JPS5834788B2 - tracking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention automatically compensates for cross polarization caused by an asymmetric medium such as rain in high frequency signals emitted from a moving object and propagating in circularly polarized waves or linearly polarized waves. This invention relates to a tracking device that performs automatic tracking.

In the field of wireless communication, from the viewpoint of effective frequency utilization, there is a method in which signals are separately placed on orthogonal polarized waves of the same frequency in a spatial propagation path, thereby essentially doubling the transmission capacity.

In this method, it is necessary to compensate for the occurrence of cross-polarized waves due to rain, etc. in the propagation path.

Since the generation of cross-polarized waves is a natural phenomenon, it fluctuates over time, and this method cannot be achieved without a method that automatically controls the cross-polarized wave compensation circuit installed at the feeder of the antenna device. It is difficult to realize.

A conventional tracking device will be explained below with reference to FIG.

In the figure, 1 is driven by an antenna drive device 2,
A self-tracking antenna that captures the beacon radio waves 28 emitted from a moving object; 3 a coupler that extracts an angular error signal from the beacon radio waves 28 captured by the self-tracking antenna 1; 4 an angular error signal that is the output of the coupler 3; 5 is a polarization converter that converts the wave into a beacon radio wave type linearly polarized wave that has passed through the coupler 3. A combiner that combines the reference signal output and the angular error signal output subjected to carrier suppression modulation by the modulator 4; 7 a mixer that converts the frequency of the output of the combiner 6 together with a local oscillator; 9 an intermediate frequency amplifier 10; 11. Consisting of a divider 12, a synchronous detector 13, and an AGC (automatic gain control) amplifier 14,
AGC amplification circuit for AGC amplifying the output of the mixer 7, 15
consists of a phase detector 16, a loop filter 17, and a voltage controlled oscillator 18, which inputs the reference signal output of the divider 12 of the AGC amplifier circuit 9, and adds the output to the mixer 11 of the AGC amplifier circuit 9 to generate the reference signal. A phase synchronization circuit 19 synchronizes the phase, a pair of synchronous detectors 2L22 to which a phase difference of 90° is given by a phase shifter 20, and a pair of synchronous detectors 24 and 25 to which the low frequency oscillation output of the low frequency oscillator 23 is applied.
and a pair of servo amplifiers 26 and 27, which performs synchronous detection demodulation of the angular error signal output of the combined signal output of the distributor 12 of the AGC amplifier circuit 9, and applies the output to the antenna drive device 2. This is a demodulation circuit.

Further, 29 is a synchronization signal terminal.

Next, the operation will be explained.

Beacon radio waves 28 emitted from a moving object to antenna 1
is received by the self-tracking antenna 1, the angular error component is extracted by the coupler 3, subjected to carrier suppression modulation by the modulator 4, and then combined with the reference signal passed through the polarization converter 5 by the combiner 6. be synthesized.

This composite signal is frequency-converted by a mixer 7 and a local oscillator 8, and after passing through an intermediate frequency amplifier 10 and a mixer 11, only the reference signal component is extracted by a distributor 12.
Automatic gain control is performed by a synchronous detector 13, an AGC amplifier 14, and an intermediate frequency amplifier 10, and a phase detector 16
, loop filter 17 and voltage controlled oscillator 18 perform phase synchronization.

After the angular error signal component is extracted by the distributor 12,
Amplitude components corresponding to two mutually orthogonal angular error components are extracted by the synchronous detectors 21 and 22, and demodulated by the synchronous detectors 24 and 25 using the same modulation signal as the modulator 4 generated by the low frequency oscillator 23. and servo amplifier 26
．． After passing through 27, the antenna driving device 2 attached to the antenna 1 is controlled.

In this way, in conventional antennas that automatically track moving objects, the antenna captures the beacon radio waves emitted from the moving object, and the angular error signal generated by the beacon radio waves and the Among the reference signals, the angular error signal is subjected to carrier suppression modulation using a low frequency modulation wave, and this is combined with the reference signal using a synthesizer such as a hybrid, and the input terminal is made into a single channel to combine the reference signal and the angular error signal. Commonly amplified by the tracking receiver.

After common amplification of both signals, only the reference signal is extracted using the phase-locked loop and automatic gain control loop, and the component including the normalized angular error signal is separately extracted using the phase-locked loop and automatic gain control loop. By performing synchronous detection demodulation, the angular error voltage regarding two orthogonal antenna mounts is extracted and combined with a servo device and a motor to track a moving object.

Therefore, in order to perform cross-polarization compensation and tracking of a moving object, two receivers are required, which has the drawback of making the device complex and expensive.

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional moving object tracking device, and provides a tracking device that can simultaneously perform cross-polarization compensation by simply adding a simple circuit to the conventional moving object tracking receiving device. is intended to provide.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a block diagram of an embodiment of the present invention, and the reference numerals used in FIG. 1 refer to the same ones as in FIG.

30 is a 90° retardation plate 31.90° retardation plate driving device 3
2.1800 retardation plate 33.A cross polarization compensation circuit comprising a 180° retardation plate driving device 34 and a polarization demultiplexer 35. is the 900° retardation plate 31 and the 180° retardation plate 33
When the signal passes through the polarization demultiplexer 35 and is split into a reference signal 36 and a cross-polarization error signal 37, the cross-polarization error signal 37 becomes 0.
The 90° retardation plate 31 and the 1800° retardation plate 33 are driven by respective drive devices 32 and 34 to compensate for cross polarization.

In addition, 38 is a reference signal 40 which is generated separately from the communication signal 39 from the reference signal output 36 of the polarization demultiplexer 35 of the cross polarization compensation circuit 30.
41 is a coupler that branches the second communication signal 42 and the cross polarization error signal 43 from the output of the cross polarization error signal 37 of the polarization demultiplexer 35; 44 is the output 43 of the coupler 41; This is a modulator that performs carrier suppression modulation using a clock signal 45 of a low frequency oscillator 56, which will be described later.

The reference signal 40 and the cross-polarization error signal 46 subjected to carrier suppression modulation are combined by the synthesizer 6 with the angle error signal 48 subjected to carrier suppression modulation by the modulator 4 using the clock signal 47 generated by the low frequency oscillator 23. , a composite signal 49 is generated.

Here, the clock frequency of the clock signal 45 is fl, and the clock frequency of the clock signal 47 is f2 (\f1).

Further, at 50, the synthesized signal 48 is sent to the AGC amplifier circuit 9.
A composite signal 51 is output from the divider 12 after being amplified by C, 52 is a reference signal also output by the divider 12, and 52 is a pair of synchronous detectors 54 degrees to which a phase difference of 900 is given by a phase shifter 53. 55, a pair of synchronous detectors 57, 5B to which the low frequency oscillation force of the low frequency oscillator 56 is applied, and a pair of servo amplifiers 59, 60, which synchronously detect the cross polarization error signal of the composite signal 50. This is a cross-polarization error signal synchronous detection circuit that demodulates.

Next, the operation will be explained.

In Figure 2, when a circularly polarized or linearly polarized signal is transmitted from a communicating player or a moving object, cross-polarized waves occur due to rain on the propagation path, so complete circularly polarized waves are transmitted. Alternatively, beacon radio waves 28 that are not linearly polarized but elliptically polarized are incident on the antenna 1 .

This elliptically polarized beacon radio wave 28 is converted into a linearly polarized wave by a 90° retardation plate 31 driven by a 90° retardation plate driving device 32, and further driven by a 180° retardation plate driving device 34. After passing through the retardation plate 33, the polarization splitter 35 separates the mutually orthogonal polarized components, respectively, into only the output 36 out of the two outputs 36 and 37.

Such an output 36 uses the output 36 as a reference signal, the output 37 as a cross-polarization error signal, and the cross-polarization error signal 37 as a reference signal 36 with in-phase components and quadrature components with a 180° phase difference plate 3.
This is obtained by controlling the drive devices 32 and 34 so that the orthogonal components for the 90° retardation plate 31 become zero as error signals for the 90° retardation plate 31, respectively.

Also, the angular error component is extracted by the coupler 3, decomposed and detected into an in-phase component and a quadrature component with respect to the reference signal 36.
The angular error voltages regarding the two orthogonal antenna mounts are extracted, and the antenna 1 is driven and controlled by the antenna driving device 2.

The reference signal 36 is extracted separately from the communication signal 39 by a coupler 38 to become a reference signal 40, and the cross-polarization error signal is branched by a coupler 41 and modulated by a clock signal 45 from a low frequency oscillator 56 in the tracking receiver. The angular error signal is subjected to carrier suppression modulation in the modulator 4 using a clock signal 47 from the low frequency oscillator 23 in the tracking receiver to become a modulated cross polarization error signal 48. becomes.

These three signals 40, 46, and 48 are combined by a combiner 6 to form a single channel, and the combined signal 49 is input to the receiver.

In the receiver, the reference signal is A by the AGC amplifier circuit 9.
GC amplification and phase synchronization is performed by a phase synchronization circuit 15, and the composite signal including the error signal is AGC amplified by an AGC amplifier circuit 9, and then band-limited by a distributor 11 to output a composite output signal 50.

FIG. 3 shows the spectrum of the error signal and the reference signal, and the spectrum of the band-limited composite output signal 50 after being combined.

The cross-polarization error component is extracted by the synchronous detectors 54 and 55 as an amplitude component corresponding to the component synchronized with the reference phase of the synchronization signal terminal 29 and the component orthogonal to the reference phase of the synchronization signal terminal 29. The same modulation signal is demodulated by the synchronous detectors 57 and 58, and after passing through the servo amplifiers 59 and 60, the driving devices 32 and 34 attached to the 900 and 1800 phase difference plates 3L33 are controlled.

In the tracking device of this embodiment having such a configuration and operation, the reference signal, angular error signal, and cross-polarization error signal are made into a single channel and commonly amplified, so that a simple circuit can be added to the conventional tracking device. By simply adding it, cross-polarized waves can be automatically compensated for, and moving objects can be tracked with high precision.

Although the above has described a tracking device including a cross-polarization automatic compensation circuit that automatically corrects cross-polarization caused by asymmetric factors such as rain, the present invention is not limited to this, and is applicable to cross-polarization without automatic compensation. It may also be used in a wave generation amount detection circuit.

As described above, the tracking device according to the present invention enables highly accurate tracking by processing the tracking reference signal and the tracking error signal in a single channel, and greatly changes the configuration of the conventional receiving device. This has the effect of enabling cross-polarization compensation simply by adding a simple configuration.

[Brief explanation of the drawing]

Fig. 1 is a block circuit diagram of a conventional tracking device, Fig. 2 is a block circuit diagram of an embodiment of the present invention, and Fig. 3 a = d.
2 is a diagram showing signal spectra of various parts of the circuit of FIG. 2. FIG. 1...Self-tracking antenna, 2...Antenna 1 drive device, 3...Coupler, 4...
・Modulator, 6...Synthesizer, 9...AG
C amplifier circuit, 15... Phase synchronized circuit, 19...
...Angle error signal synchronous detection demodulation circuit, 28...
...Beacon radio wave, 30...Cross polarization compensation circuit, 31...90° phase difference plate, 32...
90° retardation plate drive device, 33...180° retardation plate, 34...180° retardation plate drive device,
35...Polarization splitter, 36.40...Reference signal, 37,46...Cross polarization error signal, 4
8... Angle error signal, 49... Combined signal, 50... Combined signal output, 52...
Cross polarization error signal synchronous detection demodulation circuit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1 A self-tracking antenna that is driven by an antenna drive device and captures beacon radio waves, a coupler that extracts an angular error signal from the beacon radio waves captured by this self-tracking antenna, and a low-frequency modulated wave that converts the angular error signal output of this coupler. A modulator that performs carrier suppression modulation, a 90° retardation plate driven by a 90° retardation plate driver, a 180° retardation plate driven by a 180° retardation plate driver, and a polarization splitter. a cross-polarization compensation circuit for extracting a reference signal and a cross-polarization error signal from the beacon radio wave; a modulator for carrier suppression modulation of the cross-polarization error signal output of the cross-polarization compensation circuit; a synthesizer for synthesizing the angle error signal subjected to suppression modulation and the cross polarization error signal subjected to carrier suppression modulation; an AGC amplifier circuit for AGC-amplifying a signal obtained by frequency-converting the output of the synthesizer; and the AGC amplification circuit. a phase synchronization circuit that phase-synchronizes the reference signal output of the circuit; and synchronous detection demodulation of an angular error signal among the composite signal outputs of the AGC amplifier circuit and applying the angular error voltage output to the antenna driving device. circuit, and a cross-polarized circuit that synchronously detects a cross-polarization error signal out of the composite signal output of the AGC amplifier circuit and applies the cross-polarization error voltage output to the 90° phase difference plate drive device and the 180° phase difference plate drive device. A tracking device comprising a wave error signal synchronous detection demodulation circuit.