JPS61224603A - Electronic scanning antenna system - Google Patents

Abstract

PURPOSE:To suppress a beam direction error without using an air-conditioner, a special metal and an air circulating mechanism by obtaining various factors of the beam direction error of an electronic scanning antenna and correcting the beam direction error based thereupon. CONSTITUTION:A signal irradiated from the electronic scanning antenna is received by plural directions in space, the beam direction error of the electronic scanning antenna in the plural directions in space is detected from a synthesis signal equivalent to the received signal or the signal itself by an angle detector 18, the rate of expansion/contraction of the interval of arrangement of radiators of the electronic scanning antenna being a cause to the beam direction error, the beam direction error due to the fluctuation of the phase of radiator excitation and the mechanical displacement of a bore site are obtained separately by utilizing the mutual relation of plural beam direction errors by a data processor 20. Then a phase shifter control data generated from a phase shifter control data generator 14 is corrected so as to eliminate the beam direction error.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electronic scanning antenna device for monitoring beam pointing errors and correcting the beam pointing direction of an electronic scanning antenna used in a microwave landing system.

[Technical background of the invention]

The ground equipment of the microwave landing system uses a beam scanning antenna that scans a beam back and forth to transmit angular information, and the back and forth scanning beam is monitored by a monitor.

FIG. 4 is a system diagram of a beam scanning antenna and a device for monitoring a reciprocating scanning beam conventionally used in an azimuth guidance device of a microwave landing system.

In this fourth prisoner, the beam scanning antenna is connected to the radiator II.
, ~11N, phase shifter 12) ~12N.

It is a conventional electronic scanning antenna consisting of a power divider 13 and a phase shifter/data generator 14.

FIG. 5 shows the relationship between time and beam scanning angle. Also, is the azimuth of the beam scanning antenna? A'12M) when the temperature is zero and the beam scanning antenna is looked down from above.
The clockwise direction from the boresight is positive and the counterclockwise direction is negative.

The reciprocating scanning beam is in front of the beam scanning antenna, with an azimuth angle θ
The signal is received by the field monitor antenna 16 installed in the direction of F.

In addition, the beam scanning antenna is provided with a 1/2 monitor manifold 15 having a coupling hole for high frequency power in the wall of the waveguide, and a radiator 11. Either a part of the high-frequency power input to ~IIN is extracted and synthesized, or the signals radiated from the radiator 11 and ~IIN are received near the radiator and combined, and from both the left and right ends, the signal in space is It outputs a signal equivalent to the receiving apex in the direction of azimuth angles θL and θa. Note that #L=-〇a.

As described above, the field monitor antenna 16 and one integral monitor manifold 15 provide received signals at three azimuth angles. These three signals are detected by the signal detector 17. .

17. 17. The wave is detected and amplified by These video outputs are led to an angle detector J8, and as shown in FIG. 5, the time interval T of the reciprocating beam is measured, and the azimuth angle θ is determined from the relationship between time and beam scanning angle.

The data on the azimuth angles in the three directions obtained here is sent to the data processor 20 and compared with the desired reference values θF, θL, θa to determine the angular error.

This data processor 20 normally uses a 71-crop clock, and performs processing such as averaging processing of angular errors and noise analysis.

The data processed here is sent to a data display device, data printing device, etc.

Note that the standard video generator 19 generates a video equivalent to the received video, and this video is input to the angle detector 18 during the transmission suspension period of the beam scanning antenna to monitor the operation of the angle detector. .

[Problems with background technology]

In microwave landing systems, the angular information transmitted from the beam-scanning antenna is required to be very accurate, so the beam pointing error must be very small.

Generally, in an electronic scanning antenna, the member to which the radiators are attached expands and contracts due to changes in temperature, so the arrangement interval of the radiators changes and a beam pointing error occurs.

Further, from the input end of the power divider 13 to each radiator 111 to I
The delay phase of the feed line leading to IN changes depending on the temperature,
If the temperature inside the beam scanning antenna is not uniform, changes in the delay phase of each of the feed lines will not be uniform, causing an error in the relative excitation phase of the radiator, resulting in a beam pointing error.

Therefore, in the 71 chromatic wave landing system, an air conditioner is used to keep the temperature Re inside the beam scanning antenna constant, or the components attached to the radiators 11° to 11N1 and the integral monitor manifold 15 have a coefficient of thermal expansion. Measures were taken such as using a very small special metal and providing a mechanism to circulate the air inside the beam scanning antenna.

For this reason, the beam scanning antenna is expensive and has the disadvantage that it is necessary to periodically replace the rotating machine used in the air conditioner or the air circulation mechanism.

Furthermore, no matter how small a material with a coefficient of thermal expansion is used, it is impossible to completely eliminate beam pointing errors;
Since expansion and contraction of the integral monitor manifold 15 cannot be completely eliminated, there is a drawback that a detection angle error occurs due to the integral monitor manifold 15 itself.

[Purpose of the invention]

The present invention was developed to eliminate the above-mentioned conventional drawbacks, and provides an electronic scanning antenna that can suppress beam pointing errors without using an air conditioner, special materials, or air circulation mechanism. The purpose is to

[Summary of the invention]

The electronic scanning antenna device fIL of the present invention receives signals radiated from an electronic scanning antenna in multiple directions in space, or is equivalent to receiving signals radiated from an electronic scanning antenna in multiple directions in space. signals radiated from an electronic scanning antenna in one or more directions in between, and signals radiated from an electronic scanning antenna in one or more directions in space. An angle detector detects beam pointing errors of the electronic scanning antenna in multiple directions in the space from the received signal or a signal equivalent to the received signal. By using the relationship between multiple beam pointing errors, we can calculate the expansion/contraction rate of the radiator array spacing of an electronic scanning antenna, the beam pointing error due to variations in the radiator excitation phase, and the mechanical displacement of the mare length, which are the causes of beam pointing errors. The phase shifter side data generated in the phase shifter side data generator is corrected so that the beam pointing error mentioned above is eliminated.

[Embodiments of the invention]

Hereinafter, embodiments of the electronic scanning antenna device of the present invention will be described with reference to FIG. FIG. 1 is a system diagram of one embodiment of the system.

In order to avoid redundant explanation, the same parts as those in FIG. 4 are given the same reference numerals, and the explanation of the structure thereof will be omitted, and the parts different from those in FIG. 4 will be mainly described.

In FIG. 1, a data output circuit 2) is newly added to the configuration of FIG. 3. A data input circuit 22 is added, and the data processing calculation results in the data processor 20 are passed through the data output circuit 2 and the data input circuit 22'IIr to the phase shifter controlled data generator 14. I'm trying to send it out.

With this configuration, the data processor 20 separates the factors of the beam pointing error that cause the detected angle error, and calculates the beam pointing error component v caused by each factor.
The phase shifter collateral data generated in the phase shifter control data generator 14 is modified to eliminate the i-.

Next, regarding the operation of the electronic scanning antenna device of the present invention, a case will be described in which the cause of beam pointing error is separated and a case in which a detection angle error caused by the integral monitor manifold itself is removed.

The four turns of radiation of the electronic scanning antenna are given by the following equation.

Eo(= capitalInejnkdsinθeJ (6(n
) ,...,,,,,,...,,...,...(1) θ
: Observation angle n: Radiator number 2π k : Propagation constant in space (-7-).

(λ is the wavelength in space) d: radiator arrangement interval φ(n): radiator excitation phase (nl is given by the following equation) for directing the beam in the θS direction.

φ(n)=-nkd sin tIm...
・・・・・・・・・・River・・・・・・＋2) Here, due to the temperature change, the radiator array interval d becomes (1+α)
Suppose it becomes d. At this time, assuming that the radiator excitation phase is not changed, the radiation pattern is given by the following equation.

Et (9) = i InCjnk(x″)dsin
", -jnkdsin"s, ・-...-131 At this time, if the beam pointing error is Δθ, (1+α)−mun(θS+Δθ)=SmunOs ・・・・・・・・・
(Since the relationship 4I holds true, Δθ is as follows.

Δθ=-αtanθ3 ・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・＋51
Also, since the temperature of the supply 'lc line has become non-uniform, the radiator 11. Assuming that an error of Δφ(n) occurs in the relative excitation phase of ~IIN, the radiation pattern at this time is given by the following equation.

E, <o>=l IneJnkd(Sillθ−5i
nθ5) ejΔφ(n) , , , , -= (6rHere, since Δφ(n) does not depend on θ and θS, sinθ-5in#a is taken on the horizontal axis as shown in Figure 2. When Δφ(n) makes the beam orientation direction of E, (of Eo
(Assuming a deviation of In from the beam direction of 9, this deviation ΔU remains unchanged on the 5ina axis as shown in Fig.
(If the beam direction of E is deviated by Δθ from the beam direction of (θ), then Δu = sinΔθ.
・・・・・・・・・・・・・・・(7) and also,
If Δθ is the deviation in the beam direction direction of Et() with respect to Eo(’s) in the θS direction, then sin(θS + Δθ)−sinθS=ΔU...
Since the relationship (8) holds true, Δθ is as follows.

sinΔθ.

Δθ−1 Knee 1−iTTi−・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・(
9) Δθ0 = cos□ ・・・・・・・・・・・・・・・・・・
90. In the above explanation, phase shifter No. 2. Although the quantization phase error of ~12N and the phase shift amount error due to manufacturing error of the phase shifter are omitted, the same result as above is obtained when considering the error of the degree that phase shifters normally used in practical use have. It can be easily confirmed that this can be obtained.

Next, the azimuth angle θ detected from the output of the integral monitor manifold I5 is given by the following equation (b) or four equations with respect to the combined phase of the radiation wave and the integral monitor manifold 15.

Here, λg is the internal wavelength of the waveguide used in the integral monitor manifold 15.

In addition, λ. and d are the same as those used in equation (1).

(6) In both of the four equations, the positive sign corresponds to the signal output from the right side of the integral monitor manifold 15 in FIG. 1, and the negative sign corresponds to the signal output from the left side.

Now, if d becomes (l + α) d due to temperature change and the inner diameter of 1 integral monitor manifold 15 also becomes (1 + α) times, then 1 integral monitor manifold 1
The tube wavelength λg' of No. 5 is as follows.

λg' yo λg(1-α(h) ・−・・−・−・−
・・・-USA 22g (1-Pα) ・・・・・・・・・・・・
...94 Here, a is the length of the longer side of the rectangle of the inner diameter of the integral monitor manifold 15.

When the detected azimuth is given by equation (6), and if the detected azimuth shifts by Δθ due to temperature change, then θ+Δθ=±sin'λo (2, (□−Pa) −z
Since the following relationship holds true, Δθ is as follows.

I PI Δθgo-・Ni'” (Ti 10-Σ7)...Jō=±αq ・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・Q fathom Here, I Pi q= ・λ. (Ti 10-101-)・・・・・・・・・
・4COSθN.

Similarly, when the detected azimuth angle is given by equation (2), Δθ
becomes as follows.

=±αq ・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・gl) Here.

1 λ q” coa stone °2° piece °°°”°°”°°°°゛°
“°°°°゛°°°°° (2).

V) *<is) expression and (r), C;! The decoding of Equation 1) is the same as Equation (6) and Equation 4, respectively. That is,
In m115M, a positive sign corresponds to a signal output from the right side of the 1-integu dual monitor holder J5, and a negative sign corresponds to a signal output from the left side.

The mechanical axis of the beam-scanning antenna is then varied such that the bore t
1) is shifted by ΔUB, the beam pointing error is uniformly ΔθB regardless of the azimuth angle. However, this error does not appear in the output of the integral monitor manifold that is integrated with the beam scanning antenna.

Since the beam pointing error or detection azimuth error due to expansion and contraction of the radiator array interval, radiator excitation phase error, expansion and contraction of the integral monitor manifold 15, and mechanical displacement of the boresight is as described above, the field monitor antenna,
The detected azimuth angle deviations, ΔθF, Δθa, and ΔθL obtained from the output signals of the 1-integu and 2-lens monitor manifolds are expressed by the following equations. Note that Δθa and ΔθL correspond to the output signals at the right end and left end of the integral monitor manifold.

Δθ.

ΔθF=−(−α=θF+ +ΔθB)...
■Stone i] Pressure Δθ0 Δθa=αq−7,7・・・・・・・・・・・・・・・
・・・・・・・・・・・・ ■The value in the parentheses on the right side of equation (5) above is the sum of the beam pointing error components, and the negative sign in front of the parentheses means the number This is because, according to the angle detection method shown in FIG. 5, the error in the detected azimuth has the opposite sign to the beam pointing error. Also, the second right side of equations (24) and (25)
It is for the same reason that the term has a negative sign.

<zs), Cz4), Cz5), α, Δθ0. Δ
Calculating θB is as follows.

αshi■(Δθa−ΔtIt,) ・・・・・・・・・
・・・・・・・・・・・・(To) Δθ == 1
(Δθa + ΔθL) cosoM ...... (to)
Δθ8=-Δθ, +1 (ΔU1-ΔθL)t□θ
Fshiq 1(ΔθR+ΔθL)C(ヰconcave ・・・・・・・・・・・・
...(5) 2 coa o y Here, the first JJil on the right side of equations (z4) and (2, s) is due to the expansion and contraction of the integral monitor manifold, and the value excluding this is the beam pointing error. This results in an error in the detected azimuth angle. This is Δθ8'.

If ΔθL' is set as follows.

Δθa'=ΔθL'=-! −(Δθ wind 1 ΔθL) ・
・・・・・・・・・4 As above, ts), (u
), (zs) From the relationship of errors in the detected azimuth angle by the received signal at the three azimuth angles, (2B), C
As shown in equations 27) and C28), the causes of beam pointing errors can be separated.

By substituting these into the terms on the right side of equations C25), Cu), and ts), it is possible to obtain beam pointing errors or errors in detected azimuth angles for each generation factor.

Furthermore, as shown in equation (29), errors in the detected azimuth due to expansion and contraction of the integral monitor manifold can be removed.

These calculations are performed by the data processor 2U, and the calculation results are output to a display (not shown), etc., and the above α,
Δθ0. ΔθBi is input to the data generator 14 on the phase shifter side via the data output circuit 2 and the data input circuit 22, and the beam pointing error is corrected as described below.

In the phase shifter control data generator 14, the phase shifter 12.
The phase data φp(nl given to ~12N is calculated as follows.

φp (n) = −n k d s inθ3+φf(
n) ・・・・・・・・・・・・・・・・Here, φf(n) is the relative delay of the feed line from the input end of the power divider 13 to each radiator 111-11N This is a phase for correcting a phase difference.

In order to correct the beam pointing error caused by the various factors mentioned above, the formula %C30) is corrected as follows.

φfr (n) = −n k d'5irlθ'S tenφ
' f (nJ ・−・−・・−・−・・IJ) Here, d'=(1+α) d ・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・(2) θ′6
=θS−ΔθB ・・・・・・・・・・・・・・・
...... crystal...-φ'f(n)=φf(n)+nk
d'Δtlo -・"-..."-%.

Equation (32) above is a correction for the radiator array spacing, Equation (33) is a correction for the mechanical displacement of the boresight, and the second term on the right side of Equation (34) is caused by an error in the radiator excitation phase shift. This is the phase tilt added to correct beam pointing errors.

It will be clear that the above correction corrects the beam pointing error. Note that the correction shown in equation (33) corrects the beam pointing error component caused by boresight fluctuation in space, but the integral monitor manifold 1 integrated with the beam scanning antenna
Conversely, the azimuth detected from the output signal of 5 has ΔθB
Since an error of % occurs, the data processor 20
Δθ8' and ΔθL' in equation (29) are corrected as follows.

ΔθR'=ΔθL'=-! −(Δθa+ΔθL)−Δθ
B...-In the above embodiment, the angle detection error of the angle detector 18 is omitted, but this error is determined by operation monitoring using a standard video, and as a result, (zs)
, Cz4) and (zs), it is of course possible to correct ΔθF, Δθa, and ΔθL.

In the above embodiment, a case has been described in which a field monitor antenna and one integral monitor manifold are used together, but if the error of the detection azimuth angle at 30,000 different times is obtained, (zs), (z4).

Since the cause of the beam pointing error can be separated using a relationship similar to equation (25) and the beam pointing error can be corrected based on this, it goes without saying that reception may be performed using field monitor antennas in all three directions.

Furthermore, in the above embodiment, the case where one integral monitor manifold 15f with a waveguide structure was used was explained.
Of course, the present invention can also be applied to formats using transmission paths other than waveguides.

Roughly speaking, in the above embodiment, received signals in three directions are used to separate the three causes of beam pointing error, but it is possible that the cause of beam pointing error is limited to one of the above three. If the number of receiving azimuths is sufficiently guaranteed in advance, the number of receiving azimuth angles only needs to be equal to the number of this factor.

However, in order to obtain the mechanical displacement of the bore 1ite, it goes without saying that K must be received by a field monitor antenna.

In the above embodiment, we have explained the beam scanning antenna for azimuth guidance that scans the beam in both left and right directions with the pore site as the center. When scanning is not performed, the detection angle based on the signal obtained with one inkegular monitor manifold is only in one direction, so the detection angle t- in two directions is determined by the integral monitor manifold.
If you want to get rc integral monitor manifold 2
Just set up a book.

In the above embodiment, in order to correct the mechanical displacement ΔθB of the bore length, the beam scanning angle was corrected as shown in equation &;<33). Of course, ΔθB can also be corrected by changing the angle of beam scanning.

〔Effect of the invention〕

As described above, according to the electronic scanning antenna device of the present invention, various factors of the beam pointing error of the electronic scanning antenna can be determined and the beam pointing error can be corrected based on this. Beam pointing errors can be suppressed without using any mechanism.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an embodiment of the electronic scanning antenna device of the present invention, and FIGS. 2 and 3 are diagrams for explaining beam pointing errors due to errors in the radiator excitation phase in the electronic scanning antenna device, respectively. , FIG. 4 is a system diagram of a conventional electronic scanning antenna device, and FIG. 5 is a diagram for explaining the relationship between time and beam scanning angle in the conventional electronic scanning antenna device, and the principle of detecting the reciprocating scanning beam angle. I'll go. II, ~IIN... radiator, 12. ~12N... Phase shifter, 13... Power divider, 14... Phase shifter control data generator, 15... 1 integral monitor manifold, 16... Field monitor antenna, 17, ~1
7. ...Signal detector, 18...Angle detector, 19.
...Standard video generator, 20...Data processor, 2)
...Data output circuit, 22...Data input circuit. Applicant's agent Patent attorney Hiko Rin Ushiki Figure 2 Figure 3 OSlntj5

Claims (3)

[Claims] (1) Receiving signals radiated from an electronic scanning antenna in which multiple radiators are arranged and has a phase shifter that shifts the phase of the feed line from the power divider to each radiator in multiple directions in space. , or combine signals equivalent to signals radiated from the electronic scanning antenna received in multiple directions in space, or receive signals radiated from the electronic scanning antenna in one direction or multiple directions in space. and a means for synthesizing a signal equivalent to that received in one or more directions in space from the signal radiated from the electronic scanning antenna, and a means for synthesizing a signal equivalent to that received in one or more directions in space, A detection means for detecting beam pointing errors of an electronic scanning antenna in a plurality of directions, and the above-mentioned radiator array spacing that is a cause of beam pointing errors by using the mutual relationship of the plurality of beam pointing errors detected by the detecting means. data processing means for separately determining the expansion/contraction rate of the beam, beam pointing errors due to fluctuations in the radiator excitation phase, and mechanical displacement of the boresight; and a phase shifter control data generator which is supplied with the output data of the data processing means and generates phase shifter control data and outputs it to each of the phase shifters so as to eliminate beam pointing error components caused by each of the above factors. An electronic scanning antenna device comprising: (2) The data processing means synthesizes the result obtained by multiplying the expansion/contraction rate of the radiator array interval by a constant determined by the physical specifications of the means for synthesizing a signal equivalent to the received signal in the space. The electronic scanning antenna according to claim 1, wherein a detection error of a beam pointing error caused by the detecting means itself is removed by adding the signal to the beam pointing error detected by the detecting means. Device. (3) The phase shifter control data generation means adds an expansion/contraction amount due to the expansion/contraction rate of the radiator array interval to the radiator array interval, and adds the expansion/contraction amount of the radiator excitation phase to the feed line relative delay phase correction amount. Add the result of multiplying the boresight value of the beam pointing error due to fluctuation by the high frequency propagation constant in space and the radiator number, and subtract the mechanical displacement of the boresight mentioned above from the beam pointing angle, or 2. The electronic scanning antenna device according to claim 1, wherein beam pointing error of said electronic scanning antenna is corrected by changing beam scanning timing to correct displacement.