JPH0731240B2 - Beam scanning method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a beam scanning method in a radar apparatus for detecting a target using a phased array antenna which electronically two-dimensionally scans a pencil beam. It is a thing.

[Conventional technology]

FIG. 7 is a circuit configuration diagram of an example of a conventional beam scanning method, in which 1 is an element antenna and a plurality of (n
It is provided). Reference numeral 2 is an n phase shifter for setting a phase for each of the n element antennas 1, 3 is a combiner for combining these n array element system signals, and 4 is a beam scanning command unit of the radar device. The phase memory A sends a required phase value to each of the n phase shifters 2 based on the elevation step number and the azimuth step number sent from (not shown).

Next, the operation will be described.

Since the operation of this type of phased array antenna is a well-known matter, the concept of beam scanning will be mainly described below with reference to the beam scanning situation diagram of FIG.

Elevation step number from the beam scanning command unit (not shown) of the radar device And the combination of azimuth step numbers (from FIG. 8) As described above, the phase value is transmitted from the phase memory A4 to the n phase shifters 2 in order of the beam numbers 1 to 12 so that the beam can be formed in a desired direction corresponding to the beam number. Here, for convenience of explanation, assuming that the elevation angle and the azimuth coverage are satisfied by 12 beams of beam numbers 1 to 12, as shown in FIG. 8, beam scanning of beam numbers 1 to 12 is repeatedly executed. I am trying. Also, the first beam scanning of beam numbers 1 to 12
The following beam scanning of beam numbers 1 to 12 is defined as the second azimuth scanning.

[Problems to be Solved by the Invention]

Since the conventional beam scanning method has the above-described configuration and operation, as shown in FIG. 8, it is in the azimuth direction between the azimuth step number and in the elevation direction. Two-dimensionally, there is always a portion where the antenna gain is low, such as between beam numbers 1, 2, 4 and 5, and when the target to be detected by the radar device is in this portion, it is detected from other portions. There was a problem that performance deteriorated.

Further, in order to solve this problem, if the number of steps of azimuth and elevation is increased (the number of beams is increased) to make the overlapping of adjacent beams dense, the target detection performance is improved, but the beam scanning time There was a problem that was too large.

The present invention has been made in order to solve the problems of the conventional ones described above, and an object thereof is to obtain a beam scanning method capable of improving the target detection performance of a radar device and minimizing the beam scanning time. To do.

[Means for Solving the Problems]

The beam scanning method according to the present invention is an electronic pencil
In a boom scanning method of a radar device for detecting a target by using a phased array antenna that two-dimensionally scans a beam, both ends of a required azimuth coverage area are defined as beam noses at the first azimuth scanning with respect to azimuth scanning. Beam and a beam in which adjacent beams in the required azimuth coverage area have the same degree of overlap, and the beam is sequentially scanned from either one of both ends of the required azimuth coverage area according to the azimuth angle, and the second time When the azimuth scanning is performed, the beam nose is the beam having the central azimuth angle between the beam noses at the first azimuth scanning, and is equal to the overlap of the beams just before and after both ends of the required azimuth coverage. The overlapping beams are generated, and the beams are sequentially scanned in accordance with the azimuth angle similarly to the first azimuth scanning, and after the third azimuth scanning. The first and the second combination of the beam at the time of azimuth scanning is obtained so as to run alternately.

A beam scanning method according to the present invention is the beam scanning method described above, wherein in the second azimuth scanning,
Instead of generating beams immediately before and after both ends of the required azimuth coverage area, beams having both ends of the required coverage area as beam noses are generated.

A beam scanning method according to the present invention is a beam scanning method for a radar apparatus that detects a target using a phased array antenna that electronically scans a pencil beam two-dimensionally. When scanning in the azimuth direction, a beam with both ends of the required elevation coverage area as the beam nose and a beam in which the adjacent beams in the required elevation coverage area have the same degree of overlap are generated, and both ends of the required elevation coverage area are generated. The beam is sequentially scanned according to the elevation angle from either one of the above, and during the second azimuth scanning, the beam whose nose is the central elevation angle between the beam noses during the first azimuth scanning and the required elevation Beams having the same overlap as the above-mentioned beams are generated immediately above and below the both ends of the region, and the elevation angle is the same as in the first azimuth scanning. Therefore sequentially beam scanning, the third and subsequent azimuth scanning is that so as to perform alternately a combination of the first and the second beam during azimuth scanning.

Further, in the beam scanning method according to the present invention, in the above-described beam scanning method, in the elevation angle scanning at the time of the second azimuth scanning, instead of generating beams directly above and below both ends of the required elevation angle coverage, A beam with both ends of the required elevation angle coverage as beam noses is generated.

Further, in the beam scanning method according to the present invention, both ends of the required elevation angle coverage area are beam noses at the time of the first azimuth scanning with respect to the elevation scanning while performing the above-described beam scanning method with respect to the azimuth scanning. A beam and a beam in which adjacent beams in the required elevation angle coverage area have the same degree of overlap are generated, and the beam is sequentially scanned from one of both ends of the required elevation angle coverage area according to the elevation angle, and the second azimuth direction is set. A beam with the central elevation angle between each beam nose at the time of the first azimuth scanning during directional scanning as the beam nose, and a beam with an overlap equal to the overlap of the beams just above and below both ends of the required elevation angle coverage. Occurs, and the beam is sequentially scanned according to the elevation angle as in the first azimuth scanning, and the first and second azimuth scanning are performed after the third azimuth scanning. The combination of the beam at the time of azimuth scanning is obtained so as to run alternately.

Further, in the beam scanning method according to the present invention, both ends of the required elevation angle coverage area are beam noses at the time of the first azimuth scanning with respect to the elevation scanning while performing the above-described beam scanning method with respect to the azimuth scanning. Beam,
Generates a beam with which the overlap of adjacent beams in the required elevation angle coverage becomes approximately the same, and sequentially scans the beam according to the elevation angle from either one of both ends of the required elevation angle coverage,
At the time of the second azimuth scanning, the beam having the central elevation angle between the beam noses at the time of the first azimuth scanning as the beam nose and the beam having both ends of the required elevation angle coverage as the beam nose are used. Occurrence occurs, and beam scanning is performed sequentially according to the elevation angle as in the first azimuth scanning, and after the third azimuth scanning, the beam combinations for the first and second azimuth scanning are executed alternately. It is something that is done.

[Action]

Since the beam scanning method according to the present invention is as described above, even if the target to be detected by the radar device is near the center between the beam noses during a certain azimuth scanning, the beam scanning is always performed during the next azimuth scanning. Target detection performance can be improved because it can be captured near the nose. Further, the time required for beam scanning does not increase excessively because the number of beams per azimuth direction scanning is not significantly increased and is also increased only once every two times.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an apparatus for carrying out the beam scanning method according to the first to fifth embodiments of the present invention. In the figure, 1 to 3 are exactly the same as the conventional apparatus shown in FIG. 4 is the first
At the time of the second azimuth scanning, the required phase value is sent to each of the n phase shifters 2 based on the elevation step number and the azimuth step number sent from the beam scanning command unit (not shown) of the radar device. The phase memories A and 5 are phase memories B for transmitting required phase values to each of the n phase shifters 2 in the same manner as the phase memory A at the time of the second azimuth scanning, and 6 is a beam scanning of the radar device. A counter that counts scanning start triggers sent from a command unit (not shown) and outputs a switching signal that alternately switches the switch 7 to the phase memory A4 side or the phase memory B5 side each time the azimuth scanning is repeated.
Is a switch.

Next, the operation will be described.

For convenience of explanation, the elevation angle and azimuth coverage, the beam shape, and the basic beam scanning procedure are the same as those in the conventional system. First, the difference in circuit operation and then the difference in beam scanning will be described.

(1) Circuit operation The difference from the conventional method lies in the phase memory A4 to the switch 7, which will be described below. The counter 6 counts scanning start triggers from a beam scanning command unit (not shown) of the radar device, and outputs a switching signal for alternately switching the switch 7 to the phase memory A4 side or the phase memory B5 side each time azimuth scanning is repeated. Output. The phase memory A4 sends the required phase value to each of the n phase shifters 2 based on the elevation angle step number and the azimuth step number during the first azimuth scanning, and the phase memory B5 is the same as the phase memory A4. Then second
The required phase value at the time of the second scanning in the azimuth direction is sent to each of the n phase shifters 2.

Here, the difference between the first to fifth embodiments corresponding to claims 1 to 6 of the claims is that the stored phase value of the phase memory B5 is the second azimuth direction shown in FIG. 2 to FIG. Beam during scanning Is stored so that

(2) Beam scanning The first to fifth embodiments corresponding to claims 1 to 6 of the claims will be described below in order.

(I) Scanning according to the first embodiment corresponding to claim 1 of the present invention will be described below with reference to the beam scanning situation diagram of FIG.

As is clear from the comparison between FIG. 2 and FIG. 8 as to the difference from the conventional method, at the time of the first azimuth scanning, beam scanning is performed (indicated by a circle in FIG. 2) as in the conventional method, During the second azimuth scanning Beam scanning so that the central azimuth angle becomes the beam nose with respect to the azimuth step number from the first azimuth scanning Also, the overlap of the beams should be similar to that of the other beams just before and immediately after the ends of the required azimuth coverage area. Beam scanning.

(Ii) Scanning according to the second embodiment corresponding to claim 2 of the present invention The beam scanning situation of FIG. 3 will be described below with reference to the drawings.

The difference from the first embodiment is clear from the comparison between FIGS. 2 and 3 in the second azimuth scanning. The beam nose is set to the same as the azimuth step number at the first azimuth scanning.

(Iii) Scanning according to the third embodiment of the present invention will be described below with reference to the beam scanning situation diagram of FIG.

The difference from the conventional method is clear from the comparison between FIGS. 4 and 8, and at the time of the first azimuth scanning, beam scanning (shown by a circle in FIG. 4) is performed as in the conventional method. During the second azimuth scan As in the first azimuth scanning Beam scanning so that the central elevation angle becomes the beam nose. In addition, the overlap of the beams should be the same as the overlap of the other beams just above and below the both ends of the required elevation angle coverage. Beam scanning.

(Iv) Scanning according to a fourth embodiment of the present invention, which will be described below with reference to the beam scanning situation diagram of FIG.

The difference from the third embodiment is clear from the comparison between FIGS. 4 and 5 in the second azimuth scanning. Beam nose of the first azimuth scanning It is the same as.

(V) Fifth aspect corresponding to claim 5 or 6 of the present invention
Scanning according to the embodiment of the present invention. A combination of the first and second embodiments relating to azimuth scanning and the third and fourth embodiments relating to elevation scanning, that is, the first embodiment, the third embodiment, and the first embodiment. The beam scanning is performed by the combination of four sets of the embodiment and the fourth embodiment, the second and the third embodiments, and the second and the fourth embodiments. As an example of the combination, FIG. 6 shows a case where the second embodiment and the fourth embodiment are combined.

As shown in the items (i) to (v), in any case, the position near the center between the beam noses for each repetition of azimuth scanning is always the target near the beam nose at the next repetition. It can be seen that it is designed so that can be captured.

In the above embodiment, the case of two-dimensional electronic scanning is described, but the third and fourth embodiments are also applied to the case of one-dimensional electronic scanning in which the azimuth direction is mechanical rotation and the elevation angle direction is electronically scanned. The same effect can be obtained by adapting.

In addition, the beam nose was repeatedly set to the center between the mutual beam noses every time the azimuth scanning was repeated, but the mutual beam noses were divided into some number, and the beam noses were gradually increased at each repetition corresponding to the number of divisions. The angle of the beam nose may be changed.

Next, in the circuit configuration, in FIG. 1, the phase value of the phase shifter 2 can be set by the configuration of four circuits of the phase memory A4 to the switch 7, but if the memory capacity is large, the phase memory
A4, phase memory B5, and switch 7 can be realized by one memory. Further, instead of the scanning start timing from the beam scanning command unit (not shown in FIG. 1) of the radar device, for example, information for identifying the beam scanning mode should be added to the azimuth step number information or the elevation step number information. For example, the switch 7 becomes unnecessary.

〔The invention's effect〕

As described above, according to the beam scanning method of the present invention, in the beam scanning method of the radar device for detecting a target using the phased array antenna that electronically scans the pencil beam two-dimensionally, Regarding the first azimuth direction scanning, a beam having both ends of the required azimuth coverage area as the beam nose and a beam in which the adjacent beams in the required azimuth coverage area have the same degree of overlap are generated. The beam is sequentially scanned according to the azimuth angle from either one of the two ends of the azimuth coverage area, and the center azimuth angle between the beam noses during the first azimuth scanning is the beam nose during the second azimuth scanning. And a beam with an overlap equal to the overlap of the beams immediately before and after the ends of the required azimuth coverage,
As in the first azimuth scanning, the beams are sequentially scanned in accordance with the azimuth angle, and after the third azimuth scanning, the beam combinations in the first and second azimuth scannings are alternately executed. Therefore, it is possible to eliminate a portion where the antenna gain in the azimuth direction is lowered without significantly increasing the beam scanning time, and it is possible to improve the target detection performance of the radar device.

Further, according to the beam scanning method of the present invention, in the above-described beam scanning method, in the second azimuth scanning, instead of generating beams immediately before and after both ends of the required azimuth coverage area, the required azimuth coverage is changed. Since the beam with the beam nose at both ends of the range is generated, it is possible to eliminate the portion where the antenna gain in the azimuth direction is lowered without significantly increasing the beam scanning time, and to detect the target of the radar device. It has the effect of improving performance.

Further, according to the beam scanning method of the present invention, in the beam scanning method of a radar device for detecting a target using a phased array antenna that electronically scans a pencil beam two-dimensionally, the first method for elevation angle scanning is used. During the second azimuth scanning, a beam with both ends of the required elevation angle coverage as beam noses and a beam in which the adjacent beams in the required elevation coverage area are overlapped to the same extent are generated. The beam is sequentially scanned from either one of both ends according to the elevation angle, and the beam whose nose is the central elevation angle between the beam noses during the first azimuth scanning during the second azimuth scanning is required. Beams having the same overlap as the above-mentioned beams are generated immediately above and below both ends of the elevation coverage, and the same as in the first azimuth scanning. Beam scanning is performed sequentially according to the elevation angle, and the beam combinations for the first and second azimuth scanning are alternately executed after the third azimuth scanning, so the time required for beam scanning is significantly increased. In addition, it is possible to eliminate a portion where the antenna gain in the elevation direction decreases and improve the target detection performance of the radar device.

Further, according to the beam scanning method according to the present invention, in the above-described beam scanning method, in the elevation angle direction scanning at the time of the second azimuth direction scanning, instead of generating beams directly above and below both ends of the required elevation angle coverage area, In addition, since a beam with both ends of the required elevation angle coverage as the beam nose is generated, it is possible to eliminate a portion where the antenna gain in the elevation direction decreases, without significantly increasing the beam scanning required time, This has the effect of improving the target detection performance of the radar device.

Further, according to the beam scanning method according to the present invention, while performing the above-described beam scanning method for azimuth scanning, at the time of the first azimuth scanning with respect to elevation scanning, both ends of the required elevation coverage are beam nose. And a beam in which adjacent beams in the required elevation angle coverage area have the same degree of overlap, and the beam is sequentially scanned from either one of both ends of the required elevation angle coverage area according to the elevation angle. In the case of azimuth scanning, the beam whose nose is the central elevation angle between the beam noses during the first azimuth scanning is overlapped with the beam just above and below both ends of the required elevation angle coverage. Beam is generated, and the beam is sequentially scanned according to the elevation angle in the same manner as in the first azimuth scanning, and after the third azimuth scanning, the first and the second azimuth scanning are performed. Since the combination of the round first beam during azimuth scanning to run alternately, without increasing the beam scanning time required significantly, it is possible to eliminate the portion of the antenna gain in the azimuth direction and the elevation direction is reduced,
This has the effect of improving the target detection performance of the radar device.

Further, in the beam scanning method according to the present invention, both ends of the required elevation angle coverage area are beam noses at the time of the first azimuth scanning with respect to the elevation scanning while performing the above-described beam scanning method with respect to the azimuth scanning. Beam,
Generates a beam with which the overlap of adjacent beams in the required elevation angle coverage becomes approximately the same, and sequentially scans the beam according to the elevation angle from either one of both ends of the required elevation angle coverage,
At the time of the second azimuth scanning, the beam having the central elevation angle between the beam noses at the time of the first azimuth scanning as the beam nose and the beam having both ends of the required elevation angle coverage as the beam nose are used. Occurrence occurs, and beam scanning is performed sequentially according to the elevation angle as in the first azimuth scanning, and after the third azimuth scanning, the combination of the beams in the first and second azimuth scanning is executed alternately. Therefore, it is possible to eliminate a portion where the antenna gain in the azimuth direction and the elevation direction decreases and to improve the target detection performance of the radar device without significantly increasing the time required for beam scanning.

[Brief description of drawings]

FIG. 1 is a diagram showing a circuit configuration of a phased array antenna according to an embodiment of the present invention, and FIGS. 2 to 6 show examples of beam scanning situations corresponding to claims 1 to 5 of the present invention. FIG. 7 is a diagram showing a circuit configuration of a phased array antenna according to an embodiment of the conventional system, and FIG. 8 is a diagram showing an example of a beam scanning situation of the conventional system. In the figure, 1 is an element antenna, 2 is a phase shifter, 3 is a combiner, 4 and 5 are phase memories, 6 is a counter, and 7 is a switch.

Claims (6)

[Claims] 1. A beam scanning method of a radar apparatus for detecting a target using a phased array antenna, which electronically scans a pencil beam two-dimensionally, wherein a required azimuth is obtained during a first azimuth scanning with respect to azimuth scanning. A beam with both ends of the coverage area as beam noses and a beam in which the adjacent beams in the required azimuth coverage area have the same degree of overlap are generated. Beams are sequentially scanned in accordance with the angle, and in the second azimuth scanning, a beam whose nose is the central azimuth angle between the beam noses in the first azimuth scanning, and just before the ends of the required azimuth coverage area. And immediately after that, a beam having the same overlap as the beam overlap is generated, and the beams are sequentially scanned in accordance with the azimuth angle as in the first azimuth scanning, A beam scanning method characterized in that after the third azimuth scanning, the combination of the beams in the first and second azimuth scanning is alternately executed. 2. The beam scanning method according to claim 1, wherein, in the second azimuth direction scanning, instead of generating beams immediately before and after both ends of the required azimuth coverage area, both ends of the required azimuth coverage area are scanned. A beam scanning method characterized by generating a beam as a nose. 3. A beam scanning method of a radar apparatus for detecting a target using a phased array antenna which electronically scans a pencil beam two-dimensionally, wherein a required elevation angle is obtained during the first azimuth scanning with respect to elevation scanning. A beam is generated with the beam nose at both ends of the coverage area, and a beam in which adjacent beams in the required elevation angle coverage area have the same degree of overlap is generated. The beam is sequentially scanned in accordance with the following, and at the time of the second azimuth scanning, the beam having the central elevation angle between the beam noses as the beam nose at the time of the first azimuth scanning and the beam just above both ends of the required elevation angle coverage area and An overlapping beam equal to the overlapping beam is generated immediately below, and the beams are sequentially scanned according to the elevation angle as in the first azimuth direction scanning. Then, the beam scanning method is characterized in that after the third azimuth scanning, the combination of the beams in the first and second azimuth scanning is alternately executed. 4. The beam scanning method according to claim 3, wherein, in the elevation scanning in the second azimuth scanning, instead of generating beams directly above and below both ends of the required elevation coverage, the required elevation scanning is performed. A beam scanning method characterized in that a beam having beam noses at both ends of the region is generated. 5. The beam scanning method according to claim 1, wherein a beam having a nose at both ends of the required elevation angle coverage area during the first azimuth direction scanning with respect to the elevation angle direction scanning, and a beam within the required elevation angle coverage area A beam is generated so that the overlap of adjacent beams is approximately the same, and the beam is sequentially scanned from either one of both ends of the required elevation angle coverage area according to the elevation angle. During the second azimuth direction scanning, the first direction azimuth direction is scanned. The beam whose nose is the central elevation angle between each beam nose at the time of directional scanning, and the beam which has the same overlap as the beam above and below both ends of the required elevation angle coverage are generated. Similar to the azimuth scanning, the beams are sequentially scanned according to the elevation angle, and after the third azimuth scanning, the combination of the beams for the first and second azimuth scanning is performed. Beam scanning method and executes the alternately. 6. The beam scanning method according to claim 1 or 2, wherein a beam whose nose is at both ends of the required elevation coverage during the first azimuth scanning with respect to the elevation scanning, and a beam within the required elevation coverage. A beam is generated so that the overlap of adjacent beams is approximately the same, and the beam is sequentially scanned from either one of both ends of the required elevation angle coverage area according to the elevation angle. During the second azimuth direction scanning, the first direction azimuth direction is scanned. A beam with the central elevation angle between each beam nose at the time of directional scanning as the beam nose and a beam with both ends of the required elevation angle coverage as the beam nose are generated, the same as at the first azimuth scanning. Beam scanning sequentially according to the elevation angle, and after the third azimuth scanning, a combination of beams for the first and second azimuth scanning is alternately executed. Beam scanning method.