JP2957370B2 - Automatic tracking antenna device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic tracking antenna device for tracking and receiving a radio wave source such as satellite broadcasting or satellite communication on a mobile body.

[0002]

2. Description of the Related Art In recent years, a mobile object (for example, a train, a ship, a car, or an aircraft) is equipped with an antenna for mobile communication with a ground station or an artificial satellite station and for receiving broadcast waves. Is emerging. In particular, as satellite broadcasting becomes more widespread, there is an increasing need to receive satellite broadcasting even on mobile objects.

In order to receive a weak radio wave from such a satellite, a high-gain antenna with sharp directivity is generally required. In addition, an automatic tracking antenna device that tracks with high accuracy is required. Various methods have been proposed for the tracking method of the automatic tracking antenna device. Among them, a monopulse method having a fast response speed (also referred to as a simultaneous roving method).
However, it can be said that it is suitable for being mounted on an automobile or the like which is relatively small and has a high moving speed. Further, the monopulse system includes an amplitude comparison monopulse system and a phase comparison monopulse system.

Here, a conventional example of a typical phase comparison monopulse system among these monopulse systems will be described.
The amplitude comparison monopulse method will not be described.
FIG. 10 is a principle diagram of the phase comparison monopulse system. As shown in FIG. 10, horn-type antennas 1 and 2 are provided on the same plane. In the figure, reference numerals 1 'and 2' denote substantial radiation points of the antennas 1 and 2 (hereinafter referred to as antenna centers). A 90 degree phase shifter 3 is connected to the antenna 1,
Outputs of the received waves from the antennas 1 and 2 are mixed by a mixer circuit 4 and output via a low-pass filter 5.

[0005] Here, when there is a radio wave source in a direction forming an angle θ from the front direction, the reception wave of the antenna 1 is L ′ in the figure.
The phase is delayed from the reception wave of the antenna 2 by the distance of.
Here, the received wave of antenna 2 is sinωt, antenna 1,
If the distance between the centers 1 ′ and 2 ′ of 2 is L, L ′ = L ·
sin θ, the wave received by the antenna 1 is s
in (ωt−2πL ′ / λ). Here, ω represents the angular velocity of the received wave, and λ represents the wavelength.

Here, when integrated by the mixer circuit 4, the following equation is obtained. sinωt · sin (ωt−x−π / 2) = − sinωt · cos (ωt−x) = − ／ · {sin (2ωt−x) + sin (x)} where x = 2πL · sinθ / λ Therefore, if high-frequency components are removed by the low-pass filter 5, only a DC voltage component (hereinafter, referred to as a monopulse voltage) caused by the error angle θ is obtained as shown in FIG. still,
In FIG. 11, reference numeral 6 denotes a locus of the monopulse voltage with respect to a change in the error angle θ. In the illustrated example, the amplitude level is normalized to 1.

Since the distance L between the antenna centers 1 'and 2' and the wavelength λ are known constants, the error angle θ can be obtained from this voltage value, and the antenna 1 is set so that the error angle θ is always zero. 2 can be tracked with respect to the radio wave source. FIG. 12 shows an example in which this phase comparison monopulse type antenna is constituted by a planar antenna. Since a planar antenna is originally a collection of antennas in which small antenna elements are arranged in an array, a plurality of antennas can be formed by arbitrarily dividing the inside to some extent, and can be said to be suitable for the phase monopulse system.

An antenna 8 shown in FIG. 12 shows an example in which a minimum of three antennas necessary for two-axis control in elevation and horizontal directions are constituted by planar antennas, and antennas 8b and 8c
The error angle in the elevation direction from the phase difference between
The horizontal error angle can be obtained from the phase difference between the combined outputs of the antennas 8b and 8c. For example, when the illustrated antenna 8 is used as a satellite broadcast tracking antenna, receiving the satellite broadcast by combining the antenna reception waves of the antennas 8a, 8b, and 8c is an effective means for reducing the size of the device system. Although it is conceivable, actually three antennas 8a, 8b,
Since there is a combined loss when combining the antennas 8c, it is necessary to make the antenna 8 one size larger than the minimum required size, which is not very effective in reducing the size. In addition, in order to combine the three antennas 8a, 8b, 8c, it is necessary to adjust a delicate phase, and it has been difficult to obtain industrially stable performance.

For this reason, the present applicant separates and separates the receiving antenna and the monopulse antenna for detecting the tracking error angle and arranges the antenna with a very small antenna in an empty space to reduce the size of the entire system. The proposed automatic tracking antenna device has already been filed as Japanese Patent Application No. 3-309291. The antenna section of this automatic tracking antenna device is shown in FIG.
As shown in FIG. 4, an antenna (hereinafter referred to as a main antenna) 30 having a reception-only antenna 31 and microminiature elevation monopulse antennas 32 and 33 on the same plane, and a microminiature horizontal angle monopulse as shown in FIG. A sub-antenna 39 provided with antennas 37 and 38 is provided. The main antenna 30 is provided with a video receiving LNB 34, and the antennas 30 and 39 are provided with a monopulse LNB unit 35 and an error angle detection unit 36.

Originally, it is desirable to form a horizontal angle and elevation angle monopulse antenna in the main antenna 30. However, in order to make the main antenna 30 as small as possible and secure an effective receiving area of the receiving antenna 31, As shown in FIG. 13, the antenna 39 is arranged at a place different from the main antenna 30, and has a structure in which the table 80 is driven and controlled in the horizontal direction.

The main antenna 30 has a structure that can be driven and controlled in the elevation direction. However, since the sub antenna 39 is fixed at 40 degrees, the monopulse antennas 37 and 38 for horizontal angle are used so that the antenna beam width is widened. It consists of a planar antenna with one element array in the elevation direction. FIG. 16 shows a block diagram of the entire automatic tracking antenna device, which includes a reception-only antenna 31, monopulse antennas 32 and 33 for elevation angles, monopulse antennas 37 and 38 for horizontal angles.
1 is provided with a video receiving LNB 34.

The monopulse LNB unit 35 for receiving signals from the elevation monopulse antennas 32 and 33 includes one
0.678 GHz local oscillation circuit 41 and two distribution circuit 42
And two LNB circuits 40. The error angle detection unit 36 includes a high-frequency amplifier circuit 43 for the 1 to 1.3 GHz band, a mixer circuit 44 for frequency conversion, a distribution circuit 45, a band-pass filter 46 having a center frequency of 402.78 MHz, an amplifier circuit 47 for the 400 MHz band, It comprises a phase difference detection mixer circuit 48, a low-pass filter 49, a DC amplifier circuit 50, and a phase adjustment cable 51.

The horizontal angle monopulse antenna 37,
The monopulse LNB unit 35 and the error angle detection unit 36 connected to 38 have the same circuit configuration as those connected to the elevation monopulse antennas 32 and 33. Also, the two distribution circuit 81 and the C / N detection circuit 5
2. Comparison circuit 53, voltage controlled oscillator (VCO) 54, tracking channel switching circuit 55, control circuit 56, vibrator gyro 57, servo controller 5 for horizontal angle and elevation angle
8,59, horizontal angle and elevation angle servo motors 60,6
2. The rotary encoders 61 and 63 are provided.

12G received by the reception-only antenna 31
The signal in the Hz band is converted into a signal in the 1.3 GHz band by the LNB 34, distributed by the two distribution circuit 81, and one of the signals is transmitted as it is as a video signal. The other is transmitted to the C / N detection circuit 52, and a DC voltage (hereinafter, referred to as C / N voltage) corresponding to the C / N value of the channel signal set by the tracking channel switching circuit 55 is output. This C /
If the N voltage is equal to or higher than a certain value, the comparator 53 outputs an H-level signal to the control circuit 56 as a reception state.

On the other hand, the elevation monopulse antennas 32, 3
3 are converted into signals in the 1.3 GHz band by the monopulse LNB unit 35, amplified in the error angle detection unit 36, and the channel signal set by the tracking channel switching circuit 55 The frequency conversion mixer circuit 44 converts the signal into a signal having a center frequency of 402.78 MHz. The 400 MHz band signal is further amplified and input to the phase difference detection mixer circuit 48, where only the DC voltage component is detected and amplified, and output to the control circuit 56 as a monopulse voltage for the elevation direction.

Also, horizontal monopulse antennas 32 and 33
Similarly, a monopulse voltage for the horizontal direction is obtained from the received wave of, and is output to the control circuit 56. When the output of the comparison circuit 53 is at the H level, the control circuit 56 recognizes that it is in the tracking state and the internal switch S ₁ ,
The S ₂ is turned on, the monopulse voltage horizontal, the elevation for monopulse voltage, it is given as a command voltage value to the analog control servo controller 58 and 59, at a speed corresponding to the servo motor 60, 62 to the instruction voltage value The attitude of the antenna is controlled by rotating the antenna.

FIG. 17 shows a plan view and a side view of an actual automatic tracking antenna apparatus. In the figure, 74 is a power supply circuit unit, and 75 is a control circuit and a servo controller unit. In such a conventional example, the monopulse voltage 6 shown in FIG. 12 is taken as it is as a command voltage of the analog control servo controllers 58 and 59, and the servo motor 6
Since the antenna is controlled by rotating 0.61 at a speed corresponding to the command voltage, a complicated calculation for calculating the tracking error angle from the monopulse voltage in the control circuit 56 or driving the digital control servo controller is performed. No processing is required, enabling quick tracking.

[0018]

By the way, in the conventional example shown in FIG. 16, when the receiving condition changes such as a weak electric field area or rain attenuation, the monopulse voltage decreases like the characteristic of the monopulse voltage 7 in FIG. Performance could be significantly degraded. The main cause of the monopulse voltage drop is that the level of the 400 MHz band signal input to the phase difference detection miskey circuit 48 in the error angle detection unit 36 shown in FIG.

In such a case, as shown in FIG. 18, the input level of the phase difference detection mixer circuit 48 is DC detected by the DC detection diode 10, and the gain of the high frequency amplifier circuit 43 'is controlled via the DC amplifier circuit 11. It is common to configure an AGC circuit that performs the following. The high-frequency amplifier circuit 43 'is an amplifier circuit with an AGC terminal for 1.3 GHz.

However, when an ultra-small antenna is used as the monopulse antenna, the C / N value of the received signal is extremely poor, and as shown in FIG.
In the input unit, the level of the received signal (a) is hidden by the level of the noise (b), and the signal level cannot be detected, so that it is difficult to configure a general AGC circuit.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an automatic tracking antenna device capable of maintaining stable tracking performance even under a weak electric field condition. is there.

[0022]

According to the first aspect of the present invention, a first planar antenna for receiving satellite broadcasting or satellite communication, and a first planar antenna provided on the same plane as the first planar antenna. A second plane antenna group for detecting an elevation angle error angle which is extremely small as compared with the first plane antenna group, and a first error angle detection means for detecting an error angle in the elevation angle direction from a reception wave of the second plane antenna group; A third plane antenna group for detecting an error angle in the horizontal direction, which is extremely small as compared with the first plane antenna, and a second plane antenna for detecting an error angle in the horizontal direction from a reception wave of the third plane antenna group. An error angle detecting means, a first mechanism driving section for driving the first planar antenna in an elevation direction, and a first mechanism antenna and a first mechanism driving section disposed on a table which rotates in a horizontal direction. And third
The first and second plane antenna groups are fixed on the table in the elevation direction, and the first and second antennas are driven in accordance with the output signals of the second mechanism driving unit for driving the table in the horizontal direction and the first and second error angle detecting means. And C / N detecting means for detecting a DC voltage corresponding to a C / N value of a received signal from a received wave of the first planar antenna in the automatic tracking antenna device having control means for driving the second mechanism driving section. And compensates for the change in the error angle detection due to the electric field condition according to the change in the DC voltage corresponding to the C / N value output from the C / N detection means.

According to a second aspect of the present invention, in the first aspect of the present invention, a DC voltage corresponding to a C / N value output from the C / N detecting means is stored in the first and second error angle detecting means. The gain of the high-frequency amplifier circuit is controlled by a change in a DC voltage corresponding to the C / N value given to the provided high-frequency amplifier circuit. According to a third aspect of the present invention, in the second aspect of the present invention, a temperature sensor is provided near the first and second error angle detecting means, and a deterioration of an output signal of each error angle detecting means due to a temperature characteristic is corrected. The correction coefficient is determined in advance in accordance with the temperature zone, and the control means selects a correction coefficient based on the temperature information of the temperature sensor, and multiplies the output signal of the error angle detection means by the selected correction coefficient to obtain the first,
This is output as a command voltage of the second mechanism drive unit.

According to a fourth aspect of the present invention, in the first aspect of the present invention, a DC voltage corresponding to the C / N value output from the C / N detecting means is input to the voltage limiting means, and the output of the voltage controlling means is output. A voltage is applied to a high-frequency amplifier circuit provided in the first and second error angle detecting means, and the gain of the high-frequency amplifier circuit is varied by changing the output voltage of the voltage limiting means, and the upper limit of the gain is determined. Things.

According to a fifth aspect of the present invention, in the first aspect of the invention, a DC voltage corresponding to a C / N value output from the C / N detecting means is supplied to the first and second error angle detecting means. , The gain of the last-stage DC amplifier circuit provided in the first and second error angle detecting means is varied according to the change in the DC voltage corresponding to the C / N value. According to a sixth aspect of the present invention, in the first aspect of the invention, a DC voltage corresponding to the C / N value output from the C / N detecting means is supplied to the control means, and the control means responds to the C / N value. A command voltage value to the first and second mechanism driving units is variably controlled based on a change in the DC voltage.

[0026]

According to the first aspect of the invention, the amount of change in the received signal level due to the electric field condition is detected from the reception wave of the first reception-only planar antenna which is the same as the second and third planar antennas for detecting the error angle. In order to compensate for the change in the error angle detection due to the electric field condition using the DC voltage corresponding to the C / N value, the compensation control for the error angle detection can be performed without being affected by the electric field condition such as a weak electric field area or rain attenuation. It is possible to maintain stable tracking performance even under a weak electric field condition.

According to the second aspect of the present invention, the signal characteristics of the error angle detection can be prevented from deteriorating by controlling the gain of the high-frequency amplifier circuit in the error angle detection means without being affected by the electric field condition. The characteristics of the output signal of the error angle detecting means can be obtained, and stable tracking can be performed. According to the third aspect of the present invention, in the second aspect of the present invention, even when the gain of the high-frequency amplifier circuit changes at a high temperature, a low temperature, or a condition in which the temperature changes drastically, the temperature is compensated and the stable tracking is always performed. Can be performed.

According to the fourth aspect of the present invention, the DC voltage corresponding to the C / N value output from the C / N detecting means is input to the voltage limiting means, and the output voltage of the voltage control means is changed to the first and second voltages. 2
Since the gain of the high-frequency amplifier circuit is varied by changing the output voltage of the voltage limiter and the upper limit of the gain is determined, the signal is output from the C / N detector. Even if the DC voltage corresponding to the C / N value exceeds a certain value, it is possible to prevent the high-frequency amplifier circuit from saturating, always obtain a normal error angle detection output signal, and perform normal tracking. .

According to the fifth aspect of the present invention, since the gain of the DC amplifier circuit at the last stage provided in the first and second error angle detecting means is varied, it is not affected by element variations. Therefore, it is possible to prevent the signal characteristics of the error angle detection from deteriorating, obtain a constant output signal characteristic of the error angle detection means, and perform stable tracking. According to the invention of claim 6, a DC voltage corresponding to the C / N value output from the C / N detection means is provided to the control means, and the control means responds to a change in the DC voltage corresponding to the C / N value. Since the instructed voltage values to the first and second mechanism driving units are variably controlled based on this, the tracking speed can be made constant irrespective of the electric field strength without configuring an AGC circuit. If this occurs, this can be compensated.

[0030]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) In this embodiment, as shown in FIG. 1, instead of the 1.3 GHz band high frequency amplifier circuit 43 in the error angle detection unit 36 of the conventional example shown in FIG. In order to adjust the slope of the C / N voltage characteristic to the AGC characteristic of the high frequency amplifier circuit 43 ', a G signal is applied to the AGC terminal of the high frequency amplifier circuit 43' via the DC amplifier circuit 12.
The output of the C / N detection circuit 52 is input. Of course, a similar AGC circuit configuration is used for the error angle detection unit 36 on the horizontal angle side, but illustration of the circuit is omitted. Since the basic operation principle and operation of the automatic tracking antenna apparatus are the same as those of the conventional example of FIG. 16, some circuit blocks are omitted from FIG.

Next, an explanation will be given of the operation of the present embodiment regarding the changed points. In FIG. 1, monopulse antennas 32, 33
Are received by the monopulse LNB unit 3 respectively.
5, after being converted into a signal in the 1.3 GHz band and further converted into a signal in the 400 MHz band in the error angle detection unit 36, the DC voltage component corresponding to the phase difference is output by the phase difference detection mixer circuit 48 and the low-pass filter 49. Is output to the control circuit 56 as a monopulse voltage. At this time, the locus of the monopulse voltage with respect to the error angle has the characteristic of the monopulse voltage 6 in FIG.

Here, if the reception signal level of the monopulse antennas 32 and 33 is reduced by 3 dB due to a change in the reception condition, the monopulse voltage output from the error angle detection unit 36 is the monopulse voltage 7 shown in FIG. Try to decrease like the characteristics of. However, at the same time, the voltage of the reception signal of the reception-only antenna 31 drops by an amount corresponding to 3 dB, and the C / N voltage output from the C / N detection circuit 52 also decreases by an amount corresponding to 3 dB. The amount of change in the C / N voltage is changed by the DC amplifier circuit 12 to change the amount of change.
Since the signal is input to the AGC terminal 3 ', the gain of the high-frequency amplifier circuit 43' is increased by 3 dB.

Therefore, the phase difference detecting mixer circuit 48
Input level is constant, and the monopulse voltage is always
It has the characteristic of one monopulse voltage 6. The automatic tracking antenna device of the present embodiment configured as described above has a constant monopulse voltage characteristic even when there is a change in reception conditions such as a weak electric field area or a rainfall source nest, and stable tracking performance can be obtained. It is.

(Embodiment 2) By the way, in the circuit of Embodiment 1 described above, the high-frequency amplifier circuit 4 of the error angle detection unit 36
3 'generally has a temperature characteristic, and the gain tends to increase at low temperatures and decrease at high temperatures. If a general AGC circuit as shown in FIG. 18 is possible, the amount of feedback to the high-frequency amplifier circuit 43 'changes depending on the input level of the mixer circuit 48 for phase difference detection. Although the AGC function works, when the C / N voltage from the reception-only antenna 31 is used as the AGC voltage of the high-frequency amplifier circuit 43 'as in the first embodiment, the temperature characteristics of the high-frequency amplifier circuit 43' are completely reduced. AGC function does not work.

Therefore, when the temperature is low or high, the monopulse voltage characteristic fluctuates and the tracking performance may be degraded. In this embodiment, in order to solve this problem, the inside of the control circuit 56 is partially improved in addition to the circuit of FIG. That is, as shown in FIG. 2, the temperature information from the temperature sensor 15 provided near the error detection units 36, 36, the elevation angle monopulse voltage output from each of the error angle detection units 36, 36, and the horizontal monopulse. The voltage is input to the control circuit 56 and applied to the CPU 16 through the analog / digital conversion circuits 13, 14, and 15.

The CPU 16 has a predetermined coefficient for each temperature zone, selects a coefficient based on temperature information obtained from the temperature sensor 15, and generates a monopulse voltage for the elevation direction,
Each of the horizontal monopulse voltages is multiplied by its coefficient, and the voltages obtained by the multiplication are converted into digital / analog conversion circuits 17, 1, and 2.
8 to the servo controllers 58 and 59 as an instruction voltage.

At a high temperature of, for example, 70 ° C., the monopulse voltage should be about 0.7 times that at normal temperature due to a decrease in the gain of the high-frequency amplifier circuit 43 ′ in the error angle detection unit 36. For example, the selection operation of the CPU 16 may be set in advance so that when the temperature information of 70 ° C. is input, the correction coefficient of 1.3 is selected. Thus, in the present embodiment, even if the characteristics of the monopulse voltage fluctuate due to a temperature change, the command voltages to the servo controllers 58 and 59 for driving the servo motors 60 and 62 have substantially constant output characteristics. Therefore, a stable tracking performance can always be obtained even at a high temperature, at a low temperature, or under a condition where the temperature changes drastically.

FIG. 2 is a block diagram showing a main part of this embodiment, and other circuits are the same as those shown in FIGS. (Embodiment 3) In the case of Embodiments 1 and 2, the output voltage of the C / N detection circuit 52, that is, the change in the C / N voltage causes
The gain of the high-frequency amplifier circuit 43 'with a C terminal is controlled to prevent the characteristics of the monopulse voltage from deteriorating and to obtain stable tracking performance.

However, the reception power also decreases when the antenna is at an angle with respect to the satellite which is the radio wave source, and the reception-only antenna 31 has monopulse antennas 32, 33 and 3
Since the directivity is sharper than that of the antennas 7 and 38, the reduction of the reception power of the monopulse antennas 32, 33 and 37 and 38 is smaller than the reduction of the reception power of the reception-only antenna 31 at a certain angle. Therefore, when the reception power at the reception-only antenna 31 is greatly reduced, a proportional C / N voltage is input to the high-frequency amplification circuit 43 'of each error angle detection unit 36 to increase the amplification amount. Since the received power at 33, 37, and 38 has not decreased so much, the signal level becomes extremely large, exceeding the limit value of the high-frequency amplifier circuit 43 'and becoming saturated. When the high-frequency amplifier 43 'is in a saturated state, a harmonic component is generated in addition to the signal frequency, and as shown in FIG. 3, the output voltage characteristic a due to the harmonic component and the output voltage characteristic b due to the signal component are combined. The locus c of the monopulse voltage with respect to the error angle θ is disturbed with respect to the normal locus, and there may be a plurality of points where the monopulse voltage becomes zero. In this case, the monopulse voltage becomes zero even at an angle different from the satellite direction, so that it is determined that the satellite has been supplemented, and there is a risk that satellite tracking may not be performed normally.

The present embodiment has been made in view of this point. In this embodiment, instead of the DC amplifier circuit 12 used in the first and second embodiments, a voltage control means as shown in FIG. The C / N voltage output from the C / N detection circuit 52 is input to the limiter circuit 21 using the barrel limiter circuit 21, and the output voltage of the limiter circuit 21 is used to output the high-frequency amplifier circuit 4.
Control the gain of 3 '. When a voltage higher than a certain threshold is input, the limiter circuit 21 outputs the voltage of the threshold, and this threshold is set to a value that does not saturate the high-frequency amplifier circuit 43 '.

Accordingly, when the reception signal from the reception-only antenna 31 decreases due to the weak electric field area, rain attenuation, or the antenna having a certain angle with respect to the satellite, C /
The C / N voltage from the N detection circuit 52 also decreases in proportion thereto and is input to the limiter circuit 21. When the C / N voltage is equal to or higher than the threshold value, the C / N voltage is output to the high-frequency amplifier circuit 43 'as it is. The voltage equal to or higher than the threshold is applied to the high-frequency amplifier 43 '.
, The high-frequency amplifier circuit 43 'does not saturate, and no harmonic components are generated. Therefore, the monopulse voltage can be normally maintained without being disturbed.

As the limiter circuit 21, for example, FIG.
As shown in FIG. 7, a circuit composed of an operational amplifier 19 and a diode 20 is used. Although the circuits on each horizontal side are omitted, the circuit configuration is the same as the circuit on the elevation angle side. As described above, in the present embodiment, by providing the limiter circuit 21 behind the C / N detection circuit 52, the high-frequency amplifier circuit 43 'is provided.
The gain of the high-frequency amplifier circuit 43 'can be controlled within a range where the signal does not saturate, so that it can compensate for the decrease in the monopulse voltage due to the weak electric field area and the rain attenuation, and the antenna is used for the satellite which is the radio wave source. Even when the antenna has a certain angle, the high-frequency amplifier circuit 43 'is not saturated and the monopulse voltage is not disturbed. Therefore, the tracking performance of the satellite is not deteriorated even in a weak electric field area and rain attenuation, In addition, accurate tracking can be performed. (Embodiment 4) In the case of Embodiments 1, 2, and 3, the AGC is performed using the output voltage of the C / N detection circuit 52, that is, the C / N voltage.
Although the gain of the high-frequency amplifier circuit with terminal 43 'has been controlled, the output of the mixer of two series may be distorted due to variations in the characteristics of the high-frequency amplifier circuit 43' with individual AGC terminals.

Therefore, in the present embodiment, as shown in FIG.
4, the signal is converted into a 1.3 GHz band signal, one is taken out as a video signal through a splitter 81, and the other is C / N
The output voltage is input to a detection circuit 52, and the output voltage is
, And when the C / N value exceeds a certain value, H
Output level signal.

The output of the C / N detection circuit 52, C /
The N voltage is input to the DC amplifier circuit 22 with gain control in the error angle detection unit 36, and the gain of the DC amplifier circuit 22 is changed by this voltage to keep the monopulse voltage substantially constant. Since the monopulse voltage varies depending on the C / N of the input signal as shown in FIG. 7, an extra gain corresponding to this variation ratio is added.

FIG. 8 shows a specific circuit example of the DC amplifier circuit 22 with gain control. In this specific circuit, the output of the inclination correction circuit 24 is added to an inverting amplifier 23 composed of an operational amplifier, and the voltage value is used to form a parallel circuit in a feedback loop. The connected resistors R ₁ .
₁ … to switch to change the gain. That is, the C / N output of the C / N detection circuit 52 is converted to the inclination correction circuit 2
4 to a comparison circuit 26.
.. Are performed as shown in Table 1 depending on whether the signal level is H or L.

[0046]

[Table 1]

For example, in the case of A in Table 1, the switch SW
₁ is turned on, when B can switch SW ₂ is turned on, the switch SW ₃ when the C is on, to obtain a gain corresponding to C / N and so on the switch SW ₄ is turned on when the D. In this embodiment, the gain of the mixer output, which is one series, is controlled, so that the monopulse voltage is kept constant and the tracking performance can be maintained without being affected by the variation of the elements.

(Embodiment 5) Embodiments 1-4 are based on a configuration in which the gain of the amplifier circuit in the error angle detection angle unit 36 is controlled by a change in the C / N voltage output from the C / N detection circuit 52. In this embodiment, however, the change in the C / N voltage is determined by the CPU 16 of the control circuit 56, the command voltage value to the servo motor controllers 58 and 59 is controlled, and stable tracking control is performed regardless of the electric field intensity. It is like that. FIG. 9 shows a circuit configuration of the main part.

The signal received by the reception antenna 31 is converted into a 1.3 GHz band signal by the LNB 34 for video reception, and one is taken out as a video signal through the two divider 81, and the other is output to the C / N detection circuit 52. , And the C / N voltage output from the C / N detection circuit 52 is compared with a threshold value by the comparison circuit 53. If the C / N voltage value exceeds a predetermined value,
The signal "H" is output to the control circuit 56, and the control circuit 56 receiving this output controls the tracking operation of the antenna. In addition, the elevation angle monopulse voltage and the horizontal direction monopulse voltage from each error angle detection unit 36 are output. Is a CPU through the analog / digital conversion circuits 14 and 15 in the control circuit 56.
The C / N voltage of the C / N detection circuit 52 is also supplied to the CPU 1 through the analog / digital conversion circuit 13 '.
6 given.

The CPU 16 operates according to the C / N voltage.
The monopulse voltage for the elevation direction and the monopulse voltage for the horizontal direction are multiplied by a coefficient in 16, and the voltages obtained by the multiplication are output to the servo motor controllers 58, 59 through the digital / analog conversion circuits 17, 18 as command voltages. It has become. A method of multiplying the above coefficient will be described with reference to FIG. FIG. 7 shows an antenna shift angle-monopulse voltage characteristic diagram with respect to the C / N of the received signal, in which a predetermined coefficient is multiplied to match the curve of C / N 16 dB in this diagram. For example, if C / N is 14 dB, the multiplication coefficient is 1.2.

As a result, even if the C / N of the received signal, that is, the monopulse voltage is deteriorated due to the fluctuation of the electric field strength, the command voltage value sent to the servo controllers 58 and 59 becomes substantially constant, and a stable tracking performance can be obtained. .

[0052]

According to the first aspect of the present invention, the amount of change in the received signal level due to the electric field condition is obtained from the received wave of the first reception-only planar antenna which is the same as the second and third planar antennas for detecting the error angle. C / N detection means for detecting a DC voltage corresponding to the C / N value of the received signal is provided, and the C / N detection means detects the DC voltage corresponding to the C / N value. To compensate for changes in error angle detection, compensation control of error angle detection can be performed without being affected by electric field conditions such as weak electric field areas and rain attenuation, and stable tracking performance even under weak electric field conditions. This has the effect that it becomes possible to maintain

According to a second aspect of the present invention, the DC voltage corresponding to the C / N value output from the C / N detection means is converted to the first and second DC voltages.
And the gain of the high-frequency amplifier circuit is controlled by a change in the DC voltage corresponding to the C / N value, so that the error angle can be detected without being affected by the electric field condition. By controlling the gain of the high-frequency amplifier circuit in the means, it is possible to prevent the signal characteristics of the error angle detection from deteriorating, to obtain a constant output signal characteristic of the error angle detection means, and to achieve stable tracking.

According to a third aspect of the present invention, in the second aspect of the present invention, a temperature sensor is provided in the vicinity of the first and second error angle detecting means, and a deterioration amount of an output signal of each error angle detecting means due to a temperature characteristic. Is determined in advance in accordance with the temperature zone, and the control means selects a correction coefficient based on the temperature information of the temperature sensor and multiplies the output signal of the error angle detection means by the selected correction coefficient. 1. Outputs as an instruction voltage of the second mechanism driving unit, so that the temperature is compensated and the tracking is always stable even when the gain of the high-frequency amplifier circuit changes at high temperature, low temperature, or under a condition of drastic temperature change. There is an effect that can be performed.

According to a fourth aspect of the present invention, the DC voltage corresponding to the C / N value output from the C / N detecting means is input to the voltage limiting means, and the output voltage of the voltage controlling means is changed to the first and second voltages. Since the gain is given to the high-frequency amplifier circuit provided in the error angle detecting means, the gain of the high-frequency amplifier circuit is varied by changing the output voltage of the voltage limiting means, and the upper limit of the gain is determined.
Even if the DC voltage corresponding to the C / N value output from the N detection means becomes a certain value or more, it is possible to prevent the high frequency amplifier circuit from being saturated, and to always obtain a normal error angle detection output signal. There is an effect that normal tracking can be performed.

According to a fifth aspect of the present invention, a DC voltage corresponding to the C / N value output from the C / N detecting means is supplied to the first and second error angle detecting means, and a DC voltage corresponding to the C / N value is provided. Since the gain of the last-stage DC amplification circuit provided in the first and second error angle detecting means is changed according to the voltage change, the signal characteristics of the error angle detection are degraded without being affected by element variations. Can be prevented, the characteristics of the output signal of the error angle detecting means can be obtained constantly, and stable tracking can be performed.

According to a sixth aspect of the present invention, a DC voltage corresponding to the C / N value output from the C / N detecting means is supplied to the control means, and the control means changes the DC voltage corresponding to the C / N value. , The command voltage values to the first and second mechanism driving units are variably controlled, so that the tracking speed can be stabilized irrespective of the electric field strength without forming an AGC circuit, and the error angle detection is deteriorated. This has the effect that this can be compensated for even if it occurs.

[Brief description of the drawings]

FIG. 1 is a partially omitted circuit block diagram of a first embodiment of the present invention.

FIG. 2 is a partially omitted circuit block diagram of a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of a problem to be solved in a third embodiment of the present invention.

FIG. 4 is a circuit block diagram in which a part of the circuit is omitted.

FIG. 5 is a specific circuit diagram of a limiter circuit used in the embodiment.

FIG. 6 is a circuit block diagram of a fourth embodiment of the present invention, in which a part is omitted.

FIG. 7 is an operation explanatory diagram of the above.

FIG. 8 is a specific circuit block diagram of a main part of the above.

FIG. 9 is a circuit block diagram of a fifth embodiment of the present invention with a part omitted.

FIG. 10 is a principle diagram of a phase monopulse system.

FIG. 11 is a diagram showing a locus of a monopulse voltage change with respect to a change in the error angle according to the first embodiment.

FIG. 12 is a block diagram of an entire antenna device of a conventional example.

FIG. 13 is a front view of an antenna portion of a conventional example which is the basis of the present invention.

FIG. 14 is a plan view of the main antenna according to the third embodiment.

FIG. 15 is a plan view of the antenna in the horizontal angle direction according to the second embodiment;

FIG. 16 is a block diagram of the whole automatic tracking antenna device of the above.

17 (a) and (b) are a plan view and a side view of the automatic tracking antenna device of the above.

FIG. 18 is a partially omitted circuit block diagram of a conventional example using an AGC circuit configuration.

FIG. 19 is an explanatory diagram of the above problem.

[Explanation of symbols]

 12 DC amplifier circuit 31 Receiving antenna 36 Error angle detection unit 43 'High frequency amplifier circuit 52 C / N detection circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-128506 (JP, A) JP-A-2-72987 (JP, U) Patent 2768392 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01Q 3/08

Claims (6)

(57) [Claims] A first system for receiving satellite broadcasting or satellite communication.
A second planar antenna group provided on the same plane as the first planar antenna for detecting an elevation angle error angle, which is extremely small as compared with the first planar antenna; A first error angle detecting means for detecting an error angle in the elevation direction from a reception wave of the antenna group; and a third planar antenna group for detecting a horizontal error angle which is extremely small as compared with the first planar antenna. A second error angle detecting means for detecting an error angle in the horizontal direction from the reception wave of the third planar antenna group, and a first error angle driving means for driving the first planar antenna in an elevation angle direction.
The first planar antenna and the first mechanism driving unit are disposed on a table that rotates in the horizontal direction, and the third planar antenna group is fixed on the table in the elevation direction. Automatic tracking including a second mechanism driving unit for driving the table in the horizontal direction, and control means for driving the first and second mechanism driving units in accordance with output signals of the first and second error angle detecting means. The antenna device includes C / N detection means for detecting a DC voltage corresponding to a C / N value of a received signal from a received wave of the first planar antenna.
An automatic tracking antenna apparatus, which compensates for a change in error angle detection due to an electric field condition according to a change in a DC voltage corresponding to a C / N value output from a / N detection unit. 2. The C / N output from the C / N detection means.
A DC voltage corresponding to the value is supplied to a high-frequency amplifier circuit provided in the first and second error angle detecting means, and a gain of the high-frequency amplifier circuit is controlled by a change in the DC voltage corresponding to the C / N value. 2. The automatic tracking antenna device according to claim 1, wherein: 3. A temperature sensor is provided in the vicinity of said first and second error angle detecting means, and a coefficient for correcting a deterioration of an output signal of each error angle detecting means due to a temperature characteristic is determined in advance in accordance with a temperature zone. The control means selects a correction coefficient based on the temperature information of the temperature sensor, multiplies the output signal of the error angle detection means by the selected correction coefficient, and sets the command voltage of the first and second mechanism driving units. 3. The automatic tracking antenna device according to claim 2, wherein the signal is output as a signal. 4. The C / N output from said C / N detection means.
The DC voltage corresponding to the value is input to the voltage limiting means, and the output voltage of the voltage control means is supplied to the high-frequency amplifier circuit provided in the first and second error angle detecting means, and the output of the voltage limiting means is output. 2. The automatic tracking antenna device according to claim 1, wherein the gain of the high-frequency amplifier circuit is varied by changing a voltage, and an upper limit of the gain is determined. 5. The C / N output from said C / N detection means.
A DC voltage corresponding to the value is provided to the first and second error angle detecting means, and provided in the first and second error angle detecting means in accordance with a change in the DC voltage corresponding to the C / N value. 2. The automatic tracking antenna device according to claim 1, wherein the gain of the last-stage DC amplifier circuit is variable. 6. The C / N output from said C / N detection means.
Providing a DC voltage corresponding to the C / N value to the control means, and variably controlling the command voltage value to the first and second mechanism drive units based on the change in the DC voltage corresponding to the C / N value. The automatic tracking antenna device according to claim 1, wherein: