JPH1138112A - Tracking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a tracking device which can be simplified in constitution, can be reduced in weight, is hardly affected by even a sever environment, can also cope with the bit rate and modulation system of an arbitrary communication signal, and has high stability and high accuracy. SOLUTION: A synthesizer 11 generates one amplitude-modulated time division error signal by amplitude-synthesizing one modulated time division error signal obtained by means of an error signal time division selecting means 31 by inputting a tracking error signal Δ amplitude-modulated by means of a modulator 8 with a reference tracking signal Σ. Then, an envelope detector 16 generates a modulated time division error signal by detecting the envelop of the synthesized error signal and a separating and demodulating means 32 generates first and second angle error signals for controlling driving of antenna by separating and demodulating the modulated time division error signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tracking device for tracking a mobile satellite or the like.

[0002]

2. Description of the Related Art In satellite communication, a tracking device is known that tracks a satellite in a geosynchronous orbit or tracks and receives an earth observation satellite in a low orbit to track between ground stations or between them. I have.

FIG. 10 is a block diagram showing a configuration of a conventional tracking device. 10, reference numeral 2 denotes an antenna for receiving a communication signal from, for example, a mobile satellite (not shown), and reference numeral 3 denotes a signal separating means for separating a tracking reference signal Σ and a tracking error signal Δ included in the communication signal received by the antenna 2. 10a is an amplifier (low noise amplifier) for amplifying the tracking reference signal Σ, 10b is an amplifier (low noise amplifier) for amplifying the tracking error signal Δ, and 12a is an AGC for the tracking reference signal amplified by the amplifier 10a. AG with (automatic gain control)
C circuit, 12b is an AGC circuit for applying AGC to the tracking error signal amplified by the amplifier 10b, and 15 is an AGC circuit 12
a 90-degree phase shifter for rotating the tracking reference signal from a by 90 degrees; 17 an AZ detector for extracting the in-phase component AZ of the tracking error signal from the AGC circuit 12b; 18 a tracking error signal from the AGC circuit 12b This is an EL detector that extracts a quadrature component EL.

Next, the operation will be described. In FIG. 10, a communication signal received by the antenna 2 is converted into a tracking reference signal Σ and a tracking error signal Δ by a feeder 3 attached to the antenna 2.
Is separated into These tracking reference signal Σ and tracking error signal Δ
The difference between the amplitude and the phase difference between the direction of the communication signal from the tracking target and the direction of the antenna 2 (magnitude of deviation; amplitude difference) and the direction (AZ direction, E
L direction, other arbitrary directions; phase difference), so that the signal is passed to the subsequent stage while maintaining the amplitude difference and the phase difference,
It is necessary to detect the amplitude difference and the phase difference in the receiving unit. For this reason, the tracking reference signal Σ from the power supply device 3 is
The tracking error signal Δ from the power supply device 3 is amplified by the amplifier 10b and input to the receiving unit.

In the receiving section, the quadrature phase component EL of the tracking error signal is extracted by the EL detector 18 with the tracking reference signal rotated by 90 degrees by the 90-degree phase shifter 15 as a phase reference, and the 90-degree phase shift is performed. The in-phase component AZ of the tracking error signal with the tracking reference signal before being input to the
Is extracted by the AZ detector 17. The in-phase component AZ and quadrature-phase component EL of the tracking error signal extracted in this way are given to a motor of an antenna driving mechanism provided in a drive control device (not shown) of the antenna 2,
The direction of the antenna 2 is controlled.

FIG. 11 is a block diagram showing the configuration of another conventional tracking device. In FIG. 11, reference numeral 2 denotes an antenna for receiving a communication signal from, for example, a mobile satellite (not shown);
Is a power feeding device as a signal separating unit that separates a tracking reference signal Σ and a tracking error signal Δ included in a communication signal received by the antenna 2, 8 is a modulator that modulates the tracking error signal Δ with a clock signal 9 having a frequency fc, Reference numeral 11 denotes a synthesizer for synthesizing the tracking reference signal Σ and the tracking error signal modulated by the modulator 8, and 1
0 is an amplifier (low noise amplifier) that amplifies the signal synthesized by the synthesizer 11, and 12 is
AGC circuit for applying GC, 13 is a BPF (Band Pass Filter) for removing a low frequency modulation signal included in the signal from the AGC circuit 12, and 14 is a PLL (phase-phase) for generating a signal of a predetermined frequency based on the signal from the BPF 13. l
15 is a 90-degree phase shifter for rotating the phase from the PLL 14 by 90 degrees, and 17 is a PLL 1
AZ detector for extracting the in-phase component AZ of the tracking error signal from the AGC circuit 12 based on the signal from 4;
An EL detector that extracts the quadrature component EL of the tracking error signal from the AGC circuit 12 based on the signal from the 0-degree phase shifter 15. A tracking error 20 a from the AZ detector 17 is based on the clock signal 9 having the frequency fc. An amplitude detector 20b for detecting the DC component DAZ of the in-phase component AZ of the signal, and an amplitude detector 20b for detecting the DC component DEL of the quadrature phase component EL of the tracking error signal from the EL detector 18 based on the clock signal 9. is there.

FIG. 12 is a diagram showing the spectrum and waveform of the frequency distribution of each signal in the tracking device shown in FIG. 12A is a spectrum showing a frequency distribution of a tracking reference signal output from the power supply device 3, FIG. 12B is a spectrum showing a frequency distribution of a tracking error signal output from the power supply device 3, and FIG. ) Is a spectrum showing a frequency distribution of the modulated tracking error signal output from the BPSK modulator 8, FIG. 12D is a spectrum showing a frequency distribution of the synthesized modulation tracking error signal output from the synthesizer 11, FIG. 12E is a spectrum showing a frequency distribution of a modulation tracking error signal applied with AGC output from the AGC circuit 12, and FIG. 12F is a spectrum showing a frequency distribution of a tracking reference signal output from the BPF 13. FIG. 12 (g) shows the waveform of the in-phase component AZ of the tracking error signal output from the AZ detector 17, and FIG.
Represents the waveform of the quadrature phase component EL of the tracking error signal output from the EL detector 18. FIG. 12 (c),
Fc shown in (d), (e), and (f) indicates the frequency of the clock signal 9 shown in FIG.

Next, the operation will be described. In FIG. 11, a communication signal received by the antenna 2 is converted into a tracking reference signal Σ and a tracking error signal Δ by a power supply device 3 attached to the antenna 2.
Is separated into These tracking reference signal Σ and tracking error signal Δ
Are different from the direction of the antenna 2 by how much the direction of the communication signal from the tracking target is shifted from the direction of the antenna 2 (the magnitude of the shift; the amplitude difference), and in which direction (AZ direction, EL
Direction, other arbitrary direction; phase difference), it is necessary to pass the signal to the subsequent stage while maintaining the amplitude difference and the phase difference, and to detect the amplitude difference and the phase difference at the receiving unit. In this conventional example, the tracking reference signal Σ and the tracking error signal Δ are combined into one signal by using the modulator 8 and the combiner 11 so as to be suitable for a severe environment.

In the receiving section, the AZ detector 17 detects the in-phase component AZ of the tracking error signal based on the in-phase tracking reference signal.
Are extracted, and the quadrature phase component EL of the tracking error signal is extracted by the EL detector 18 based on the quadrature tracking reference signal. Thereafter, the DC component DAZ of the in-phase component AZ of the tracking error signal is extracted by the amplitude detector 20a, and the DC component DEL of the quadrature component EL of the tracking error signal is extracted by the amplitude detector 20b.

Incidentally, it is necessary to supply a drive control signal to a motor or the like of an antenna drive mechanism provided in a drive control device (not shown) of the antenna 2, and in order to obtain the drive control signal, the tracking error signal .DELTA. Carrier signal is modulated by the clock signal 9 and pre-processed so that it can be easily separated into the in-phase component AZ and the quadrature-phase component EL in the receiving unit. Accordingly, the receiving unit detects only the carrier component (tracking reference signal Σ) by removing the carrier-suppressed modulated low-frequency modulated signal by the BPF 13 and the like, and detects the tracking reference signal having the same phase component as the carrier component. (PLL14
) And the tracking reference signal of the quadrature phase component (the output of the 90-degree phase shifter 15), phase and amplitude detection of the modulation tracking error signal from the AGC circuit 12 is performed, and the in-phase component AZ of the tracking error signal and the quadrature detection are performed. The phase component EL is extracted from the AZ detector 17 and the EL detector 18, respectively, and
In steps a and 20b, detection is performed using the low frequency fc clock signal 9, and the respective DC components DAZ and DEL are extracted. These DC components DAZ and DEL are supplied to a motor or the like as drive signals for the motor or the like, and control the direction of the antenna 2. This conventional tracking device is used when a received signal is modulated without a modulated sideband or a modulated sideband near a carrier. Therefore, it cannot be used for signals such as BPSK and QPSK. In the spectrum separation of the tracking reference signal, a reference for detection is created by suppressing the side band by the BPF 13 and the PLL 14.

[0011]

The conventional tracking device as described above is installed on the ground as equipment for a ground station, so that it is installed in space or uses a Ka band frequency on the ground. The environmental conditions of the apparatus are milder, and the weight and size conditions are milder than in the case where the power supply is performed.

Therefore, in the conventional tracking device shown in FIG. 10, the tracking reference signal and the tracking error signal must be separately transmitted to the receiving unit, which makes it difficult to reduce the size of the device. It is difficult to satisfy the phase difference and the amplitude difference between the above two signals, which are the requirements for tracking accuracy under severe environmental conditions such as space, and therefore, they cannot be used in severe environments such as outer space. is there.

Further, in the conventional tracking apparatus shown in FIG. 11, even if the environmental conditions are severe, the phase difference and the amplitude difference between the two signals of the tracking reference signal and the tracking error signal, which are the tracking accuracy requirements, are 1 signal. A carrier that reproduces a tracking reference signal used to separate the two signals combined into one in the receiving unit, although the conditions are satisfactorily satisfied and the weight and size conditions are relaxed. Regeneration circuit (BPF
13) and special equipment such as
There is a problem that it is difficult to reduce the size and weight.
In addition, a tracking signal such as a tracking reference signal or a tracking error signal may not be assigned a dedicated signal due to signal processing or the like, and a data signal for communication is shared for tracking. The reproduction circuit must support the bit rate (data rate) and modulation method of all communication signals, and if the lowest receivable level is not lower than the reception level for communication, the antenna will initially track the target direction. Operation cannot start when the reception level is low. In other words, the antenna and the receiver can be stably reduced in size and weight with only one channel, and phase and amplitude can be detected. However, a special carrier recovery circuit is required, and it can be used for any communication signal bit rate and any modulation method. There is a problem that it is difficult to do. The tracking reference signal needs to be unmodulated, and in the case of an arbitrary bit rate signal or an arbitrary modulation signal, carrier recovery becomes considerably difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the structure can be reduced in size and weight, is less susceptible to severe environments, and has a bit rate of an arbitrary communication signal and an arbitrary bit rate. Corresponds to communication signal modulation method,
It is an object of the present invention to provide a tracking device with high stability and high accuracy.

[0015]

According to a first aspect of the present invention, there is provided an antenna for receiving a communication signal from a tracking target, and a signal separating means for separating a tracking reference signal and a tracking error signal contained in the communication signal received by the antenna. A modulating means for modulating the tracking error signal separated by the signal separating means; and a first angle having the same phase as the tracking reference signal, wherein the tracking error signal modulated by the modulating means is branched into two. The second angle error signal having the same phase as the tracking reference signal by rotating the other by a predetermined degree, and alternately time-dividing the first angle error signal and the second angle error signal. Error signal time-division selecting means for selecting and outputting as one modulation time-division error signal; and amplitude-combining the modulation time-division error signal with an in-phase tracking reference signal to produce one amplitude modulation / time-division error signal Compositing means to output as An envelope detection means for performing envelope detection on the one amplitude modulation / time division error signal, and separating and demodulating the time division error signal obtained by performing the envelope detection to obtain a first signal for antenna drive control. And a separating / demodulating means for outputting the angle error signal and the second angle error signal.

In the second invention, the error signal time-division selecting means splits the tracking error signal into two and outputs the first and second tracking error signals as a first tracking error signal and a second tracking error signal. A 90-degree phase shifter that rotates the tracking error signal by 90 degrees and outputs the same as a second angle error signal; a signal that uses the first tracking error signal as a first angle error signal; A time-division switch for alternately selecting and outputting the angle error signal.

According to a third aspect of the present invention, the modulation means amplitude-modulates the tracking error signal with a predetermined clock signal.

According to a fourth aspect of the present invention, the error signal time division selecting means and the modulating means are constituted by one modulator.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a tracking device according to the present embodiment. In FIG. 1, reference numeral 1 denotes a tracking target such as a mobile satellite, 2 denotes an antenna for receiving a communication signal from the tracking target 1, and 3 denotes a tracking reference signal Σ and a tracking error signal Δ included in a communication signal received by the antenna 2. The power supply device 10a as a signal separating unit that performs amplification is an amplifier (low-noise amplifier) that amplifies the tracking reference signal Σ. Reference numeral 8 denotes a modulator as a modulation unit for amplitude-modulating the tracking error signal Δ separated by the power supply device 3 with a clock signal 9 having a frequency fc. Reference numeral 31 denotes a first branch which splits the tracking error signal Δ modulated by the modulator 8 into two, and one of which is in phase with the tracking reference signal Σ.
Angle error signal (in-phase component AZ of tracking error signal Δ)
The other is used as a second angle error signal (a quadrature component EL of the tracking error signal Δ) rotated by 90 degrees, and the first angle error signal and the second angle error signal are alternately time-divided. Error signal time division selecting means for selecting and outputting as one modulation time division error signal. The error signal time division selecting means 31 splits the modulation tracking error signal input from the modulator 3 into two and outputs the first and second tracking error signals as a first tracking error signal and a second tracking error signal. A 90-degree phase shifter 5 that rotates the tracking error signal by 90 degrees in phase and outputs it as a second angle error signal;
And a time division switch 6 for alternately selecting a signal as the angle error signal and the second angle error signal based on the clock signal 7 having the frequency fm and outputting the signal as one time division error signal. I have.

Reference numeral 10b denotes an amplifier (low noise amplifier) for amplifying the time-division error signal (modulation time-division error signal) from the time-division switch 6, and reference numeral 11 denotes an in-phase modulation time-division error signal from the amplifier 10b. Is a synthesizer as a synthesizing means for amplitude-synthesizing the tracking reference signal and outputting as one amplitude modulation / time-division error signal.

In the receiving section, reference numeral 12 denotes a combiner 11 for removing components common to the tracking reference signal Σ and the tracking error signal Δ, such as the distance to the tracking target 1 and fluctuations in the power of the transmission signal of the tracking target 1. To the amplitude modulation and time division error signal from
An AGC circuit for applying C. Reference numeral 16 denotes an envelope detector as envelope detection means for performing envelope detection on the amplitude-modulated / time-division error signal subjected to AGC by the AGC circuit 12.
Reference numeral 32 separates the envelope time-division error signal obtained by envelope detection by the envelope detector 16 into a first angle error signal and a second angle error signal, and further demodulates the first angle error signal and the second angle error signal. It is a separating / demodulating means for outputting a DC component DAZ of the angle error signal and a DC component DEL of the second angle error signal. The separating / demodulating means 32 separates the modulated time-division error signal from the envelope detector 16 into an in-phase component AZ and a quadrature-phase component EL of the tracking error signal Δ based on the clock signal 7 having the frequency fm. 19, and an amplitude for amplitude detection of the in-phase component AZ separated by the separation switch 19 based on the clock signal 9 of the frequency fc and outputting as a DC component DAZ of a first angle error signal (in-phase component AZ). Amplitude detection is performed on the quadrature component EL separated by the detector 20a and the separation switch 19 based on the clock signal 9 having the frequency fc, and is output as the DC component DEL of the second angle error signal (quadrature phase component EL). And an amplitude detector 20b.

In this embodiment, the error signal time division selecting means 31 and the modulator 8 are separately provided. However, the present invention is not limited to this. The configuration may be made up of a single modulator performed in advance. In this case, the configuration is slightly simplified.

FIG. 2 is a signal waveform diagram for explaining the operation of the tracking device shown in FIG. FIG. 2A shows the waveform of the tracking reference signal Σ output from the power supply device 3, where t is time,
A indicates the amplitude. FIG. 2B shows a waveform of the tracking error signal Δ output from the power supply device 3, where t indicates time and B indicates amplitude. FIG. 2C shows the second output from the 90-degree phase shifter 5.
Angle error signal (the quadrature component E of the tracking error signal Δ)
L), where t indicates time and B indicates amplitude. FIG.
(D) is a waveform of the in-phase component AZ of the amplitude modulation / time division error signal output from the synthesizer 11, where t is time, A +
B indicates the amplitude of the signal of FIG. 2A and the signal of FIG. 2B. FIG. 2E shows the waveform of the quadrature phase component EL of the amplitude modulation / time division error signal output from the combiner 11.
t is time, A + B (90 °) is the signal of FIG.
The amplitude due to the signal (c) is shown. FIG. 2F shows the waveform of the envelope time-division error signal output from the envelope detector 16. FIG. 2 (g) shows the waveform of the amplitude modulation / time division error signal output from the synthesizer 11, where Tc indicates the amplitude modulation period by the clock signal 9 having the frequency fc, and Tm indicates the time when the clock signal 7 has the frequency fm. Indicates a division cycle.

FIG. 3 is a diagram for explaining the phase relationship between the tracking reference signal Σ and the tracking error signal Δ in the present embodiment. FIG. 3A shows a vector representation of the relationship when the tracking reference signal Σ and the tracking error signal Δ are in phase. Then, as shown in FIG. 3B, the tracking error signal Δ
Is modulated to produce + Δ and −Δ as shown in FIG. 3C, and these are added to Σ as shown in FIG. 3D. As a result, a signal whose amplitude is modulated as shown in FIG. That is, when the tracking reference signal Σ and the tracking error signal Δ are in phase, an amplitude modulation (envelope modulation) signal as shown in FIG. 3E is generated.

FIG. 4 is a diagram for explaining the phase relationship between the tracking reference signal Σ and the tracking error signal Δ in the present embodiment. FIG. 4A shows a vector representation of the relationship when the tracking reference signal Σ and the tracking error signal Δ are orthogonal and have a phase difference of 90 degrees. Then, the tracking error signal Δ is modulated as shown in FIG. 4B to produce + Δ and −Δ as shown in FIG. 4C, and these are added to Σ as shown in FIG. 4D. I do. As a result, a signal not subjected to amplitude modulation is obtained as shown in FIG. That is, when the tracking reference signal Σ and the tracking error signal Δ are orthogonal and have a phase difference of 90 degrees, a signal without amplitude modulation as shown in FIG. 4E is generated.

FIG. 5 is a diagram for explaining how the phase relationship between the tracking reference signal Σ and the tracking error signal Δ corresponds to the relationship between the tracking target and the antenna beam axis in the present embodiment. is there. In FIG. 5A, S is the tracking target, AZ is the in-phase component of the tracking error signal Δ, EL is the quadrature phase component of the tracking error signal Δ, θ is the angle between the tracking target S and the antenna beam axis, and 2 is the antenna. Reference numeral 3 denotes a power supply device. As shown in FIG. 5B, the position of the tracking target S is in the + direction of the in-phase component AZ, the + direction of the quadrature component EL, the-direction of the in-phase component AZ, and the-direction of the quadrature component EL. In this case, as shown in FIG. 5C, the tracking error signal Δ is a vector in the same direction, + 90 ° rotation direction, reverse direction, and −90 ° rotation direction with respect to the tracking reference signal Σ. FIG.
When the tracking targets S are located at the positions as shown in (d), the tracking error signal Δ is a vector as shown in FIG.

FIGS. 6 to 8 are diagrams for explaining an operation for determining whether the offset direction (error direction) of the antenna with respect to the tracking target is left, right, up, or down. FIG. 9 is a diagram showing a clock signal fm used for the determination.

First, as shown in FIG.
Is in the positive direction of the in-phase component AZ of the tracking error signal Δ, the vector indicating the relationship between the tracking reference signal Σ and the tracking error signal Δ is as shown in FIG. The tracking reference signal Σ is modulated by the tracking error signal Δ, and this modulated signal is
FIG. 6C shows a vector as shown by a solid line.
The waveform is as shown in FIG. The modulated signal having the waveform as shown in FIG. 6 (d) is subjected to envelope detection to become a signal as shown in FIG. 6 (e). The polarity of the signal depends on the timing of the clock signal having the frequency fm as shown in FIG. When the result of the determination is the same polarity every half cycle as shown in FIG. 6 (f), a positive waveform signal is obtained. When this signal is detected by a clock signal of frequency fc, the offset direction of the antenna becomes FIG. 6 (g) showing that it is the right direction
A positive DC component as shown in FIG.

Next, as shown in FIG.
Is located at the intersection of the in-phase component AZ and the quadrature component EL of the tracking error signal Δ, that is, at the position of zero, the vector indicating the relationship between the tracking reference signal Σ and the tracking error signal Δ is shown in FIG. ). In this case, the tracking error signal Δ
No vector has been displayed since no occurrence has occurred.
Therefore, even if the tracking reference signal Σ is modulated by the tracking error signal Δ, it remains as it is, and is displayed as a vector as shown in FIG. 7C, and a signal as shown in FIG. It becomes the signal of the signal Σ itself. After that, even if detected, the tracking error signal Δ is not included.
As shown in (e) to (g), a DC component indicating an error cannot be obtained.

Next, as shown in FIG.
Is in the negative direction of the in-phase component AZ of the tracking error signal Δ, the vector indicating the relationship between the tracking reference signal Σ and the tracking error signal Δ is as shown in FIG. 8B. The tracking reference signal Σ is modulated by the tracking error signal Δ, and this modulated signal is
FIG. 8C shows a vector as shown by a solid line.
The waveform is as shown in FIG. The modulated signal having the waveform as shown in FIG. 8D is subjected to envelope detection to become a signal as shown in FIG. 8E, and the polarity of the signal depends on the timing of the clock signal having the frequency fm as shown in FIG. If the result of this determination is a half-cycle with a different polarity as shown in FIG. 8 (f), the signal has a negative waveform. When this signal is detected by a clock signal of frequency fc, the offset direction of the antenna becomes FIG. 8 showing the left direction
A negative DC component as shown in (g) is obtained.

Next, the operation will be described. In FIG. 1, a communication signal from a tracking target 1 received by an antenna 2 is transmitted by a feeder 3 attached to the antenna 2 to a tracking reference signal Σ.
And a tracking error signal Δ. The amplitude difference and phase difference between the tracking reference signal Σ and the tracking error signal Δ indicate how much the direction of the communication signal from the tracking target 1 is shifted from the direction of the antenna 2 (the size of the shift; amplitude difference). Direction (AZ direction, EL direction, other arbitrary directions; phase difference), so it is necessary to pass the signal to the subsequent stage while maintaining the amplitude difference and phase difference, and to detect the amplitude difference and phase difference at the receiving unit. There is.

The tracking error signal Δ separated by the power supply device 3 is amplitude-modulated by the modulator 8, further branched into two by the distributor 4, and output as a first tracking error signal and a second tracking error signal. The first tracking error signal is directly input to the time-division switch 6 as a first angle error signal (the in-phase component AZ of the tracking error signal Δ), and the second tracking error signal is converted to a 90-degree phase shifter 5 by the 90-degree phase shifter 5. The signal is rotated by a degree and is input to the time division switch 6 as a second angle error signal (a quadrature component EL of the tracking error signal Δ). In the time division switch 6, the first angle error signal and the second angle error signal are alternately selected based on the clock signal 7, and output as one modulation time division error signal. This modulated time-division error signal is amplified by the amplifier 10 b and input to the synthesizer 11. In the combiner 11, the modulated time-division error signal from the amplifier 10b is amplitude-synthesized with the tracking reference signal Σ from the power supply device 3 amplified by the amplifier 10a, and output as one amplitude-modulated / time-division error signal. You. The amplitude synthesis is equivalent to amplitude modulation because the modulation time division error signal and the tracking reference signal Σ are in phase with each other.

The receiving unit removes components common to the tracking reference signal Σ and the tracking error signal Δ, such as fluctuations in the distance to the tracking target 1 and the power of the transmission signal of the tracking target 1, by using the synthesizer 11. The AGC circuit 12 applies an AGC (response that does not absorb the frequency fm of the clock signal 7 and the frequency fc of the clock signal 9) to the amplitude modulation / time division error signal, and the envelope detection is performed by the envelope detector 16. You. The envelope time-division error signal obtained by the envelope detection is separated from the in-phase component AZ and the quadrature phase component EL of the tracking error signal Δ by the separation switch 19 that performs a switching operation based on the clock signal 7 having the frequency fm. Is separated into The separated in-phase component AZ and quadrature phase component EL are input to the amplitude detector 20a and the amplitude detector 20b, respectively.
DC component D of the first angle error signal (in-phase component AZ), which is amplitude-detected based on clock signal 9 of low frequency fc.
AZ and the DC component DEL of the second angle error signal (quadrature component EL) are output from the amplitude detector 20a and the amplitude detector 20b, respectively. The DC components DAZ, DEL of the first and second angle error signals thus taken out.
Have positive, negative, and zero polarities, respectively, and are supported as antenna drive signals by a motor of an antenna drive mechanism provided in a drive control device (not shown) of the antenna 2 to control the direction of the antenna 2.

By switching the gain bandwidth of the AGC circuit 12, an arbitrary modulated signal or an arbitrary bit rate signal can be easily handled. The clock signal 9 is also necessary for detecting the polarities of the in-phase component AZ and the quadrature component EL.

According to the present embodiment, the tracking reference signal and the tracking error signal separated from each other are amplitude-modulated and then branched into two.
One is a first angle error signal having the same phase as the tracking reference signal, and the other is rotated by 90 degrees as a second angle error signal having the same phase as the tracking reference signal. A signal and a second angle error signal are alternately time-divisionally selected to obtain one modulation time-division error signal, and the modulation time-division error signal is amplitude-synthesized with a tracking reference signal to generate one amplitude modulation signal.
A time-division error signal is obtained, and then a time-division error signal obtained by envelope detection of the amplitude modulation / time-division error signal is separated (time-division detection) and demodulated to obtain a first angle for antenna driving. Is configured to output the DC component of the error signal for use and the DC component of the error signal for the second angle, so that the configuration can be reduced in size and weight, hardly affected by a severe environment, and the bit rate of an arbitrary communication signal. Or a modulation method of an arbitrary communication signal, and a tracking device with high stability and high accuracy can be obtained at low cost.

That is, both the first angle error signal and the second angle error signal have the same phase as the tracking reference signal and one time-division error signal by the 90-degree phase shifter. Can be used as a single channel, so that most of the data from the antenna to the receiving unit can be transmitted through the single channel. Therefore, the configuration can be reduced in size and weight, and it can cope with severe environments. In addition, since the time-division error signal is reproduced by envelope detection, carrier wave reproduction becomes unnecessary, and it is possible to cope with a bit rate of an arbitrary communication signal and a modulation method of an arbitrary communication signal. Further, since the amplitude difference and the phase difference between the tracking reference signal and the tracking error signal can be detected by envelope detection and time division detection, antenna drive control can be performed with high accuracy, and the stability and accuracy of the device can be improved. Further, an amplitude modulation method is used in which the influence of a severe environment such as temperature does not cause a relative change between three signals (a tracking reference signal, a first angle error signal, and a second angle error signal). Since the phase modulation of the filter or the like due to the change does not cause a relative change between the three signals, the amplitude modulation method is used, so that the stability and accuracy of the device are improved.

[0037]

As described above, according to the first aspect, the first aspect
Since both the angle error signal and the second angle error signal have the same phase as the tracking reference signal and are one time-division error signal, one transmission channel can be used, and the configuration is small. In addition, it is possible to reduce the weight and to cope with a severe environment. In addition, since the time-division error signal is reproduced by envelope detection, it is not necessary to reproduce the carrier wave, and it is possible to obtain an effect that it is possible to cope with an arbitrary communication signal bit rate and modulation method. Also,
Since the amplitude difference and the phase difference between the tracking reference signal and the tracking error signal can be detected by the envelope detection and the time division detection, the antenna drive control can be performed with high accuracy, and the effect of increasing the stability and accuracy of the device can be obtained. In addition, the influence of a severe environment such as temperature or the phase rotation of a filter due to a change in Doppler frequency does not cause a relative change between the tracking reference signal, the first angle error signal, and the second angle error signal. Since the amplitude modulation method is used, the effect of increasing the stability and accuracy of the device can be obtained.

According to the second aspect, the error signal time division selecting means is constituted by the distributor, the 90-degree phase shifter, and the time division switch, so that one time division error signal can be generated. In addition, the circuit configuration can be simplified.

According to the third aspect, the modulating means modulates the amplitude of the time-division error signal with the second clock signal. Therefore, the tracking reference signal, the first angle error signal, and the second angle signal are used. The modulation does not cause a relative change between the three signals with the error signal, and the modulation can be realized with a simple circuit configuration.

According to the fourth aspect, since the error signal time division selecting means and the modulating means are constituted by one modulator, the constitution is simplified and the size and weight of the apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a tracking device according to an embodiment of the present invention.

FIG. 2 is a signal waveform diagram for explaining an operation of the tracking device shown in FIG.

FIG. 3 is a diagram for explaining a phase relationship between a tracking reference signal and a tracking error signal in the embodiment.

FIG. 4 is a diagram for explaining a phase relationship between a tracking reference signal and a tracking error signal in the embodiment.

FIG. 5 is a diagram for explaining how a phase relationship between a tracking reference signal and a tracking error signal corresponds to a relationship between a tracking target and an antenna beam axis in the embodiment.

FIG. 6 is a diagram illustrating an operation of determining whether the offset direction of the antenna with respect to the tracking target is left, right, up, or down in the embodiment.

FIG. 7 is a diagram illustrating an operation of determining whether the offset direction of the antenna with respect to the tracking target is left, right, up, or down in the embodiment.

FIG. 8 is a diagram for describing an operation of determining whether the offset direction of the antenna with respect to the tracking target is left, right, up, or down in the embodiment.

FIG. 9 is a diagram showing a clock signal used for the determination.

FIG. 10 is a block diagram illustrating a configuration of a conventional tracking device.

FIG. 11 is a block diagram showing a configuration of another conventional tracking device.

12 is a diagram illustrating a spectrum and a waveform of a frequency distribution of each signal in the tracking device illustrated in FIG. 11;

[Explanation of symbols]

1, S tracking target, 2 antennas, 3 feeding device (signal separation means), 4 distributor, 5, 15 90 degree phase shifter, 6
Time division switch, 7, 9 clock signal, 8 modulator (modulation means), 10a, 10b amplifier, 11 synthesizer (synthesis means), 12, 12a, 12b AGC circuit, 1
3 BPF, 14 PLL, 16 envelope detector (envelope detector), 17 AZ detector, 18 EL detector,
19 Separation switch, 20a, 20b Amplitude detector, 3
1 Error signal time division selecting means, 32 separation / demodulation means.

Claims (4)

[Claims] 1. A tracking device for tracking a tracking target such as a mobile satellite, comprising: an antenna for receiving a communication signal from the tracking target; and a tracking reference signal and a tracking error signal included in the communication signal received by the antenna. Signal separating means, a modulating means for modulating the tracking error signal separated by the signal separating means, and a tracking error signal modulated by the modulating means, branched into two, and one of them is in phase with the tracking reference signal. A first angle error signal; and a second angle error signal having the same phase as the tracking reference signal obtained by rotating the other by a predetermined degree. The first angle error signal and the second angle Error signal time division selecting means for alternately time division selecting error signals for use and outputting as one modulation time division error signal, and the tracking of the modulation time division error signals from the error signal time division selection means in phase. Base Synthesizing means for amplitude-synthesizing the quasi-signal and outputting as one amplitude modulation / time-division error signal;
Envelope detection means for envelope detection of the amplitude modulation / time division error signal of the present invention, and a time division error signal obtained by envelope detection by the envelope detection means, separated, demodulated and used for the antenna drive control. And a separating / demodulating means for outputting the first angle error signal and the second angle error signal. 2. The distributing device according to claim 2, wherein the error signal time division selecting means splits the input tracking error signal into two and outputs the first and second tracking error signals as a first tracking error signal and a second tracking error signal.
A 90-degree phase shifter for rotating the tracking error signal by 90 degrees in phase and outputting it as a second angle error signal; a signal using the first tracking error signal as a first angle error signal;
2. A tracking device according to claim 1, further comprising a time-division switch for alternately selecting and outputting the angle error signal. 3. The tracking device according to claim 1, wherein said modulation means modulates the amplitude of the tracking error signal with a predetermined clock signal. 4. The tracking device according to claim 1, wherein said error signal time division selecting means and said modulating means are constituted by a single modulator.