JP2877991B2 - Monopulse radar goniometer - 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 type radar goniometer for two-dimensionally measuring a monopulse angle in an electronic scanning antenna.

[0002]

2. Description of the Related Art In a monopulse type radar goniometer, the direction of a target beam present in a beam (hereinafter, referred to as "boresight direction") to the azimuth (AZ) direction and elevation (EL) are measured by one beam transmission. ) Direction (hereinafter, referred to as “off-bore sight angle”). Hereinafter, first, the principle of angle measurement will be described with reference to FIG.
Thereafter, a conventional angle measuring method will be described with reference to FIGS.

In FIG. 4, as shown in FIG.
The radar device 41 emits a scanning beam two-dimensionally from the antenna 42 to scan the covered area evenly.
As shown in FIG. 4B, there are two types of antenna patterns, a sum (Σ) pattern and a difference (Δ) pattern in which the phases are inverted with respect to each other. Among them, the sum (使用) pattern is used for transmission and reception, and the difference (Δ) pattern is used for reception. However, when performing monopulse angle measurement in two directions, azimuth (AZ) and elevation (EL), the delta _AZ beam for azimuth, respectively formed independently delta _EL beam for elevation.

Then, as shown in FIGS. 4 (c) and 4 (d),
In the azimuth angle measurement, Δ _AZ / Σ (reception amplitude ratio) is obtained, and in the elevation angle measurement, Δ _EL / Σ (reception amplitude ratio) is obtained. By referring to the respective monopulse reference tables, off boresight azimuth Δθ and off It is converted into boresight elevation Δφ, and finally the boresight direction is added to output azimuth and elevation.

Therefore, a conventional monopulse radar goniometer is configured as shown in FIG. 5, and the azimuth angle measuring system (FIG. 5 (a)) and elevation angle measurement system (FIG. 5 (b)), (Δ AZ / Σ) video, (delta _EL /
I) The corresponding video is input from the receiver. These are the reception amplitude ratios, also called monopulse video, and the sign is determined depending on whether the Δ video and the Σ video are in phase or opposite phase. The monopulse video is assumed to be input in a digital format for the sake of simplicity.

The reference table is created with the monopulse curve characteristic at the beam center slice plane as a representative. In the azimuth angle measuring system (FIG.
The off-bore sight azimuth converter 51 obtains the off-bore sight azimuth Δθ based on the azimuth monopulse reference table, and the adder 52 adds Δθ and the bore sight azimuth θ _bore to output the azimuth θ. Also in the elevation angle measuring system (FIG. 5B), the elevation φ is output in the same procedure.

[0007]

As described above, in the monopulse radar goniometer, a monopulse reference table created using the monopulse curve characteristic on the beam center slice plane as a representative is used. Then, simply
In the conventional method of obtaining the azimuth θ and the elevation φ by setting Δθ + θ _bore = θ and Δφ + φ _bore = φ, the problem that the angle measurement error is inevitable and the angle measurement error becomes larger as the target deviates from the beam center. is there. This is a problem common to both the azimuth angle measurement and the elevation angle measurement. Hereinafter, azimuth angle measurement will be described as an example.

In FIG. 6, as shown in FIG.
Δ _{AZ (-)} pattern and Δ _{AZ (+)} pattern are formed with respect to the Σ pattern, and the slice plane A is the beam center,
Assuming that the target is on the slice plane B deviated from the beam center in the elevation direction, the monopulse curve characteristics of the slice plane A and the monopulse curve characteristics of the slice plane B are as follows.
It is not strictly equal, and is different as shown in FIG. Therefore, in the target angle measurement existing on the slice plane B, an angle measurement error occurs according to the conventional method. The slice plane B in the azimuth angle measurement is defined by the boresight elevation Δφ. The relationship between the off-boresite azimuth Δθ obtained by calculating the target existing in the slice plane B by the monopulse curve of the slice plane A and the angle measurement error is as follows. , FIG.
(C). This angle measurement error curve is shown in FIG.
Although it is shown as a straight line in (c), it is actually a curve, but the inclination increases as the slice plane B moves away from the beam center, so that the angle measurement error increases. In the past, it was difficult to obtain the monopulse curve characteristics on various slice planes, so that the occurrence of angle measurement errors was tolerated.However, precise approach radar requires accurate angle measurement, and improvement is expected. It is rare.

SUMMARY OF THE INVENTION An object of the present invention is to provide a monopulse type radar goniometer capable of correcting an angle measurement error occurring at a target located at a position distant from the beam center when measuring the angle with the monopulse curve characteristic of the beam center slice plane as a representative. To provide.

[0010]

To achieve the above object, a monopulse radar goniometer according to the present invention has the following configuration. That is, the monopulse radar goniometer according to the first invention includes an azimuth monopulse reference table created on the basis of the monopulse curve characteristics on the beam center slice plane, and receives an azimuth reception amplitude ratio (azimuth difference beam) input from the outside. A monopulse / off-bore sight azimuth converter for converting the reception level of the beam by the reception level of the sum beam into an off-bore sight azimuth with reference to the azimuth mono-pulse reference table; a mono-pulse curve at a beam center slice plane; An elevation monopulse reference table created as a representative of characteristics is provided, and an elevation reception amplitude ratio (a value obtained by dividing an elevation difference beam reception level by a sum beam reception level) input from the outside is used for the elevation. Refer to the monopulse reference table for off bore size. A monopulse / off-boresight elevation converter for converting to elevation; an angle-measuring corrector that receives outputs of the two converters and performs angle-correction for both azimuth and elevation; Off-bore sizing to correct off-bore azimuth on the slice plane
An azimuth corrector that outputs the to azimuth correction value and an off-bore sight elevation correction that corrects off-bore sight elevation on the slice plane in azimuth
And a elevation corrector that outputs a value, azimuth
Compensators include off-bore sight azimuth and off-bore sight
Elevation is input and the elevation compensator is
From fbosite elevation and azimuth corrector
Off-bore sight azimuth correction value is entered, or
Is an off-boresight elevator
Azimuth and off-bore site azimuth are entered
The compensator includes off-bore sight azimuth and the elevation
Off boresight elevation correction value from the
Linked with angle measuring corrector comprising as input; Ofuboa of the angle measuring corrector off boresight azimuth correction value and the adder and angle measuring corrector adds the boresight azimuth
And an adder for adding the site elevation correction value and the boresight elevation. Further, the angle measurement corrector is provided with the azimuth compensator.
Off-bore sight azimuth correction value from
Off-boresight elevation from the motion compensator
With an additional azimuth corrector to enter positive values,
Creates an off-bore sight azimuth correction value output from the corrector.
You may make it start. Alternatively, the angle measurement correction
The off-bore sight from the elevation compensator
Elevation correction value and OFF from the azimuth corrector
Additional elevator to enter boresight azimuth correction value
Off-box output from the goniometer
Even if you create an acite elevation correction value
Good.

Further, the monopulse type radar goniometer according to the second invention has a monopulse curve characteristic on a beam center slice plane.
Monopulse reference table for azimuth
Azimuth reception amplitude ratio input from outside
(The reception level of the difference beam for azimuth is
Divided by the bell) for the azimuth monopulse reference table
To convert to off-bore sight azimuth
Pulse / off-bore sight azimuth converter; in beam
Created as a representative of the monopulse curve characteristics in the heart slice plane
Elevation monopulse reference table
Elevation reception amplitude ratio (E
Reception level of difference beam for elevation is received by sum beam
Monolevel pulse for the elevation)
Off boresight elevation with reference to reference table
To monopulse / off boresight elevation
A converter; receiving azimuths from outputs of both converters;
Angle measurement correction that performs angle measurement correction for both elevations
Sly in off boresight elevation
Off-bore sight to correct off-bore sight azimuth
Azimuth compensator and off-bore that output toazimuth correction values
Off-bore sight elevating at the slice plane at site azimuth
Off boresight elevation correction
And an elevation compensator that outputs a value.
Compensators include off-bore sight azimuth and off-bore sight
Elevation is input and the elevation compensator is
From fbosite elevation and azimuth corrector
Off-bore sight azimuth correction value is entered, or
Is an off-boresight elevator
Azimuth and off-bore site azimuth are entered
The compensator includes off-bore sight azimuth and the elevation
Off boresight elevation correction value from the
Linked with angle measuring corrector comprising as input; incurred on the entire range of measurement of combination patterns of azimuth received amplitude ratio and elevation received amplitude ratio angle, before they
Monopulse / off-bore sight azimuth converter and mono
To a pulse / off boresight elevation converter,
Further, these conversion outputs are given to the angle measurement corrector,
Off-bore sight azimuth correction value and off-bore
Asite elevation correction value
And the combination of the elevation reception amplitude ratio
An angle measurement table creator to be created;
Azimuth received amplitude ratio created by forming unit and Jer Besho
The off-button associated with the combination of
Asite azimuth correction value and off-bore site elevation
An angle measurement table memory for storing an offset correction value ; an azimuth reception amplitude ratio and an elevation reception amplitude ratio externally input during angle measurement as an index ;
Monopulse angle measuring transducer reads and outputs A site elevation correction value and; the off-boresight azimuth
Adder for adding the correction value and boresight azimuth and before
And an adder for adding the off-boresight elevation correction value and the boresight elevation.

[0012]

Next, the operation of the monopulse radar goniometer according to the present invention having the above-described structure will be described. In the first invention,
Both off-boresight azimuth and off-boresight elevation based on the slice plane at the beam center, actually sequentially corrected in consideration of the slice plane target is present, it adds. In the second aspect, correction values for the entire range of angle measurement are obtained and stored in advance, and the corresponding correction values are read and added at the time of angle measurement. Therefore, highly accurate angle measurement is possible. According to the second aspect, the speed of angle measurement can be increased.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a monopulse radar goniometer according to an embodiment of the present invention. In FIG. 1, a monopulse type radar goniometer according to the first embodiment includes an angle compensator 1
Monopulse / off-bore sight azimuth converter 5 described above
It is provided between the 1 and monopulse / off boresight elevation converter 53 and the adders 52 and 54.

The angle measuring corrector 1 includes an azimuth corrector 1a ₁ ,
It has a configuration which is connected in series elevation corrector 1b and azimuth corrector 1a ₂ in this order. That is,
The output (Δθ ₂ ) of the azimuth corrector 1a _{1 in} the preceding stage is input to the azimuth corrector 1a _{2 in} the subsequent stage and is also input to the elevation corrector 1b. The output (Δθ ₃ ) of the azimuth corrector 1 a _{2 at} the subsequent stage is one input of the adder 52. The output (Δφ ₂ ) of the elevation corrector 1b is one input of the adder 52 and is also the input of the azimuth corrector 1a _{2 at} the subsequent stage.

Here, the angle compensator 1 has a monopulse /
From the off-boresight azimuth converter 51 and the monopulse / off-boresight elevation converter 53, the off-boresight azimuth Δθ and the off-boresight elevation Δφ, which are the results of angle measurement based on the monopulse curve characteristic at the beam center, are input. As described above (FIG. 6), the characteristic of the angle measurement error in the azimuth angle measurement is determined by the value of the off boresight elevation, and the characteristic of the angle measurement error in the elevation angle measurement is determined by the value of the off boresight azimuth. Decided. Therefore, off-boresight azimuth Δθ is input to the azimuth corrector 1a ₁ and azimuth corrector 1a _2, off-boresight elevation Δφ is input to the elevation corrector 1b, azimuth corrector 1a
To enter the off-boresight elevation Δφ is to _1,
The azimuth corrector 1a ₂ is input the output of the elevation corrector 1b a (Δφ _2), elevation corrector 1b
Receives the output (Δθ ₂ ) of the azimuth corrector 1a ₁ . Each corrector has an antenna pattern by changing several slice planes, and has characteristic curves of angle measurement errors on various slice planes formed by analyzing the influence of the slice planes.

[0016] In the above configuration, first, in front of the azimuth corrector 1a _1, off-boresight elevation Δ
The azimuth angle measurement error corresponding to the off-bore sight azimuth Δθ is obtained from the angle measurement error curve determined by φ, the obtained azimuth angle measurement error is subtracted from the off-bore sight azimuth Δθ, and the correction value Δθ ₂ of the off-bore sight azimuth is obtained. calculate.

Next, in the elevation corrector 1b,
Seeking elevation angle measurement error corresponding to the off-boresight elevation [Delta] [phi from the angle measurement error curve determined by the off-boresight azimuth [Delta] [theta] _2, by subtracting the obtained elevation angle measurement errors from off boresight elevation [Delta] [phi, off Boresight elevation correction value Δφ
Calculate ₂ .

[0018] Finally, in the subsequent azimuth corrector 1a _2, obtains the azimuth angle measurement errors corresponding to the off-boresight azimuth Δθ from the angle measurement error curve determined by off-boresight elevation [Delta] [phi _2, measuring the determined azimuth angular The error is subtracted from the off-bore sight azimuth Δθ to calculate the off-bore sight azimuth correction value Δθ ₃ .

Then, the adder 52 adds the off-bore sight azimuth correction value Δθ ₃ and the bore sight azimuth θ _bore to output an azimuth θ. Further, the adder 54 adds the off-boresight elevation correction value [Delta] [phi ₂ and boresight elevation phi _bore, and outputs the elevation phi.

As described above, in the angle compensator 1, the off-boresight azimuth and the off-boresight elevation are corrected and updated by alternately passing the azimuth corrector and the elevation corrector in consideration of the beam slice plane. Therefore, although there are three stages in the illustrated example, the correction value can converge to a true value. Hereinafter, description will be made using specific numerical values.

FIG. 2 shows that the off-boresight azimuth Δθ and the off-boresight elevation Δφ before correction are both 0.5.
° indicates that it gradually converges to a true value. Note that, for easy understanding, the error curves of azimuth (FIG. 2A) and elevation (FIG. 2B) are equally represented by a linear expression.

In FIG. 2 (a), since Δφ = 0.5 °, the error curve at the time of the 0.5 ° upper slice gives:
The azimuth angle measurement error when Δθ = 0.5 ° is 0.05 °.
Therefore, the correction value Δθ _{2 for} off-bore sight azimuth is ΔΔ
θ ₂ = 0.5 ° −0.05 ° = 0.45 °. Then, FIG.
In (b), since Δθ ₂ = 0.45 °, the elevation curve error when Δφ = 0.5 ° is 0.045 ° due to the error curve for the 0.45 ° right slice. Therefore, the correction value Δφ ₂ of the off boresight elevation is Δφ ₂
= 0.5 °-0.045 ° = 0.455 °. Next, in FIG. 2A, since Δφ ₂ = 0.455 °, 0.45 °
Due to the error curve for the 5 ° upper slice, Δθ ₂ =
The azimuth angle measurement error at 0.45 ° is 0.04095 °. Therefore, the correction value Δθ ₃ of the off-bore sight azimuth is Δθ
₃ = 0.5 °-0.04095 ° = 0.45905 °.

Although FIG. 1 shows a three-stage configuration, if the same is repeated, the correction value of off-bore sight azimuth becomes Δθ ₄ = 0.5 ° −0.04207 ° = 0.45793 °, Δ
_{θ 5 = 0.5 ° -0.04195 ° =} 0.45805 °, Δθ 6 = 0.5
° -0.04196 ° = 0.45804 °. Further, the correction value of the off-bore sight elevation is Δφ ₃ = 0.5 ° −0.0
4177 ° = 0.45823 °, Δφ ₄ = 0.5 °-0.04197 ° =
_{0.45803 °, Δφ 5 = 0.5 °} -0.04196 ° = 0.45804 °
Is obtained. That is, finally, Δθ ₆ = Δφ ₅ = 0.45804
° and converge. Then, the value of Δθ _{3 in} the third stage gives an error of 0.001 °, so it can be said that practically three stages are sufficient.

FIG. 1 shows a configuration in which the accuracy of the azimuth angle measurement is improved. However, in order to improve the accuracy of the elevation, it is necessary to use one azimuth corrector and two elevation correction devices. Good. In short, the greater the number of azimuth correctors and elevation correctors, the higher the accuracy will be. However, it is only necessary to appropriately configure the azimuth corrector and the elevation corrector depending on which accuracy is the main. May be provided one by one, or a single corrector for only one of azimuth and elevation may be used.

FIG. 3 shows a monopulse radar goniometer according to another embodiment of the present invention. The monopulse type radar goniometer according to the second embodiment includes a circuit according to the first embodiment,
An angle measurement table creator 2, an angle measurement table memory 3, and a monopulse angle measurement converter 4 are added to shorten the time required for the correction operation according to the present invention and to speed up angle measurement.

In FIG. 3, the angle measurement table creator 2
A combination pattern of the azimuth reception amplitude ratio (Δ _AZ / Σ) and the elevation reception amplitude ratio (Δ _EL / Σ) is generated for the entire range of the angle measurement, and these are generated by the monopulse / off boresight azimuth converter 51 and the monopulse / off. The two outputs (off boresight azimuth correction value Δθ) of the angle measurement corrector 1 are given to the corresponding ones of the boresight elevation converter 53.
_3, set stored in off-boresight elevation correction value [Delta] [phi ₂₎ azimuth received amplitude ratio (Δ _AZ / Σ) and elevation received amplitude ratio (delta corner table memory 3 measuring in association with a combination of _EL / sigma). That is, the correction value is obtained in advance before the angle measurement.

Next, at the time of angle measurement, the monopulse angle measurement converter 4 outputs the azimuth reception amplitude ratio (Δ _AZ /
Sigma) video and elevation received amplitude ratio (Δ _EL / Σ)
The off boresight azimuth .DELTA..theta. And off boresight elevation .DELTA..phi. Are read from the angle measurement table memory 3 using the video as an index, and are read out by the adder 52 and 54.
Output to the corresponding one. As a result, the azimuth θ is output from the adder 52, and the elevation φ is output from the adder 54.

The circuit of the first embodiment is suitable when the capacity of the memory is insufficient, and the circuit of the second embodiment is suitable when there is not enough time for the operation.

[0029]

As described above, according to the monopulse radar goniometer of the present invention, in the first invention, both off-bore sight azimuth and off-bore sight elevation based on the slice plane at the beam center are provided. actually sequentially corrected in consideration of the slice plane target is present, adds, and in the second invention, is stored in search of correction values for the entire range of pre-angle measurement, corresponds to the time of angle measurement Since the correction values are read and added, there is an effect that highly accurate angle measurement can be performed. Also, according to the second aspect, there is an effect that the angle measurement can be speeded up.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a monopulse type radar goniometer according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing that an angle measurement error correction value of the present invention converges to a true value.

FIG. 3 is a block diagram illustrating a configuration of a monopulse radar goniometer according to another embodiment of the present invention.

FIG. 4 is a diagram illustrating the principle of monopulse radar angle measurement.

FIG. 5 is a block diagram showing a configuration of a conventional monopulse type radar goniometer.

FIG. 6 is an explanatory diagram of occurrence of an angle measurement error when a target is out of the beam center.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS ₁ Angle measurement corrector 1a ₁ Azimuth corrector 1a ₂ Azimuth corrector 1b Elevation corrector 2 Angle measurement table creator 3 Angle measurement table memory 4 Monopulse angle measurement converter 51 Monopulse / off boresight azimuth converter 52 Adder 53 Monopulse / off boresight elevation converter 54 Adder

Claims (4)

(57) [Claims] 1. An azimuth monopulse reference table prepared as a representative of a monopulse curve characteristic on a beam center slice plane, and an azimuth reception amplitude ratio (a reception level of an azimuth difference beam and a reception level of a sum beam) inputted from outside. A monopulse / off-boresight azimuth converter for converting the value obtained by dividing by the above) into the off-boresight azimuth with reference to the azimuth monopulse reference table; for the elevation created by representing the monopulse curve characteristic on the beam center slice plane as a representative A monopulse reference table is provided, and an elevation reception amplitude ratio (a value obtained by dividing the reception level of the elevation difference beam by the reception level of the sum beam) input from the outside is off-bored with reference to the elevation monopulse reference table. Monopa to convert to site elevation Scan / off boresight elevation transducer and; receiving said output of both transducers, a measuring angle corrector performs angle measuring correction for both azimuth and elevation, the slice plane in the off-boresight elevation in Ofuboa to correct the off-boresight azimuth
An azimuth corrector that outputs the site azimuth correction value and an off-bore sight elevation that corrects the off-bore sight elevation in the slice plane at off-bore azimuth
And a elevation corrector for outputting a correction value, mackerel
Off-bore sight azimuth and off-bore size
The elevation is input to the elevation corrector
Is the off boresight elevation and the azimuth compensator
Off-bore sight azimuth correction value from
Alternatively, the elevation corrector has an off boresight element
And off-bore sight azimuth are entered.
The off-bore sight azimuth and the elevator
Off-bore sight elevation correction from the motion compensator
Angle measuring corrector formed by connecting such values are entered and, the angle measuring corrector off boresight azimuth correction value and the adder and angle measuring corrector off adding the boresight azimuth
An adder for adding the boresight elevation correction value and the boresight elevation value ; and a monopulse radar goniometer. 2. A monopulse laser on a beam center slice plane.
Monopulse base for azimuth created with typical characteristics
A quasi-table is provided, and the azimuth receiving
Width ratio (Receive level of difference beam for azimuth
Signal level ) divided by the monopulse reference for azimuth
Convert to off-bore sight azimuth with reference to table
A monopulse / off-bore sight azimuth converter; b
Monopulse curve characteristics at the center slice plane
Monopulse reference table for elevation created by
Elevation reception amplitude ratio input from outside
(The reception level of the elevation difference beam is
Value divided by the reception level)
Off-bore site elevator with reference to the Luz standard table
Monopulse / off-boresight elevator
Receiving the outputs of both converters,
Angle measurement that performs angle measurement correction for both
The compensator is used for off boresight elevation.
Off-bore to compensate for off-site azimuth on the rice surface
Azimuth compensator that outputs site azimuth correction value and off
Off-bore sighting at the slice plane at boa sight azimuth
Off boresight elevation to compensate for elevation
An elevation compensator that outputs a compensation value.
Off-bore sight azimuth and off-bore size
The elevation is input to the elevation corrector
Is the off boresight elevation and the azimuth compensator
Off-bore sight azimuth correction value from
Alternatively, the elevation corrector has an off boresight element
And off-bore sight azimuth are entered.
The off-bore sight azimuth and the elevator
Off-bore sight elevation correction from the motion compensator
An angle-measuring corrector connected so that a value is input ; generating a combination pattern of an azimuth reception amplitude ratio and an elevation reception amplitude ratio for the entire range of angle measurement, and converting them to the monopulse / off boresight azimuth conversion. Vessels and
For monopulse / off boresight elevation converter
Furthermore, these conversion outputs are given to the angle measurement corrector,
Off-bore sight azimuth correction value and
Azimuth reception amplitude
Combination and association of ratio and elevation reception amplitude ratio
Angle measuring table creator; and the angle measuring table
Azimuth reception amplitude ratio and elevator
The option associated with the combination of the option reception amplitude ratios
Fubosite azimuth correction value and off-boresite elevation
Measuring the angular table memory storing Shon correction value; off measuring azimuth reception amplitude ratio is input from the outside at the time of corners and elevation received amplitude ratio from the angle measuring table memory as an index boresight azimuth correction value and the O
Monopulse angle measuring transducer reads and outputs full boresight elevation correction value and; the off-boresight azide
A monopulse radar goniometer, comprising: an adder for adding a mass correction value and boresight azimuth; and an adder for adding the off-boresight elevation correction value and boresight elevation. 3. The azimuth compensator further includes an azimuth compensator.
Off-bore sight azimuth correction value from the
Off-bore sight elevation from elevation compensator
Measurement with an additional azimuth compensator
Off boresight azimuth correction value output from angle corrector
2. The monopulse system according to claim 1, wherein
Radar goniometer . 4. The angle measuring corrector further includes the elevator.
Off-boresight elevation from the motion compensator
Positive value and off-bore sight azima from the azimuth corrector
Additional elevation compensator for inputting
Off-boresight elevator output from the goniometer
2. The method according to claim 1, wherein the correction value is generated.
No-pulse radar goniometer .