JP2830596B2 - Monopulse angle measuring circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monopulse angle measuring circuit, and more particularly, to a monopulse angle measuring circuit in a radar apparatus for tracking a beam by scanning the direction of an antenna beam in accordance with the movement of a target.

[0002]

2. Description of the Related Art A conventional monopulse angle measuring circuit measures the amplitude and phase of a sum beam and a difference beam obtained from a monopulse antenna as shown in FIG. The phase difference between the sum beam and the difference beam is calculated, and the detected target is detected using the previously input amplitude ratio and monopulse data indicating the relationship between the phase difference and the angle shown in (b) and (c) of FIG. Measure the position. For example, when the target exists at the position shown in FIG.
Since the phase difference is measured as β, the angle indicating the deviation from the beam direction based on the monopulse data shown in (b) and (c) is γ. Here, the angle range for angle measurement processing is
The minimum target in which angle measurement is difficult is limited to a range in which the angle can be accurately measured at the longest distance. Normally, the amplitude ratio that is an angle inside the half width at the boundary is targeted for angle measurement.

[0003]

In this conventional monopulse angle measuring circuit, the range in which the angle can be measured is determined based on the smallest target at the longest distance, so that the target distance approaches as shown in FIG. Thus, even when the S / N ratio is improved and the angle measurement range can be expanded, the angle measurement range remains constant. For this reason, in a radar device that performs beam tracking by scanning the direction of the antenna beam in accordance with the movement of the target, as shown in FIG. There is a problem that the influence of the movement of the camera on the angle becomes large and it becomes difficult to continue tracking. An object of the present invention relates to a monopulse angle measuring circuit that can maintain tracking continuity even when a target comes close.

[0004]

SUMMARY OF THE INVENTION The present invention provides an angle measuring range determining means for determining a range in which monopulse angle measurement is possible based on detected distance information, and an amplitude of a difference beam and a sum beam for monopulse angle measurement. A monopulse data storage unit for storing a combination of data of a ratio and a phase difference and an angle indicating a deviation from a beam center , based on the determined angle measurement range;
The monopulse used from the monopulse data storage means
And angle measuring means for determining a single pulse angle within the angle measuring range based on the amplitude and phase of the sum beam and the difference beam of the monopulse pattern.

[0005]

Next, the present invention will be described with reference to the drawings. FIG. 1 shows a monopulse angle measuring circuit according to one embodiment of the present invention. In the figure, detection distance information a, sum beam information b, and difference beam information c are generated by a monopulse type radar device (not shown). Detection distance information a is information indicating a distance at which the amplitude of the sum beam is equal to or greater than a specified value, sum beam information b is information indicating the amplitude and phase of the sum beam of the monopulse pattern, and difference beam information c is information of the difference beam of the monopulse pattern. This is information indicating the amplitude and the phase.

The angle measurement range determination circuit 1 outputs angle measurement range information d indicating a range in which angle measurement is possible from the detected distance information a.
In the range in which the angle measurement is possible, as shown in FIG. 3, the S / N is improved when the target distance that can be detected is reduced.
As shown by the solid line. Further, in order to simplify the processing of this circuit, there is a method of defining the range stepwise as shown by a broken line in FIG.

The monopulse data storage circuit 2 has an amplitude ratio (difference beam amplitude / sum beam amplitude) and a phase difference (difference beam phase−sum beam amplitude) between the sum beam and the difference beam shown in FIGS. 2 (b) and 2 (c). Data indicating the relationship between the phase) and the angle indicating the deviation from the beam center is stored, and a combination of the data is output as monopulse data e. The angle measurement processing circuit 3 inputs the sum beam information b, the difference beam information c, and the monopulse data e, and performs monopulse angle measurement. The range of the monopulse data e used at that time is angle measurement range information d.
Determined based on For example, when the angle measuring range is determined by the solid line in FIG. 4, the angle is measured in a range of 0.5 deg or less at a distance of 20 NM, and the angle is measured in a range of 1.0 deg or less at a distance of 5 NM. Here, FIG. 4 shows an example in which the half width is 1 °.

Therefore, in this angle measuring circuit, the angle measuring range judging circuit 1 outputs angle measuring range information d capable of angle measurement based on the detected distance information a, and on the other hand, the monopulse data storage circuit 2 outputs a monopulse data. The data e is output, and the angle measurement processing circuit 3 determines the monopulse data e to be used based on the angle measurement range information d. For this reason, when the target approaches, the angle measurement range information d is expanded, so that the range of the monopulse data e to be used is also expanded, and the tracking of the target can be easily continued.

[0009]

As described above, according to the present invention, as the target becomes closer, the range in which the angle can be measured is expanded , and
Since the corresponding monopulse data is determined, the radar apparatus that scans the target with an aerial beam and performs beam tracking has an effect that the tracking continuation can be maintained with a high probability even when the target is short. In particular, when a large acceleration occurs at a short distance, the tracking probability is greatly improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of an angle measuring circuit according to the present invention.

FIG. 2 is an explanatory diagram of a monopulse antenna pattern and monopulse data.

FIG. 3 is a diagram showing a relationship between relative S / N and distance.

FIG. 4 is a diagram showing a relationship between an angle measurement range and a distance.

FIG. 5 is a diagram showing a relationship between a movement of a target and an angle measurement range.

[Explanation of symbols]

 1 angle measurement range determination circuit 2 monopulse data storage circuit 3 angle measurement processing circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01S 7/00-7/42 G01S 13/00-13/95 H01Q 3/00-3/46 H01Q 21 / 00-21/30 H01Q 23/00 H01Q 25/00-25/04

Claims (1)

(57) [Claims] 1. A monopulse angle measuring circuit of a radar apparatus having a monopulse antenna, wherein an angle measurement range determining means for determining a range in which monopulse angle measurement is possible based on detected distance information, and for performing monopulse angle measurement. Monopulse data storage means for storing a combination of the amplitude ratio and the phase difference between the difference beam and the sum beam and the angle indicating the deviation from the beam center , based on the determined angle measurement range
Monopulse used from the monopulse data storage means
A monopulse angle measuring circuit, comprising: an angle measuring means for determining data and performing monopulse angle measurement within an angle measuring range based on the amplitude and phase of a sum beam and a difference beam of the monopulse pattern.