JPH0578794B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a redundant configuration of a monopulse tracking receiver used to track an antenna direction in the direction in which received radio waves arrive.

Summary of the Invention The present invention provides a monopulse method in which a reference received signal and two error signals regarding two orthogonal axes are combined into two channels or one channel in order to track the antenna pointing direction in the direction in which received radio waves arrive. In the tracking receiver, a signal synthesizing circuit for synthesizing the two error signals or a signal synthesizing circuit for synthesizing the synthesized error signal outputted from the signal synthesizing circuit and the reference received signal is formed by a hybrid circuit. The hybrid circuit has a redundant configuration in which the current and standby tracking receivers are respectively connected to the two output terminals of the hybrid circuit.

It is possible to eliminate the need for a changeover switch to change over from the current to the standby, prevent switching failures due to faulty switch contacts, and improve reliability.

Conventionally, in antenna pointing direction detection using a monopulse method, one reference signal and two Two error signals for each axis of the dimension are input to the tracking receiver. Here, the reference signal is a tracking signal reception signal whose amplitude becomes almost maximum when the antenna pointing direction and the tracking signal arrival direction match, and whose phase is almost constant within the angle range where the antenna pointing direction can be detected, and the error signal The amplitude becomes almost zero when the antenna pointing direction and the tracking signal arrival direction match, and the amplitude increases as the angle of deviation between the antenna pointing direction and the tracking signal arrival direction increases, and This is a tracking signal reception signal whose phase is reversed depending on the direction of deviation of the antenna pointing direction, centered on the angle where the direction of arrival of the tracking signal coincides with the direction of arrival of the tracking signal.

The method of obtaining these signals is described, for example, by Inoue and Kaizuka, "Design and Characteristics of Antenna Tracking Drive System for Quasi-millimeter-Wave Satellite Communication," Research and Practical Application Report of the Institute of Telecommunications, Vol. 26.
Volume, No. 4, pp1327-1348, published on April 22, 1977, Kenichi Miya, "New Edition Satellite Communication Engineering", published by Lateis,
As shown in pp. 258-264, published on April 8, 1972, there are methods that use a plurality of primary radiators, that is, electromagnetic horns, and methods that detect higher-order modes.

In a method using multiple horns, for example, four primary radiators are arranged symmetrically, beams are slightly shifted from each other with respect to the antenna axis, and a feeding circuit is configured so that the sum of each horn can be obtained. , this output is used as a reference signal. For example, if the feeder circuit is configured to obtain the difference between the horn outputs arranged in the east-west direction, an error signal in the east-west direction will be obtained, and the feeder circuit is configured to obtain the difference between the horn outputs arranged in the north-south direction. In this case, an error signal in the north-south direction can be obtained.

In addition, in the higher-order mode detection method, when the antenna directly faces the tracking signal transmission source, the only electromagnetic field mode induced in the primary radiator is the fundamental mode.
Higher-order modes are induced when the direction of the antenna is shifted. This basic mode is used as a reference signal, and the higher-order mode is used as an error signal.

Here, when four horns are used, the reference signal is sometimes called a sum signal because the sum of all horn outputs is used, and the error signal is sometimes called a difference signal because the difference between the horn outputs is taken.

Tracking receivers for processing these reference signals and error signals to obtain a voltage proportional to the pointing direction error of the antenna include three-channel systems, two-channel systems, and one-channel systems. As an example showing these configurations and principles, the previously referenced Inoue and Kaizuka, "Design and Characteristics of Antenna Tracking Drive System for Quasi-millimeter-Wave Satellite Communication," Research Practical Application Report of the Institute of Telecommunications, Vol. 26
Volume, No. 4, pp1327-1348, published in 1977, Kenichi Miya, "New Edition Satellite Communication Engineering", Lateis Publishing, pp265-
267, published in 1972. The 3-channel method is the most principled method, in which the reference signal is controlled by an automatic gain control (AGC) amplifier so that the output is constant, and at the same time the error signal is amplified with the same gain, thereby reducing the error using the amplitude of the reference signal as a reference. The signals are normalized, each error signal is detected using the phase of the reference signal as a reference, and a DC voltage proportional to the error angle with respect to the two axes is obtained. In the 3-channel system, circuits such as a frequency converter and an AGC amplifier up to the detection stage are required for a total of three channels, one channel for the reference signal and two channels for the error signal. For this reason, in general, the two-channel method or the one-channel method is used in terms of pointing direction error detection accuracy and economical efficiency.
The channel method is often used.

As an example of a two-channel method, two error signals are given a path difference, or a phase shifter is used to give them a phase difference of 90 degrees, and they are synthesized, that is, orthogonally synthesized, and the output detected by the reference signal and the reference signal are combined at the time of detection. There is a method of obtaining the error voltage regarding the two axes by obtaining the output detected by a signal whose phase is shifted by 90 degrees.

In the one-channel system, two error signals are orthogonally combined, further modulated at a low frequency, and then combined with a reference signal. After frequency converting this and applying AGC,
Detection is performed using a reference signal and a signal whose phase is shifted by 90 degrees, and further detection is performed using a low frequency signal to obtain a DC voltage proportional to the error angle regarding the two axes.

Another method is to modulate the two error signals with two low frequency signals having a phase difference of 90 degrees, combine them, and further combine them with the reference signal. After converting the frequency and applying AGC, the signal is detected using a reference signal, and then detected using a low frequency signal with a phase difference of 90 degrees to obtain a DC voltage proportional to the error angle regarding the two axes. FIG. 3 is a block diagram showing an example of a redundant configuration of a conventional tracking receiver. That is, the reference received signal input terminal 1a, the error signal input terminal 1
The reference reception signal and two error signals inputted from the receivers b and 1c are input to the working or standby tracking receiver through changeover switches _S1 to _S3 , respectively. The tracking receivers 14 and 15 in FIG. 3 show an example of a one-channel system. Two error signals inputted from the error signal input terminals 1b and 1c are combined by a signal synthesizer 3a after one of them is phase-shifted by 90° through a 90° phase shifter 2. The combined error signal output from the signal combiner 3a is subjected to amplitude modulation or phase modulation using a low frequency signal by the modulator 4, and is inputted to the signal combining circuit 3b, which receives the modulated combined error signal. and the reference reception signal input from the reference signal input terminal 1a are combined into one channel. The output of the signal synthesis circuit 3b is frequency-converted by a frequency converter 6 into a signal in an intermediate frequency band, and is amplified by an amplifier 8. Note that the low frequency oscillator 5 is an oscillator for the above-mentioned low frequency modulation, and the local oscillator 7 is an oscillator for frequency conversion.

The gain of the amplifier 8 is controlled by an automatic gain control circuit 9, and its output amplitude is kept constant. The signal separation circuit 10 separates the output signal of the amplifier 8 into a reference signal and an error signal, and outputs them to the product detector 11a.
Further, the error signal is phase-shifted by 90° and input to the product detector 11b. The product detector 11a performs product detection on the error signal using the reference signal and converts the error signal into a product detector 1.
2a, and the product detector 11b performs product detection on the 90° phase-shifted error signal using the reference signal and sends it to the product detector 12b. Product detector 12a, 1
2b performs multiplicative detection on each input using the low frequency signal output from the low frequency oscillator 5, and outputs two-dimensional error voltages to detection error output terminals 13a and 13b. In the conventional circuit above, switching between working and standby is as follows:
This is done by switching the changeover switches _S1 to _S3 .

Problems to be Solved by the Invention The redundant configuration of the conventional tracking receiver described above is unreliable because the switches S ₁ to _{S 3} for switching the three input signals from active to standby have moving parts. There is a drawback. If the changeover switch also has a redundant configuration, the configuration will be complicated, and furthermore, signal passing loss will increase. Furthermore, if switching is performed by an electrical active element without using a mechanical switch, the transmission loss of each signal increases. The present invention aims to solve the above-mentioned conventional drawbacks and improve reliability by making it possible to switch between active and standby using a simple circuit without using a switch.

Configuration of the Invention The redundant configuration of the tracking receiver of the present invention is a monopulse tracking receiver that inputs a reference received signal and two error signals related to two orthogonal axes to track the antenna orientation direction in the direction in which received radio waves arrive. A signal synthesis circuit for synthesizing the two error signals or a signal synthesis circuit for synthesizing the synthesis error signal outputted from the signal synthesis circuit and the reference received signal is constituted by a hybrid circuit, The circuit is characterized in that a working and standby tracking receiver is connected to the two output terminals of the circuit, respectively.

Embodiments of the Invention Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. That is, a reference reception signal and two error signals are input from the reference signal input terminal 1a and error signal input terminals 1b and 1c, respectively. The error signal input from the error signal input terminal 1c is shifted in phase by 90° through a 90° phase shifter 2, and then sent to a signal synthesizer 3.
a, and the signal synthesizer 3a synthesizes and outputs the signal and the error signal input from the error signal input terminal 1b. The combined error signal output from the signal combiner 3a is subjected to amplitude modulation or phase modulation at a low frequency by the modulator 4, and is input to the signal combining circuit 3b. The signal for the above modulation is sent to the active tracking receiver 1.
(The output of the low frequency oscillator 5 of the backup tracking receiver 15 is also connected to the modulator 4, but when the active tracking receiver 14 is in operation, , since power is not supplied to the backup tracking receiver 15, no signal is output from its low frequency oscillator 5). The signal synthesis circuit 3b synthesizes the modulated synthesis error signal and the reference reception signal inputted from the reference signal input terminal 1a to form one channel. The signal synthesizer 3b is composed of a hybrid circuit, and inputs one of its two outputs to the frequency converter 6 of the active tracking receiver 14 and inputs the other to the frequency converter 6 of the backup tracking receiver 15. . That is, the difference between FIG. 1 and FIG. 3 is that the input terminals 1a, 1b, 1c, phase shifter 2, signal synthesis circuits 3a, 3b, and modulator 4 are shared by the active and backup systems in FIG. In contrast, in Fig. 3, each system is provided independently. The other parts below the frequency converter are the same in FIGS. 1 and 3. In this embodiment, the error signal and reference signal are temporarily combined in the one-channel tracking receiver, so if the signal combining circuit that performs this combining is a hybrid circuit, two systems of combined output can be obtained, so this can be used. This allows signals to be branched to active and standby circuits without adding any parts. When the working tracking receiver is operated, the frequency converter 6 of the working tracking receiver 14 converts the frequency into an intermediate frequency band signal, and the signal is amplified by the amplifier 8. Note that the local oscillator 7 is an oscillator for frequency conversion.

The gain of the amplifier 8 is controlled by an automatic gain control circuit 9, and its output level is kept constant. The signal separation circuit 10 separates the output of the amplifier 8 into a reference signal and an error signal, and outputs the signal to the product detector 11a.
Further, the error signal is phase-shifted by 90° and input to the product detector 11b. The product detector 11a performs product detection on the error signal using the reference signal and converts the error signal into a product detector 1.
2a, and the product detector 11b performs product detection on the 90° phase-shifted error signal using the reference signal and sends it to the product detector 12b. Product detector 12a, 1
2b performs multiplicative detection on each input signal using the low frequency signal output from the low frequency oscillator 5, and outputs two-dimensional error voltages to detection error output terminals 13a and 13b.

The backup tracking receiver 15 includes a low frequency oscillator 5, a frequency converter 6, a local oscillator 7, an amplifier 8, an automatic gain control circuit 9, a signal separation circuit 10, and a product detector 11a, 11b, 12a, 12b similar to the above. A redundant circuit is constructed.

In this embodiment, switching from the active tracking receiver 14 to the backup tracking receiver 15 is achieved by stopping the power supply to the active tracking receiver 14 and switching to the backup tracking receiver 15.
This can be done by supplying power to 5. Since no changeover switch is used in the signal circuit, reliability is improved and loss does not increase. In addition, the 90° phase shifter 2, the signal synthesizer 3a,
Although redundant circuits are not provided for 3b and modulator 4, the probability that these parts will fail is extremely small, and there is no reliability problem.

FIG. 2 is a block diagram showing another embodiment of the present invention, in which the signal combiner 3b and modulator 4 are also made redundant. In this case, the signal synthesizer 3a is configured with a hybrid circuit, and two output terminals of the signal synthesizer 3a are connected to the modulator 4a of the active tracking receiver 14 and the modulator 4b of the backup tracking receiver 15. Further, the reference reception signal inputted from the reference signal input terminal 1a is branched into two by the signal branching circuit 16. One output of the signal branch circuit 16 is sent to the signal combiner 3b of the active tracking receiver 14.
and the other output is sent to the backup tracking receiver 15.
The signal is input to the signal synthesizer 3c. Tracking receiver 1
The operations of 4, 15, etc. are the same as described above, so the explanation will be omitted. In this case, by making all active elements redundant, a higher degree of reliability is guaranteed.

Tracking reception systems with a 1-channel configuration include methods that modulate each of the two error signals and then combine them.Also, in a tracking receiver with a 2-channel configuration, the two error signals are combined, but the error signal and the reference signal are combined. Synthesis with signals is not performed. In either case, the signal synthesis circuit used to synthesize three channels (one reference signal and two error signals) into two channels or one channel is configured with a hybrid circuit. Of course, by inputting the two outputs of the circuit to the current and standby inputs, the subsequent circuits can be made redundant. For channels that do not use a signal combining circuit, a new signal branching circuit using a hybrid circuit may be inserted, and the two outputs of the signal branching circuit may be input into the current and backup channels.

Effects of the Invention As described above, in the present invention, a signal synthesis circuit for synthesizing two error signals or a signal synthesis circuit for further synthesizing the output of the signal synthesis circuit with a reference signal is provided by a hybrid circuit. Since the hybrid circuit is structured so that the two outputs of the hybrid circuit are inputted to the working and standby, there is no need for a switch circuit for switching between the working and standby, improving reliability and not increasing loss. . In the case of high frequencies, such as those using waveguides, the construction is particularly simple, with fewer components and active elements, and improved reliability.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a block diagram showing another embodiment of the present invention;
FIG. 3 is a block diagram showing an example of a redundant configuration of a conventional tracking receiver. In the figure, 1a... reference signal input terminal, 1
b, 1c...Error signal input terminal, 2...90° phase shifter, 3a, 3b, 3c...Signal combiner, 4, 4
a, 4b...Modulator, 5...Low frequency oscillator, 6...
...Frequency converter, 7...Local oscillator, 8...Amplifier, 9...Automatic gain control circuit.

Claims (1)

[Claims] 1. A standard that is a tracking signal reception output in which the amplitude is approximately the maximum when the antenna pointing direction and the tracking signal arrival direction match, and the phase is approximately constant within the angle range where the antenna pointing direction can be detected. When the antenna pointing direction and the tracking signal arrival direction match, the amplitude becomes almost zero, and as the angle of deviation between the antenna pointing direction and the tracking signal arrival direction increases, the amplitude increases and the antenna pointing direction An antenna and a feeding circuit configured to output an error signal, which is a tracking signal reception output, whose phase is inverted depending on the direction of deviation of the antenna pointing direction, centered on the angle where the direction of arrival of the tracking signal coincides with the direction of arrival of the tracking signal. A monopulse type tracking receiver that inputs the reference signal and the two error signals regarding two orthogonal axes to obtain a voltage proportional to the error between the antenna pointing direction and the direction of arrival of the tracking signal, comprising: A first composite signal synthesized by giving a phase difference of 90 degrees between two error signals is combined with the reference signal or a signal equivalent to the first reference signal which is a signal phase-synchronized with the reference signal, and the first composite signal. Detection is performed using a second reference signal equivalent signal in which the phase of the reference signal equivalent signal is shifted by 90 degrees, or the first composite signal and the first composite signal are detected.
by detecting a signal obtained by giving a phase shift of 90 degrees to the composite signal of the first reference signal or the second reference signal, or modulating the first composite signal with a low frequency signal. After that, the second composite signal combined with the reference signal is combined with the first reference signal equivalent signal and the second composite signal.
By detecting with a signal equivalent to the reference signal of , and then detecting with the low frequency signal, or by modulating each of the two error signals with two low frequency signals having a phase difference of 90 degrees, and then combining the two error signals to generate a third synthesis signal. After detecting a fourth composite signal obtained by further combining the signal with the reference signal using the first reference signal equivalent signal or the second reference signal equivalent signal, the two low frequency signals having a phase difference of 90 degrees from each other are detected. In a tracking receiver that obtains a DC voltage proportional to the antenna pointing direction error by detection, the two error signals are given a phase difference,
or a signal synthesis circuit for modulating and synthesizing to create a first composite signal or a third composite signal, or combining a composite signal output from the signal synthesis circuit with the reference signal with or without modulation; A signal combining circuit for producing a second combined signal or a fourth combined signal is configured by a hybrid circuit, and the hybrid circuit of the working and standby tracking receivers is connected to two output terminals of the hybrid circuit, respectively. A redundant configuration of a tracking receiver characterized in that a portion of a circuit subsequent to a signal synthesis circuit is connected.