, the number of elements corresponding to the subarray output e2 and the subarray output e3 is one element at a time.

The beam shaping unit 34 uses the subarray output e2 and the subarray output e3 to form a beam b1 and a beam b2 that cover the entire observation angle range, as shown in FIG. The beam in the case of phase monopulse angle measurement can be expressed by the following equation. For the phase monopulse method, see IEICE, Revised Radar Technology, pp. 262-264 (1996).

here,
bm (θ); Σ beam output (m = 1 to 2)
e (θ); element pattern (n = 1 to 4)
W (n): complex weight (n = 1 to 4)
n: Element number (n = 1 to 4)
λ; wavelength In the case of phase monopulse angle measurement, the angle can be measured using the Δ beam of the following equation.

here,
Δm (θ); Δ beam output (m = 1 to 2)
en (θ); element pattern W (n); complex weight (n = 1 to N)
n: Element number (n = 1 to N)
λ; wavelength

Using bm and Δm, the error voltage can be expressed by the following equation.

here,
*: Complex conjugate
The angle measurement value θ can be calculated by using a correspondence table (or polynomial approximation value) of ε and the error voltage ε and θ stored in advance.

Next, a method for forming a narrow beam will be considered. First, the beam shaping unit 34 controls the line length of the power feeding circuit of the subarray by the plurality of first elements 12a and the plurality of fourth elements 12a ′, and forms a Σ beam in a predetermined direction θ0 ± Δθ. Next, as shown in FIG. 3B, the beam shaping unit 34 uses the entire elements of the plurality of first elements 12a, the second element 11a, the third element 11a ′, and the plurality of fourth elements 12a ′. , Θ0 ± Δθ, the beam b3 is formed by the following equation using DBF.

In the case of phase monopulse angle measurement, angle measurement can be performed using a Δ beam of the following equation.

here,
bm (θ); Σ beam output (m = 3)
Δm (θ); Δ beam output (m = 3)
en (θ); subarray pattern d (n); position of phase center of subarray
W (n); complex weight (n = 1 to 4)
n: Element number (n = 1 to 4)
λ; wavelength By this, a beam with a narrow beam width can be formed using the entire aperture, and the angle measurement accuracy can be improved. In FIG. 3, the solid line indicates the Σ beam, and the broken line indicates the Δ beam. For simplicity, in Example 1, the number of elements of the plurality of first elements 12a and the number of elements of the plurality of fourth elements 12a ′ are each four, but the number of elements is not limited to four, Other numbers may be used. In the first embodiment, phase monopulse angle measurement has been described. However, as the monopulse angle measurement method, another method such as an amplitude monopulse method may be used.

  As described above, according to the radar apparatus according to the first embodiment, even with a small antenna, the element spacing is narrow and the wide angle is covered by the second element 11a and the third element 11a ′ having a small number of elements, and the number of elements is large. By covering the beam width of the plurality of first elements 12a and the plurality of fourth elements 12a ′ with a predetermined angle and forming a narrow beam using the entire element in the angle range, the angle measurement accuracy is improved. Can be improved.

  In the radar apparatus according to the first embodiment, the directivity directions of the subarray beams of the plurality of first elements and the plurality of fourth elements are controlled by the power feeding circuit. For this reason, the beam directing direction that can be formed by the antenna with the entire aperture is limited to the range of θ0 ± Δθ.

  Further, considering that the beam is formed in a wide range, it is necessary to scan the subarray beam. For this reason, as shown in FIG. 4, the antenna of the radar apparatus according to the second embodiment of the present invention includes a plurality of first elements 14a and a plurality of fourth elements 14a 'formed by snake waveguides. A frequency scan is performed using a waveguide. The remaining configuration of the radar apparatus according to the second embodiment is the same as that of the radar apparatus according to the first embodiment.

  The snake waveguide is composed of a snake line as a feed line in the vertical direction and a slot waveguide 16 as shown in FIG. 6 in the horizontal direction, and the phase of each antenna element 14a is changed by changing the frequency. The beam can be scanned in a varied manner.

The beam scanning by the snake waveguide can be expressed by the following equation.

here,
λg; In-tube wavelength λ; Wavelength λc; Center frequency wavelength ε; Dielectric constant d; Element spacing L; Snake waveguide length
Θp; Direction Direction The beam shaping unit 34 can control the direction of the subarray pattern by frequency scanning using the snake waveguide, as shown in FIG. 5B, and uses the entire element in the beam range of the subarray. Any narrow beam can be formed.

  As described above, according to the radar apparatus according to the second embodiment, even with a small antenna, the element spacing is narrow, the wide angle is covered by the second element 11a and the third element 11a ′ having a small number of elements, and the number of elements is large. The beam widths of the plurality of first elements 14a and the plurality of fourth elements 14a ′ having a predetermined angle are covered with the beam width of the plurality of first elements 14a and the plurality of fourth elements 14a ′. By performing a frequency scan, an angle measurement accuracy can be improved in a wide range by forming a narrow beam using the entire element in a scannable angle range.

  In the radar apparatus according to the first and second embodiments, a beam is formed in the same direction (one direction) by a subarray of a plurality of first elements and a plurality of fourth elements. The radar apparatus according to the third embodiment forms a Σ beam in two directions of a predetermined angle θp1 and θp2, and a Δ beam is formed by a subarray difference between the second element and the third element. . FIG. 7 is a diagram illustrating an antenna of a radar apparatus according to Embodiment 3 of the present invention. FIG. 8 is a diagram showing a wide-angle beam and a narrow-angle beam formed by the antenna according to the third embodiment of the present invention.

  The number of elements 17a and 17a 'shown in FIG. In the first embodiment, four elements are required in one direction, but in the third embodiment, eight elements are required in two directions.

  The beam shaping unit 34 covers the entire observation angle range with the second element 11a and the third element 11a ′, and is centered on the first predetermined range and the second predetermined angle θp2 direction centered on the first predetermined angle θp1 direction. Σ beams b3 and b4 that cover the second predetermined range with the plurality of first elements 17 and the plurality of fourth elements 17a ′ are formed (FIG. 8B), and the second element 11a and the third element 11a ′ are formed. Δ beams Δ1, Δ2 (FIG. 8B) are formed by the difference between the two.

  The angle measuring unit 37 performs phase monopulse angle measurement based on the Δ beam and the Σ beam formed by the beam shaping unit 34.

  As described above, according to the radar apparatus according to the third embodiment, even with a small antenna, the element spacing is narrow and the wide angle is covered by the second element 11a and the third element 11a ′ having a small number of elements, and the number of elements is large. In order to cover the predetermined two directions with the beams of the plurality of first elements 17 and the plurality of fourth elements 17a ′ having a wide angle range, a target in a wide angle range is detected, and in a specific two directions, a Σ of a narrow angle beam width is detected. The angle measurement accuracy can be improved by the phase monopulse by the Δ beam of the beam and the wide angle beam.

  FIG. 9 is a diagram illustrating an antenna of a radar apparatus according to Embodiment 4 of the present invention. FIG. 10 is a diagram showing a wide-angle beam and a narrow-angle beam formed by the antenna according to the fourth embodiment of the present invention.

  As shown in FIG. 9, the radar apparatus according to the fourth embodiment includes a plurality of first elements 18a and a plurality of fourth elements 18a ′ as snake waveguides as shown in FIG. This is characterized in that frequency scanning is performed using this snake waveguide. The remaining configuration of the radar apparatus according to Embodiment 4 is the same as that of the radar apparatus according to Embodiment 3.

  The beam shaping unit 34 can change the directing directions of the Σ beams b3 and b4 by performing frequency sweep using a snake waveguide, as shown in FIG. Δ4 can be formed. Thereby, highly accurate angle measurement can be implemented.

  In the antenna using the snake waveguide shown in FIG. 9, the phase of the antenna surface (wavefront inclination) changes by changing the frequency, so as shown in FIGS. 11B and 11C, The beam direction changes.

  Here, a method for changing the center frequency will be described. In the case of the FMCW system, as shown in FIG. 12, a down sweep signal or an up sweep signal that linearly changes the frequency from a higher (lower) side to a lower (higher) side is used. The down sweep signal or the up sweep is transmitted and received by the transceiver 20. The FFT unit 32 performs FFT on the received signal from the transceiver 20 and converts it to a beat frequency Σ.

  Further, as shown in FIG. 12A, the down sweep signal or the up sweep signal is divided into the first half and the second half, the signs of the first half and the second half are inverted, and the FFT unit 32 performs the FFT to perform FIG. The Δ beam shown in b) is obtained. In the case of the snake waveguide, the Σ beam and the Δ beam correspond to the Σ beam and the Δ beam on the angle axis, so that phase monopulse angle measurement can be performed.

  As described above, according to the radar apparatus according to the fourth embodiment, the effects of the radar apparatus according to the embodiment can be obtained, and the phase monopulse of the Σ beam and the Δ beam having a narrow beam width can be obtained in two specific directions. The angle measurement accuracy can be improved by the beam.

  The present invention can be used in a radar apparatus that measures the direction of a vehicle or the like with high accuracy.

DESCRIPTION OF SYMBOLS 10 Antenna 11a, 11a 'Antenna transmission / reception array 12a, 12a' Antenna reception array 20 Transmitter / receiver 21 Transmitter 22 Mixer 30 Signal processor 31 AD converter 32 FFT part 33 DBF part 34 Beam shaping part 35 Detection part 36 Ranging and speed measurement Part 37 Angle measuring part

Claims (4)

An antenna in which a plurality of elements are sequentially divided into a plurality of first elements, a second element, a third element, and a plurality of fourth elements;
A beam that covers the entire observation angle range with the second element and the third element is formed, and a beam that covers a predetermined range around the predetermined angle with the plurality of first elements and the plurality of fourth elements is formed. And a beam shaping unit that forms a beam in an arbitrary direction within the predetermined range centered on the predetermined angle over the plurality of elements,
An angle measuring unit that performs monopulse angle measurement based on the beam formed by the beam shaping unit;
A radar apparatus comprising: A plurality of elements are sequentially divided into a plurality of first elements, a second element, a third element, and a plurality of fourth elements, and the plurality of first elements and the plurality of fourth elements perform frequency scanning. An antenna composed of a wave tube;
A plurality of first elements formed of the snake waveguide, which forms a beam covering the entire observation angle range with the second element and the third element, and scans a predetermined range centered on a predetermined angle; Forming a beam covered with the plurality of fourth elements, and forming a beam in an arbitrary direction within the predetermined range centered on the predetermined angle with the plurality of elements as a whole; and
An angle measuring unit that performs monopulse angle measurement based on the beam formed by the beam shaping unit;
A radar apparatus comprising: An antenna in which a plurality of elements are sequentially divided into one or more first elements, one or more second elements, one or more third elements, and one or more fourth elements;
The entire observation angle range is covered with the second element and the third element, and the first predetermined range centered on the first predetermined angle and the second predetermined range centered on the second predetermined angle are the first elements. Forming a Σ beam that is covered with the plurality of fourth elements, and forming a Δ beam by the difference between the second element and the third element,
An angle measuring unit that performs phase monopulse angle measurement based on the Δ beam and the Σ beam formed by the beam shaping unit;
A radar apparatus comprising: A plurality of elements are sequentially divided into one or more first elements, one or more second elements, one or more third elements, and one or more fourth elements, and the plurality of first elements and the plurality of fourth elements. An antenna composed of a snake waveguide whose elements are frequency scanned;
The snake guide that covers the entire observation angle range with the second element and the third element, and performs frequency scanning of the first predetermined range centered on the first predetermined angle and the second predetermined range centered on the second predetermined angle. A beam shaping unit that forms a Σ beam that is covered with the plurality of first elements and the plurality of fourth elements each formed of a wave tube;
An angle measuring unit that performs phase monopulse angle measurement based on the Δ beam and the Σ beam formed by the beam shaping unit;
A radar apparatus comprising:

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