JP2008151582A - Radar system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radar system capable of detecting azimuthal angles in a horizontal direction and an elevation direction while preventing the system from increasing in size. <P>SOLUTION: An receiving antenna unit comprises M×N-pieces of antenna elements arranged in a two-dimensional matrix by arranging N-pieces of antenna rows, which each comprises M-pieces of antenna elements arranged in a row at regular intervals along an elevation direction, at regular intervals along a horizontal direction intersecting the elevation direction at right angles. First and second unit antennas formed by grouping the antenna rows have overlapping antenna apertures of the sample size, and the antenna apertures are set at the same positions in the elevation direction and at difference positions in the horizontal direction. By inserting phase-adjusting parts 30a-30h in electric supply lines of the antenna rows in such a way the path lengths of the electric supply lines from an output terminal TLo to each antenna element AE may be different from one another by ΔR, directivity in the elevation direction is adjusted. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radar apparatus that detects an arrival angle of a radar wave, and more particularly, to a radar apparatus that detects an arrival angle in two directions of a horizontal direction and an elevation angle direction.

  In recent years, it has been recognized that securing automobile safety and reducing traffic accident damage is important all over the world, and governments not only in Japan but also in EU countries are making efforts to reduce traffic fatalities by half. . Specifically, pre-crash systems (PCS) such as detecting collisions in advance, alerting the driver, and intervening braking are being actively studied to reduce the collision damage of automobiles.

  In order to detect the collision in advance, information such as the distance, direction, and relative speed between the vehicle and the obstacle is necessary, and millimeter wave radar (hereinafter referred to as “radar device”) suitable for detecting such information. Development is underway.

  By the way, in this type of radar apparatus, for example, an antenna array is formed by arranging a plurality of antenna elements in a line at equal intervals along the elevation direction (vehicle height direction), and this antenna array is formed in the horizontal direction (vehicle width). It is known that a plurality of antenna elements are arranged at equal intervals in the direction) and the antenna elements arranged in a two-dimensional array are used as one antenna.

In addition, in this type of radar apparatus, in order to enable azimuth detection, a plurality of antennas (arrayed antennas) as described above must be prepared.
For example, when it is necessary to detect the azimuth in the horizontal direction, it is necessary to arrange a plurality of antennas side by side along the horizontal direction, and it is also necessary to detect the azimuth in two directions, the horizontal direction and the elevation direction. When there is a plurality of antennas, it is necessary to arrange a plurality of antennas in the elevation direction (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2006-201013 (FIG. 12)

However, in this way, when detecting the orientations in two directions, there is a problem that the space necessary for installing the antenna is two-dimensionally expanded and the apparatus size is increased.
In particular, when the installation space (particularly in the elevation angle direction) is limited as in the on-vehicle radar device, it is difficult to apply a radar device such as the above-described conventional device.

  In order to solve the above-described problems, an object of the present invention is to provide a radar apparatus capable of detecting both azimuth angles in the horizontal direction and the elevation angle direction while suppressing an increase in size of the apparatus.

  In the radar apparatus of the present invention made to achieve the above object, the antenna section is orthogonal to the elevation direction, with an antenna array comprising a plurality of antenna elements arranged at predetermined intervals along a preset elevation angle direction. A plurality of unit antennas are arranged along the horizontal direction, and a plurality of unit antennas having different positions in the horizontal direction are formed by grouping antenna rows. Then, the horizontal direction detecting means detects the arrival angle in the horizontal direction of the radar wave (reflected wave) received by the antenna unit, based on the received signal of each unit antenna constituting the antenna unit.

  In the radar apparatus of the present invention, the phase adjustment means adjusts the phase of the received signal of each antenna element constituting the antenna array so that the directivity in the elevation angle direction of the antenna array constituting the unit antenna is different for each unit antenna. The elevation angle direction detection means detects the arrival angle of the radar wave received by the antenna section in the elevation direction based on the received signal obtained from each unit antenna constituting the antenna section and phase-adjusted by the phase adjustment means. To do.

  That is, as shown in FIG. 10, a radar wave having a wavelength λ coming from an azimuth of an angle θ [rad] with respect to the front surface of the antenna array is generated by an antenna array including a pair of antenna elements AE arranged at a distance d. When received, the path difference ΔR between the radar waves received by both antenna elements AE is expressed by equation (1), and the phase difference Δφ [rad] of both received signals based on this path difference ΔR is expressed by equation (2). Desired.

  In other words, when the reception signals of the pair of antenna elements AE arranged at the interval d are combined after the phase is delayed by Δφ, the antenna array composed of the pair of antenna elements AE is expressed by equation (3). The directivity is such that the sensitivity becomes maximum with respect to the radar wave coming from the azimuth of the angle θ calculated from. Note that equation (3) is a variation of equation (2).

  That is, by adjusting the phase of the received signal of each antenna element AE constituting the antenna array, the directivity in the array direction of the antenna elements AE constituting the antenna array (and hence the elevation angle direction of the unit antennas) can be arbitrarily set. Can do. Therefore, the directivity in the elevation direction can be made different for each unit antenna, and the arrival angle in the elevation direction can be obtained from the difference in the intensity of the received signal appearing between the unit antennas based on the difference in directivity. is there.

  As described above, in the radar apparatus of the present invention, the unit antennas need to be arranged so that the positions of the unit antennas are different from each other in the horizontal direction as in the conventional apparatus, but are different from each other in the elevation direction. There is no.

  Therefore, according to the radar apparatus of the present invention, compared with a radar apparatus that detects only the arrival angle in one direction (horizontal direction), the apparatus scale (especially the size in the elevation angle direction) is not increased and the two directions (horizontal direction) are increased. Direction, elevation angle direction) can be detected.

  In other words, it is possible to simply configure a radar apparatus that can detect the arrival angle in two directions by using the antenna unit used in the radar apparatus that detects only the arrival angle in one direction.

  Further, since the radar apparatus of the present invention can detect an object in a wide range in the elevation angle direction, high accuracy is not required for positioning in the elevation direction when the radar apparatus is attached to a vehicle or the like, and the installation work is simplified. Can be done.

  By the way, the phase adjusting means is, for example, a feed line in which the physical path length to each antenna element constituting the antenna array is set to be different by a certain length shorter than the wavelength of the radar wave according to the arrangement order in the elevation angle direction. It may be comprised.

  In this case, as a method of adjusting the phase of the received signal of each antenna element, the path length is ΔR = λg × Δφ / 2π, where Δφ [rad] is the magnitude of the phase to be adjusted, λg is the in-line wavelength of the received signal. It may be set differently.

  In addition, the phase adjusting unit is, for example, a feed line that is set such that the electrical path length to each antenna element constituting the antenna array is different by a certain length shorter than the wavelength of the radar wave according to the arrangement order in the elevation angle direction. It may be.

  Specifically, the feed line is configured so that the physical path length is constant for each antenna element constituting the antenna array, and on the wiring board forming the feed line, the other parts What is necessary is just to comprise so that the electrical path length of a feeder line may be adjusted by providing the adjustment part from which a dielectric constant differs.

  In other words, even for signals of the same frequency, the in-line wavelength differs depending on the dielectric constant of the substrate, so the dielectric constant of the adjustment part and the length wired to the adjustment part should be set appropriately. Thus, the electrical path length can be arbitrarily adjusted.

In particular, when the adjustment part is made of a substance capable of controlling the dielectric constant, a control unit that variably controls the dielectric constant of the adjustment part may be provided.
In this case, the directivity (beam direction) of each unit antenna can be arbitrarily changed by controlling the dielectric constant of the adjustment portion by the control means, and thus can be used in a wider range of applications.

  By the way, when the radar apparatus of the present invention includes A / D conversion means for individually A / D converting received signals from the respective antenna elements constituting the antenna array, the phase adjustment means includes an A / D conversion section. The phase of the received signal of each antenna element may be adjusted by correcting the received data that has been A / D converted in step 1 by arithmetic processing.

  In this case, the phase of the received signal and thus the directivity in the elevation angle direction of each unit antenna can be arbitrarily set only by the received data calculation process, so that the device configuration can be simplified.

  The A / D conversion means may be provided individually for each antenna element, but switching means for sequentially selecting any one of the antenna elements constituting the antenna array and supplying it to the A / D conversion means. By providing, A / D conversion means is provided for each antenna array, and the A / D conversion means may be configured to A / D convert received signals from each antenna element constituting the antenna array by time division operation. Good.

In this case, the scale of the A / D conversion means can be greatly reduced as compared with the case where the A / D conversion means is provided for each antenna element.
In the radar apparatus according to the present invention, the elevation angle direction detection means may be, for example, an arrival angle in the elevation direction based on an intensity difference or an intensity ratio of signal components based on reflected waves from the same object detected for each unit antenna. May be configured to detect.

  That is, if the directivity in the elevation direction is different for each unit antenna, as shown in FIG. 4, the intensity of the signal component detected by these plural (two in the figure) unit antennas for the same object is Since they are different from each other, the arrival direction of the radar wave can be specified from the intensity difference and the intensity ratio.

  In the radar apparatus of the present invention, when the antenna unit includes a transmission antenna in addition to the unit antenna, the horizontal beam width of the transmission antenna is wider than the combined width of all unit antennas. It is desirable to be set as follows.

  In this case, the characteristics of the reception signal of each unit antenna in the elevation angle direction do not fluctuate greatly according to the arrival angle in the horizontal direction, so that the processing of the reception signal can be simplified.

In the radar apparatus of the present invention, it is desirable that the antenna unit is set so that the antenna openings of the plurality of unit antennas overlap each other.
Such a setting can be realized, for example, by configuring separate unit antennas for even-numbered antenna rows and odd-numbered antenna rows.

  In this case, the size of the antenna unit in the horizontal direction can be reduced, and the device can be further downsized. Further, it is possible to form more unit antennas having a large antenna opening in a limited installation space, and as a result, it is possible to improve both the detection accuracy of the arrival angle in the horizontal direction and the vertical direction.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
<Overall configuration of radar device>
FIG. 1 is a block diagram showing the overall configuration of the radar apparatus 1 of the present embodiment.

  The radar device 1 is mounted on a vehicle and detects the position (relative distance, azimuth in the horizontal direction and elevation direction) and relative speed of an object (preceding vehicle or obstacle) existing in front of the vehicle. .

  As shown in FIG. 1, the radar apparatus 1 oscillates at a frequency in the millimeter wave band and generates a signal that is frequency-modulated so that the frequency changes in a triangular wave shape, and distributes power to the output of the oscillator 11. The power distributor 12 that generates the transmission signal Ss and the local signal L, the transmission antenna 13 that transmits the radar wave according to the transmission signal Ss from the power distributor 12, and the object that reflects the radar wave transmitted from the transmission antenna 13 Receiving antenna unit 14 that receives the reflected wave from and outputs two systems of received signals R1 and R2, and is provided for each received signal Ri (i = 1, 2), and based on received signal Ri and local signal L The reception processing unit 15 that generates the reception data Di and the oscillator 11 are activated, and the position of the object is determined based on the reception data D1 and D2 obtained from each reception processing unit 15 during the operation of the oscillator 11. Microcomputer that executes a process of obtaining a and the relative velocity and a (hereinafter referred to as "microcomputer") 17.

The reception processing unit 15 includes a mixer 21 that generates a beat signal by mixing the local signal L with the reception signal Ri, a filter that removes unnecessary signal components from the output of the mixer 21, and an amplifier that amplifies the output of the filter. And an AD converter 25 that generates received data Di by sampling the output of the IF circuit 23.
<Configuration of transmitting antenna and receiving antenna section>
FIG. 2 is an explanatory diagram schematically showing the configuration of the transmission antenna 13 and the reception antenna unit 14.

  As shown in FIG. 2, the transmission antenna 13 includes P (P = 6 in the drawing) antenna elements AE arranged in a line at equal intervals along the elevation direction (vertical direction in the figure). In addition, the feed lines that feed power to the antenna elements AE constituting the transmission antenna 13 are configured such that the physical path lengths are all the same length (not shown).

  On the other hand, the receiving antenna unit 14 moves the antenna array AL composed of M (M = 8 in the drawing) antenna elements AE arranged in a line at equal intervals along the elevation direction in a horizontal direction ( By arranging N (N = 8 in the drawing) at equal intervals along the horizontal direction in the figure, the antenna element AE includes M × N antenna elements AE arranged in a two-dimensional matrix.

  However, each antenna array AL is numbered according to the arrangement order in the horizontal direction, and the array antenna formed by the odd-numbered antenna arrays AL1, AL3, AL5,... Is the first unit antenna AF1, and the even-numbered antenna array. The array antenna formed by AL2, AL4, AL6,... Is called a second unit antenna AF2.

  That is, the first and second unit antennas AF1 and AF2 have antenna openings of the same size that overlap each other, and the antenna openings are set so that the positions in the elevation direction are the same and the positions in the horizontal direction are different. Yes.

  The reception antenna unit 14 outputs a reception signal of the first unit antenna AF1 (that is, a combination of reception signals from the respective antenna arrays AL1, AL3, AL5,... Constituting the first unit antenna AF1) R1. A first output terminal T1 and a second reception signal of the second unit antenna AF2 (that is, a combination of reception signals at the respective antenna arrays AL2, AL4, AL6,... Constituting the second unit antenna AF2) R2 is output. An output terminal T2 is provided.

  And the physical of the feed line from the output terminal TLo (TL1o, TL3o, TL5o,...) Of each antenna array AL (AL1, AL3, AL5,...) Constituting the first unit antenna AF1 to the first output terminal T1. Each of the path lengths is configured to have the same length. Similarly, the output terminals TLo (TL2o, TL4o, TL6o, TL6o, TL6o) of the respective antenna arrays AL (AL2, AL4, AL6,...) Constituting the second unit antenna AF2 are configured. ...) to the first output terminal T1, the physical path length of the feed line is configured to be the same.

  That is, the directivity in the horizontal direction (arrangement direction of the antenna array AL) of the first and second unit antennas AF1 and AF2 has the maximum beam intensity in the front direction, and the horizontal beam width is the same as that of the transmitting antenna 13. It is set to be smaller than the beam width in the horizontal direction. However, here, the horizontal beam width of the transmission antenna 13 is set to be wider than the horizontal width of the region occupied by the beams of the first and second unit antennas AF1 and AF2.

Further, the number of antenna elements AE constituting the transmission antenna 13 is smaller than the number of antenna elements AE constituting the antenna array AL of the reception antenna unit 14, and the size of the antenna opening in the elevation direction is smaller in the transmission antenna 13. That is, with respect to the directivity in the elevation angle direction, the beam width of the transmission antenna 13 is wider than the antenna array AL (and thus the first and second unit antennas AL1 and AL2) of the reception antenna unit 14.
<Configuration of feed line in each antenna array>
Here, FIG. 3A is an explanatory diagram schematically showing the configuration of the feed line from the antenna element AE to the antenna array output terminal TLo in each antenna array AL constituting the first unit antenna AF1. (B) is an explanatory view schematically showing the configuration of the feed line from the antenna element AE to the antenna array output terminal TLo in the antenna array AL constituting the second unit antenna AF2.

  As shown in FIGS. 3A and 3B, each antenna element AE constituting the antenna array AL is connected to a phase adjusting unit 30 (30a to 30h), and an output terminal of the antenna array AL. The physical path length of the feed line from TLo to each phase adjustment unit 30 is set to be the same length.

  The phase adjustment units 30a to 30h are composed of feed lines having different path lengths by ΔR, and the phase adjustment unit 30a is the shortest, and is configured to be longer in the order of 30b, 30c,.

  In the antenna array AL constituting the first unit antenna AF1, as shown in FIG. 2A, the phase adjustment unit 30a having the shortest path length is provided with respect to the antenna element AE positioned at the uppermost position in the elevation angle direction. The phase adjustment unit 30h having the longest path length is connected to the antenna element AE that is connected and located at the lowest position in the elevation angle direction, and the path that is located on the lower side with respect to the antenna element AE between them is routed. A long phase adjustment unit 30 is connected.

  Further, in the antenna array AL constituting the second unit antenna AF2, as shown in FIG. 2B, the phase adjustment unit 30a having the shortest path length with respect to the antenna element AE positioned at the lowest position in the elevation angle direction is provided. The phase adjustment unit 30h having the longest path length is connected to the antenna element AE that is connected and located at the uppermost position in the elevation angle direction. A long phase adjustment unit 30 is connected.

  That is, in the antenna array AL constituting the first unit antenna AF1, the reception signal of each antenna element AE is received from the antenna element AE adjacent to the upper side with reference to the reception signal of the antenna element AE positioned at the uppermost position in the elevation angle direction. The received signal is synthesized after being delayed by a phase difference Δφ (see equation (2)) corresponding to the path difference ΔR. Similarly, in the antenna array AL constituting the second unit antenna AF2, the received signal of each antenna element AE is based on the received signal of the antenna element AE located at the lowermost position in the elevation angle direction, and the antenna element AE adjacent to the lower side thereof. The received signal is synthesized after being delayed by a phase difference Δφ (see equation (2)) corresponding to the path difference ΔR.

  As a result, as shown in FIG. 4, the directivity in the elevation direction of each antenna array AL that constitutes the first unit antenna AF1, and thus the first unit antenna AF1, has a maximum beam intensity at an angle −θ downward from the front direction. Thus, the directivity in the elevation direction of each antenna array AL constituting the second unit antenna AF2 and thus the second unit antenna AF2 has a maximum beam intensity at an angle + θ upward from the front direction.

  However, the angle θ is obtained using the equation (3). For example, when λ = d = 4 [mm], if Δφ = 31 [deg], θ = 5 [deg], Δφ = If it is 12 [deg], θ = 2 [deg].

The transmitting antenna 13 and the receiving antenna unit 14 are formed on the single wiring board together with the feed line. However, the transmission antenna 13 and the reception antenna unit 14 may be formed on separate wiring boards.
<Processing by microcomputer>
In the microcomputer 17, the received data D1, which is obtained by sampling the beat signals generated from the received signals R1, R2 from the first and second unit antennas AF1, AF2 having different horizontal positions and different elevation directions. Each D2 is subjected to FFT processing.

  As a so-called FMCW radar, the signal component based on the reflected wave from the object that reflected the radar wave is extracted from the result of the FFT process, and the distance and relative velocity with the object specified from the signal component are obtained. Execute the process.

  Further, the microcomputer 17 extracts signal components based on the same object from the FFT result based on the reception data D1 and the FFT result based on the reception data D2, and uses information such as a phase difference between the two signal components. Using a known high resolution algorithm such as beam forming or MUSIC, processing as horizontal direction detecting means for calculating the arrival angle of the reflected wave in the horizontal direction is executed.

  Further, the microcomputer 17 obtains an intensity difference or intensity ratio of signal components based on the same object extracted from the FFT result based on the reception data D1 and the FFT result based on the reception data D2, and is shown in the graph shown in FIG. Based on a table created by using the relationship (indicating the correspondence between the intensity difference or intensity ratio and the direction of the elevation angle), and the elevation angle for determining the arrival angle in the elevation angle direction from the obtained intensity difference or intensity ratio Processing as direction detecting means is executed.

Since the transmission beam of the transmission antenna 13 is configured to include the entire reception beam of the first and second unit antennas AF1 and AF2, the directivity in the elevation direction of the first and second unit antennas AF1 and AF2 is set. Does not change greatly depending on the horizontal arrival angle of the reflected wave.
<Effect>
As described above, in the radar apparatus 1, the receiving antenna unit 14 arranges a plurality of antenna arrays AL composed of a plurality of antenna elements AE arranged in a line at equal intervals along the elevation angle direction along the horizontal direction. The odd-numbered antenna arrays AL1, AL3, AL5,... Constitute the first unit antenna AF1, and the even-numbered antenna arrays AL2, AL4, AL6,.

  Moreover, by providing the phase adjustment units 30a to 30h in the path of the feed line from the antenna array output terminal TLo to each antenna element AE and adjusting the path length, the antenna array AL constituting the first unit antenna AF1; The antenna array AL that constitutes the second unit antenna AF2 has different elevation directivity.

  That is, in the radar apparatus 1, the unit antennas AF1 and AF2 need to be arranged so that the positions in the horizontal direction are different from each other as in the conventional apparatus, but the positions are different in the elevation direction. There is no.

  Therefore, according to the radar device 1, the arrival angle in two directions (horizontal direction and elevation direction) can be increased without increasing the device scale as compared with a radar device that detects only the arrival angle in one direction (horizontal direction). Can be detected.

  In other words, it is possible to simply configure a radar apparatus that can detect the arrival angle in two directions by using the antenna unit used in the radar apparatus that detects only the arrival angle in one direction.

  Further, according to the radar device 1, since the object can be detected in a wide range not only in the horizontal direction but also in the elevation angle direction, the positioning in the elevation angle direction when attaching the radar device 1 to a vehicle or the like has high accuracy. It is not necessary and can be easily attached.

In this case, how much the normal direction of the opening surfaces of the transmission antenna 13 and the first and second unit antennas AF1 and AF2 is deviated with respect to the axle of the vehicle to which the radar apparatus 1 is attached is determined as an attachment error (elevation angle direction). ([Alpha] [deg.], [Beta] [deg.] In the horizontal direction) is measured in advance and stored in the microcomputer 17, and the microcomputer 17 may be configured to correct the orientation detection result based on the mounting error. For example, an electronic level may be used for measuring the mounting error α ° in the elevation angle direction, or a sensor that detects the posture of the vehicle with respect to the road surface may be used.
<Modification>
In the present embodiment, the phase adjustment unit 30 is provided for each antenna element AE. However, for example, as illustrated in FIG. 5, the phase adjustment unit 30 may be provided on one side every time the feed line branches. However, in this case, the path length adjusted by each phase adjusting unit 30 needs to be set to be ½ of the path length adjusted by the preceding phase adjusting unit 30. In FIG. 5, the phase adjustment unit 30 d (adjustment path length: 4 × ΔR) is used for the first stage branch near the antenna array output terminal TLo, and the phase adjustment unit 30 b is used for the second stage branch. (Adjustment path length: 2 × ΔR) is used, and the phase adjustment unit 30a (Adjustment path length: ΔR) is used in the third branch.

In this embodiment, one reception processing unit 15 is provided for each reception signal Ri. However, only one reception processing unit 15 is provided, and any one of the reception signals Ri is provided to the single reception processing unit 15. Alternatively, the reception processing unit 15 may be configured to process the reception signal Ri that is time-division multiplexed by the switch by providing a switch that alternately supplies the switch.
[Second Embodiment]
Next, a second embodiment will be described.

  In the present embodiment, since the configuration of the feeding path from each antenna element AE constituting the antenna array AL to the output terminal TLo of the antenna array AL is different from that of the first embodiment, the different parts are The explanation is centered.

  That is, in the present embodiment, as shown in FIG. 6, in the antenna array AL constituting the unit antenna AF (AF1, AF2), power is supplied to each antenna element AE other than the antenna element AE located at the uppermost position in the elevation angle direction. Phase adjusting portions 31b to 31h having a dielectric constant of the wiring board different from those of other portions are provided on the line.

  The phase adjusters 31b to 31h are adjusted in length so that the electrical path lengths are different by ΔR, the phase adjuster 30b is the shortest, and the lengths are 30c, 30d,. It is comprised so that it may become.

  That is, if the dielectric constant of the phase adjustment unit 31 (31b to 31h) is lower than the dielectric constant of other parts, the reception signal that has passed through the phase adjustment unit 31 is compared with the reception signal that does not pass through the phase adjustment unit 31. As a result, the directivity in the elevation angle direction of the unit antenna AF is maximized at an angle downward from the front direction.

  On the contrary, if the dielectric constant of the phase adjustment unit 31 is higher than the dielectric constant of the other part, the reception signal that has passed through the phase adjustment unit 31 has the length compared to the reception signal that does not pass through the phase adjustment unit 31. As a result, the phase advances by the corresponding amount, and as a result, the directivity in the elevation angle direction of the unit antenna AF is maximized at an angle upward from the front direction.

  Then, by appropriately selecting the dielectric constant, insertion position, and insertion size of the phase adjustment unit 31, the directivity in the elevation direction of the first and second unit antennas AF1 and AF2 is on the one hand at an angle downward from the front direction. The beam intensity is maximized, and on the other hand, the beam intensity is maximized at an angle upward from the front direction.

The radar apparatus 1 of the present embodiment configured as described above can obtain the same effects as those of the first embodiment.
<Modification>
In the present embodiment, the phase is adjusted according to the size of the phase adjustment unit 31, but as shown in FIG. 7, a substance whose dielectric constant can be controlled by an applied voltage instead of the phase adjustment unit 31 (31 b to 31 h). And a dielectric constant control circuit 33 for generating an applied voltage to each phase adjusting unit 32 and controlling the applied voltage, thereby providing each antenna element AE by providing a variable phase adjusting unit 32 (32b to 32h). You may comprise so that the phase of the received signal from may be controlled.

In this case, the directivity in the elevation direction of each unit antenna AF1, AF2 can be arbitrarily set.
[Third Embodiment]
Next, a third embodiment will be described.

Note that the radar apparatus 3 of the present embodiment differs from the radar apparatus 1 of the first embodiment only in a part of the configuration and a part of the processing in the microcomputer. Therefore, the description will be omitted, and the description will be focused on the different parts.
<Overall configuration>
In the first embodiment, the reception antenna unit 14 outputs the reception signals R1 and R2 for each of the unit antennas AF1 and AF2, and the reception processing unit 15 is provided for each of the reception signals R1 and R2. In the present embodiment, 8, the reception antenna unit 14 outputs reception signals R1 to R8 for each antenna array AL, and a reception processing unit 15 is provided for each of the reception signals R1 to R8, and is obtained from each reception processing unit 15. Based on the received data D1 to D8 for each antenna array, the microcomputer 17 is configured to execute beam formation of the unit antennas AF1 and AF2 by arithmetic processing.
<Configuration of receiving antenna section>
Here, FIG. 9 is an explanatory diagram schematically showing the configuration of the feed line from the antenna element AE in each antenna array AL to the output terminal TLo of the antenna array AL.

  As shown in FIG. 3, each antenna element AE constituting the antenna array AL is connected to a switch 34 (34a to 34h), and a feed line extending from the antenna array output terminal TLo to each switch 30 is connected. The route lengths are set to be the same length.

In addition, multiple switches 34a to 34h provided in each antenna element AE are turned on in turn so that the received signals of the antenna elements AE are time-division multiplexed from the output terminal TLo. A switch switching control unit 35 is provided to control so that a signal is output.
<Processing by microcomputer>
The following processing is executed for each of the reception data Dj (j = 1, 2,..., 8) generated by the reception processing unit 15 based on the multiplexed reception signal that is time-division multiplexed.

  First, the reception data Dj is separated into reception data for each antenna element AE, and the phase of the reception signal for each antenna element AE represented by each separated reception data (hereinafter referred to as “element reception data”) is shifted by Δφ. The reception data for each antenna array AL (hereinafter referred to as “column reception data”) is generated by correcting and adding the element reception data so as to be the same.

  It should be noted that the phase Δφ used for correcting the element reception data is different between the antenna array AL constituting the first unit antenna AF1 and the antenna array AL constituting the second unit antenna AF2.

  Next, for each unit antenna AF (AF1, AF2), the reception data for each unit antenna AF is generated by adding the column reception data of each antenna column AL belonging to that unit antenna AF.

In the following processing, the same processing as in the first embodiment is executed using the generated reception data for each unit antenna AF.
<Effect>
In the radar apparatus 3 configured as described above, the directivity in the elevation angle direction of the unit antenna AF is made different for each unit antenna AF by adjusting the phase of the received signal. The same effect as that of the radar apparatus 1 of the embodiment can be obtained.

Moreover, in the radar apparatus 3, the setting of the directivity in the elevation angle direction (beam formation) of the antenna array AL, and hence the unit antenna AF, is appropriately adjusted to the phase difference Δφ used when generating the column reception data from the element reception data. Therefore, the beam directivity (beam direction) in the elevation angle direction can be arbitrarily set, and the directivity can be easily changed.
<Modification>
In the present embodiment, a switch 34 is provided for each antenna element AE constituting the antenna array AL, and a signal obtained by time-division multiplexing the received signal of each antenna element AE is processed by the reception processing unit 15 for each antenna array AL. In this configuration, the switch 34 is omitted, and a reception processing unit 15 is provided for each antenna element, and the reception data obtained by sampling the reception signal for each antenna element AE obtained from each reception processing unit 15 is obtained. Based on this, the above-described processing may be executed.
[Other Embodiments]
In the above embodiment, the case where the number of unit antennas is two has been described, but the number of unit antennas may be three or more.

1 is a block diagram showing an overall configuration of a radar apparatus according to a first embodiment. Explanatory drawing which shows the structure (arrangement | positioning of an antenna element) of a transmission antenna and a receiving antenna part. Explanatory drawing which showed typically the structure of the feed line in an antenna row | line | column. The graph which shows the directivity of the 1st and 2nd unit antenna which comprises a receiving antenna part. Explanatory drawing which shows the modification of the structure of the feed line in an antenna row | line | column. Explanatory drawing which showed typically the structure of the feed line in the antenna row | line | column of 2nd Embodiment. Explanatory drawing which shows the modification of 2nd Embodiment. The block diagram which shows the whole structure of the radar apparatus of 3rd Embodiment. Explanatory drawing which shows the structure of the feed line in the antenna row | line | column of 3rd Embodiment. Explanatory drawing which shows the relationship between the delay of a received signal, and directivity.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,3 ... Radar apparatus 11 ... Oscillator 12 ... Power divider 13 ... Transmission antenna 14 ... Reception antenna part 15 ... Reception processing part 17 ... Microcomputer (microcomputer) 21 ... Mixer 23 ... IF circuit 25 ... AD converter 30,31 , ... Phase adjustment section 32 ... Variable phase adjustment section 33 ... Dielectric constant control circuit 34 ... Switch 35 ... Switch switching control section AE ... Antenna element AF ... Unit antenna AL ... Antenna array

Claims (10)

A plurality of antenna arrays composed of a plurality of antenna elements arranged at regular intervals along a preset elevation angle direction are arranged along a horizontal direction orthogonal to the elevation angle direction, and the antenna arrays are grouped. And an antenna unit that forms a plurality of unit antennas whose horizontal positions are different from each other;
A horizontal direction detecting means for detecting an arrival angle in a horizontal direction of a radar wave received by the antenna unit based on a reception signal of each unit antenna constituting the antenna unit;
In a radar apparatus equipped with
Phase adjustment means for adjusting the phase of the received signal of each antenna element constituting the antenna row so that the directivity in the elevation angle direction of the antenna row constituting the unit antenna differs for each unit antenna;
Elevation angle direction detection means for detecting the arrival angle of the radar wave received by the antenna section in the elevation angle direction based on the received signal obtained from each unit antenna constituting the antenna section and phase-adjusted by the phase adjustment means; ,
A radar apparatus comprising: The phase adjusting means is
The physical path length to each antenna element constituting the antenna array is composed of a feed line set so as to be different by a certain length shorter than the wavelength of the radar wave according to the arrangement order in the elevation angle direction. The radar apparatus according to claim 1. The phase adjusting means is
The electrical path length to each antenna element constituting the antenna array is composed of a feed line that is set to be different by a certain length shorter than the wavelength of the radar wave according to the arrangement order in the elevation angle direction. The radar apparatus according to claim 1. The feed line is configured so that a physical path length is constant for each antenna element constituting the antenna row,
4. The electrical path length of the feed line is adjusted by providing an adjustment portion having a dielectric constant different from that of other portions on a wiring board forming the feed line. The radar apparatus described. The adjustment part is made of a substance capable of controlling the dielectric constant,
The radar apparatus according to claim 4, further comprising a control unit that variably controls a dielectric constant of the adjustment portion. A / D conversion means for individually A / D converting received signals from each antenna element constituting the antenna array,
2. The phase adjusting means adjusts the phase of the received signal of each antenna element by correcting the received data A / D converted by the A / D converting means by arithmetic processing. The radar device described in 1. For each of the antenna arrays, switching means is provided that sequentially selects any one of the antenna elements constituting the antenna array and supplies the A / D conversion means,
The radar apparatus according to claim 6, wherein the A / D conversion unit performs A / D conversion on a reception signal from each antenna element constituting the antenna array by a time division operation.   The elevation angle direction detecting means detects an arrival angle in the elevation angle direction based on an intensity difference or an intensity ratio of signal components based on a reflected wave from the same object detected for each unit antenna. The radar device according to any one of claims 1 to 7. The antenna unit includes a transmission antenna separately from the unit antenna,
9. The beam width in the horizontal direction and the elevation angle direction of the transmitting antenna is set to be wider than the combined width of all unit antenna beams. The radar apparatus described.   The radar apparatus according to claim 1, wherein the antenna unit is set so that antenna openings of the plurality of unit antennas overlap each other.

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