JPS6156807B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tracking method for tracking a target using a signal obtained by multiple amplitude modulating radio waves or light from the target using an antenna system or an optical system. When guiding a flying object to a target using radio waves, if the target interferes with the flying object using radio waves, the flying object will be disturbed and it will no longer be possible to guide it to the target. There is. Among the guidance methods using radio waves, one method for tracking reflected radio waves from a target is a tracking method using a conical scan antenna. This tracking method using a conical scan antenna modulates the amplitude of reflected radio waves from a target that are not amplitude modulated by eccentrically rotating the radar antenna.
After amplifying the signal, the amplitude modulated wave is extracted by amplitude detection, and by phase detection of the amplitude modulated wave at the frequency at which the antenna beam is rotating, An azimuth angle error signal and an elevation angle error signal, which are the deviations, are extracted. However, in such a conical scan antenna tracking system, if the conical scan antenna is subjected to radio wave interference due to amplitude modulated signals at a frequency close to the frequency at which the conical scan antenna rotates, the modulation will be extremely severe while tracking the target. Since the jamming waves are generally shallow and the modulation is very deep, the tracking system cannot know the correct target position and not only loses sight of the target, but also tracks against the amplitude modulated jamming source. I can't even do anything. In this way, since the conical scan antenna rotates the antenna beam at only one frequency, it has the disadvantage of being susceptible to amplitude modulation radio wave interference. The same thing can also be said when tracking light from a target using an optical system. In view of the above points, the present invention tracks a target using a signal obtained by multiple amplitude modulating radio waves or light from the target using an antenna system or an optical system, thereby making it less susceptible to interference by radio waves or light. The aim is to provide a highly reliable tracking method. In the present invention, radio waves or light from a target are subjected to multiple amplitude modulation by decentering a plurality of components of an antenna system or an optical system and rotating them at a plurality of different frequencies, and detection is performed at the frequency of each rotation. Using the output, it is possible to obtain an error signal corresponding to the angular (direction) deviation between the target and the reference axis (boresight), and if there is interference at one rotational frequency, the other The error signal based on the frequency of is selected to enable tracking.
As a result, even if radio waves or light are interfered with by amplitude modulated waves, it is extremely difficult to interfere with radio waves or light by multiple amplitude modulated waves by multiple frequencies.
It becomes rare for the tracking system to be disturbed by amplitude modulated radio or optical interference sources. First, regarding the present invention, the principle of a tracking system that rotates an antenna beam using two eccentric antennas (including a radio wave lens, a reflector, and a feed horn) will be explained. As shown in Figure 1, take a coordinate system on the focal plane of the antenna system, and let r ₁ be the eccentric distance of the first antenna (physically an angle), and the eccentric distance (physically an angle) of the second antenna on the coordinates. is the angle) is r ₂ , and the angular velocities of rotation of the first antenna and the second antenna are ω ₁ and ω _{2 ,} respectively. The center O around which the first antenna rotates is called the boresight, and is the reference axis of this tracking system. Also, the rotation center of the second antenna is
O ₂ , the target position is Or, and the tip of the antenna beam is P. The x-coordinate of Or is z ₁ and the y-coordinate is z ₂ , and the x-coordinate of P is P ₁ and the y-coordinate is P ₂ . Furthermore, when Or is the origin, the x coordinate of P is x ₁ and the y coordinate is x ₂ . θ(t) is the rotation angle of P in Or, θ ₁ is the first
The rotation angle of the antenna is θ ₁ =ω ₁ t, θ ₂ is the rotation angle of the second antenna, θ ₂ =ω ₂ t, and θ ₃ is the angle when looking at the target from the reference axis O. In Figure 1, the position of Or seen from the reference axis O
z is expressed by the following formula. In this case, it will be explained below that z can be demodulated at two angular frequencies ω ₁ and ω ₂ . On the coordinates, the distance r from the target position Or to the tip P of the beam is expressed by the following equation. r=[(r ₁ cosθ ₁ +r ₂ cosθ ₂ −r ₃ cosθ ₃ ) ² + (r ₁ sinθ ₁ +r ₂ sinθ ₂ −r ₃ sinθ ₃ ) ² ] = [r ₁ ² + r ₂ ² + r ₃ ² + 2r ₁ r ₂ cos(θ ₁ −θ ₂ )−2r ₁ r ₃ cos(θ ₁ −θ ₃ )−2r ₂ r ₃ cos(θ ₂ −θ ₃ )]〓
………(2) However, θ ₁ = ω ₁ t, θ ₂ = ω ₂ t, and ω
₁ , _ω2 is positive when rotating counterclockwise. The output W(t) after modulation is expressed as W(t)=a(r,t) _sinωct (3) where _ωc is the angular frequency of the carrier wave. When the antenna pattern is approximated by a Gaussian shape, the amplitude term a(r, t) is approximated as follows. a (r, t) = exp (-r ² / γ ² ) ......(4) However, γ ² is a quantity approximated by the antenna pattern, and r is determined by equation (2). . When |r ² /γ ² |≪1, equation (4) can be approximated as follows, and has a characteristic close to a(r, t)≒1−r ² /γ ² (4)'. When the amplitude modulation output in equation (3) is detected, sinω _c t is removed, so regarding equation (4), what happens in the output signal when sinusoidal signals of three frequencies pass through the nonlinear circuit? The question is whether spectral signals are included, but according to the formula for the expansion of a multi-frequency Fourier series, Equation (4) includes signals at angular frequencies ω ₂ −ω ₁ , ω ₁ , ω _{2 .} It can be done. Therefore, considering the phase detection output regarding demodulated signal components of angular frequencies ω ₁ and ω ₂ ,
By attaching a generator or pick-up to the shaft of each antenna rotating at ω ₁ and ω ₂ and extracting a signal synchronized with the rotation of the shaft, it is possible to create the reference signals P and Q necessary for phase detection. can. And the phase detection outputs Z ₁ and Z ₂ are However, is the average of one cycle. Equations (7) and (8) show that it is possible to extract error signals for the elevation angle and azimuth angle using the two signals ω ₁ and ω ₂ , respectively. In order to show that the signals of equations (7) and (8) can actually be demodulated from equation (4), the results of a computer simulation are shown in FIG. This figure shows that r ₁ = 1, r ₂ =
0.6, r ₃ = 0, ω ₁ = 1 (rad/sec), ω ₂ = 6 (r
This shows an example in which a computer numerically calculates the trajectory of the beam tip in the case of (ad/sec). FIG. 3 shows the error signal output after synchronous detection when r ₃ is changed in the case of FIG. 2. Here, the solid line A shows the case when demodulating at an angular frequency ω ₁ , and the solid line B shows the case when demodulating at an angular frequency ω ₂ . However, θ ₃ =0. From this figure, it can be seen that the input/output characteristics have extremely good linearity, indicating that it is suitable for a tracking system. In FIG. 1, it can be seen that when r ₂ =0, the well-known modulation and demodulation system of a conical scan antenna is used, and the explanation up to now also includes a description of the modulation and demodulation system of a conical scan antenna. The vector of r ₂ is
The important thing is whether or not it is possible to rotate the beam not around the origin O but around the origin O ₂ (one end of r ₂ ), so next we will discuss how to rotate the beam as shown in Figure 1. explain. A specific example will be explained with reference to FIG. In this figure, the antenna system is comprised of a parabolic antenna 1, a reflector 2, and a feedhorn 3. Here, FIG. 1 and FIG. 4 will be explained in relation to each other. The reflector 2 in FIG. 4 is eccentric by an angle r ₁ and rotates at an angular velocity ω ₁ as shown in FIG. 1. Further, the feed horn 3 in FIG. 4 is eccentric by an angle r ₂ and rotates at an angular velocity ω ₂ as shown in FIG. 1. Since the reflector 2 and the feed horn 3 each have directivity (the antenna gain changes depending on the angle), they correspond to the coordinate system shown in FIG. Next, the overall configuration of an embodiment of the tracking method of the present invention is shown in FIG. In this figure, the antenna system ANT is adapted to be driven by an antenna servo device having a servo amplifier SA. Incoming radio waves including radio waves from the target are sent to the antenna system.
It is received by ANT and goes into mixer MIX. This mixer MIX receives the oscillation output from the local oscillator LO and converts the received signal into an appropriate intermediate frequency. At this time, since the antenna system ANT has a configuration as shown in FIG. 4, for example, the arriving radio waves are subjected to multiple amplitude modulation. The received signal converted to an intermediate frequency is amplified by an intermediate frequency amplifier IFA, and then sent to a demodulator.
It is demodulated by DET and the carrier component is removed. The demodulated signal is amplified by an amplifier LFA and applied to band pass filters BPF1, BPF2, and BPF5. The bandpass filter BPF1 passes only frequencies near _ω1 and adds them to the multipliers MUT1 and MUT2. The bandpass filter BPF2 passes only frequencies near _ω2 and applies them to multipliers MUT3 and MUT4. On the other hand, the bandpass filter BPF5 passes only frequencies near ω ₂ −ω ₁ and applies them to the phase detector PD, synchronous detector SD, and n/m multiplier DM. An n/m multiplier is a combination of a frequency divider, a multiplier, and a phase shifter. Since the signal component of ω ₂ - ω ₁ of the demodulated signal does not include information about θ ₃ , it can be used as a reference signal, and since the ratio between ω ₁ and ω ₂ is known, it can be calculated by the n/m multiplier DM. By dividing and multiplying the reference signal of ω ₂ - ω ₁ , P in equations (5) and (6),
Q can be created. That is, the reference signal
R ₁ = cosω ₁ t, R ₂ = −sinω ₁ t, R ₃ = cosω ₂ t, R ₄ =
−sinω ₂ t can be created. Note that these reference signals R ₁ to R ₄ may be created by providing a generator, a pickup, etc. on the rotation axis of the antenna system ANT. Now, the multiplier MUT1 multiplies the ω ₁ signal included in the demodulated signal by the reference signal R ₁ and applies the multiplier to the low-pass filter LPF1 and the band-pass filter BPF3. The multiplication result is the low pass filter LPF1
The high frequency component is removed at , and the azimuth error signal Ez=r ₃ cos(θ ₃ +φ) is applied to the servo amplifier SA via the switching circuit SW.
The multiplier MUT2 multiplies the signal of ω ₁ and the reference signal R ₂ and applies the product to the low-pass filter LPF2. The harmonic components of this multiplication result are removed by the low-pass filter LPF2, and the elevation angle error signal E is sent via the switching circuit SW.
It is designed to be applied to the servo amplifier SA as _L = r ₃ sin (θ ₃ +φ). Similarly, the multiplier MUT3 multiplies the ω ₂ signal included in the demodulated signal by the reference signal R ₃ and applies it to the low-pass filter LPF3. The harmonic components of this multiplication result are removed by a low-pass filter LPF3, and the result is given to the servo amplifier SA as an azimuth error signal via a switching circuit SW. The multiplier MUT4 multiplies the signal of ω ₂ by the reference signal R ₄ , and applies the low-pass filter.
Add to LPF4 and bandpass filter BPF4. The harmonic components of the multiplication result are removed by a low-pass filter LPF4, and the result is given to the servo amplifier SA as an elevation angle error signal via a switching circuit SW. That is, the azimuth error signal and the elevation angle error signal can be obtained from the signals of ω ₁ and ω ₂ , respectively. The switching circuit SW selects the azimuth error signal and the elevation angle error signal based on the ω ₂ signal when there is a DC signal from the detector DT1, i.e. Z ₂ , and selects the azimuth error signal and the elevation angle error signal based on the ω ₁ signal when there is a DC signal from the detector DT2, i.e. Select _Z1 . On the other hand, the multiplier MUT5 is the antenna system
The reference signals R ₂ and R ₃ obtained in synchronization with the rotating shafts are multiplied by ω ₁ and ω ₂ of the ANT, and the multiplication result is passed through the low-pass filter LPF5 to the phase detector PD.
Add to. As a result, the output of the phase detector PD is
sinφ is obtained. This sinφ is when φ is close to zero
sinφ≒φ, and the phase change φ from the high frequency circuit part to the phase detector PD from the output of the phase detector PD.
can be known. If the phase difference φ is known, a voltage proportional to sinφ can be generated between the high frequency circuit section and the phase detector PD using a voltage controlled phase shifter whose phase amount changes in proportion to the input voltage.
By inputting and controlling the voltage controlled phase shifter, the phase amount φ can always be made zero. Therefore, it can be used as a tracking system calibration circuit. once angular frequency ω
A demodulated signal component of angular frequency ω ₁ and a reference signal of angular frequency ω ₁ , a demodulated signal component of angular frequency ω ₂ and a reference signal of angular frequency ω ₂ , a demodulated signal component of angular frequency ω ₂ - ω ₁ and a reference signal of ω ₂
If the positional relationship of the reference signals of -ω ₁ is aligned, the signal component of the angular frequency ω ₂ - ω ₁ will be included in the demodulated signal whenever there is an incoming radio wave, so the angular frequency ω ₂ - By looking only at the change in the phase of the signal of ω ₁ , it is possible to know the change in the phase of the signal components of ω ₁ and ω ₂ , and it is possible to reduce the cause of crosstalk by setting φ to zero. The multiplier MUT6 calculates ω of the antenna system ANT.
₁ and ω ₂ by reference signals R ₁ and R ₃ obtained in synchronization with the rotating shaft, and the multiplication result is applied to the synchronous detector SD via the low-pass filter LPF6.
As a result, cosφ is obtained at the output of the synchronous detector SD. This cosφ becomes cosφ≈1 when φ is close to zero, and the presence of an incoming radio wave can be ideally detected. The output of this synchronous detector SD is then passed through a low pass filter LPF7 to an intermediate frequency amplifier.
The automatic gain control signal AGC is applied to IFA and amplifier LFA. Next, the reason why the above configuration can continue to track the radio waves from the target even in the presence of amplitude modulated interfering radio waves will be explained. The interfering radio wave C(t) is determined as shown in the following equation. C(t)=(1+d cosω _j t) cosω _e t (9) After amplitude detection, the signal of d cosω _j t is definitely demodulated. When ω _j is close to ω ₁ and ω ₂ , BPF1
Alternatively, a demodulated signal of the interfering radio wave is output to BPF2.
Then, the interference signal is further transmitted to BPF3 or BPF4.
The signal is applied to the detector DT1 or DT2 via the detector DT1 or DT2, where the alternating current component is extracted. When the signal received by the antenna is a jamming wave as shown in equation (9), the received signal ω ₁ (t) is calculated from equations (3) and (9) as ω ₁ (t)=(1+d cosωjt)a(r, t) cos
ωct (14) Since there is a constant term in equation (4), a component proportional to d cosωjt is output in the signal after amplitude detection. If ωj=ω ₂ +Δω ……(15), then the _amplifier (BPF
When amplified in 2), y ₁ (t) = d cos (ω ₂ + Δω) t + er ₂ cos (ω ₂ t−θ ₃ ) ... (16) (however, e is a proportionality constant), and on the other hand, When amplified by an amplifier with a central angular frequency ω ₁ , the signal component is y ₂ (t)=fr ₃ cos(ω ₁ t−θ ₃ ) (17). However, f is a proportionality constant.
The phase detection output is Z ₁ = {2 ₁ ( ₂ +) + 2 ₃ ( ₂ + ₃ )} × (- ₂ ) = dr ₁ sin Δωt + r ₃ sin θ ₃ ... (18) The interference signal is an AC component and the signal is a DC component. Becomes an ingredient. On the other hand, the other phase detection output is Z ₂ =2 ₃ ( ₁ + ₃ ) x ( _-1 ) = r ₃ sin θ ₃ (19), and the signals of equation (18) and equation (19) are compared. At this time, the switching circuit SW switches between Z ₁ (azimuth error signal E _Z and elevation error signal E _L due to ω ₁ ) and Z ₂ (azimuth error signal E _Z and elevation error signal E _L due to ω ₂ ).
Compare the values of _Z1 and Z2, and if the values of Z1 and _Z2 are different, select only the one that is not being interfered with and install the servo amplifier.
Add to SA. For example, when alternating current appears at the output of DT1, it indicates that _Z1 is being interfered with, so SW selects _Z2 . In this way, the target position can always be accurately known regardless of the presence of jamming radio waves. Selected Z ₁ or Z ₂
Accordingly, the antenna servo device having the servo amplifier SA drives the antenna system ANT so that Z ₁ or Z ₂ becomes zero to track the target. From the above explanation, by eccentrically rotating two of the antenna system components, such as the antenna, radio wave lens, reflector, and feed horn, and applying multiple amplitude modulation to the incoming radio waves, it is possible to achieve tracking that is extremely resistant to radio interference. It turns out that the system is realizable. Note that if the reference signals R ₁ to R ₄ are generated from the ω ₂ - ω ₁ signal included in the demodulated signal by the frequency divider/multiplier DM, the reference signals can be generated by attaching a generator or pickup to the antenna rotation axis. It is cheaper than creating one. However, the phase detector
When it is desired to obtain sinφ and cosφ using PD and synchronous detector SD as shown in FIG. 5, a reference signal obtained from the antenna rotation axis side is also required. In the above embodiment, the case where the target is tracked by radio waves has been described, but the present invention can also be applied to the case where the target is tracked optically. Since the differences between the two are slight, only the components of the optical system that replaces the radio wave antenna system are shown. In FIG. 6, the optical system includes a first rotating lens 10, a second rotating lens 11, an amplitude modulation reticle 12 disposed on a focal plane 15, and a condensing lens 13.
and a detector 14 that converts light into an electrical signal. First and second rotating lenses 10, 11
are eccentric and rotate at different angular frequencies of ω ₁ and ω ₂ , respectively. Then, a trajectory of a light spot as shown in Fig. 2 is drawn on the surface of the amplitude modulation reticle 12, and the light from the target light source is subjected to multiple amplitude modulation, so that the detector output has an amplitude as shown in equation (3). Generates a modulated wave. The demodulation circuit and the like thereafter are the same as the configuration shown in FIG. 5 described in the previous embodiment. Next, instead of the amplitude modulation reticle described above,
Using a frequency modulation reticle has a similar performance improvement effect, so we will discuss its principle and configuration, but since there are many common parts, we will only discuss the differences between amplitude modulation and frequency modulation. FIG. 7 shows a typical frequency modulation reticle. Here, the white parts transmit light, and the black parts block light. From Figure 1, the output m(t) of the detector in the case of a point light source is m(t) = sgn sinθ(t) ...(10) where sgn y=1 y≧0 -1 y<0 ...(11 ) θ(t)=mtan ^-1 r ₁ cos ω ₁ t+r ₂ cos ω ₂ t-r ₃ cos θ ₃ /r ₁ sin ω ₁ t+r ₂ sin ω ₂
tr ₃ sin θ ₃ (12). In formula (12), m indicates the number of divisions of the reticle, and in the example of FIG. 7, the number of divisions m=6. The instantaneous frequency of equation (12) is dθ(t)/dt=m[r ₁ ² ω ₁ +r ₂ ² ω ₂ +r ₁ r ₂ (ω ₁ +ω ₂ )cos(ω ₂ t/r ₁ ² +r ₂ ² +r ₃
² +2r ₁ r ₂ cos(ω ₂ t-ω ₁ t) -ω ₁ t)-r ₁ r ₃ ω ₁ cos(ω ₁ t-θ ₃
)/-2r ₁ r ₃ cos(ω ₁ t-θ ₃ ) −r ₂ r ₃ ω ₂ cos(ω ₂ t-θ ₃ )]/-2
r ₂ r ₃ cos(ω ₂ t-θ ₃ )...(13) Comparing the expression for amplitude modulation in equation (4) and the expression for frequency modulation in equation (13), of course they are different, but in the end the angular frequency ω ₁ , ω ₂ , ω ₂ −ω ₁ is a Fourier series problem when the fundamental waves enter a nonlinear circuit, and from the formula of Fourier series expansion, the angular frequencies ω ₁ , ω ₂ , ω ₂
Since it is known that the frequency component of -ω ₁ is included in the output of equation (13), the subsequent signal flow can be considered as a tracking system in the same way as in the case of amplitude modulation. Figure 9 shows the angular frequency ω when the locus of the light spot as shown in Figure 8 is drawn on the reticle of Figure 7.
The results of a computer simulation of the input-output relationship for _ω1 and _ω2 are shown. In FIG. 9, the solid line J is the input/output characteristic for ω ₁ , and the solid line K is the input/output characteristic for ω ₂ , where r ₁ = 1, r ₂ = 0.15, ω
The case where ₁ = 1 (rad/sec) and ω ₂ = 4 (rad/sec) is shown. Therefore, the configuration of the tracking system using the frequency modulation reticle is as shown in FIG. 6, similar to the case where the amplitude modulation reticle is used. In addition, in Figure 4, the parabolic antenna, reflector,
Although an antenna system having a feed horn is shown, an antenna system having a radio wave lens or the like may be used. Further, although FIG. 6 shows an optical system having a rotating lens and a reticle, it may also be an optical system having a mirror or the like. The servo device used in the present invention is a DC input signal type that drives an antenna system or optical system to a target using an azimuth error signal and a height angle error signal, which are DC signals, and a free-gear type servo device that uses an AC type servo device. When the rotational angular velocity is ω ₁ , the antenna or the optical system may be driven toward a target using an alternating current signal of r ₃ cos (ω ₁ t−θ ₃ ) synchronized with the error angular frequency. As described above, according to the present invention, since the target is tracked using a signal obtained by multiple amplitude modulation of radio waves or light from the target using an antenna system or an optical system, there is no interference caused by radio waves or light. It is possible to obtain a highly reliable tracking method that is not easily affected.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the target position, antenna beam tip, etc. using a coordinate system on the focal plane of the antenna system to explain the principle of the tracking method according to the present invention, and Fig. 2 is an explanatory diagram showing the trajectory of the antenna beam tip. 3 is a graph showing an example of the input/output characteristics in the case of FIG. 2, FIG. 4 is a perspective view showing an example of an antenna system in an embodiment of the present invention,
Fig. 5 is a block diagram showing the overall configuration of the embodiment, Fig. 6 is a block diagram showing an example of an optical system in another embodiment of the present invention, and Fig. 7 is a front view showing an example of a frequency modulation reticle. 8 is a graph showing an example of the locus of a light spot drawn on the frequency modulation reticle, and FIG. 9 is a graph showing the input/output characteristics in the case of FIG. 8. 1...parabolic antenna, 2...reflector, 3...
...Feed horn, 10, 11...Rotating lens,
12...Amplitude modulation reticle, 13...Condensing lens, 14...Detector, ANT...Antenna system, SA...Servo amplifier, MIX...Mixer, LO
...Local oscillator, IFA...Intermediate frequency amplifier,
DET...Demodulator, LFA...Amplifier, BPF1 to
BPF5...Band pass filter, LPF1 to LPF7
...Low pass filter, MUT1 to MUT6...
Multiplier, PD...Phase detector, SD...Synchronized detector, DM...n/m multiplier, SW...Switching circuit, DT
1, DT2...detector.

Claims (1)

[Claims] 1. To receive radio waves, at least two of the components of the antenna system are eccentrically rotated at different angular frequencies (ω ₁ , ω ₂ ),
creating a rotating antenna beam and multiple amplitude modulating radio waves from the target using the antenna system;
The angular frequency (ω
₁ , ω ₂ ) and the angular frequency (ω ₁ , ω ₂ )
A tracking method characterized in that a target is tracked by an antenna servo device using an azimuth angle error signal and an elevation angle error signal obtained by synchronous detection at the same frequency using a reference signal. 2 _The angular frequencies _{( ω 1} , _{ω 2} ) The tracking method according to claim 1, wherein the reference signal is created. 3. To receive radio waves, at least two of the components of the antenna system are eccentrically rotated at different angular frequencies (ω ₁ , ω ₂ );
creating a rotating antenna beam and multiple amplitude modulating radio waves from the target using the antenna system;
The angular frequency (ω
₁ , ω ₂ ) and the angular frequency (ω ₁ , ω ₂ )
This is a tracking method in which a target is tracked by an antenna servo device using an azimuth angle error signal and an elevation angle error signal obtained by synchronously detecting the same frequency using a reference signal of The angular frequencies (ω ₁ , ω
₂ ) with a difference in angular frequency (ω ₂ −ω ₁ ) and a signal component with an angular frequency (ω ₁ , ω ₂ ) synchronized with an axis rotating with an angular frequency (ω ₁ , ω ₂ ) in the antenna system. A DC signal obtained by synchronous detection with a reference signal of a difference angular frequency (ω ₂ −ω ₁ ) created from the reference signal is used as an automatic gain control signal, and the multiple amplitude modulation signal before detection or the demodulation signal after detection is used as an automatic gain control signal. A tracking method that is characterized by being added to the amplifying amplifier. 4. To receive radio waves, at least two of the components of the antenna system are eccentrically rotated at different angular frequencies (ω ₁ , ω ₂ );
creating a rotating antenna beam and multiple amplitude modulating radio waves from the target using the antenna system;
The angular frequency (ω
₁ , ω ₂ ) and the angular frequency (ω ₁ , ω ₂ )
This is a tracking method in which a target is tracked by an antenna servo device using an azimuth angle error signal and an elevation angle error signal obtained by synchronously detecting the same frequency using a reference signal of The angular frequencies (ω ₁ , ω
₂ ) with a difference in angular frequency (ω ₂ −ω ₁ ) and a signal component with an angular frequency (ω ₁ , ω ₂ ) synchronized with an axis rotating with an angular frequency (ω ₁ , ω ₂ ) in the antenna system. Changes in phase characteristics that occur when a signal multiplexed by the antenna system passes through an amplifier by phase-detecting a reference signal with a difference angular frequency (ω ₂ −ω ₁ ) created from the reference signal. A tracking method characterized in that crosstalk due to synchronous detection necessary for extracting the azimuth angle error signal and the elevation angle error signal is reduced by detecting and correcting the azimuth angle error signal and the elevation angle error signal. 5. To track a target light source, at least two of the components of the optical system are decentered and rotated at different angular frequencies (ω ₁ , ω ₂ ),
Draw a rotating locus on the amplitude modulation reticle or frequency modulation reticle surface placed on the focal plane of the optical system, perform multiple amplitude modulation or multiple frequency modulation on the light from the light source, and detect the signal. The azimuth error signal and height obtained by synchronously detecting the same frequency using the signal component of the angular frequency (ω ₁ , ω ₂ ) of the obtained demodulated signal and the reference signal of the angular frequency (ω ₁ , ω ₂ ) A tracking method that uses an angular error signal to track a target using an antenna servo device. 6 The angular frequency (ω ₁ , ω ₂ ) is obtained by dividing and multiplying a signal having an angular frequency (ω ₂ −ω ₁ ) that is the difference between the angular frequencies (ω ₁ , ω ₂ ) included in the demodulated signal. ) The tracking method according to claim 5, wherein the reference signal is created. 7. To track a target light source, at least two of the components of the optical system are decentered and rotated at different angular frequencies (ω ₁ , ω ₂ ),
Draw a rotating locus on the amplitude modulation reticle or frequency modulation reticle surface placed on the focal plane of the optical system, perform multiple amplitude modulation or multiple frequency modulation on the light from the light source, and detect the signal. The azimuth error signal and height obtained by synchronously detecting the same frequency using the signal component of the angular frequency (ω ₁ , ω ₂ ) of the obtained demodulated signal and the reference signal of the angular frequency (ω ₁ , ω ₂ ) A tracking method in which a target is tracked by an antenna servo device using an angular error signal, the angle of the difference between the angular frequencies (ω ₁ , ω ₂ ) contained in the demodulated signal obtained by the detection. Frequency (ω ₂
−ω ₁ ) and a reference signal of angular frequency (ω ₁ , ω ₂ ) synchronized with the axis rotating with angular frequency (ω ₁ , ω ₂ ) in said antenna system, the difference angular frequency ( A DC signal obtained by synchronous detection with a reference signal of ω ₂ −ω ₁ ) is applied as an automatic gain control signal to an amplifier that amplifies the multiple amplitude modulation signal before detection or the demodulation signal after detection. Tracking method. 8. To track a target light source, at least two of the components of the optical system are decentered and rotated at different angular frequencies (ω ₁ , ω ₂ ),
Draw a rotating locus on the amplitude modulation reticle or frequency modulation reticle surface placed on the focal plane of the optical system, perform multiple amplitude modulation or multiple frequency modulation on the light from the light source, and detect the signal. The azimuth error signal and height obtained by synchronously detecting the same frequency using the signal component of the angular frequency (ω ₁ , ω ₂ ) of the obtained demodulated signal and the reference signal of the angular frequency (ω ₁ , ω ₂ ) A tracking method in which a target is tracked by an antenna servo device using an angular error signal, the angle of the difference between the angular frequencies (ω ₁ , ω ₂ ) contained in the demodulated signal obtained by the detection. Frequency (ω ₂
−ω ₁ ) and a reference signal of angular frequency (ω ₁ , ω ₂ ) synchronized with the axis rotating with angular frequency (ω ₁ , ω ₂ ) in said antenna system, the difference angular frequency ( By performing phase detection on the reference signal of ω ₂ −ω ₁ ), changes in phase characteristics that occur when the signal multiplexed by the antenna system passes through the amplifier are detected and corrected, and an azimuth error signal is obtained. and a tracking method characterized by reducing crosstalk due to synchronous detection required to extract the elevation angle error signal.