JP2768392B2 - 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 a 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 antenna attitude control device that tracks accurately is required. The tracking method of the tracking antenna is based on a self-tracking method that receives radio waves arriving from the target, detects a azimuth error, and automatically controls the attitude of the antenna in that direction, and according to the trajectory data of the target obtained in advance. The method can be broadly divided into a program tracking method for tracking a target. However, on a moving object, the self-tracking method is superior to a train running on a predetermined track.

The self-tracking method uses a continuous roving method in which the main beam of one antenna is scanned by some means and the azimuth information of a target is detected from the obtained change in the received wave, and a method using a plurality of antennas. There is a simultaneous roving method in which an azimuth pointing error of an antenna is instantaneously detected from a difference between received waves of the antennas. In particular, the simultaneous roving method is also called a monopulse method to distinguish it from a continuous roving method.

[0005] By the way, in the case of a moving body, particularly a small-sized automobile having a high moving speed, the monopulse system capable of instantaneous detection is more suitable than the continuous roving system in which a response error remains a problem. Further, the monopulse method includes an amplitude comparison monopulse method and a phase monopulse method. Here, a conventional example of the phase monopulse method will be described.
The amplitude comparison monopulse method will not be described.

FIG. 6 shows the principle of the phase monopulse system. Horn antennas 1 and 2 are provided on the same plane.
Antenna center). 9 for antenna 1
The 0-degree phase shifter 3 is connected. The outputs of the antennas 1 and 2 are mixed by the mixer circuit 4 and output via the low-pass filter 5.

Here, there is a radio wave source in a direction forming an angle of θ from the front direction, and if the received wave of the antenna 2 is defined as sinωt, the antenna 1 has L ′ at the antenna center 1 ′.
The phase is delayed from the antenna 2 by the distance of. If the distance between the antenna centers 1 'and 2' is L, L '= L.sin
θ, the received wave of the antenna 1 eventually becomes sin
(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 the DC voltage component caused by the error angle θ is obtained as shown in FIG. In FIG. 7, reference numeral 6 denotes a locus of a change in the DC voltage with respect to a change in the error angle θ.

Since the distance L and the wavelength λ between the antenna centers 1 ′ and 2 ′ are known constants, the error angle θ can be obtained from this voltage value, and the attitude of the antennas 1 and 2 can be controlled. FIG. 8 shows an example in which this phase 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.

FIG. 8 (a) shows a basic form of a monopulse antenna for two-axis control in elevation and horizontal directions.
a to 7d, for example, error angles in the elevation direction at 7a and 7c, (7a & 7c)
And (7b & 7d), the horizontal error angle can be detected. Here, the symbol & indicates the synthesis. FIG.
8 (b) and 8 (c) are monopulse antennas each composed of a minimum of three antennas necessary for two-axis control. FIG.
And 8b, the horizontal error angle can be obtained, and (8a & 8b) and 8c can obtain the elevation error angle. FIG.
In (c), the error angle in the elevation direction is 9b and 9c, 9a
And (9b & 9c), the horizontal error angle can be obtained.

These phase monopulse systems are already known technologies and have been used for tracking radars and the like for a long time, and FIG. 9 shows an example in which they are applied to satellite broadcast reception.
The antenna 9 in the figure is composed of 9a to 9c shown in FIG. 8 (c), each of which converts into a signal wave of 12 GHz band (hereinafter referred to as LNB (Low Noise Block converter)).
10 are connected. Also, the local oscillation circuit 11 is originally LN
A local oscillator circuit (10.678) inside each of B10
GHz), but are shared to eliminate variations in the frequencies, and the difference between the outputs of the LNBs 10 is based on only the phase difference information.

The two distribution circuits 12, three distribution circuits 13,
14, a synthesizing circuit 15, a video signal synthesizing circuit 19, a horizontal error angle detecting circuit 16, an elevation error angle detecting circuit 17, a control circuit 18, antenna driving devices 20 and 21 for rotating the antenna 9 in the elevation and horizontal directions, etc. Each circuit is provided. The control circuit 18 calculates and detects the error angles of the antenna 9 in the horizontal and elevation directions from the horizontal direction error angle detection circuit 16 and the elevation angle error angle detection circuit 17, and accordingly sets the antenna driving devices 20, 21 to the error angles. Is controlled so as to become 0, and tracking is performed.

[0013]

The minimum antenna area required for satellite broadcast reception is divided, for example, as shown in FIG. 8 (c), and the elevation and horizontal directions are determined based on the phase difference between the received waves of the individual antennas. An error angle is detected, and three antennas 9a to 9a are detected.
Obtaining a video signal by synthesizing the received wave of c is very advantageous in reducing the size of the tracking antenna at first glance because the antenna area can be used effectively, but as can be seen from the block diagram of FIG. Distribute the reception waves of the individual antennas 9a to 9c,
It is necessary to combine them, resulting in a complicated circuit configuration.

In addition, the signal waves input to the horizontal error angle detecting circuit 16, the elevation angle error angle detecting circuit 17, and the video signal synthesizing circuit 19 need to be finely adjusted in phase. It is difficult to combine received waves, and it cannot be said that 100% of the antenna receiving area is effectively used, and there is a problem in that it is difficult to have a stable quality in industry.

The present invention has been made in view of the above points, and provides a small-sized tracking antenna device which has a simple antenna configuration, is easy to manufacture and adjust industrially, and is capable of high-speed, high-accuracy tracking. It is intended to provide.

[0016]

According to the present invention, there is provided 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 for detecting an error angle in an elevation angle direction. A second plane antenna, first error angle detection means for detecting an error angle in the elevation direction from a reception wave of the second plane antenna, a third plane antenna for detecting an error angle in the horizontal direction, Second error angle detecting means for detecting an error angle in the horizontal direction from the reception wave of the third planar antenna, and a mechanism for driving the first planar antenna in the elevation direction are mounted on a table which rotates in the horizontal direction. And the third planar antenna is fixedly mounted on the table in the elevation direction.

According to the second aspect, the antenna element of the third planar antenna in the elevation angle direction is constituted by one element. Also,
According to a third aspect of the present invention, a gyro is provided which immediately shifts to tracking in the horizontal direction when the radio wave is cut off, and immediately reacquires the signal after the radio wave is restored. Further, in the fourth aspect, a DC servo motor and an analog control servo controller are provided for directly inputting an error angle corresponding voltage detected from the second and third planar antennas as an analog instruction voltage when tracking a radio wave.

According to a fifth aspect of the present invention, there is provided a control means for shortening the initial capturing time by searching from the elevation angle immediately before the power is turned off at the time of the initial capturing. According to a sixth aspect of the present invention, there is provided a voltage controlled oscillator and a channel switching circuit capable of switching a channel frequency to be tracked.

[0019]

Thus, dedicated antennas for each of the first planar antenna, the second planar antenna for detecting the elevation angle error angle, and the third planar antenna for detecting the horizontal error angle are provided.
Fix the third planar antenna on the table in the elevation direction,
By detecting and processing the error angles in the elevation and horizontal directions at each antenna output, it is compact, high-speed, high-precision, simple in configuration, and easy to manufacture and adjust industrially. It becomes.

According to the second aspect of the present invention, since the third planar antenna has one antenna element in the elevation direction, the beam width in the elevation direction is sufficiently wide (about 32 degrees per element). Even if it is fixed in the elevation direction, it can be used sufficiently in the elevation angle range from Kyushu to Hokkaido. In claim 3, when the radio wave is cut off, the system immediately shifts to tracking in the horizontal direction,
By providing a gyro that instantaneously recaptures after radio wave recovery, when the radio wave is interrupted, the horizontal angle direction immediately shifts to gyro tracking with a low-cost gyro, so it is possible to recapture as soon as the radio wave returns .

According to a fourth aspect of the present invention, there is provided a DC servo motor and an analog control servo controller for directly inputting an error angle corresponding voltage detected from the second and third planar antennas as an analog instruction voltage when tracking a radio wave. This enables high-speed tracking. Further, in the fifth aspect, at the time of the initial capture, a control means for shortening the initial capture time by searching from the elevation angle immediately before the power is turned off is provided. Radio waves can be captured.

According to the sixth aspect of the present invention, a voltage-controlled oscillator and a channel switching circuit capable of switching a channel frequency to be tracked are provided, so that when a tracking channel disappears, for example, when a satellite breaks down. It is possible to easily change channels.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. In the present invention, a dedicated antenna for a video receiving antenna, a monopulse antenna for a horizontal angle and a monopulse antenna for an elevation angle are provided to achieve simplification and commonality of the circuit configuration after the antenna.

FIGS. 1 to 3 show the configuration of the antenna portion of the present invention. As shown in FIG. 2, the tracking antenna device comprises a reception-only antenna 31 and a microminiature elevation-dedicated monopulse antenna 32, 33. An antenna (hereinafter referred to as a main antenna) 30 formed on the same plane and an antenna 39 provided with ultra-small horizontal angle dedicated monopulse antennas 37 and 38 as shown in FIG. The main antenna 30 is provided with a receiving LNB 34, and the antennas 30 and 39 have
A monopulse LNB unit 35 and an error angle detection unit 36 are provided.

In the present invention, as shown in FIG. 1, the main antenna 30 and the monopulse antenna 39 dedicated to horizontal angle are arranged on the table 80 at a position different from the main antenna 30. Originally, it is desirable to form horizontal and elevation monopulse antennas in the main antenna 30. However, the main antenna 30 should be as small as possible and the receiving antenna 31
Table 8 in the horizontal direction to secure the effective area of
In this mechanism, only the antenna 39 of the horizontal angle monopulse antennas 37 and 38 is fixed at another position on the table 80 at an angle of 40 °.

Further, monopulses 37 and 38 dedicated to horizontal angle are used.
Since the antenna element array in the elevation direction is composed of one element, the beam width in the elevation direction is sufficiently wide (about 32 degrees per element), and even if the beam width in the elevation direction is fixed, It can be used in the elevation range. In addition, since the monopulse dedicated antenna is provided, the monopulse LNB unit 35 and the error angle detection unit 3
6 can be integrated in a block, and are common to the horizontal and elevation angles, so that the same adjustment method is possible.

FIG. 4 is a block diagram of the entire tracking antenna device of the present invention. The tracking antenna device includes an antenna 31 for image reception, monopulse antennas 32 and 33 for elevation angles, and monopulse antennas 37 and 38 for horizontal angles. For L
NB34 is provided. Monopulse antenna for elevation 3
The monopulse LNB unit 35 that receives signals from the signals 2 and 33 includes a local oscillation circuit 41 of 10.678 GHz, a two-distribution circuit 42, and two LNB circuits 40.

The error angle detecting unit 36 is 1 to 1.3 G
Hz band amplification circuit 43, frequency conversion mixer circuit 4
4, 2 distribution circuit 45, center frequency is 402.78 MHz
, A 400 MHz band amplification circuit 47, a phase difference detection mixer circuit 48, a low pass filter 49, a DC amplification 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. Further, the signal from the two distribution circuit 81 is input to the C / N detection circuit 52, and the comparison circuit 53 outputs an H level signal when the C / N value exceeds a certain value.
Further, a voltage controlled oscillator (VCO) 54, a tracking channel switching circuit 55, a control circuit 56, an oscillator type gyro 57,
There are provided servo controllers 58 and 59 for horizontal angle and elevation angle, servo motors 60 and 62 for horizontal angle and elevation angle, and rotary encoders 61 and 63.

1 received by the video receiving antenna 31
The signal in the 2 GHz band is converted into a signal in the 1.3 GHz band by the LNB 34 and distributed by the two distribution circuit 81, and one of them is transmitted as a video signal as it is. And the other is C
/ N detection circuit 52, and if the C / N value is equal to or greater than a certain value, it is determined to be in a receiving state and the comparison circuit 53
Accordingly, an H-level signal is output to control circuit 56.

On the other hand, the elevation monopulse antennas 32, 3
3 are received by the monopulse LNB unit 35.
After being converted into a signal of 3 GHz band, the error angle detection unit 36 further adds a signal of 400 MHz to the signal of the channel to be tracked.
The signal is converted into a signal in the z band, amplified, and sent to the control circuit 56 as a voltage value corresponding to the tracking error. When the output of the comparison circuit 53 is at the H level and the antenna is in the tracking state, the control circuit 56 turns on the internal switches S ₁ and S ₂ and responds to the error angles detected from the monopulse antennas 32, 33, 37 and 38. The voltages (hereinafter, referred to as monopulse voltages) are used as they are, and the servo controllers 58 and 59 for analog control are used.
, And the servo motors 60 and 62 are driven to control the attitude of the antenna.

Therefore, in the control circuit 56, there is no need to calculate a monopulse voltage into an error angle or to perform complicated processing for driving a digital control servo controller.
It enables quick tracking. Here, the provision of the voltage controlled oscillator (VCO) 54 and the tracking channel switching circuit 55 makes it possible to easily change, for example, when the broadcast wave of the tracking channel stops existing due to a satellite failure or the like. .

As the control modes of the control circuit 56, there are mainly three modes: an initial acquisition mode, a tracking mode (described above), and a reacquisition mode. In the initial acquisition mode, the elevation data in the reception and tracking state is always rotary. Encoder 63
The elevation data immediately before the power is turned off is stored in the RAM, and the search is started from the elevation angle when the power is turned on. Therefore, in most cases, the data can be captured in a short time.

Further, in the reacquisition mode, the gyro 57 is used for tracking in the horizontal direction, and when the radio wave is cut off, the gyro tracking is immediately shifted to the horizontal angle direction. . FIG. 5 shows a plan view and a side view of an actual tracking antenna device. 7 in the figure
4 is a power supply circuit unit, 75 is a control circuit and a servo controller unit.

[0035]

As described above, the present invention provides a first planar antenna for receiving satellite broadcasts or satellite communications, and an elevation angle error detector provided on the same plane as the first planar antenna. A second plane antenna, first error angle detection means for detecting an error angle in the elevation direction from a reception wave of the second plane antenna, a third plane antenna for detecting an error angle in the horizontal direction, Second error angle detecting means for detecting an error angle in the horizontal direction from the reception wave of the third planar antenna, and a mechanism for driving the first planar antenna in the elevation direction are mounted on a table which rotates in the horizontal direction. Since the third planar antenna is arranged and fixed in the elevation direction on the table, the first planar antenna, the second planar antenna for detecting the elevation angle error angle, and the horizontal Third plane for detecting the error angle of the direction By providing a dedicated antenna for each of the teners, fixing the third planar antenna on the table in the elevation direction, and detecting and processing the error angle in the elevation direction and the horizontal direction with each antenna output, It is compact, high-speed, high-precision, has a simple configuration, and has an effect of being easily manufactured and adjusted industrially.

According to the second aspect of the present invention, the antenna element in the elevation direction of the third planar antenna is composed of one element, so that the beam width in the elevation direction is sufficiently large (about 32 degrees per element). Even if it is fixed in the elevation direction, it can be used sufficiently in the elevation angle range from Kyushu to Hokkaido. In claim 3, when the radio wave is cut off, the system immediately shifts to tracking in the horizontal direction,
By providing a gyro that instantaneously recaptures after radio wave recovery, when the radio wave is interrupted, the horizontal angle direction immediately shifts to gyro tracking with a low-cost gyro, so it is possible to recapture as soon as the radio wave returns .

According to a fourth aspect of the present invention, there is provided a DC servo motor and an analog control servo controller for directly inputting the voltage corresponding to the error angle detected from the second and third planar antennas as an analog instruction voltage when tracking a radio wave. This enables high-speed tracking. Further, in the fifth aspect, at the time of the initial capture, a control means for shortening the initial capture time by searching from the elevation angle immediately before the power is turned off is provided. Radio waves can be captured.

According to the sixth aspect of the present invention, a voltage-controlled oscillator and a channel switching circuit capable of switching a channel frequency to be tracked are provided, so that when a tracking channel disappears, for example, when a satellite breaks down. It is possible to easily change channels.

[Brief description of the drawings]

FIG. 1 is a front view of an antenna part according to an embodiment of the present invention.

FIG. 2 is a plan view of the main antenna according to the first embodiment.

FIG. 3 is a plan view of the antenna in the horizontal angle direction according to the first embodiment;

FIG. 4 is a block diagram of the entire tracking antenna device.

5 (a) and 5 (b) are a plan view and a side view of the tracking antenna device of the above.

FIG. 6 is a principle diagram of a phase monopulse system.

FIG. 7 is a diagram showing a locus of a DC voltage change with respect to a change in the error angle according to the first embodiment.

FIG. 8 is an explanatory diagram of a monopulse antenna.

FIG. 9 is a block diagram of the entire antenna device of a conventional example.

[Explanation of symbols]

 31 First planar antenna 32, 33 Second planar antenna 34 LNB for reception 35 LNB unit for monopulse 36 Error angle detection unit 37, 38 Third planar antenna 80 Table

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuru Maeda 1048 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. Inventor Yasuhiro Fujii 1048 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Works, Ltd. (56) References JP-A-2-212790 (JP, A) JP-A-2-72987 (JP, U)

Claims (6)

(57) [Claims] 1. A first planar antenna for receiving satellite broadcasting or satellite communication or the like, a second planar antenna provided on the same plane as the first planar antenna for detecting an elevation angle error angle, and First error angle detection means for detecting an error angle in the elevation direction from a reception wave of the second planar antenna, a third plane antenna for detecting an error angle in the horizontal direction, and a reception wave of the third plane antenna A second error angle detecting means for detecting an error angle in the horizontal direction and a mechanism for driving the first planar antenna in the elevation direction are provided on a table which rotates in the horizontal direction. A tracking antenna device wherein a planar antenna is fixedly mounted on the table in an elevation direction. 2. The tracking antenna device according to claim 1, wherein the antenna element in the elevation angle direction of the third planar antenna is constituted by one element. 3. The tracking antenna device according to claim 1, further comprising a gyro that immediately shifts to tracking in the horizontal direction when the radio wave is cut off, and immediately reacquires the signal after the radio wave is restored. 4. A direct current servo motor and an analog control servo controller for directly inputting an error angle corresponding voltage detected from the second and third planar antennas as an analog instruction voltage when tracking a radio wave. The tracking antenna device according to claim 1. 5. The tracking antenna apparatus according to claim 1, further comprising control means for searching from an elevation angle immediately before power-off to shorten an initial capturing time at the time of initial capturing. 6. The tracking antenna device according to claim 1, further comprising a voltage controlled oscillator capable of switching a channel frequency to be tracked and a channel switching circuit.