JPH0731237B2 - Angle tracking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention utilizes an electric wave radiated by a target or an electric wave reflected from the target to detect an angle of the target and determine an angle for tracking the target. The present invention relates to a tracking device.

[Outline of the Invention] The present invention relates to an angle tracking device for tracking a target by using radio waves from the target, which is a group antenna composed of two antennas for tracking the azimuth angle or the elevation angle. The target angle can be tracked by the servo device or the electronic method, and both the azimuth angle and the elevation angle can be tracked by using the two set antennas.

"Prior Art" The monopulse receiver of FIG. 3 and the antenna device of FIG. 4 used in the monopulse receiver, which are conventional examples, will be described.

Since the monopulse antenna 50 is a pair-structured antenna, the first input signal 11 and the second input signal 13 are received and become the monopulse antenna first output 51 and the monopulse antenna second output 53, and the monopulse comparator 54. To the monopulse antenna first output 51 and the monopulse antenna second output 53, and the monopulse comparator sum output 55, and the monopulse antenna first output 51 and the monopulse antenna second output 53. To the monopulse comparator difference output 57, which is the difference signal of each. In the third mixer 60, the monopulse comparator sum output 55 and the second local oscillator output 71 which is the output of the second local oscillator 70 are mixed to form the third mixer output 61, which is input to the second intermediate frequency amplifier 64. Then, it becomes the second intermediate frequency amplifier output 65 and is input to the phase detector 68.

In the fourth mixer 62, the monopulse comparator difference output 57 and the second local oscillator output 71 which is the output of the second local oscillator 70 are mixed to form the fourth mixer output 63, and the third intermediate frequency amplifier 66.
Is input to the third intermediate frequency amplifier output 67, and the phase detector 68 phase-detects the third intermediate frequency amplifier output 67 using the second intermediate frequency amplifier output 65 as a reference signal, and becomes the phase detector output 69. Since the phase detector output 69 is an angular error between the target position and the center of the antenna beam, the target can be angle-tracked if the phase detector output 69 is obtained.

“Problems to be Solved by the Invention” In the conventional example of FIG. 3, the first input signal 11 and the second input signal 13 are respectively X ₁₁ = Asin (ωt + α) (1) X ₁₃ = Asin (ωt−α) … (2) However, A is the first input signal 11 and the second input signal 13
Is the signal strength, and α is the phase term of the input signal. Monopulse antenna first output 51 and monopulse antenna second output
Monopulse comparator sum output, which is the sum signal of output 53
55, and the monopulse comparator difference output 57, which is the difference signal between the monopulse antenna first output 51 and the monopulse antenna second output 53, is X ₅₅ = cosαsin (ωt) (3) X ₅₇ = sinαsin (ωt) )… (4) The monopulse comparator sum output 55 is frequency converted in the third mixer 60 and amplified in the second intermediate frequency amplifier 64 to become the second intermediate frequency amplifier output 65. The monopulse comparator difference output 57 is frequency-converted by the fourth mixer 62 and amplified by the third intermediate frequency amplifier 66 to become the third intermediate frequency amplifier output 67, and the phase detector 68 outputs the second intermediate frequency amplifier output 65. The phase detector output 69 is X ₆₉ = << sinαsin (ωit) cosαsin (ωit) >> = sin2α (5), and the target angle error is obtained. However, << is a symbol indicating the time average of the product, and ωi is the angular frequency of the intermediate frequency.

Note that θ in FIGS. 4 and 6 is an amount substantially proportional to α.

The problems of such a conventional phase difference type monopulse antenna are summarized as follows.

(Ii) It is expensive because it is necessary to accurately maintain the phase of each channel from the monopulse antenna 50 to the phase detector 68.

(RO) Monopulse antenna 50 and monopulse comparator
Since 54 is matched by the path length, the phase also changes at the same time when the used frequency is changed, and since the frequency and the phase are related to each other, the usable frequency is wide band. This is difficult to manufacture.

"Means for Solving the Problem" In order to solve these problems, the angle tracking device of the first invention of the present application has a configuration in which a first antenna and a second antenna for receiving radio waves from a target are combined. And a pair of antennas in which the centers of the antenna beams are inclined outward, a mechanical servo device for driving the pair of antennas integrally, a local oscillator, an output of the first antenna, and the local portion. A first mixer for mixing the output of the oscillator, a second mixer for mixing the output of the second antenna and the output of the local oscillator, a reference signal generator, and the reference The first output of the signal generator is used for the first
Of the mixer and the output of the second mixer are alternately switched into a time-divided signal, and only the necessary frequency component of the time-divided output of the switch is passed. An intermediate frequency amplifier; an amplitude detector that amplitude-detects the output of the intermediate-frequency amplifier; and a synchronous detector that synchronously detects the output of the amplitude detector with the second output of the reference signal generator. As a configuration for driving the group antenna by the mechanical servo device so that the angle error signal proportional to the displacement angle (θ) from the target group antenna reference axis which is the output of the detector becomes zero There is.

In the angle tracking device of the second invention of the present application, the first antenna and the second antenna for receiving the radio waves from the target have a set configuration, and the centers of the antenna beams are inclined outward. An antenna, a local oscillator, a first mixer for mixing an output of the first antenna and an output of the local oscillator, and an output of the second antenna and an output of the local oscillator. Second mixer for, and a first mixer for electronic angle tracking using the antenna pair.
And an angle tracking modulation signal generator for generating a second modulation signal output, and a first modulator for modulating or multiplying the output of the first mixer by the first modulation signal output of the modulation signal generator. Alternatively, a multiplier and a second of the modulation signal generator
A second modulator or multiplier that modulates or multiplies the output of the second mixer with the modulated signal output of, a reference signal generator, and the first output of the reference signal generator. A switch that alternately switches the output of the first modulator or multiplier and the output of the second modulator or multiplier to obtain a time-divided signal, and a switch of the time-divided output of the switch. An intermediate frequency amplifier that passes only the necessary frequency component, an amplitude detector that amplitude-detects the output of the intermediate frequency amplifier, and a synchronous detector that synchronously detects the output of the amplitude detector with the second output of the reference signal generator. The angle tracking modulation signal generator receives an angle error signal proportional to a displacement angle (θ) from a target combined antenna reference axis, which is an output of the synchronous detector, and receives the first and first angle error signals. Bee with 2 antennas The first and second modulated signal outputs corrected by the width and the outward tilt angle of the antenna beam center are generated to electronically angle the pair of antennas so that the angular error signal is zero. It is configured to track.

"Operation" The operating principle of the present invention will be described below.

From the first embodiment of the present invention and the second antenna configuration diagram of FIG. 1, the first input signal 11 and the second input signal 13 are respectively expressed as X ₁₁ = Asin (ωt + α) (6) X ₁₃ = Asin (ωt −β) (7) However, A is the first input signal 11 and the second input signal 13
, And α and β are phases due to the difference in propagation of radio waves generated from the geometrical relative relationship between the antennas when the radio waves reach each antenna.

The amplitude characteristics of the first antenna 14 and the second antenna 16 are a (θ) and b (θ), respectively, and variables A, a (θ) and b (θ) are set.
When each of these is normalized, a (θ) = cos (φ + θ) (8) b (θ) = cos (φ−θ) (9) approximately. However, the displacement angle θ from the target center (reference axis B of the combined antenna consisting of the first and second antennas in FIG. 2) and the tilt angle φ of the antenna beam center are −π / 4 <θ <π / 4. (10) 0 <φ <π / 4 (11) Here, a (θ) + b (θ) = 2cosφcosθ (12) a (θ) -b (θ) = 2sinφsinθ (13). However, the tilt angle φ of each antenna beam center
Is the offset angle of the antenna, so cosφ and sinφ
Is a constant.

Since the phase of the carrier wave is not used, the switcher output 27, which alternately switches the first mixer output 19 and the second mixer output 21 into a time-divided signal, has an average value of the formula (1
Since the amplitude modulation component is proportional to the sum component of 2) and the amplitude modulation component is proportional to the difference component of equation (13), the amplitude modulation signal is approximately X ₂₇ = (cosφcosθ + sinφsinθsinΩt) × sin (ωt + γ) (14). However, Ω is the angular frequency of the reference signal generator first output 45 for switching the input signal,
γ is a phase term determined by the first input signal 11 and the second input signal 13.

Let the local oscillator output 39 be X ₃₉ = sin (ωrt) (15).

Since the average value that is the DC component of the amplitude is the AGC amplifier output 37, the AGC amplifier output becomes X ₃₇ = cos θ (16) from the switch output 27 of equation (14), and only the necessary frequency component of the switch output 27 is obtained. The intermediate frequency amplifier output 29, which is the output of the intermediate frequency amplifier 28 to be passed, is created by the frequency of the difference between the switch output 27 and the local oscillator output 39, and the amplification is stabilized by the AGC amplifier output 37, so that the intermediate frequency amplifier is Output 29 is Becomes However, ωi = ω−ωr (18). Since the error component of the angle signal is included in the AC component after amplification and detection, the output 33 of the bandpass amplifier becomes X ₃₃ = 2sinφ (tanθ) sinΩt (19). However, the second output 47 of the reference signal generator is set to X ₄₇ = sinΩt (20). Since the angle error output 35 is the average of the products of the bandpass amplifier output 33 and the reference signal generator second output 47, X ₃₅ = << 2 (tan θsinΩt) sinΩt >> = tin θ (21) is obtained. The angle error output 35 is input to a mechanical servo device 48, and the servo device 48 integrates a group antenna composed of the first antenna 14 and the second antenna 16 into a body, and the boresight of the group antenna ( The combined antenna reference axis B of FIG. 2 is directed toward the target direction so that the displacement angle Χ from the target combined antenna reference axis becomes zero.

Since the principle of angle tracking has been described with reference to FIG. 1, the electronic circuit included after the receiving antenna is not moved mechanically by the electronic method in the second embodiment of the present invention shown in FIG. It will be explained that the antenna can be used for angle tracking of the radio wave from the target by using. From the embodiment shown in FIG. 1 and the antenna configuration diagram shown in FIG. 2, since the first antenna output 15 and the second antenna output 17 are weighted by the amplitude characteristics a (θ) and b (θ) of the antenna, respectively, X ₁₅ = Aa (θ) sin (ωt + α) = Acos (φ + θ) sin (ωt + α) (6a) X ₁₇ = Ab (θ) sin (ωt + α) = Acos (φ-θ) sin (ωt-β) (7b) To do. Here, as shown in FIG. 2, when the target direction is θ, the direction of the pair of antennas is inclined by (θ + δ) by an electronic method. Modulation signal generator first output (corrected by the beam width of the first and second antennas 14 and 16 and the inclination angle of the antenna beam center to the outside) in which the angle error signal is corrected by the characteristics of the antenna pattern
41 and the second output 43 of the modulation signal generator are respectively defined as X ₄₁ = cos (φ + θ + δ) (22) X ₄₃ = cos (φ−θ−δ) (23), the first multiplier output 23 and a second multiplier output 25 respectively _{X 23 = X 15 · X 41} = Acos (φ-θ) cos (φ + θ + δ) sin (ωit + γ) ...
(24) X ₂₅ = X ₁₇ · X ₄₃ = A cos (φ + θ) cos (φ−θ−δ) sin (ωit + γ)…
(25)

The operation of the switch output 27 will be described. The sum signal of the amplitudes of the first multiplier output 23 and the second multiplier output 25 is c (δ) = cos (φ−θ) cos (φ + θ + δ) + cos (φ + θ) cos (φ−θ−δ) = 2cosδcos2φ + 2cos (2φ + δ) ) (26), the difference signal between the amplitudes of the first multiplier output 23 and the second multiplier output 25 is d (δ) = cos (φ−θ) cos (φ + θ + δ) −cos (φ + θ) cos (φ− θ−δ) = −2sin2φsinδ (27), and the intermediate frequency amplifier output 29 is the same as equation (17). Therefore, the output 31 of the amplitude detector is the carrier regenerator 76 of FIG.
From the carrier regenerator output 77 {X ₇₇ = sin (ωit + γ)} of When target tracking is used, it is used under the condition of | θ | <| φ | << π / 4 (28b) δ ≈ 0 (28c).
35 is Becomes However, E (), E {} or E [] is a symbol representing the average of one cycle, φ is a constant, and k is substantially constant from the condition of the expression (28a). Since a signal proportional to δ is output, the antenna is aimed at the target so that the angle error output 35 becomes zero. This is the first without the use of a servo drive to drive the mechanical antenna.
By using the multiplier 22 and the second multiplier 24 so that δ≈0, the position of the target (θ) can be known and the angle tracking of the radio wave from the target can be performed electronically. It has become.

[Example] Hereinafter, an example of the angle tracking device according to the present invention will be described with reference to the drawings.

The first embodiment of FIG. 1 and FIG. 2 of the configuration diagram of the antenna used in the embodiment of FIG. 1 will be described.

The first input signal 11 is input to the first antenna 14 to become the first antenna output 15, which is mixed with the local oscillator output 39 which is the output of the local oscillator 38 in the first mixer 18 and frequency-converted to produce the first mixer output. It becomes 19 and is input to the switch 26.

The second input signal 13 is input to the second antenna 16 and becomes the second antenna output 17, which is mixed with the local oscillator output 39 which is the output of the local oscillator 38 in the second mixer 20 and frequency-converted to output the second mixer output. 21 and the reference signal generator 44
The first mixer output 19 and the second mixer output 21 are input to the switch 26 by the reference signal generator first output 45, which is the output of the above, and are switched alternately to become the switch output 27. The switch output 27, which is the output of the switch 26, is input to the intermediate frequency amplifier 28 where the amplitude of the switch output 27 is made constant by the AGC amplifier output 37, becomes the intermediate frequency amplifier output 29, and is input to the amplitude detector 30 and the amplitude. An amplitude detector output 31 which is the detected signal is obtained. One output of the amplitude detector output 31 is input to the bandpass amplifier 32, becomes a bandpass amplifier output 33 which is a narrow band signal, and is input to the synchronous detector 34.
The other DC output of the amplitude detector output 31 is input to the AGC amplifier 36, becomes an AGC amplifier output 37 which is a DC signal, and is returned to the intermediate frequency amplifier 28 to make the intermediate frequency amplified output 29 constant.

In the synchronous detector 34, the band-pass amplifier output 33 is synchronously detected with the second output 47 of the reference signal generator 44, which is the output of the reference signal generator, as a reference signal, and becomes the angular error output 35, which is input to the mechanical servo device 48. The servo device 48 moves so that the first antenna 14 and the second antenna 16 are directed toward the target so that the angular error output 35 becomes zero, that is, θ = 0 in FIG.
The boresight (antenna reference axis B in FIG. 2) of the antenna set consisting of the first antenna 14 and the second antenna 16 faces the target.

The second embodiment of FIG. 5 will be described, but the first embodiment of FIG.
It should be sufficient to explain only the differences from the embodiment.

The second embodiment of FIG. 5 is an electronic angle tracking device, which uses the set antenna of FIG. 2 as part of its construction.

The first mixer output 19 of the first mixer 18 is input to the first multiplier (or modulator) 22 and is the output signal of the angle tracking modulation signal generator 40 which is a kind of non-linear generator. A multiplication operation is performed together with the signal generator first output 41 to become the first multiplier output 23, which is input to the switch 26. The second mixer output 21 of the second mixer 20 is input to the second multiplier (or modulator) 24 to perform a multiplication operation together with the modulation signal generator second output 43 which is the output signal of the modulation signal generator 40. Then, it becomes the second multiplier output 25 and is input to the switch 26.
The angle error output 35 is applied to the modulation signal generator 40, and the modulation signal generator 40 modifies the angle error output 35 according to the characteristics of the antenna pattern to modify the modulation signal generator first output 41 and second output 43.
And the beam of the antenna pair is scanned so that the angular error output 35 becomes zero.

The other description is the same as that of the first embodiment shown in FIG. In this way, the angle is tracked by using the radio wave from the target.

The advantage of making the antenna angle φ variable in the antenna of FIG. 6 will be described. If the first input signal 11 and the second input signal 13 are to be received at the maximum power when the target is in the center direction of the first antenna 14 and the second antenna 16, the first antenna rotating device 72 and the second antenna rotating device It is only necessary to set the antenna tilt angle φ to zero by 74, so when the target is supplemented, the antenna tilt angle φ is set to zero in advance, and after the target is supplemented, the antenna tilt angle φ is set and the tracking proceeds. You can take this method. At the time of tracking, the antenna tilt angle φ is selected so that the antenna patterns cross each other when the gain of the first antenna 14 and the second antenna 16 is reduced by 3 dB, and the antenna beam width is set to a higher frequency. For example, the antenna beam width is narrow, and the antenna beam width is widened by decreasing the frequency used, so that the angle tracking characteristic is further improved by selecting the antenna tilt angle φ according to the frequency.

FIG. 7 will be described. The output 29 of the intermediate frequency amplifier of FIG. 5 is output 29 of the intermediate frequency amplifier by the carrier regenerator 76 in the amplitude detector 30.
A carrier wave having the same frequency and phase as that of is reproduced, and the intermediate frequency amplifier output 29 is synchronously detected by the synchronous wave detector 78 at the carrier wave regenerator output 77 to become the amplitude detector output 31.

In the above description, it was possible to explain that the angle tracking device can be configured with the amplitude comparison type monopulse antenna of the present invention instead of the conventional phase comparison type monopulse antenna.

A supplementary explanation will be given on the first embodiment of FIG. 1 and the second embodiment of FIG.

(I) In the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. 5, the explanation has been made on the azimuth angle or the elevation angle uniaxial axis, but it can be applied to the azimuth angle and elevation angle biaxial angle tracking. .

(B) Amplitude detector 30 is the base band (base band)
Since the purpose is to drop (the necessary signal component of the amplitude detection output approaches 0 near the frequency), the amplitude detector 30
Alternatively, the intermediate frequency amplifier output 29 may be taken into a digital computer by an AD (analog / digital) converter and the signal may be dropped to the base band in the computer.

(Ha) In the case of the digital system, the synchronous detector 34 of FIGS. 1 and 5 takes in the bandpass amplifier output 33 and the reference signal generator second output 47 into the digital computer by the AD converter and multiplies them inside the digital computer. May be used to obtain the angular error output.

(B) In the antenna configuration diagram of FIG. 2, when the antenna is used in a wide band, when the inclination angle φ of the antenna is fixed, the antenna becomes too wide at a high frequency and the inclination angle φ of the antenna becomes narrow at a low frequency. If the antenna angle is made variable, the tracking characteristic will be further improved.

(V) The modulation signal generator first output 41 and the modulation signal generator second output 43 are respectively set to X ₄₁ = cos {ωlt− (π / 2) sign [cos (φ + θ +
δ)]} ≈ cos (φ + θ + δ) sin ωlt (22) X ₄₃ = cos {ωlt− (π / 2) sign [cos (φ−θ−
δ)]} ≈cos (φ−θ−δ) sinωlt (23) The signal may be placed on the carrier wave of phase modulation or balanced modulation.

Where ωl is the angular frequency of the carrier wave of the signal to the first multiplier 22 and the second multiplier 24, Is.

(And) The antennas mentioned here are parabolic antennas,
It may be either a horn antenna or an electronic scanning antenna.

(C) cos (φ + θ + δ) and cos in equations (22) and (23)
(Φ−θ−δ) is an approximation of the antenna pattern, and since this pattern differs depending on the antenna, the modulated signal first output and the modulated signal first output which are the outputs of the modulated signal generator 40 matched with each antenna. It is necessary to have two outputs each.

[Advantages of the Invention] The advantages of the angle tracking device according to the present invention are as follows.

(Ii) Since the four antennas (two pair antennas) can track the two axes of the azimuth angle and the elevation angle, the angle tracking device is extremely simple.

(RO) When tracking angles with a mechanical servo device,
Although it was necessary to attach the group antenna to the servo device via the mechanical gimbal, according to the configuration of the second aspect of the invention, the mechanical gimbal is not required and the angle tracking can be performed electronically. Therefore, the tracking device is extremely economical.

Since the angle error output does not depend on the phase of the 35 carrier waves, the antenna system can have a very wide band and can be easily manufactured.

(2) Compared with the conventional phase comparison type monopulse type angle tracking device, there is some loss due to tilting the antenna for the sum signal, but the antenna gain is fully utilized for the difference signal. Therefore, when a sufficient signal strength can be expected, it is very effective as a wideband angle tracking device.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment of an angle tracking device according to the present invention, FIG. 2 is a block diagram of an antenna used in the embodiment of FIG. 1, and FIG. 3 is a block diagram of a conventional example. Fig. 4 is a block diagram of an antenna used in the conventional example of Fig. 3, Fig. 5 is a block diagram of a second embodiment of the present invention, and Fig. 6 is a block diagram of a rotary antenna. FIG. 7 is a block diagram showing the configuration of the amplitude detector used in the second embodiment. 11 …… first input signal, 13 …… second input signal, 14 …… first
Antenna, 15 ... First antenna output, 16 ... Second antenna, 17 ... Second antenna output, 18 ... First mixer, 19 ...
... 1st mixer output, 20 ... 2nd mixer, 21 ... 2nd mixer output, 22 ... 1st multiplier, 23 ... 1st multiplier output, 24 ... 2nd multiplier, 25 ...... Second multiplier output, 26
...... Switcher, 27 …… Switcher output, 28 …… Intermediate frequency amplifier, 29 …… Intermediate frequency amplifier output, 30 …… Amplitude detector, 31 …… Amplitude detector output, 32 …… Band pass amplifier, 33
...... Band pass amplifier output, 34 …… Synchronous detector, 35 …… Angle error output, 36 …… AGC amplifier, 37 …… AGC amplifier output,
38 ... Local oscillator, 39 ... Local oscillator output, 40 ... Modulation signal generator, 41 ... Modulation signal generator first output, 43 ... Modulation signal generator second output, 44 ... Reference signal generator , 45 ……
Reference signal generator 1st output, 47 ... Reference signal generator 2nd output, 48 ... Servo device, 50 ... Monopulse antenna,
51 …… Monopulse antenna first output, 53 …… Monopulse antenna second output, 54 …… Monopulse comparator, 55 ・ ・ ・
… Monopulse comparator sum output, 57 …… Monopulse comparator difference output, 60 …… Third mixer, 61 …… Third mixer output, 62…
4th mixer, 63 4th mixer output, 64 2nd intermediate frequency amplifier, 65 2nd intermediate frequency amplifier output, 66 3rd intermediate frequency amplifier, 67 3rd intermediate frequency Amplifier output, 68
...... Phase detector, 69 …… Phase detector output, 70 …… Second local oscillator output, 71 …… Second local oscillator output, 72 …… First antenna rotating device, 74 …… Second antenna rotating device, θ …… The displacement angle from the center of the target, φ …… The antenna tilt angle.

Claims (3)

[Claims] 1. A combined antenna in which a first antenna and a second antenna for receiving radio waves from a target are combined, and the center of each antenna beam is inclined outward.
A mechanical servo device that drives the combined antenna as an integral unit; a local oscillator; a first mixer for mixing the output of the first antenna and the output of the local oscillator; and the second oscillator. Second mixer for mixing the output of the antenna of the antenna with the output of the local oscillator, a reference signal generator, and the first output using the first output of the reference signal generator.
Of the mixer and the output of the second mixer are alternately switched into a time-divided signal, and only the necessary frequency component of the time-divided output of the switch is passed. An intermediate frequency amplifier; an amplitude detector that amplitude-detects the output of the intermediate-frequency amplifier; and a synchronous detector that synchronously detects the output of the amplitude detector with the second output of the reference signal generator. An angle tracking is performed by driving the group antenna by the mechanical servo device so that an angle error signal proportional to a displacement angle (θ) from a target group antenna reference axis which is an output of the detector becomes zero. A characteristic angle tracking device. 2. A pair antenna in which a first antenna and a second antenna for receiving radio waves from a target have a pair configuration, and the center of each antenna beam is inclined outward.
A local oscillator; a first mixer for mixing the output of the first antenna and the output of the local oscillator; and a first mixer for mixing the output of the second antenna and the output of the local oscillator. Two mixers, an angle tracking modulation signal generator that generates first and second modulation signal outputs for electronic angle tracking using the pair antenna, and a first of the modulation signal generators. A first modulator or multiplier that modulates or multiplies the output of the first mixer with a modulation signal output, and a second modulation signal output of the modulation signal generator modulates the output of the second mixer. Alternatively, a second modulator or multiplier for multiplication, a reference signal generator, and an output of the first modulator or multiplier and a second modulator using the first output of the reference signal generator Alternately switch output with multiplier A switching device for the temporally split signal Te, the intermediate frequency amplifier for passing only necessary frequency components of the switching output divided temporally,
An amplitude detector that amplitude-detects the output of the intermediate frequency amplifier;
A synchronous detector for synchronously detecting the output of the amplitude detector with the second output of the reference signal generator, wherein the angle tracking modulation signal generator is an output of the synchronous detector. An angle error signal proportional to a displacement angle (θ) from a reference axis is received, and the first and second beam widths of the first and second antennas and the first and second beam lines corrected by the inclination angle of the antenna beam center to the outside are corrected. An angle tracking device characterized by generating a modulated signal output and electronically angle-tracking using the group antenna so that the angle error signal becomes zero. 3. Antennas for the first and second antennas
3. An antenna rotating device for varying the angle at which the center of the beam is inclined outward, respectively.
The described angle tracking device.