JP2005164281A - Beam scanning method, and radar system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a beam scanning method capable of restraining interference of a transceiving beam, and capable of shortening a data rate of electron scan as to an azimuth direction. <P>SOLUTION: This method/system is constituted of a pulse signal generating step for generating a radar pulse signal, a pulse signal synchronization step for synchronizing transmission timing of the radar pulse signal, a transceiving beam formation step for transmitting the radar pulse signal from two antenna faces and for forming two transceiving beams of the same elevation angle concurrently, and a beam scan control step for electron-scanning a prescribed important monitoring azimuth range by one transceiving beam, and for electron-scanning an azimuth range outside the important monitoring azimuth range by another transceiving beam. The beam scan control step is a step for starting the beam formation by switching to the another antenna face, when finishing the beam formation outside the important monitoring azimuth range by the one antenna face, during a beam formation period within the important monitoring azimuth range. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a beam scanning method and a radar apparatus. More specifically, the present invention relates to a radar apparatus that simultaneously forms two or more transmission / reception beams by phased array antennas provided in different directions and performs electronic scanning of the transmission / reception beams. Regarding improvements.

  In the case of a radar apparatus that electronically scans all directions by a fixed phased array antenna (hereinafter referred to as an array antenna), at least three array antennas provided in different directions are required. In this case, if a transmission / reception beam is formed by the antenna surface of each array antenna and electronic scanning is performed simultaneously, the scanning time for all directions can be shortened.

  18 (a) and 18 (b) are diagrams schematically showing a conventional radar device. FIG. 18 (a) shows an appearance during electronic scanning, and FIG. A cross section is shown. This radar device is a fixed radar composed of three array antennas, and monitors a target in the air. Each array antenna is installed in a different direction in a horizontal plane, and a transmission / reception beam can be simultaneously formed by each antenna surface. By electronically scanning the three transmission / reception beams formed at the same time in the elevation angle and the azimuth direction, the three different monitoring coverages corresponding to the respective antenna surfaces are simultaneously scanned, so that all directions can be monitored.

  19 (a) and 19 (b) are diagrams showing electronic scanning by the radar apparatus of FIG. 18, and FIG. 19 (a) shows an operating state for each of the antenna surfaces 201 to 203. FIG. In b), the state of transmission / reception beam formation for each beam orientation is shown for each elapsed time. The antenna surfaces 201 to 203 are arranged so that all directions are equally divided into three, and the scanning range in the azimuth direction of the transmitted and received beams 101 to 103 is such that the beam 101 of the antenna surface 201 is 0 ° to 120 °. Until now, the beam 102 on the antenna surface 202 is from 120 ° to 240 °, and the beam 103 on the antenna surface 203 is from 240 ° to 360 °. The beams 101 to 103 are simultaneously formed by the antenna surfaces 201 to 203, and are sequentially scanned in different beam directing directions while electronically scanning in the elevation direction, so that all directions can be sequentially scanned by one transmission / reception beam. In comparison, the time required to scan all directions, that is, the data rate can be shortened.

  20 (a) and 20 (b) are diagrams showing another example of electronic scanning by the radar device of FIG. 18. In FIG. 20 (a), electronic scanning is sequentially performed by each antenna surface 201-203. FIG. 20B shows the state of transmission / reception beam formation for each beam directing direction for each elapsed time. In this example, a transmission / reception beam is formed by one of the three antenna surfaces 201 to 203, and when electronic scanning by the antenna surface is completed in the azimuth direction, switching to another antenna surface is started and electronic scanning is started. The When the data rate in this case is T, if the beam forming period, that is, the number of hits per unit time is the same, the electronic scanning data rate in FIG. 19 is T / 3, and the scanning time for all directions is as follows. Is shortened.

  In the conventional beam scanning method as described above in which a plurality of transmission / reception beams are simultaneously formed, there is a problem in that transmission signals from other antenna surfaces are mixed with reception signals from one antenna surface, resulting in interference of transmission / reception beams. It was.

  FIG. 21 is a diagram showing a transmission / reception pattern of transmission / reception beams formed by the radar apparatus of FIG. The transmission / reception beam is formed by the radar pulse signal 110 transmitted from the antenna surfaces 201 to 203, and the transmission / reception pattern 111 alternately repeats the transmission period A1 corresponding to the pulse width and the reception period. This reception period is A2-A1, where the pulse repetition period is A2.

  FIG. 22 is a diagram showing a transmission / reception pattern for each antenna surface in the electronic scanning of FIG. Even if the transmission / reception pattern 111 of the transmission / reception beams simultaneously formed by the antenna surfaces 201 to 203 is the same, the transmission of the radar pulse signal 110 is performed for each of the antenna surfaces 201 to 203. Deviation in timing occurs. For this reason, interference of transmission and reception beams occurs between the antenna surfaces 201 to 203. For example, a part of the transmission period in the transmission / reception pattern 111 of the transmission / reception beam (beam directing direction 120 ° + a) formed by the antenna surface 202 is in the transmission / reception pattern 111 of the transmission / reception beam (beam directing direction a) formed by the antenna surface 201. Since it overlaps with the reception period, the antenna surface 201 is in the reception state when the antenna surface 202 is in the transmission state during this overlap period, and the transmission signal from the antenna surface 202 is mixed into the reception signal by the antenna surface 201 and interference occurs. End up.

  In order to prevent interference in such a transmission / reception beam, a radar apparatus has been proposed in which the frequency of a radar pulse signal to be transmitted is different for each antenna surface (for example, Patent Document 1). In this radar apparatus, the frequency (band) of the radar pulse signal transmitted from the antenna surface is different for each antenna surface, and the frequency band is not overlapped between the antenna surfaces.

23 and 24 are diagrams showing electronic scanning in a conventional radar apparatus. FIG. 23 shows transmission / reception patterns of beams 101 and 102 formed at different transmission frequencies for each antenna surface. The details of the main part are shown. The beams 101 and 102 that are simultaneously formed as transmission and reception beams have different center frequencies f ₁ and f _{2 and} have a frequency band that does not overlap between the beams. For this reason, even if the transmission period and the reception period overlap between the antenna surfaces, the frequency is different, so that interference of transmission and reception beams can be suppressed.

  However, since it is not easy to sufficiently remove frequency components outside the pass band by using a band pass filter or the like, there is a problem that interference occurs between the antenna surfaces in the transmission and reception beams.

  Therefore, in order to prevent interference in the transmission / reception beam, it is conceivable to perform electronic scanning by synchronizing the transmission timing of the radar pulse signal to be transmitted between the antenna surfaces.

  25 (a) and 25 (b) are diagrams showing an example of electronic scanning by the radar device. FIG. 25 (a) shows an operation state for each of the antenna surfaces 201 to 203, and FIG. ) Shows a transmission / reception pattern in the formed transmission / reception beam for each of the antenna surfaces 201 to 203. Since the transmission timing of the radar pulse signal is synchronized between the antenna surfaces, it is possible to avoid the transmission period and the reception period in the transmission / reception pattern from overlapping between the antenna surfaces. For this reason, even if the frequency band of a transmission / reception beam is the same between antenna surfaces, interference of the transmission / reception beam can be prevented.

  Usually, the transmission / reception pattern in the transmission / reception beam differs depending on the elevation angle of the transmission / reception beam to be formed in order to obtain a gain corresponding to the coverage area for electronic scanning. In addition, by making the beam forming period in a specific azimuth range longer than other azimuth ranges, the number of hits in a specific azimuth range is increased, and the coverage in this azimuth range, that is, the detection distance, is extended and focused. Scanning is performed. In such a case, the beam scanning method described above has a problem that when a plurality of transmission / reception beams are simultaneously formed on each antenna surface, the transmission period and the reception period may overlap between the antenna surfaces.

  FIG. 26 is a diagram showing electronic scanning in the elevation direction by a conventional radar device. When the beam formation for one elevation angle is completed, the next beam formation is started by changing the elevation angle of the transmission / reception beam. For example, electronic scanning in the elevation angle direction is performed while sequentially increasing the beam pointing elevation angles of the beams 101 to 103 formed by the antenna surfaces 201 to 203. At this time, a radar pulse signal having a transmission / reception pattern corresponding to the beam pointing elevation angle is transmitted.

  FIG. 27 is a diagram showing an example of a transmission / reception pattern of a transmission / reception beam formed in electronic scanning for each antenna surface. The transmission timing of the radar pulse signal is synchronized between the antenna surfaces 201 to 203, and the beam forming period is the same on all antenna surfaces. Beam formation for each azimuth is started at the same time on all the antenna surfaces 201 to 203 and simultaneously ended, and the next beam formation with a different beam directivity elevation angle, that is, a transmission / reception pattern, is started simultaneously. For this reason, it can avoid that a transmission period and a reception period overlap between antenna surfaces. For example, when the beam pointing elevation angle is c, a transmission / reception beam is formed with a pattern 301, and when the beam pointing elevation angle is d (> c), a transmission / reception beam is formed with a pattern 302 different from the pattern 301.

FIGS. 28 and 29 are diagrams showing an example of electronic scanning by the radar device. FIG. 28 shows a state in which intensive scanning is performed by a transmission / reception beam formed by the antenna surface 201, and FIG. Transmission / reception patterns 301 and 302 in the formed transmission / reception beam are shown for each of the antenna surfaces 201 to 203. By making the beam forming period of the beam 101 formed by the antenna surface 201 longer than that of the other beams 102 and 103, the inside of the azimuth range (important monitoring azimuth range) covered by the antenna surface 201 is preferentially scanned. . Since the electron scanning within the important monitoring azimuth range has a long beam forming period, the beam forming on the other antenna surfaces 202 and 203 is completed before the beam forming of the beam 101 is completed, and the next beam forming with a different beam pointing elevation angle is performed. Be started. For this reason, transmission / reception beams having different transmission / reception patterns are formed at the same time, the transmission period and the reception period overlap between the antenna surfaces, and transmission / reception beam interference occurs.
JP-A-5-180926

  As described above, the conventional beam scanning method has a problem that transmission / reception beam interference occurs when weighted scanning is performed.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a beam scanning method and a radar apparatus that can suppress interference between transmission and reception beams even when intensive scanning is performed. . In particular, it is an object of the present invention to provide a beam scanning method capable of suppressing transmission / reception beam interference and simultaneously reducing the electronic scanning data rate in the azimuth direction.

  A beam scanning method according to the present invention is a beam scanning method that performs electronic scanning of a transmission / reception beam by m (m ≧ 3) antenna surfaces including phased array antennas provided in different directions. From a pulse signal generation step for generating a radar pulse signal having a different transmission / reception pattern depending on an elevation angle, a pulse signal synchronization step for synchronizing the transmission timing of the radar pulse signal, and n (2 ≦ n ≦ m−1) antenna surfaces A transmission / reception beam forming step of transmitting a radar pulse signal and simultaneously forming n transmission / reception beams having the same elevation angle, electronic scanning of a predetermined emphasis monitoring azimuth range in the azimuth direction by one of the transmission / reception beams, Electronic scanning of the azimuth range outside the priority monitoring azimuth range in the azimuth direction using the transmit / receive beam The beam scanning control step comprises a beam forming period in the priority monitoring azimuth range that is longer than that outside the priority monitoring azimuth range, and one antenna is formed during the beam forming period in the priority monitoring azimuth range. When the beam formation outside the priority monitoring azimuth range by the surface is completed, the step is configured to start the beam formation by switching to another antenna surface.

  That is, n transmission / reception beams smaller than the number m of antenna surfaces are formed at the same time, and one transmission / reception beam electronically scans a predetermined emphasis monitoring azimuth range in the azimuth direction, and the transmission / reception beam has the same elevation angle. The azimuth range outside the priority monitoring azimuth range is electronically scanned in the azimuth direction by the (n−1) transmission / reception beams. Moreover, the beam forming period in the priority monitoring azimuth range is longer than outside the priority monitoring azimuth range, and during the beam forming period in the priority monitoring azimuth range, the beam formation outside the priority monitoring azimuth range by one antenna surface is completed. Switching to another antenna surface starts beam forming. Since the beam forming period in the priority monitoring azimuth range is longer than outside the priority monitoring azimuth range, beam formation in the priority monitoring azimuth range by one antenna surface and the priority monitoring azimuth range by other n-1 antenna surfaces When the beam forming outside is started at the same time, the beam forming outside the focus monitoring azimuth range by another antenna surface is finished first before the beam forming within the focus monitoring azimuth range is finished. At this time, the beam formation that has been completed first is switched to another antenna surface, and beam formation for the same elevation angle is started, so that it is possible to efficiently perform electronic scanning using less transmission / reception beams than the number of antenna surfaces. Since the elevation angles of the transmission / reception beams formed at the same time are always the same, the transmission / reception patterns of the transmission / reception beams are the same, and interference of the transmission / reception beams between the antenna surfaces can be suppressed. In particular, if the number of transmission / reception beams formed simultaneously is the same, after the beam formation outside the focus monitoring azimuth range by one antenna surface is completed, the beam from the antenna surface is completed until the beam formation within the focus monitoring azimuth range is completed. Compared with waiting for formation, the data rate of electronic scanning in the azimuth direction can be shortened.

  In the beam scanning method according to the present invention, in addition to the above-described configuration, the beam scanning control step covers the above-described important monitoring azimuth range by electronic scanning of a transmission / reception beam by one antenna surface, and a beam forming period within this important monitoring azimuth range. It is configured to be a step of sequentially performing beam formation by other antenna surfaces. According to such a configuration, the focus monitoring azimuth range is covered by electronic scanning of the transmission / reception beam by one antenna surface, and the other antenna surface is used during the beam forming period within the focus monitoring azimuth range by the antenna surface. Since the beam formation is performed sequentially, the azimuth direction electron scanning can be performed by efficiently using n transmission / reception beams.

  In the beam scanning method according to the present invention, in addition to the above-described configuration, the beam scanning control step is a step in which the scanning range of the transmission / reception beam with respect to each antenna surface is the same for all antenna surfaces with respect to the electronic scanning in the azimuth direction simultaneously performed. Configured to be. According to such a configuration, when each antenna surface is arranged so that the direction of each antenna surface divides the entire azimuth equally, transmission / reception formed by each antenna surface for simultaneous electronic scanning in the azimuth direction is performed. Since the beam scanning range is formed uniformly in all directions, it is possible to effectively suppress the interference of the transmission and reception beams between the antenna surfaces.

  In the beam scanning method according to the present invention, in addition to the above-described configuration, the beam scanning control step covers the important monitoring azimuth range by electronic scanning of transmission / reception beams by two or more antenna surfaces, and covers a part of the important monitoring azimuth range. During the beam forming period within the priority monitoring azimuth range by one antenna surface, beam forming by other antenna surfaces covering the outside of the priority monitoring azimuth range is sequentially performed, and a part of the important monitoring azimuth range is electronically scanned. When completed, the electronic scanning is performed by switching to an antenna surface that covers the other part of the priority monitoring azimuth range. According to such a configuration, transmission / reception is performed while suppressing interference of transmission / reception beams between antenna surfaces even when the important monitoring azimuth range is covered by electronic scanning of transmission / reception beams by two or more antenna surfaces. Electron scanning of the beam can be performed efficiently.

  In the beam scanning method according to the present invention, in addition to the above-described configuration, the beam scanning control step is such that the important monitoring azimuth range is smaller than 360 ° / m, and the beam forming period within the important monitoring azimuth range is outside the important monitoring azimuth range. Step of sequentially performing electronic scanning within the transmission / reception blank range of the radar pulse signal generated in the azimuth direction after the end of the electronic scanning of the priority monitoring azimuth range when the beam forming period is less than (m−1) / (n−1) times Configured to be. During the beam forming period within the priority monitoring azimuth range by one antenna surface, beam formation outside the priority monitoring azimuth range by n-1 transmit / receive beams is sequentially performed using the other m-1 antenna surfaces. Is called. At this time, the priority monitoring azimuth range is smaller than 360 ° / m, and the beam forming period within the priority monitoring azimuth range is (m−1) / (n−1) of the beam forming period outside the priority monitoring azimuth range. If it is less than double, a transmission / reception blank range in which no radar pulse signal is transmitted and beam formation is not performed occurs in the azimuth direction. Since the inside of this transmission / reception blank range is sequentially electronically scanned after the end of the electronic scanning of the priority monitoring azimuth range, even when the transmission / reception blank range occurs, the electronic scanning in the azimuth direction can be performed efficiently.

  According to the beam scanning method and the radar apparatus of the present invention, when beam formation outside the focus monitoring azimuth range by one antenna surface is completed during the beam forming period within the focus monitoring azimuth range, the beam is switched to another antenna surface. Since formation is started, electronic scanning can be performed efficiently using transmission / reception beams smaller than the number of antenna surfaces, and the elevation angles of the transmission / reception beams formed at the same time are always the same. It is possible to suppress the occurrence of interference between transmission and reception beams. In particular, if the number of transmission / reception beams formed simultaneously is the same, after the beam formation outside the focus monitoring azimuth range by one antenna surface is completed, the beam from the antenna surface is completed until the beam formation within the focus monitoring azimuth range is completed. Compared to waiting for formation, the data rate of electronic scanning in the azimuth direction can be reduced.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration example of a radar apparatus according to Embodiment 1 of the present invention. This radar device 1 is a fixed type radar composed of three phased array antennas 8 provided on a horizontal plane toward different directions, and electronically scans all directions, such as an aircraft in the air or a ship on the sea. The target is monitored.

  The radar apparatus 1 includes a transmission / reception beam forming unit 2, a pulse signal synchronization unit 3, a pulse signal generation unit 4, a beam scanning control unit 5, and a target detection unit 9. The transmission / reception beam forming unit 2 is provided for each phased array antenna 8 composed of a number of element antennas, a phase control unit 7 that performs phase control on transmission / reception signals from each element antenna, and a transmission / reception processing unit 6. Consists of.

  Each phased array antenna 8 has a flat antenna surface installed in different directions, and can perform electronic scanning of transmission / reception beams in all directions. By transmitting radar pulse signals from two antenna surfaces of each phased array antenna 8, two transmission / reception beams having the same elevation angle can be simultaneously formed.

  The pulse signal generator 4 is a radar pulse signal generator, and outputs radar pulse signals having different transmission / reception patterns depending on the elevation angle of the transmission / reception beam. This radar pulse signal is generated based on the control data regarding the beam pointing elevation angle of the transmission / reception beam input from the beam scanning control unit 5, and is output to the transmission / reception processing unit 6. Here, the transmission / reception pattern in the radar pulse signal is a transmission / reception repetitive pattern in which the transmission period of the transmission signal and the reception period of receiving the reflection echo of the transmission signal are alternately repeated.

  The pulse signal synchronization unit 3 outputs a synchronization signal for synchronizing the transmission timing of the radar pulse signal between the phased array antennas 8 to the transmission / reception processing unit 6. The target detection unit 9 performs identification processing such as the distance to the target and the direction based on the reception signal input from the transmission / reception processing unit 6.

  The beam scanning control unit 5 controls the transmission / reception processing unit 6 to perform electronic scanning of the transmission / reception beams by the three phased array antennas 8. In this electronic scanning control, a predetermined emphasis monitoring azimuth range is electronically scanned in the azimuth direction by one transmission / reception beam, and an azimuth range outside the emphasis monitoring azimuth range is electronically scanned in the azimuth direction by another transmission / reception beam. That is, by increasing the beam forming period in the priority monitoring azimuth range than outside the priority monitoring azimuth range, the number of hits per unit time in the priority monitoring azimuth range is increased, and the coverage in this azimuth range, that is, detection The distance can be extended and the scanning can be focused. The beam forming period is assumed to be a time for continuously transmitting and receiving radar pulse signals in the same direction. The scanning range of the transmission / reception beam with respect to each antenna surface is the same for all antenna surfaces with respect to the electronic scanning in the azimuth direction performed simultaneously.

  At this time, when beam formation outside the focus monitoring azimuth range by one antenna surface is completed during the beam forming period within the focus monitoring azimuth range, beam formation is started by switching to another antenna surface. In other words, when the beam forming of another transmission / reception beam is completed while the priority scanning is performed by one transmission / reception beam, the beam formation is started by switching to another antenna surface where the beam formation is not performed. In this way, when the beam formation by all the antenna surfaces is completed, the next beam formation with a different elevation angle is similarly performed.

  Since the beam forming period within the priority monitoring azimuth range is longer than that outside the priority monitoring azimuth range, beam formation within the priority monitoring azimuth range by one antenna surface and beam formation outside the priority monitoring azimuth range by another antenna surface Are started at the same time, before the beam formation in the priority monitoring azimuth range is finished, the beam formation outside the priority monitoring azimuth range by the other antenna surface is finished first. At this time, the beam formation that has been completed first is switched to another antenna surface, and beam formation for the same elevation angle is started, so that it is possible to efficiently perform electronic scanning using less transmission / reception beams than the number of antenna surfaces. In addition, since the elevation angles of the transmission / reception beams formed at the same time are always the same, the transmission / reception patterns of the transmission / reception beams are the same, and interference of the transmission / reception beams between the antenna surfaces can be suppressed. In particular, if the number of transmission / reception beams formed simultaneously is the same, after the beam formation outside the focus monitoring azimuth range by one antenna surface is completed, the beam from the antenna surface is completed until the beam formation within the focus monitoring azimuth range is completed. Compared with waiting for formation, the data rate of electronic scanning in the azimuth direction can be shortened.

  FIGS. 2A and 2B are diagrams showing an example of beam scanning by the radar apparatus of FIG. 1. FIG. 2A shows the priority monitoring areas for the antenna surfaces 21 to 23. 2 (b) shows a state transition state in the operation state for each of the antenna surfaces 21 to 23. Each phased array antenna 8 is arranged so that the directions of the antenna surfaces 21 to 23 equally divide all directions into three. For example, the scanning range of the transmitted and received beams 11 to 13 in the azimuth direction is the antenna surface 21. The beam 11 on the antenna surface 22 is from 0 ° to 120 °, the beam 12 on the antenna surface 22 is from 120 ° to 240 °, and the beam 13 on the antenna surface 23 is from 240 ° to 360 °. Here, among these scanning ranges, the scanning range by the antenna surface 21 is the priority monitoring azimuth range.

  An electronic scanning by the beam 11 on the antenna surface 21 covers the important monitoring area consisting of the important monitoring azimuth range, and the beams 12 and 13 on the antenna surfaces 22 and 23 are formed while beam forming is performed within this important monitoring azimuth range. Thus, beam formation is sequentially performed in another scanning range (azimuth range from 120 ° to 360 °). In other words, beam formation (azimuth a) is started by the beam 11 in the intensive monitoring azimuth, and simultaneously, beam formation is started by the beam 12 in the azimuth 120 ° + a, and the beam formation of the beam 12 is completed during the beam forming period of the intensive monitoring azimuth. Then, switching from the antenna surface 22 to the antenna surface 23 is started, and beam scanning at the azimuth 240 ° + a by the beam 13 is started.

  FIG. 3 is a diagram illustrating an example of a transmission / reception pattern of a transmission / reception beam formed by the radar apparatus of FIG. 1 for each antenna surface. The transmission timing of the radar pulse signal is synchronized between the antenna surfaces 21 to 23. Further, the beam forming period of the beam 11 formed by the antenna surface 21 is longer than the beam forming periods of the beams 12 and 13 formed by the other antenna surfaces 22 and 23. Here, it is assumed that the beam forming periods of the beams 12 and 13 are the same, and the beam forming period by the antenna surface 21 that electronically scans the priority monitoring direction is twice the beam forming period by the other antenna surfaces 22 and 23. . Thereby, the number of hits per unit time in the priority monitoring azimuth range can be made twice the number of hits in other azimuth ranges.

  By making the beam forming period by the antenna surface 21 longer than the beam forming periods by the other antenna surfaces 22 and 23, it is possible to focus scanning on the priority monitoring direction covered by the antenna surface 21.

  Beam formation is simultaneously started by the antenna surfaces 21 and 22 at the beam directivity elevation angle c. When beam formation by the antenna surface 22 is completed during the beam formation period by the antenna surface 21, beam formation by the antenna surface 23 is started. A transmission / reception pattern of the transmission / reception beam at the beam directivity elevation angle c is a common pattern 31 between the antenna surfaces 21 to 23. Beam formation by the antenna surfaces 21 and 23 at the beam directivity elevation angle c is completed at the same time. After the completion, the next beam formation by the antenna surfaces 21 and 22 is started at a beam directivity elevation angle d different from the beam directivity elevation angle c. The transmission / reception pattern at the beam directivity elevation angle d is a pattern 32 different from the pattern 31.

  That is, when beam formation by the antenna surface 22 is completed while beam formation is being performed by the antenna surface 21 in the priority monitoring direction, beam formation is started by the antenna surface 23 at the same beam directivity elevation angle. When the beam formation by all the antenna surfaces 21 to 23 is completed, the elevation angle is changed and the next beam formation is started. This makes it possible to always synchronize the transmission and reception beams that are formed at the same time, avoid the overlap of the transmission period and the reception period in the transmission and reception pattern between the antenna surfaces, and prevent interference of the transmission and reception beams. it can.

  Steps S101 to S107 in FIG. 4 are flowcharts showing an example of operations in beam scanning by the radar apparatus in FIG. First, the pulse signal generation unit 4 generates a radar pulse signal corresponding to the beam pointing elevation angle based on the control data from the beam scanning control unit 5, and outputs the radar pulse signal to the transmission / reception beam forming unit 2 (step S101). The transmission / reception beam forming unit 2 transmits a radar pulse signal from the antenna surface of each phased array antenna 8 based on the synchronization signal from the pulse signal synchronization unit 3 to simultaneously form a plurality of transmission / reception beams (step S102).

  Next, the beam scanning control unit 5 starts beam formation in the priority monitoring azimuth range by the antenna surface 21 and beam formation in another azimuth range by the antenna surface 22 at the same time. When the beam formation by the antenna surface 22 is completed during the beam formation period in the importance monitoring direction after the start of the important scan, the antenna surface on which the transmission / reception beam is formed is switched, and the beam formation by the antenna surface 23 is started (step S103). To S105). When the beam formation by the antenna surfaces 21 and 23 is completed, the elevation angle is changed, a radar pulse signal corresponding to the elevation angle is generated, and the next beam formation is started (steps S106 and S107).

  According to the present embodiment, when beam formation outside the focus monitoring azimuth range by one antenna surface is completed during the beam forming period within the focus monitoring azimuth range, beam formation is started by switching to another antenna surface. Therefore, it is possible to efficiently perform electronic scanning using transmission / reception beams smaller than the number of antenna surfaces, and the elevation angles of the transmission / reception beams formed at the same time are always the same. It can be suppressed from occurring.

Embodiment 2. FIG.
In the first embodiment, the example in which the scanning range of the transmission / reception beam formed by the antenna surface 21 is set as the priority monitoring azimuth range has been described. In contrast, in the present embodiment, a case will be described in which the priority monitoring azimuth range includes a part of the scanning range by the antenna surface 21 and a part of the scanning range by the antenna surface 23.

  5 (a) and 5 (b) are diagrams showing an example of beam scanning according to the second embodiment of the present invention. FIG. 5 (a) shows an important monitoring area for the antenna surfaces 21 to 23. FIG. FIG. 5B shows a state transition state in the operation state for each of the antenna surfaces 21 to 23. The important monitoring azimuth range is a range of −30 ° to 0 ° of a scanning range in the azimuth direction of a transmission / reception beam formed by the antenna surface 23 and a range of 0 ° to 90 ° of a scanning range by the antenna surface 21. It consists of. That is, the priority scan is performed across the two antenna surfaces 21 and 23.

  First, the beam 13 (beam directing direction 360 ° -a) by the antenna surface 23 and the beam 11 (beam directing direction 120 ° -a) by the antenna surface 21 are formed at the same time. The formation of the beam 12 (beam orientation azimuth 240 ° -a) by the surface 22 is started. When the beam formation of the beams 13 and 12 is completed, the elevation angle is changed and the next beam formation is started.

  When the electronic scanning in the elevation angle and azimuth direction of a part of the priority monitoring azimuth range (range from −30 ° to 0 °) performed in this way is completed, the other part (from 0 ° to 90 °) of the priority monitoring azimuth range is completed. Electronic scanning in the range (1) is started. That is, the beam 11 (beam directing azimuth b) by the antenna surface 21 and the beam 12 (beam directing azimuth 120 ° + b) by the antenna surface 22 are simultaneously formed. 13 (beam orientation azimuth 240 ° + b) is formed. When the beam formation of the beams 11 and 13 is completed, the elevation angle is changed and the next beam formation is started.

  That is, the critical monitoring azimuth range is covered by electronic scanning of the transmission and reception beams by the two antenna surfaces 23 and 21, and during the beam forming period in the critical monitoring azimuth range by the antenna surface 23 that covers a part of this important monitoring azimuth range, The beam forming is sequentially performed by the other antenna surfaces, and when the electronic scanning of a part of the important monitoring azimuth range is completed, the electronic scanning is performed by switching to the other antenna surface 21 covering the other part of the important monitoring azimuth range. Is called. Even in such a case, the interference of transmission and reception beams can be suppressed without increasing the data rate in electronic scanning in the azimuth direction. Other configurations and operational effects are the same as those of the first embodiment.

Embodiment 3 FIG.
In the first and second embodiments, the example in which the priority scan is performed has been described. In contrast, in the present embodiment, a description will be given of a case where beam scanning without priority scanning is performed.

  6 (a) and 6 (b) are diagrams showing an example of beam scanning that is not accompanied by priority scanning according to Embodiment 3 of the present invention. FIG. 6 (a) shows each of the antenna surfaces 21 to 23. A state transition state in the operation state is shown, and FIG. 6B shows a transmission / reception pattern in the formed transmission / reception beam for each of the antenna surfaces 21 to 23.

  In this beam scanning, two transmission / reception beams are simultaneously formed, and beam formation is performed by sequentially switching the antenna surfaces 21 to 23 while performing electronic scanning in the elevation direction. First, the beam formation (azimuth a) of the beam 11 by the antenna surface 21 is started, and the beam formation (azimuth 120 ° + a) of the beam 12 by the antenna surface 22 is started at the same time. When the beam formation by the antenna surfaces 21 and 22 is completed, the elevation angle is changed and the same beam formation is performed. When the electronic scanning in the elevation direction is thus completed, the antenna surface is switched, and beam formation by the antenna surface 23 (azimuth 240 ° + a) and beam formation by the antenna surface 21 (azimuth b) are started at a predetermined elevation angle. The

  When the beam formation by the antenna surfaces 23 and 21 is completed, the same electronic scanning is performed by changing the elevation angle. When the electronic scanning in the elevation angle direction ends, beam formation by the antenna surface 22 (azimuth 120 ° + b) and beam formation by the antenna surface 23 (azimuth 240 ° + b) are started. Here, the transmission / reception patterns of the transmission / reception beams simultaneously formed by the antenna surfaces 21 to 23 are the same, and the beam forming period is also the same between the antenna surfaces.

  In this way, a uniform coverage is formed in all directions, and the two directions of transmission and reception beams can be efficiently monitored using two transmission and reception beams without causing interference between the transmission and reception beams.

Embodiment 4 FIG.
In Embodiments 1 and 2, the example in which the priority monitoring azimuth range is 120 ° has been described. In contrast, in the present embodiment, a case where the priority monitoring azimuth range is smaller than 120 ° will be described.

  FIGS. 7A and 7B are diagrams showing an example of beam scanning according to the fourth embodiment of the present invention. FIG. 7A shows the priority monitoring areas for the antenna surfaces 21 to 23. FIG. 7B shows a state transition state in the operation state for each of the antenna surfaces 21 to 23. Here, it is assumed that the emphasis monitoring azimuth range is 90 °, and this emphasis monitoring azimuth range is a part of a scanning range of −30 ° to 0 ° in the azimuth direction of the beam 13 by the antenna surface 23 and scanning by the antenna surface 21. A part of the range consists of a range from 0 ° to 60 °. Electronic scanning by each of the antenna surfaces 21 to 23 is performed in the same manner as the beam scanning in FIG. 5 (Embodiment 2). Even in such a case, the interference of transmission and reception beams can be suppressed without increasing the data rate in electronic scanning in the azimuth direction.

  At the time of electronic scanning in the priority monitoring area, an area where electronic scanning by the transmission / reception beam is not performed, that is, a transmission / reception blank area occurs. This transmission / reception blank area can be covered by performing the beam scanning (embodiment 3) without the priority scanning of FIG. 6 after the end of the priority scanning.

  FIGS. 8A and 8B are diagrams showing an operation state at the time of beam scanning in FIG. 6. FIG. 8A shows the focus monitoring area and electronic scanning in the focus monitoring area. An area where electronic scanning has been performed is shown, and FIG. 8B shows a transmission / reception blank area that was not scanned during electronic scanning in the priority monitoring area. Simultaneously with the electronic scanning within the priority monitoring azimuth range (range from −30 ° to 60 °), the azimuth range from 90 ° to 180 ° and the azimuth range from 210 ° to 300 ° are electronically scanned. Assuming that this azimuth range is a simultaneous scanning azimuth range (simultaneous scanning area), a range excluding the priority monitoring azimuth range and the simultaneous scanning azimuth range from all azimuths (from 60 ° to 90 °, from 180 ° to 210 °, 300 The range from 0 ° to 330 ° is a transmission / reception blank range (transmission / reception blank area). Such a transmission / reception blank area can be covered by the beam scanning not accompanied by the above-described priority scanning, and a uniform covering area can be formed in the azimuth direction.

  In the present embodiment, three phased array antennas 8 are used, and electronic scanning is performed in the 90 ° priority monitoring azimuth range by a transmission / reception beam whose beam forming period is twice the beam forming period in the simultaneous scanning azimuth range. An example has been described in which the beam scanning without the priority scanning is performed on the transmission / reception blank area generated when In general, the transmission / reception blank area uses m (m ≧ 3) phased array antennas 8 and the beam forming period is not more than (m−1) / (n−1) times the beam forming period in the simultaneous scanning azimuth range. This is considered to occur when electronic scanning is performed within a focus monitoring azimuth range smaller than 360 ° / m by a certain transmission / reception beam. Accordingly, even in such a case, the above-described beam scanning without the priority scanning can be applied.

Embodiment 5 FIG.
In the first, second, and fourth embodiments, the case where there is one priority monitoring area has been described. In contrast, in the present embodiment, a case will be described in which a plurality of priority monitoring areas having different orientations are provided.

  FIG. 9 is a diagram showing an example of two priority monitoring areas. These priority monitoring areas A and B are provided in different directions without overlapping. In such a case, since one priority monitoring area can be connected to the other priority monitoring area and regarded as one priority monitoring area, beam scanning can be performed as in the first, second, and fourth embodiments. .

  FIG. 10 is a diagram illustrating an example of three priority monitoring areas having the same orientation with respect to the antenna surface. These priority monitoring areas are provided for each of the antenna surfaces 21 to 23, and have the same orientation with respect to the antenna surfaces 21 to 23, respectively. That is, it is formed so that all directions are equally divided into three. In such a case, the omnidirectional monitoring is performed by performing the same beam scanning as in the third embodiment by changing the beam forming period in the important monitoring area and in the area other than the important monitoring area. Can do.

Embodiment 6 FIG.
In the first to fifth embodiments, examples in which three phased array antennas 8 are used and transmission / reception beams are simultaneously formed by two antenna surfaces have been described. On the other hand, in the present embodiment, a case where m (m ≧ 4) phased array antennas 8 are used and transmission / reception beams are simultaneously formed by n (2 ≦ n ≦ m−1) antenna surfaces will be described. To do.

  FIG. 11 is a diagram showing an example of beam scanning according to the sixth embodiment of the present invention, in which the priority monitoring areas for the antenna surfaces 41 to 44 are shown. The radar apparatus according to the present embodiment includes four phased array antennas 8 and can transmit radar pulse signals from two of the antenna surfaces 41 to 44 to simultaneously form two transmission / reception beams. Each phased array antenna 8 is arranged so that the directions of the antenna surfaces 41 to 44 equally divide all directions into four. For example, the scanning range in the azimuth direction of the transmission / reception beam is from −45 ° with respect to the antenna surface 41. From 45 ° to 45 ° for the antenna surface 42, from 135 ° to 225 ° for the antenna surface 43, and from 225 ° to 315 ° for the antenna surface 44. Here, among these scanning ranges, the scanning range by the antenna surface 41 is the priority monitoring azimuth range.

  Electronic scanning by the antenna surface 41 covers the important monitoring area consisting of the important monitoring azimuth range. While beam formation is performed within this important monitoring azimuth range, the antenna surfaces 42 to 44 allow other scanning ranges (45 °). Beam formation within the azimuth range from 315 ° to 315 °. The beam forming period in the priority monitoring azimuth range is three times longer than in the other azimuth ranges. As a result, the number of hits per unit time within the priority monitoring azimuth range can be made three times larger than in other azimuth ranges.

  Also according to this embodiment, it is possible to suppress interference between transmission and reception beams without increasing the data rate in electronic scanning in the azimuth direction. Other configurations and operational effects are the same as those of the first embodiment.

Embodiment 7 FIG.
In the first to sixth embodiments, examples in which a plurality of transmission / reception beams are simultaneously formed by the flat phased array antenna 8 have been described. In contrast, in this embodiment, a case where a plurality of transmission / reception beams are formed by a cylindrical phased array antenna will be described.

  12 (a) and 12 (b) are diagrams showing an example of beam scanning according to the seventh embodiment of the present invention. FIG. 12 (a) shows a focus monitoring area for the cylindrical array antenna 50. FIG. FIG. 12B shows the state transition in electronic scanning. The radar apparatus according to the present embodiment includes a cylindrical phased array antenna (cylindrical array antenna 50) installed with a central axis perpendicular to a horizontal plane. For example, two transmission / reception beams are transmitted in different directions. They can be formed simultaneously.

  Here, it is assumed that two excitation reception systems for forming a transmission / reception beam by the cylindrical array antenna 50 are provided, and among the beams 51 to 53 respectively formed within an azimuth range that equally divides all directions into three, First, the beam 51 and the beam 52 are formed at the same time. When the beam 51 and the beam 52 are completed, the electron scanning is repeated to repeat the beam scanning. The scanning ranges of the beams 51 to 53 are the beam 51 from 0 ° to 120 °, the beam 52 from 120 ° to 240 °, and the beam 53 from 240 ° to 360 °. Among these scanning ranges, the scanning range of the beam 51 is the priority monitoring azimuth range.

  At the same time as the beam formation (azimuth a) is started by the beam 51 in the intensive monitoring azimuth, the beam formation is started at the azimuth 120 ° + a by the beam 52, and the beam formation of the beam 52 is finished during the beam forming period of the intensive monitoring azimuth. Beam formation by the beam 53 in the azimuth 240 ° + a is started. When the beam formation at the azimuth a and 240 ° + a by the beams 51 and 53 is completed, the elevation angle is changed and the same beam scanning is repeated. When the beam scanning in the elevation angle direction ends, beam formation by the beam 51 is started in an azimuth b (> a) different from the azimuth a, and at the same time, beam formation by the beam 52 in the azimuth 120 ° + b is started. When the beam formation of the beam 52 is completed during the beam formation period of the beam 51 in the priority monitoring azimuth, the beam formation by the beam 53 in the azimuth 240 ° + b is started. In this way, beam scanning is performed in all directions. The beam forming period in the priority monitoring azimuth range is twice as long as in other azimuth ranges, and the number of hits per unit time can be doubled. Other configurations are the same as those in the first embodiment.

  Even with such a configuration, transmission / reception beam interference can be suppressed without increasing the data rate in electronic scanning in the azimuth direction. Note that if the azimuth range outside the priority monitoring azimuth range is divided into n and the number of hits per unit time within this azimuth range is N, the number of hits within the priority monitoring azimuth range may be N × n. it can. Even when a plurality of priority monitoring areas having different azimuths are provided, if the priority monitoring areas are connected, they can be regarded as one priority monitoring area, and thus beam scanning can be performed in the same manner.

Embodiment 8 FIG.
In the first to seventh embodiments, examples in which beam scanning is performed by electronic scanning in the azimuth direction have been described. In contrast, in the present embodiment, a case will be described in which beam scanning in the azimuth direction is performed by rotation of m antenna surfaces having different azimuths in a horizontal plane.

  FIGS. 13A and 13B are diagrams showing an example of beam scanning according to the eighth embodiment of the present invention. FIG. 13A shows one antenna surface 61 of the rotary array antenna 60. FIG. FIG. 13 (b) shows the antenna rotation speed and the number of hits for each beam directing direction. The radar device according to the present embodiment includes a phased array antenna (rotational array antenna 60) that can rotate the direction of the antenna surface in the azimuth direction. For example, the radar device transmits a radar pulse signal from one antenna surface 61, One transmission / reception beam (beam 71) can be formed in the direction of the antenna surface 61.

  Here, the priority monitoring azimuth range is a range from 90 ° to 180 °, and the rotation speed of the antenna surface 61 (antenna rotation speed) in this priority monitoring azimuth range is slower than in other azimuth ranges, It is possible to increase the number of hits per unit time within the priority monitoring azimuth range and extend the radar detection distance.

  FIG. 14 is a diagram showing another example of beam scanning according to the eighth embodiment of the present invention. In this radar apparatus, two antenna surfaces 81 and 82 provided in the opposite direction are rotated integrally, and two antenna beams 81 and 82 are respectively transmitted to these antenna surfaces 81 and 82 as antennas. The surfaces 81 and 82 can be formed simultaneously. In such a case, if the antenna rotation speed is slowed down, both the beams 91 and 92 are subjected to intensive scanning, so the range from 270 ° to 0 ° is also the intensive monitoring azimuth range. Therefore, in beam scanning by rotation of a plurality of antenna surfaces, important monitoring areas corresponding to the number of antenna surfaces are generated in the azimuth direction.

Embodiment 9 FIG.
FIG. 15 is a diagram showing an example of beam scanning according to the ninth embodiment of the present invention. The beam scanning according to the present embodiment is different from the beam scanning (Embodiment 8) of FIG. 13 in that electronic scanning in the azimuth direction is performed. For example, when the rotation speed of the antenna surface 61 is constant, the beam 71 is directed in the azimuth direction with respect to the antenna surface 61 during the period from when the azimuth of the antenna surface 61 becomes 90 ° −θ ₁ to 180 °. By performing electronic scanning, it is possible to perform important scanning within the important monitoring azimuth range. That is, when the azimuth of the antenna surface 61 becomes 90 ° −θ ₁ , the beam directing azimuth with respect to the antenna surface 61 is set to 90 ° −θ _1, and the beam 71 is opposite to the rotation direction with the rotation of the antenna surface 61. Is electronically scanned. When the azimuth of the antenna surface 61 reaches 180 °, the beam directing azimuth with respect to the antenna surface 61 is set to 90 °. As a result, the data rate within the priority monitoring azimuth range (range from 90 ° to 180 °) can be increased to (180−90 + θ ₁ ) / 360 times the data rate within the other azimuth ranges.

Alternatively, when the azimuth of the antenna surface 61 becomes 90 °, the electronic scanning in the direction opposite to the rotation direction is started, and when the azimuth of the antenna surface 61 reaches 180 ° + θ ₂ , the beam directing with respect to the antenna surface 61 is performed. The azimuth may be 90 ° + θ ₂ . In this case, the data rate in the priority monitoring azimuth range can be increased to (180−90 + θ ₂ ) / 360 times the data rate in the other azimuth ranges.

Further, when the azimuth of the antenna surface 61 becomes 90 ° −θ ₁ , the beam directivity azimuth with respect to the antenna surface 61 is set to 90 ° −θ _1, and the beam 71 is opposite to the rotation direction as the antenna surface 61 rotates. Is electronically scanned. Then, when the orientation of the antenna surface 61 reaches 180 ° + θ ₂ , the beam directing orientation with respect to the antenna surface 61 may be 90 ° + θ ₂ . In this case, the data rate in the priority monitoring azimuth range can be increased to (180−90 + θ ₁ + θ ₂ ) / 360 times the data rate in the other azimuth ranges.

In such a beam scanning, a transmission / reception blank range (a range from 90 ° −θ ₁ to 90 ° or a range from 180 ° to 180 ° + θ ₂ ) is generated. In order to prevent transmission / reception blanks from occurring, it is conceivable to adjust the number of hits in the focus monitoring azimuth range or other azimuth ranges and assign them to beam scans in the transmission / reception blank ranges.

  16 (a) to 16 (c) are diagrams showing beam scanning according to the ninth embodiment of the present invention. FIG. 16 (a) shows a transmission / reception blank area generated in the azimuth direction. FIG. 16B shows a case where beam scanning is performed within the transmission / reception blank range by increasing the number of hits within the priority monitoring azimuth range. FIG. In the figure, the beam is scanned within the transmission / reception blank range by reducing the number of hits.

For example, by assigning _{1/2 of} the period T × θ 1/360 (T: data rate) during which the antenna surface 61 rotates within the transmission / reception blank range to beam scanning within the priority monitoring azimuth range, The number of hits is reduced and the remaining half is assigned to beam scanning within the transmit / receive blank range. Alternatively, the number of hits in the azimuth range can be reduced by performing electronic scanning in the forward direction with respect to the rotation direction in the azimuth range outside the priority monitoring azimuth range, and beam scanning can be performed in the transmission / reception blank range.

  17 (a) and 17 (b) are diagrams showing beam orientations with respect to the antenna surface in the beam scanning of FIG. 16 for each antenna surface orientation. FIG. 17 (a) shows the adjustment of the number of hits. FIG. 17B shows a case where beam scanning is performed within the transmission / reception blank range by adjusting the number of hits.

When the hit number is not adjusted, the beam directing direction with respect to the antenna surface 61 is changed from 90 ° to 90 ° -θ ₁ when the direction of the antenna surface 61 is 90 ° -θ ₁ , and the direction of the antenna surface 61 is When 180 ° + θ ₂ , it is discontinuously switched from 180 ° to 180 ° + θ ₂ . For this reason, a transmission / reception blank range occurs in the azimuth direction. On the other hand, when the number of hits is adjusted and the inside of the transmission / reception blank range is beam-scanned by reducing the number of hits in the azimuth range outside the priority monitoring azimuth range, the transmission / reception blank range does not occur, It is possible to perform beam scanning with the number of hits outside the priority monitoring azimuth range being equal. That is, the beam directing direction with respect to the antenna surface 61 is changed from 90 ° + θ ₂ to 90 ° with the rotation of the antenna surface 61 until the direction of the antenna surface 61 becomes 180 ° + θ ₂ until it becomes 90 ° −θ ₁ . by electronic scanning in the forward direction to - [theta] _1, it is possible to prevent the transmission and reception blank range occurs.

  In the first, second, fourth, and seventh embodiments, examples have been described in which the priority scan is performed for a predetermined range in the azimuth direction, but the present invention is not limited to this. The priority monitoring range may be designated in the elevation direction, or beam scanning may be performed by designating both the azimuth direction and the elevation direction.

It is the block diagram which showed one structural example of the radar apparatus by Embodiment 1 of this invention. It is the figure which showed an example of the beam scanning by the radar apparatus of FIG. It is the figure which showed an example of the transmission / reception pattern of the transmission / reception beam formed with the radar apparatus of FIG. 1 for every antenna surface. It is the flowchart which showed an example of the operation | movement in the beam scanning by the radar apparatus of FIG. It is the figure which showed an example of the beam scanning by Embodiment 2 of this invention. It is the figure which showed an example of the beam scanning not accompanied by the priority scan by Embodiment 3 of this invention. It is the figure which showed an example of the beam scanning by Embodiment 4 of this invention. It is the figure which showed the operation state at the time of the beam scanning of FIG. It is the figure which showed an example of two important point monitoring areas. It is the figure which showed an example of three important point monitoring areas which make the direction with respect to an antenna surface the same. It is the figure which showed an example of the beam scanning by Embodiment 6 of this invention. It is the figure which showed an example of the beam scanning by Embodiment 7 of this invention. It is the figure which showed an example of the beam scanning by Embodiment 8 of this invention. It is the figure which showed the other example of the beam scanning by Embodiment 8 of this invention. It is the figure which showed an example of the beam scanning by Embodiment 9 of this invention. It is the figure which showed the beam scanning by Embodiment 9 of this invention. It is the figure which showed the beam directivity direction with respect to the antenna surface in the beam scanning of FIG. 16 for every direction of the antenna surface. It is the figure which showed the conventional radar apparatus typically. It is the figure which showed the electronic scan by the radar apparatus of FIG. It is the figure which showed the other example of the electronic scanning by the radar apparatus of FIG. It is the figure which showed the transmission / reception pattern of the transmission / reception beam formed with the radar apparatus of FIG. It is the figure which showed the transmission / reception pattern for every antenna surface in the electronic scanning of FIG. It is the figure which showed the electronic scan in the conventional radar apparatus. It is the figure which showed the electronic scan in the conventional radar apparatus. It is the figure which showed an example of the electronic scanning by a radar apparatus. It is the figure which showed the electronic scanning of the elevation angle direction by the conventional radar apparatus. It is the figure which showed an example of the transmission / reception pattern of the transmission / reception beam formed in electronic scanning for every antenna surface. It is the figure which showed an example of the electronic scanning by a radar apparatus. It is the figure which showed an example of the electronic scanning by a radar apparatus.

Explanation of symbols

1 radar device, 2 transmit / receive beam forming unit, 3 pulse signal synchronization unit,
4 pulse signal generator, 5 beam scanning controller, 6 transmission / reception processor, 7 phase controller,
8 phased array antenna, 9 target detector

Claims (6)

In a beam scanning method of performing electronic scanning of a transmission / reception beam for every elevation angle in all directions by a phased array antenna composed of a large number of element antennas,
A pulse signal generation step for generating a radar pulse signal having different transmission / reception patterns depending on the elevation angle of the transmission / reception beam;
A pulse signal synchronization step for synchronizing the transmission timing of the radar pulse signal;
Among the m (m ≧ 3) phased array antennas provided in different directions, the radar pulse signals are transmitted from n (2 ≦ n ≦ m−1) antenna surfaces, respectively, and different n pieces A transmit / receive beam forming step for simultaneously forming a transmit / receive beam;
A beam scanning control step that electronically scans within a predetermined emphasis monitoring azimuth range with one of the transmission / reception beams, and electronically scans an azimuth range outside the emphasis monitoring azimuth range with the other transmission / reception beams,
In the beam scanning control step, the beam forming period in the priority monitoring azimuth range is made longer than that outside the priority monitoring azimuth range, and the beam forming period within the priority monitoring azimuth range is outside the priority monitoring azimuth range by one antenna surface. A beam scanning method characterized in that, when the beam formation in is completed, the beam switching is started by switching to another antenna surface.   The beam scanning control step covers the important monitoring azimuth range by electronic scanning of the transmission / reception beam by one antenna surface, and sequentially performs beam formation by other antenna surfaces during the beam forming period in the important monitoring azimuth range. The beam scanning method according to claim 1, wherein the beam scanning method is performed.   2. The beam according to claim 1, wherein the beam scanning control step is a step in which a scanning range of the transmission / reception beam with respect to each antenna surface is the same for all antenna surfaces with respect to simultaneous electronic scanning in the azimuth direction. Scanning method.   The beam scanning control step covers the emphasis monitoring azimuth range by electronic scanning of transmission / reception beams by two or more antenna surfaces, and a beam within the emphasis monitoring azimuth range by one antenna surface covering a part of the emphasis monitoring azimuth range. During the formation period, beam formation by other antenna surfaces is sequentially performed, and when electronic scanning of a part of the focus monitoring azimuth range is completed, switching to another antenna surface covering the other part of the focus monitoring azimuth range is performed. The beam scanning method according to claim 1, wherein the step of performing electronic scanning is performed.   In the beam scanning control step, the focused monitoring azimuth range is smaller than 360 ° / m, and the beam forming period within the focused monitoring azimuth range is (m−1) / (n -1) When it is less than or equal to double, the step is a step of sequentially performing electronic scanning within a transmission / reception blank range of a radar pulse signal generated in the azimuth direction after completion of electronic scanning of the emphasis monitoring azimuth range. Beam scanning method. A radar apparatus that performs electronic scanning of a transmission / reception beam for every elevation angle in all directions by a phased array antenna composed of a large number of element antennas,
Pulse signal generating means for generating radar pulse signals having different transmission / reception patterns depending on the elevation angle of the transmission / reception beam;
Pulse signal synchronization means for synchronizing the transmission timing of the radar pulse signal;
It consists of m (m ≧ 3) phased array antennas provided in different directions, and among these phased array antennas, the radar pulse signals are respectively transmitted from n (2 ≦ n ≦ m−1) antenna surfaces. Transmit / receive beam forming means for transmitting and forming different n transmit / receive beams simultaneously;
A beam scanning control unit that electronically scans within a predetermined emphasis monitoring azimuth range with one of the transmission / reception beams, and electronically scans an azimuth range outside the emphasis monitoring azimuth range with the other transmission / reception beams;
The beam scanning control means makes the beam forming period within the important monitoring azimuth range longer than outside the important monitoring azimuth range, and out of the important monitoring azimuth range by one antenna surface during the beam forming period within the important monitoring azimuth range. When the beam formation in is finished, the radar apparatus switches to another antenna surface to start the beam formation.

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