JPH0534446A - Target detection circuit - Google Patents

Abstract

PURPOSE:To provide a target detection circuit whose resolution performance is enhanced. CONSTITUTION:When receiving beam information (a), a beam integrating circuit 1 integrates information on the positions of plural beams which are considered to be responses to the same target. An elevation angle measuring circuit 2 and a target separating circuit 4 perform monopulse measurement of the angles of elevation of the uppermost beam and the lowermost beam in the direction of elevation among all beam information (b) and determine whether or not the difference between both of the angles measured is more than a specified value. An azimuth measuring circuit 3 and an azimuth-target separating circuit 5 perform a similar process as to an azimuth. A plural-target judging circuit 6 finds the phase difference between an addition beam and a subtraction beam as to each beam involved in the information (b) on all the beams, and when the phase difference is other than 0 deg. or 180 deg. (g) judges that there are two targets. When information(g) on the judgement of plural targets indicates two targets, a target deciding circuit 7 uses both or either of information (e) about elevation information and information (f) about azimuth separation to output target information (h) as to the two targets.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a target detecting circuit in a radar device of a monopulse angle measuring system.

[0002]

2. Description of the Related Art As is well known, there are two-dimensional radar and three-dimensional radar in radar devices, and the angle measuring method is one in which both the elevation direction and the azimuth direction are monopulse angle-measured. In some cases, the angle in the direction in which the monopulse is not measured is obtained by another means.

In any case, in the monopulse angle measuring type radar apparatus, the coverage area is scanned by the antenna, a plurality of beams considered to be the response from the same target are put together, and the monopulse angle measuring of the beam close to the target is performed. A target detection method is adopted in which the target position is determined using a value.

Specifically, for example, as shown in FIG. 2, when the beams 1 to 7 are scanned by the antenna and the targets are detected in the beams 3 and 4, the targets are detected from the respective monopulse angle measurement values. The monopulse angle measurement value of the beam (for example, the beam 3) close to is set as the target position.

[0005]

As described above, according to the conventional target detection method, a plurality of beams which are considered to be responses from the same target are put together, and the target is detected by using the monopulse angle measurement value of one beam from the beams. Since detection is performed, there is a problem that correct target detection cannot be performed in the case where there are a plurality of targets that are close to each other and the beams affected by them are combined as a response from the same target.

For example, as shown in FIG. 3, there are two targets A and B which are close to each other, and they are beam 1 to beam 2
When the response is up to 0, all the beams are judged to be responses from the same target and are combined, so that the monopulse angle measurement in which the targets A and B are distinguished cannot be performed.

In short, the ability to correctly detect a target unless it is separated by more than a certain interval is called resolution performance. In the conventional target detection method, for example, as shown in FIG. At least 2 as undetected position
Since the beam step is required, there is a problem that the resolution performance cannot be about 3 times or less of the beam step.
In recent years, shortening the coverage scanning time has become one of the development issues, but for that purpose, the interval between beam steps must be widened, and improvement is desired.

It is an object of the present invention to provide a target detection circuit which can improve the resolution performance of a monopulse angle measuring type radar device.

[0009]

In order to achieve the above object, the target detection circuit of the present invention has the following configuration. That is, the target detection circuit of the first aspect of the invention is a target detection circuit in a radar device that performs monopulse angle measurement in the elevation direction and the azimuth direction; the target detection circuit is a plurality of beam positions that are considered to have the same target response. A beam integrating means for collecting information; and an elevation measuring means for receiving the output of the beam integrating means, selecting an uppermost beam and a lowermost beam in the elevation direction, and performing monopulse angle measurement of those elevation angles; An azimuth angle measuring means for receiving the output of the beam integrating means and selecting the rightmost beam and the leftmost beam in the azimuth direction for monopulse angle measurement; and receiving the output of the beam integrating means, the same Target determination means for determining the presence of a plurality of targets from the phase difference between the sum beam and the difference beam of the plurality of beams that are considered to be the target response of the plurality of beams; High and low target separation means for determining whether the difference between the two angle measurement values is a specified value or more; and A direction for determining whether the difference between the two angle measurement values is a specified value or more in response to the output of the azimuth angle measurement means. Target separation means; and a plurality of target determination means,
Target determining means for determining the position of the target by receiving the outputs of the high and low target separating means and the azimuth target separating means, respectively.

Further, the target detecting circuit of the second invention is a target detecting circuit in a radar device for measuring a monopulse angle in one of the elevation direction and the azimuth direction; the target detecting circuit has the same target response and Beam integrating means for collecting positional information of a plurality of possible beams; and an angle measuring method for receiving the output of the beam integrating means, selecting two beams that are most distant in a direction related to the monopulse angle measuring, and measuring those angles by the monopulse angle. Means for receiving the output of the angle measuring means and determining whether or not the difference between the two angle measurement values is a prescribed value or more; and for receiving the output of the beam integrating means, the same target response is considered. A plurality of targets determining means for determining the existence of a plurality of targets from the phase difference between the sum beam and the difference beam of the plurality of beams; Target determining means for determining a position of a target by receiving an angle value in a direction in which monopulse angle measurement is not performed;

[0011]

Next, the operation of the target detecting circuit of the present invention constructed as described above will be described. In the present invention, when there are targets approaching each other, focusing on the fact that the outer beam has a small angle measurement error among a plurality of beams that are considered to have the same target response, the azimuth direction and the elevation direction (first 1 invention)
Alternatively, in either one (second invention), the outermost beam is detected and it is determined whether or not the angular difference between them is equal to or greater than a specified value, and the presence of an approaching target is determined by the phase difference between the sum beam and the difference beam. Detect by. Then, when there is a target approaching, an angle in two directions (a height angle and an azimuth angle in both or one of the height direction and the azimuth direction) showing a specified value or more is output as target information.

As a result, even if the two targets are close to each other by about one beam step, the two targets can be accurately detected, and the resolution performance can be improved more than ever before.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a target detection circuit according to an embodiment of the present invention. In the present embodiment, the case where the present invention is applied to a three-dimensional radar that performs monopulse angle measurement in the elevation direction and the azimuth direction is shown. Less than,
Description will be made with reference to FIG. 3 as appropriate.

In FIGS. 1 and 3, the beam integration circuit 1
The beam information a input to is generated by a three-dimensional radar device (not shown), and includes the direction and response information of the beam scanned by the antenna, and the response information includes the signal for detecting the target distance and the sum. An amplitude signal containing phase information of the beam and an amplitude signal containing phase information of the difference beam are included.

The beam integrating circuit 1 collects the direction and response information of adjacent beams (for example, the beam of number 1 to the beam of number 20 in FIG. 3) having the same target response, and collects the direction information and the response information. As b, it is output in parallel to the elevation angle measuring circuit 2, the azimuth angle measuring circuit 3, and the multiple target determination circuit 6 in units of target.

The elevation angle measuring circuit 2 selects the uppermost beam (for example, the beam of number 7) and the lowermost beam (for example, the beam of number 10) from all the beam information b, and uses the respective response information. Angle measurement information that includes the elevation angle and azimuth angle obtained from each beam
Is output to the high / low target separation circuit 4.

Further, the azimuth angle measuring circuit 3 uses the total beam information b.
Select the leftmost beam (eg beam number 1) and the rightmost beam (eg beam number 19) from
The monopulse angle measurement is performed using the respective response information, and the azimuth angle measurement information d containing the azimuth angle and the elevation angle obtained from each beam is output to the azimuth target separation circuit 5.

The height target separation circuit 4 receives the height measurement information c, compares the height angles of the upper beam 7 and the lower beam 10, and determines whether the difference is greater than or equal to a specified value. The specified value is an empirical reasonable value such as 3/4 of the beam width.
In the example of FIG. 3, the difference in elevation angle between the beam 7 and the beam 10 is less than or equal to a specified value. The high / low target separation circuit 4 puts together this judgment result and the high / low angle measurement information c and puts it together into the high / low separation information e.
Is output to the target determination circuit 7.

The azimuth target separation circuit 5 receives the azimuth angle measurement information d, compares the azimuth angles of the beam 1 on the left side and the beam 19 on the right side, and determines whether the difference is equal to or more than a specified value. The specified value is an empirical reasonable value as described above. In the example of FIG. 3, the angle of the beam 1 reflects the position of the target A, and the angle of the beam 19 reflects the position of the target B. That is all. The azimuth target separation circuit 5 compiles this determination result and the azimuth angle measurement information d, and outputs it as the azimuth separation information f to the target determination circuit 7.

Next, the multiple target determination circuit 6 executes the phase difference between the sum beam and the difference beam of the response information of each beam in the total beam information b. This phase difference is 0 ° or 180 when there are multiple targets.
Angle other than °, 0 ° or 180 ° when not present
Angle. This determines the presence of multiple goals. In the example of FIG. 3, the numbers 8, 9, 12, and 13 that are close to both the target A and the target B indicate that the phase difference between the sum beam and the difference beam in the azimuth direction is an angle other than 0 ° or 180 °. Therefore, it is possible to determine that there are multiple targets in the azimuth direction. This determination result is output to the target determination circuit 7 as the multiple target determination information g.

The target determination circuit 7 receives the multiple target determination information g as a control signal, and when there are no multiple targets,
The height information and the azimuth information obtained from the height separation information e and the azimuth separation information f are averaged to output target information h for one target. On the other hand, when there are multiple targets, the high / low separation information e
And the azimuth separation information f are detected that the difference in the angle measurement values by the beams in the two directions is a specified value, and when both information are both above the specified value, the elevation angle and the azimuth in the two directions in both directions are detected. The angle is output as the target information h of two targets, and when the information of any one is equal to or more than the specified value, the elevation angle and the azimuth angle in two directions in any one of them are output as the target information h of the two targets. . In the example of FIG. 3, it is in the azimuth direction that the angle measurement values of the beams in the two directions are equal to or more than the specified value.
The respective azimuth angles and elevation angles of 19 are output as two targets. In the present invention, it can be seen that the two targets can be correctly detected even if they are separated by one beam step.

When applied to a radar device for measuring a monopulse angle in only one of the elevation direction and the azimuth direction,
Either the elevation measurement circuit 2 and the elevation target separation circuit 4 or the azimuth measurement circuit 3 and the orientation target separation circuit 6 will be provided.

[0023]

As described above, according to the target detecting circuit of the present invention, both the azimuth direction and the elevation direction (first invention).
Alternatively, in either one (second invention), the outermost beam with a small angle measurement error is detected, and it is determined whether or not the angular difference between them is equal to or greater than a specified value. It is detected by the phase difference with the beam. Then, when there is a target approaching, the angles in two directions (the height angle and the azimuth angle in both the height direction and the azimuth direction, or both of the height direction and the azimuth direction) indicating the specified value or more are output as the target information. Even if the two targets are close to each other by about one beam step, the two targets can be accurately detected, and there is an effect that the resolution performance can be further improved as compared with the conventional case. This effect becomes more remarkable when the interval between beam steps is wide.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a target detection circuit according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of beam scanning of an antenna.

FIG. 3 is an explanatory diagram of a target detection operation when two targets are close to each other.

FIG. 4 is an explanatory diagram of resolution performance obtained by a conventional target detection operation when two targets are close to each other.

[Explanation of symbols]

1 beam integrated circuit 2 High and low angle measuring circuit 3 azimuth angle measuring circuit 4 High and low target separation circuit 5 direction target separation circuit 6 Multiple target judgment circuit 7 Target decision circuit

Claims (2)

[Claims] 1. A target detection circuit in a radar device for monopulse angle measurement in elevation direction and azimuth direction; the target detection circuit is a beam integration means for collecting positional information of a plurality of beams considered to have the same target response. An elevation measuring means for receiving an output of the beam integrating means, selecting an uppermost beam and a lowermost beam in a height direction, and performing a monopulse angle measurement of those elevation angles; and an output of the beam integrating means. And a azimuth angle measuring means for selecting the rightmost beam and the leftmost beam in the azimuth direction and measuring their azimuth angle by a monopulse; and the same target response is considered upon receiving the output of the beam integrating means. A plurality of target determination means for determining the existence of a plurality of targets based on the phase difference between the sum beam and the difference beam of the plurality of beams; and a difference between the two angle measurement values defined by the output of the elevation angle measurement means. A high / low target separating means for determining whether or not the above; an azimuth target separating means for receiving an output of the azimuth angle measuring means and determining whether or not a difference between both angle measurement values is a specified value or more; A target detecting circuit for receiving the outputs of the means, the height target separating means, and the azimuth target separating means to determine the position of the target, and a target detecting circuit. 2. A target detection circuit in a radar device for measuring a monopulse angle in either one of a high-low direction and an azimuth direction; the target detection circuit outputs position information of a plurality of beams considered to have the same target response. A beam integrating means for collecting; an angle measuring means for receiving the output of the beam integrating means, selecting two beams most distant from each other in a direction relating to the monopulse angle measuring, and measuring the angles of those beams by the monopulse; output of the angle measuring means A target separating means for determining whether or not the difference between the two angle measurement values is equal to or more than a specified value; and a sum beam of a plurality of beams that are considered to have the same target response and receive the output from the beam integrating means A plurality of target determination means for determining the presence of a plurality of targets based on the phase difference from the beam; the outputs of the target separation means and the plurality of target determination means; Target detecting circuit comprising the; receiving, a target determination means for determining the position of the target.