JPH02161382A - Video display circuit for radar - Google Patents

Abstract

PURPOSE:To contrive the decrease of an azimuth error of a digital beam forming radar by using a monopulse coefficient generator for generating a variable value, based on beam directional azimuth information of an antenna, and selecting a monopulse coefficient. CONSTITUTION:When a beam pattern of a digital beam forming (DBF) antenna 1 is different by the directional direction, a monopulse coefficient outputted from a monopulse coefficient generator 7 is made variable, based on azimuth information from an azimuth information generator 6, and a monopulse coefficient by which an error of a video display becomes small is selected, and stored in a monopulse coefficient use register 8. Subsequently, when a reflecting signal is inputted from a target to the antenna 1, with respect to patterns of the sum and a difference of two pieces of beam patterns, a difference signal/a sum signal are detected by a DELTA/SIGMA detector 4 through a SIGMA receiver/a DELTA receiver 2, 3, respectively, multiplied by the monopulse coefficient stored in the register 8 by an angle correction computing element 5, and a deflection angle correction quantity from a beam nose angle is derived from a prescribed approximate expression. In such a way, an azimuth error can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to improvements in radar video display circuits.

[Conventional technology]

The video display circuit of a normal digital beamforming (hereinafter abbreviated as DBF) radar uses one type of monopulse coefficient for each elevation angle scan, multiplies this by the Δ signal/Σ signal, and calculates P P I (PlanPosition
n Indication) is displayed on the scope.

The principle of detecting orientation errors using monopulses is shown in pages 275 to 279 of IEICE Line Radar Technology, and FIG. 3 shows a system diagram of such a conventional video display circuit.

Next, the operation will be explained. When the reflected signal from the target is input to the antenna 10 and the antenna has a monopulse antenna pattern, the input received in the pattern of the sum of two beam patterns is input to the Σ receiver 2. Further, the input received in the pattern of the difference between the two beam patterns is input to the Δ receiver 3. The Σ signal obtained by the Σ receiver 2,
The Δ signal obtained by the Δ receiver 3 is input to a Δ/Σ detector 4 that detects the Δ signal/Σ signal. This output and the monopulse coefficient created by the monopulse coefficient setter 11 are multiplied together by the angle correction calculator 5, and the amount of declination correction from the beam nose angle is determined using the following approximate formula, and the amount of angle correction is calculated and output. do.

The following formula is used as an approximate formula.

φ knee φII −MX (Δ/Σ) One φ and two angle correction amount φ for φ? I: Beam nose azimuth φ7, target azimuth M: monopulse coefficient Δ/Δ signal Σ/Σ signal, and the target was displayed in PPI after being corrected by the amount of declination correction from this beam nose angle.

[Problem to be solved by the invention]

Since the conventional circuit is configured as described above, DB
Even when the beam pattern is different between the front azimuth and the end of the azimuth in the F antenna, only a fixed value can be selected as the monopulse coefficient, which has the drawback of increasing the azimuth error in video display.

The present invention was made to solve these problems, and it is an object of the present invention to obtain a radar video display circuit that can reduce the azimuth error of video display even when the beam pattern differs depending on the beam direction direction in a DBF radar. With the goal.

[Means to solve the problem]

A radar video display circuit according to the present invention uses a monopulse coefficient generator that generates variable values based on antenna beam direction information, and selects monopulse coefficients that can reduce errors in video display.

[Effect]

In the video display circuit according to the present invention, the monopulse coefficient can be varied based on the information on the beam direction direction of the antenna to correct the angle from the target beam nose, so that the direction correction error is reduced.

〔Example〕

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

In FIG. 1, 1 is a DBF antenna, and 2 to 5 are the same as the conventional circuit described above. 6 is an azimuth information generator, 7 is a monopulse coefficient generator into which azimuth information from the azimuth information generator 6 is input, and 8 is a register for monopulse coefficients.

In the video display circuit of this embodiment configured as described above, when the beam pattern of the antenna pattern of the DBF antenna 1 whose phase can be digitally controlled is different between the front direction and the direction end, the direction information generator 6 The monopulse coefficient, which is the output of the monopulse coefficient generator 7, can be varied based on the azimuth information from the monopulse coefficient generator 7. Therefore, at this time, a monopulse coefficient that reduces the error in video display is selected based on the beam orientation of the antenna, and is stored in the monopulse coefficient register 8.

On the other hand, as in the conventional circuit, when the reflected signal from the target is input to the DBF antenna 1, if it has a monopulse antenna pattern, the input received in the pattern of the sum of two beam patterns will be transmitted to the Σ receiver. 2 is input. Also 2
The input received by the difference pattern of the beam patterns is Δ
The signal is input to the receiver 3. The Σ signal obtained by the Σ receiver 2 and the Δ signal obtained by the Δ receiver 3 are input to a Δ/Σ detector 4 that detects the Δ signal/Σ signal. The output of this Δ/Σ detector 4 and the monopulse coefficient stored in the monopulse coefficient register 8 are multiplied by the angle correction calculator 5, and the amount of declination correction from the beam nose angle is calculated using the following approximate formula. , calculate and output the angle correction amount.

The following formula is used as an approximate formula.

φ, -φi-MX (Δ/Σ) φ8-φ7: Angle correction amount φM: Beam nose azimuth φ, 1: Target azimuth M: Monopulse coefficient (varies depending on the azimuth) Δ: Δ signal Σ; Σ signal this The target PPI is displayed by correcting the deviation angle from the beam nose angle.

In the above embodiment, an azimuth information generator 6 is provided to correct the azimuth direction, but instead of this, an elevation information generator 9 is provided as shown in FIG. 2 to correct the elevation direction. It is also possible to implement, and the same effect as the above embodiment can be obtained. Note that the following equation is used as an approximate equation at this time.

φ! −φr−MX(Δ/Σ) φ! -φ, : Angle correction amount φ, : Beam nose elevation angle φt : Target elevation angle M : Monopulse coefficient (changes depending on the elevation angle) Δ : Δ signal Σ : Σ signal [Effects of the Invention] As described above, according to the present invention, For example, we have provided an azimuth information generator that generates information on the beam orientation of the antenna, and a monopulse coefficient generator that generates variable monopulse coefficients depending on the beam orientation, so that when the beam pattern differs depending on the beam orientation in a DBF antenna, This also has the effect of reducing orientation errors in video display.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a radar video display circuit according to an embodiment of the present invention, FIG. 2 is a system diagram showing another embodiment of the invention, and FIG. 3 is a system diagram of a conventional video display circuit. FIG. 4 is an explanatory diagram of a monopulse beam pattern. 1...DBF antenna, 2...Σ receiver, 3...
Δ receiver, 4...Δ/Σ detector, 5... Angle correction calculator, 6... Direction information generator, 7... Monopulse coefficient generator, 8... Monopulse coefficient register, 9...
- Elevation angle information generator, 10... antenna, 11... monopulse coefficient setter. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A Δ/Σ detector that calculates a Δ signal/Σ signal from the sum video (Σ signal) and difference video (Δ signal) of the digital beamforming radar, and an azimuth information generator that generates information on the beam orientation of the antenna. 1. A video display circuit for a radar, comprising: a monopulse coefficient generator that generates variable monopulse coefficients depending on the beam direction direction; and an angle correction calculator that performs angle correction using the monopulse coefficients.