JPS6228875B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic antenna tracking and receiving device used in satellite communications and the like.

As an antenna tracking method that automatically directs the antenna to a target object such as an artificial satellite, the antenna is moved in steps to find the direction of the maximum level of the signal arriving from the target object. The track method is used. In this system, Japanese Patent Application No. 52-26218 (Japanese Unexamined Patent Publication No. 53-1979) was proposed by inventors including the inventor of the present invention.
The configuration of Publication No. 110496) (hereinafter referred to as the prior application) is a simplified version of this step track system, but this system also uses a generator directly connected to the motor that drives the antenna tracking, and a generator that is directly connected to the motor that drives the antenna tracking. An absolute value circuit was required to take the absolute value of the generator's output, making the configuration somewhat complicated.

An object of the present invention is to provide an automatic tracking receiving device that further simplifies the configuration of the prior application.

In the present invention, by applying a predetermined DC voltage with a fixed delay time instead of the generator and absolute value circuit that serve as input signals of the integrating circuit in the previous application,
There is an automatic tracking receiver configured to perform the same operation.

In the configuration of the prior application, a generator directly connected to the antenna drive motor outputs a voltage proportional to the rotational speed of the motor. In other words, when driving an antenna at a constant speed, a constant voltage will be output, but
Naturally, there is a delay after the motor starts until it reaches a constant speed. Supplying the generator output to the integral circuit input through the absolute value circuit in this manner is equivalent to supplying a constant voltage with a certain amount of delay (rise time). Therefore,
If the circuit is configured to apply a constant voltage to the input of the integral circuit with a predetermined delay time from the start of rotation of the motor, the generator and the absolute value circuit can be omitted.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, showing a tracking device that automatically drives the antenna about the AZ axis and the EL axis so as to direct the antenna in the direction of the maximum reception level. An antenna 1 with a beam-like pattern receives signals from a target. This received signal is amplified by an amplifier 2, and converted into a signal having a voltage A proportional to the received signal level by a detector 3 including a low-pass filter. This signal with voltage A is applied to an adder circuit 5 together with an almost inverted output B by a sample-and-hold integrator circuit 4 (this circuit will be described in detail later), where both signals are added and the polarity is inverted. After that, it will be output. This addition circuit 5
The output C is supplied to a comparator circuit 6 which outputs a pulse when the voltage falls below a predetermined voltage value -W, and a comparator circuit 6' which outputs a pulse when the voltage exceeds a predetermined voltage value +V having the opposite polarity to -W. The signal level is in the increasing direction and becomes a detection signal indicating forward rotation, and the comparison circuit 6' becomes a reversal detection signal outputted when the signal level is reversed. These rotation detection signals are supplied to monostable multivibrators 7, 7' which form a delay time, and produce a gate output having the delay time width. These monostable multivibrators 7,
The output of 7' is supplied to the adder circuit 8, and no matter which of these outputs is detected, the sample and hold switch is
Drive _S1 . The switch S ₁ is an electronic switch having switching circuits S _1A and S _1B with contacts k ₁ and k ₂ .

Since one of these gate outputs, output D, is generated from a reversal detection signal, it is necessary to reverse the driving of the antenna when this output is generated. This gate output D is the antenna drive motor 1
The output D is supplied to a forward/reverse switching circuit 9 that switches the rotation direction of the motors 5 and 16, and the rotation of the motor is reversed every time this output D is input. Repeating this reversal several times means that one axis (for example, the AZ axis) is at its maximum value, so this repetition is detected by the AZ/EL switching circuit 10 and the other axis is detected. All you have to do is switch to the axis (EL axis). This can be constructed using a simple counter. The switches S ₂ and S ₃ are switched by the AZ and EL switching signals, and predetermined integrated voltages are supplied to the integrating circuit 4 by the voltage supply circuits 11 and 12, respectively. On the other hand, the AZ/EL switching circuit 10 is
Forward/reverse commands for the AZ axis, i.e. AZ, CW, AZ,
Create a CCW switching command and set each electronic switch.
S ₄ and S ₅ to switch the polarity of the drive power 13 supplied to the motor 15, and also create forward and reverse rotation commands for the EL axis, that is, EL, UP, EL, and DOWN switching signals, and switch the respective electronic switches S ₆ and _S7 to control the polarity of the drive power 14 that is supplied to the motor 16 to control normal rotation and reverse rotation. These drive motors 15 and 16 are coupled to the AZ and EL axes of the antenna 1 via reduction gears 17 and 18 of gear mechanisms.

The operation of the tracking device having such a configuration will be explained using an operation waveform diagram.

Figure 2 a, b, and c are operation waveform diagrams of Figure 1. Figure 2 a shows the antenna angle at point A in Figure 1 when the antenna 1 is rotated around the target object (satellite) direction. Signal level diagram for Figure 2b
The solid line represents the voltage waveform diagram at point B in Figure 1, and the solid line represents the voltage waveform at point B in Figure 1.
The broken line in Figure b is an inversion of the voltage waveform in Figure 1A,
Also, Fig. 2 c shows the output of the adder circuit 5 (C in Fig. 1)
FIG.

Assume that the received signal level from the antenna 1 at A in FIG. 1 reaches point P in FIG. 2 a, and at this point the antenna is first shifted to the automatic tracking state and driven from the AZ axis. In this case, the switch S ₄ or S ₅ and the switch S ₂ operate so that the drive voltage input 13 is supplied to the AZ-axis motor 15 . The operations of these switches S ₄ and S ₅ are switched according to the CW and CCW directions of the AZ axis. First, assuming that the connection is made in the direction in which the reception level increases by the forward/reverse switching circuit 9, the voltage at point P in FIG. 2 gradually increases in the positive direction at point A as shown in FIG. 2a. Further, at point B, the voltage increases in the opposite direction (negative direction).

When the automatic tracking state is entered, the sample-and-hold integration circuit 4 operates as a sample-and-hold circuit or an integration circuit for the voltage at point B according to the switching of the switch _S1 . First, the sample and hold circuit consists of an operational amplifier A ₁ , a resistor with equal resistance
It is composed of R ₁ , R ₂ and a switch circuit S _1A , and when the switch is on the contact k ₂ side, it outputs a voltage that is an inversion of the input voltage A, and the switch holds the voltage value at the moment when the contact k ₂ is disconnected. Also, during this holding time, it simultaneously operates as an integrating circuit. In other words, in the integrating circuit consisting of operational amplifier A ₁ , capacitor C ₁ , resistor R ₃ and switch circuit S _1B , one of the capacitors is grounded when the switch is on the k ₂ side, but when the switch is on the k ₁ side, one of the capacitors is grounded. From the moment it is switched on, the voltage of the voltage supply circuit 11 is supplied via the switch S ₂ and outputs an integral value proportional to this supply voltage. Note that this integrated output corresponds to the slope of the solid line arrow in FIG. 2b. The output of this sample-and-hold integration circuit is integrated at the slope point, sampled and held at the vertical point, as shown in Figure 2b,
This operation is repeated to reach near the peak value.

When the voltages at points A and B in Figure 1 are inverted and summed by the adder circuit 5, the voltage at point C becomes 0 at the time of sample hold and becomes a negative slope voltage, as shown in Figure 2 c. . When this negative voltage exceeds the set level W of the comparison circuit 6 on the negative side, a pulse output is generated at the output of the comparison circuit 6, and this output is shaped by the monostable multivibrator 7 into a pulse of a predetermined width. This pulse width must be set equal to the aforementioned delay time. This pulse is added to the adder circuit 8
Sample and hold the new reception level by operating switch _S1 through . Point Q in FIGS. 2b and 2c indicates the newly sampled and held voltage.

By repeating the sample-hold and integration operations in this way, when the reception level reaches around the maximum level, the voltage at the output point B of the sample-hold integration circuit 4 becomes larger than the increase in the reception level, and the voltage at the output point C of the adder circuit becomes larger than the increase in the reception level. The voltage becomes a positive voltage as shown in FIG. 2c. When this positive voltage exceeds the set level V of the positive comparator circuit 6', a pulse is output to the output of the comparator circuit 6'. That is, when the integral value exceeds the reception level and the output is reversed, a pulse is output. This pulse output is pulse-shaped by a monostable multivibrator 7'. This shaped pulse passes through the adder circuit 8, drives the switch _S1 , and newly samples and holds the reception level.

In addition, this shaped pulse is simultaneously supplied to the forward/reverse switching circuit 9, and this circuit causes the switch _S4 or
Drive _S5 to reverse the antenna drive direction. Since this inversion is performed every time an inversion pulse is generated, repeating this inversion a predetermined number of times indicates that the peak is near. Therefore, the repetition of this reversal is detected several times, and the AE/EL switching circuit 10 switches the antenna from the AZ axis to the EL axis. aerial
The AZ axis and the EL axis are switched by the AZ/EL switching circuit 10, and the AZ axis and the EL axis are automatically tracked alternately, and the direction in which the reception level is maximum is automatically tracked. In this case, for example, if automatic tracking of the EL axis is performed first, the AZ/EL switching circuit 10 counts the number of reverse rotation command pulses from the comparison circuit 6' and the monostable multivibrator 7' from 2 to 4 times. All you have to do is switch automatic tracking to the AZ axis.

Here, the aforementioned delay time will be explained. The drive power supplies 13 and 14 that drive the motors 15 and 16 are switched by driving switches S ₄ to S ₇ by the rising edge of the monostable multivibrators 7 and 7', and the polarity of the drive power supplies is reversed. Even if the antenna is driven in a certain direction, it has inertia, so it does not immediately reverse rotation, but moves a little in that direction, stops, and then rotates in the opposite direction. Therefore, it is necessary to start the integration after the time period until this reversal has elapsed, and it is necessary to set a setting so that the output of the integrated voltage does not overtake the reception level voltage in the middle of the slope of the reception level, and a delay is required during this time. This is the reason. A specific example of this delay time is, for example, an antenna with a diameter of 10 m (beam width approximately 0.4 m).
When tracking a geostationary satellite in steps at a speed of 0.03°/sec, the time is set to approximately 0.2 seconds. This delay time is determined by mechanical conditions such as the structure (weight, size) of the antenna, the ratio of the reducer, the performance of the drive motor, etc.
It is also related to the reference voltage of the setting value of 12, the integrating circuit, and the adding circuit.

Further, the antenna drive motor of this embodiment can be reversed by supplying AC power (for example, 50 Hz, 3 phases, 200 V) and switching and connecting two phases of the power with an electronic switch. When using a triax as this electronic switch, it is necessary to switch at a point where the phase is zero, but the phase shift is at most
Since it is 20ms, there is no problem with the delay of 0.2 seconds.

In addition, in automatic tracking, when switches S4 _{to S7} are connected in the direction to decrease the reception level by the forward/reverse switching circuit 9, the antenna drive motor operates in the same way as when the reception level is near the maximum value. After that, the forward/reverse switching circuit 9 operates the switches _S4 to _S7 in the direction of increasing the reception level, so that the operation is similar to that described above.

When tracking a geostationary satellite using this automatic tracking device, there is little need for continuous tracking, so automatic tracking may be performed at predetermined time intervals, for example, 15 minutes instead of 16 minutes.

Although the embodiments of the present invention have shown driving the antenna by a motor, it can also be applied to a circuit that electronically controls the beam of the antenna. Additionally, the present invention provides an antenna
Although the AZ and EL axis drives have been described, the invention can of course be applied to X and Y drives, or only to the AZ axis (azimuth detection). Note that the adder circuit 5, the comparator circuits 6, 6', and the monostable multivibrators 7, 7' can be any electronic circuit as long as it has the function of forming an equivalent gate by the received signal level and the output of the sample-hold integration circuit. Can be used. Further, although the embodiments of the present invention have been described for tracking local maximum values, a similar system can be applied as is by reversing the polarity of the signal system when automatically tracking local minimum values. Therefore, it has a wide range of applications, including automatic balancing control devices that not only automatically track the antenna to a target but also track the minimum value.

This tracking device can track the controlled object at the maximum speed, and the switching period between normal rotation and reverse rotation at the maximum value or minimum value can be arbitrarily set using an analog value, and the tracking error can be relatively small. Furthermore, a generator and an absolute value circuit are not required, and the configuration of the tracking device can be made simple and inexpensive by employing a switching circuit such as an electronic switch.

[Brief explanation of the drawing]

Figure 1 is a system diagram of an embodiment of the present invention, Figure 2 a,
b and c are operation level diagrams of FIG. 1; In the figure, 1... Antenna, 2... High frequency amplifier, 3... Detector,
4...Sample hold (integrator) circuit, 5...Addition circuit, 6, 6'...Comparison circuit, 7, 7'...Monostable multivibrator, 8...Addition circuit, 9...Forward/reverse switching circuit, 10...AZ/EL switching Circuit, 11, 12... Voltage setting circuit, 13, 14... Drive power supply, 15, 16...
Motor, 17, 18...Reducer, S ₁ ...Sample hold switch, S ₂ ...AZ switch, S ₃ ...EL switch, S ₄ ...AZ CW switch, S ₅ ...AZ CCW switch, S ₆ ...EL UP switch, S ₇ ...EL DOWN switch.

Claims (1)

[Claims] 1. An antenna having a beam-like pattern; a driving means capable of directing the beam of the antenna in a predetermined direction;
a level detecting means for detecting a received voltage corresponding to the level of a received signal received by the antenna; and a level detecting means for inverting and outputting the received voltage when a predetermined switching signal is input, and a level detecting means for detecting a received voltage corresponding to the received signal level received by the antenna; holding and integrating means for holding an inverted voltage, inputting and integrating a preset voltage at the same time, and superimposing this integrated value on the inverted voltage and outputting the result; a first gate forming means for outputting a first gate having a predetermined width from a time when the received voltage becomes larger than the superimposed voltage; and a second gate forming means for outputting a second gate having a predetermined width from a time when the received voltage becomes smaller than the superimposed voltage by a second set value or less. a second gate forming means for generating the switching signal when the first or second gate is output; and a switching signal forming means for generating the switching signal when the first or second gate is output; It is characterized in that it includes a drive switching signal forming means for creating an inverted drive switching signal, and a means for supplying the drive switching signal to the driving means, and the antenna tracks the maximum value of the received signal level in a stepwise manner. automatic tracking receiver.