JPH05142320A - Tracking antenna device - Google Patents

Abstract

PURPOSE:To provide a small and simple antenna structure for conducting tracking at high speed with high accuracy, which can be easily manufactured and adjusted industrially. CONSTITUTION:An antenna for receiving only and a very small type of monopulse antenna for only elevation angle are formed on the same flat surface, to form a main antenna 30. An antenna 39 is formed by a very small type monopulse antenna for only horizontal angle. A receiving LNB is provided on the main antenna 30, while an LNB unit 35 for monopulse and an error angle detection unit 36 are provided on the antennas 30, 39. The monopulse antenna 39 for only horizontal angle is arranged on a table 80, aside from the main antenna 30 and the main antenna 30. Only the monopulse antenna 39 for only horizontal angle is fixed at an angle 40 deg. on the different position on the table 80.

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, there has been a mobile object (for example, a train, a ship, an automobile, an aircraft) equipped with an antenna for mobile communication with a ground station or an artificial satellite station and for receiving a broadcast wave. It is appearing. In particular, with the spread of satellite broadcasting, there is a growing need to receive satellite broadcasting on mobile units.

In order to receive a weak radio wave from such a satellite, a high-gain antenna having a sharp directivity is generally required. Therefore, when trying to receive on a moving body, the satellite which is the radio wave source is always high speed. In addition, an antenna attitude control device that accurately tracks is required. The tracking method of the tracking antenna is based on the self-tracking method that receives the radio wave coming from the target, detects the azimuth error, and automatically controls the attitude of the antenna in that direction. It can be roughly classified into a program tracking method for tracking a target. However, on a moving body, the self-tracking method is dominant except for a train that runs on a predetermined track line.

The self-tracking method uses a continuous roving method in which the main beam of one antenna is scanned by some means and the target azimuth information is detected from changes in the received wave obtained, and a plurality of antennas are used. 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 respective antennas. In particular, the simultaneous roving method is also called a monopulse method in a sense to be distinguished from a continuous roving method.

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

FIG. 6 shows the principle of the phase monopulse system. The horn antennas 1 and 2 are provided on the same plane, and 1'and 2'are the substantial radiation points of the antennas 1 and 2 (hereinafter,
It is called the center of the antenna). 9 for antenna 1
The 0-degree phase shifter 3 is connected, and the outputs of the antennas 1 and 2 are mixed by the mixer circuit 4 and output through the low-pass filter 5.

Here, if there is a radio wave source in a direction forming an angle of θ with respect to the front direction, and the received wave of the antenna 2 is sin ωt, then in the antenna 1, L'at the antenna center 1 '.
The phase lags behind the antenna 2 by the distance of. If the distance between the antenna centers 1'and 2'is L, then L '= L.sin
Since it can be expressed as θ, the received wave of the antenna 1 is eventually sin
It can be expressed as (ωt−2πL ′ / λ). However, ω represents the angular velocity of the received wave, and λ represents the wavelength.

[0008] Here, when integrated by the mixer circuit 4, the following equation is obtained. sin ωt · sin (ωt−x−π / 2) = −sin ωt · cos (ωt−x) = −1 / 2 · {sin (2ωt−x) + sin (x)} where x = 2πL · sin θ / λ Therefore, if the high-frequency component is removed by the low-pass filter 5, only the DC voltage component due to the error angle θ can be obtained as shown in FIG. In FIG. 7, reference numeral 6 is a locus of the DC voltage change with respect to the change of the error angle θ.

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 attitude control of the antennas 1 and 2 becomes possible. FIG. 8 shows an example in which this phase monopulse type antenna is configured by a planar antenna. Since a planar antenna is originally an assembly of antennas in which small antenna elements are arranged in an array, a plurality of antennas can be configured by arbitrarily dividing the inside and can be said to be suitable for the phase monopulse system.

FIG. 8A shows a basic form of a monopulse antenna for biaxial control in elevation and horizontal directions.
It is composed of four same antennas a to 7d. For example, 7a and 7c are elevation angle error angles, (7a & 7c).
And (7b & 7d) can detect the error angle in the horizontal direction. In addition, the above-mentioned & symbol represents composition. Figure 8
8 (b) and 8 (c) are monopulse antennas composed of a minimum of three antennas required for biaxial control, and FIG. 8 (b) shows 8a.
And 8b, the error angle in the horizontal direction can be obtained, and (8a & 8b) and 8c can obtain the error angle in the elevation direction. Also, FIG.
In (c), 9b and 9c are elevation angle error angles, 9a
The error angle in the horizontal direction can be obtained by (9b & 9c).

These phase monopulse systems are already known techniques and have been used for tracking radars and the like for a long time. An example in which they are applied for satellite broadcast reception is shown in FIG.
The antenna 9 in the figure is composed of 9a to 9c shown in FIG. 8 (c), and is a converter (hereinafter referred to as an LNB (Low Noise Block converter)) that drops signal waves in the 12 GHz band.
10 are connected. Also, the local oscillator circuit 11 is originally LN
Local circuit (10.678) inside each B10
However, it is common in order to eliminate the variation in each frequency, and the difference between the outputs of each LNB 10 is due to the phase difference information only.

Also, the two-distribution circuit 12, the three-distribution circuit 13,
14, a combination circuit 15, a video signal combination circuit 19, a horizontal direction error angle detection circuit 16, an elevation angle direction error angle detection circuit 17, a control circuit 18, an antenna drive device 20, 21 for rotating the antenna 9 in the elevation direction and the horizontal direction. Each circuit is equipped with. The control circuit 18 arithmetically detects the error angles in the horizontal direction and the elevation angle direction of the antenna 9 from the horizontal direction error angle detection circuit 16 and the elevation angle direction error angle detection circuit 17, and accordingly detects the antenna drive devices 20 and 21. Is controlled so as to be 0, and tracking is performed.

[0013]

The minimum necessary antenna area required for satellite broadcast reception is divided, for example, as shown in FIG. 8C, and the elevation angle and horizontal direction are determined from the phase difference of the received waves of the individual antennas. Error angle is detected, and 3 antennas 9a-9
Obtaining a video signal by synthesizing the received waves of c is very advantageous in reducing the size of the tracking antenna at first glance because the antenna area can be effectively used. However, as can be seen from the block diagram of FIG. 9, Received waves of the individual antennas 9a to 9c are distributed,
It has to be synthesized, resulting in a complicated circuit configuration.

Moreover, the input signal waves to the horizontal direction error angle detection circuit 16, the elevation angle direction error angle detection circuit 17, and the video signal synthesis circuit 19 require delicate phase adjustment. It is difficult to combine the received waves, and it is difficult to say that the antenna reception area is used 100% effectively, and it is difficult to have stable quality industrially.

The present invention has been provided in view of the above points, and provides a small tracking antenna device which has a simple antenna structure, is easily manufactured and adjusted industrially, and is capable of high-speed and high-precision tracking. It is intended to be provided.

[0016]

SUMMARY OF THE INVENTION The present invention is directed to a first plane antenna for receiving satellite broadcasting or satellite communication, and an elevation angle error angle detecting device provided on the same plane as the first plane antenna. A second plane antenna, a first error angle detecting means for detecting an error angle in the elevation angle direction from a received wave of the second plane antenna, a third plane antenna for detecting an error angle in the horizontal direction, and A second error angle detecting means for detecting an error angle in the horizontal direction from the received wave of the third plane antenna and a mechanism section for driving the first plane antenna in the elevation direction are placed on a table which rotates in the horizontal direction. The third planar antenna is fixedly arranged on the table in the elevation angle direction.

In the second aspect, the antenna element in the elevation angle direction of the third planar antenna is composed of one element. Also,
According to the third aspect, a gyro is provided which immediately shifts to horizontal tracking when the radio wave is cut off and instantly re-captures after the radio wave is restored. Further, in claim 4, a DC servo motor and an analog control servo controller are provided to which the error angle corresponding voltages detected from the second and third planar antennas are directly input as analog instruction voltages during radio wave tracking.

According to a fifth aspect of the present invention, at the time of initial capture, control means is provided for searching the elevation angle immediately before the power is turned off to shorten the initial capture time. Further, according to the present invention, a voltage controlled oscillator and a channel switching circuit that can switch the channel frequency to be tracked are provided.

[0019]

Thus, the dedicated antennas of the first plane antenna, the second plane antenna for detecting the elevation angle error angle, and the third plane antenna for detecting the horizontal error angle are provided.
The third planar antenna is fixed on the table in the elevation direction,
By detecting and processing the error angle in the elevation direction and the horizontal direction from each antenna output, it is small, high-speed, highly accurate, has a simple structure, and is easy to manufacture and adjust industrially. It will be.

In the second aspect of the invention, since the antenna element in the elevation direction of the third planar antenna is composed of one element, the beam width in the elevation direction is sufficiently wide (about 32 degrees for one element). Even if it is fixed in the elevation direction, it can be sufficiently used in the elevation range from Kyushu to Hokkaido. In claim 3, when the electric wave is cut off, the operation immediately shifts to horizontal tracking,
By providing a gyro that recaptures instantly after the radio wave returns, the inexpensive gyro immediately shifts to gyro tracking in the horizontal angle direction when the radio wave is cut off, so it is possible to recapture at the moment the radio wave returns. ..

Further, in claim 4, a DC servo motor and an analog control servo controller are provided in which an error angle corresponding voltage detected from the second and third planar antennas is directly inputted as an analog instruction voltage when the radio wave is tracked. This enables high-speed tracking. Further, according to claim 5, at the time of initial capture, the control means is provided to search from the elevation angle immediately before the power is turned off to shorten the initial capture time. Radio waves can be captured.

Further, according to the present invention, since the voltage controlled oscillator and the channel switching circuit that can switch the channel frequency to be tracked are provided, when the tracking channel disappears, such as when the satellite fails. The channel can be changed easily.

[0023]

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

1 to 3 show the structure of the antenna portion of the present invention. In this tracking antenna device, as shown in FIG. 2, a reception-only antenna 31 and ultra-compact elevation-only monopulse antennas 32 and 33 are provided. An antenna (hereinafter referred to as a main antenna) 30 configured on the same plane, and an antenna 39 provided with ultra-small horizontal angle dedicated monopulse antennas 37 and 38 as shown in FIG. Further, the main antenna 30 is provided with a receiving LNB 34, and the antennas 30 and 39 are
An LNB unit 35 for monopulse and an error angle detection unit 36 are provided.

In the present invention, as shown in FIG. 1, the main antenna 30 and the horizontal-angle-dedicated monopulse antenna 39 are arranged on the table 80 at a position different from the main antenna 30. Originally, it is desirable to configure horizontal and elevation monopulse antennas in the main antenna 30, but the main antenna 30 should be made as small as possible and the receiving antenna 31
In order to secure the effective area of
The mechanism is such that it rotates every 0, and only the antenna 39 of the monopulse antennas 37 and 38 for horizontal angle is fixed at another position on the table 80 at an angle of 40 °.

Further, monopulses 37 and 38 for horizontal angle only
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 with one element), and even if it is fixed in the elevation direction, It can be used well in the elevation range. Further, since the monopulse dedicated antenna is provided, the monopulse LNB unit 35 and the error angle detection unit 3 are provided.
6 can be integrated in a block manner, and since both horizontal and elevation angles are common, the same adjustment method is possible.

FIG. 4 shows a block diagram of the entire tracking antenna device of the present invention, which is provided with a video reception dedicated antenna 31, elevation angle monopulse antennas 32 and 33, and horizontal angle monopulse antennas 37 and 38, and the antenna 31 receives video reception. For L
NB34 is provided. Elevation monopulse antenna 3
The monopulse LNB unit 35 that receives the signals from the circuits 2 and 33 is composed of a 10.678 GHz local oscillator circuit 41, a dual distribution circuit 42, and two LNB circuits 40.

The error angle detection unit 36 is 1 to 1.3 G
Hz band amplifier circuit 43, frequency conversion mixer circuit 4
4, 2 distribution circuit 45, center frequency is 402.78 MHz
The band pass filter 46, 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 that of the elevation angle 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, a vibrator type gyro 57,
It is provided with horizontal angle and elevation angle servo controllers 58 and 59, horizontal angle and elevation angle servo motors 60 and 62, and rotary encoders 61 and 63.

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

On the other hand, elevation monopulse antennas 32 and 3
The received wave of No. 3 is 1.
After being converted to a 3 GHz band signal, the error angle detection unit 36 further tracks the channel signal and 400 MHz.
The signal is converted into a z-band signal, 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 to correspond to the error angles detected from the monopulse antennas 32, 33, 37 and 38. The voltage (hereinafter, referred to as a monopulse voltage) is kept as it is, and the analog control servo controllers 58 and 59 are used.
Is given as an instruction voltage value to drive the servo motors 60 and 62 to control the attitude of the antenna.

Therefore, in the control circuit 56, no complicated processing for calculating a monopulse voltage into an error angle or driving a servo controller for digital control is required.
It enables quick tracking. Here, the voltage-controlled oscillator (VCO) 54 and the tracking channel switching circuit 55 are provided so that they can be easily changed when the broadcasting wave of the tracking channel is no longer present due to, for example, a satellite failure. ..

The control mode of the control circuit 56 mainly includes three modes: an initial acquisition mode, a tracking mode (described above), and a reacquisition mode. In the initial acquisition mode, the elevation angle data in the reception tracking state is always rotated. Encoder 63
The elevation angle 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, so that most cases can be captured in a short time.

Further, in the re-acquisition mode, the gyro 57 is used for horizontal tracking, and when the radio wave is cut off, the gyro 57 immediately shifts to the gyro tracking in the horizontal angle direction, so that the re-acquisition is possible at the moment when the radio wave is restored. .. FIG. 5 shows a plan view and a side view of an actual tracking antenna device. 7 in the figure
Reference numeral 4 is a power supply circuit unit, and 75 is a control circuit and servo controller unit.

[0035]

As described above, the present invention provides a first plane antenna for receiving satellite broadcasting or satellite communication, and an elevation angle error angle detecting device provided on the same plane as the first plane antenna. A second plane antenna, a first error angle detecting means for detecting an error angle in the elevation angle direction from a received wave of the second plane antenna, a third plane antenna for detecting an error angle in the horizontal direction, and A second error angle detecting means for detecting an error angle in the horizontal direction from the received wave of the third plane antenna and a mechanism section for driving the first plane antenna in the elevation direction are placed on a table which rotates in the horizontal direction. Since the third planar antenna is disposed on the table while being fixed in the elevation direction, the first planar antenna, the second planar antenna for detecting the elevation angle error angle, and the horizontal plane are arranged. Direction plane angle detection third plane By providing a dedicated antenna for each tena, fixing the third planar antenna on the table in the elevation direction, and detecting and processing the error angles in the elevation direction and the horizontal direction from the respective antenna outputs, It has a small size, a high speed, a high precision, a simple structure, and is industrially manufactured and adjusted easily.

In the second aspect, since the antenna element in the elevation direction of the third planar antenna is composed of one element, the beam width in the elevation direction is sufficiently wide (about 32 degrees for one element). Even if it is fixed in the elevation direction, it can be sufficiently used in the elevation range from Kyushu to Hokkaido. In claim 3, when the electric wave is cut off, the operation immediately shifts to horizontal tracking,
By providing a gyro that recaptures instantly after the radio wave returns, the inexpensive gyro immediately shifts to gyro tracking in the horizontal angle direction when the radio wave is cut off, so it is possible to recapture at the moment the radio wave returns. ..

Further, in claim 4, a DC servo motor and a servo controller for analog control are provided in which the error angle corresponding voltage detected from the second and third planar antennas is directly inputted as an analog instruction voltage when the radio waves are tracked. This enables high-speed tracking. Further, according to claim 5, at the time of initial capture, the control means is provided to search from the elevation angle immediately before the power is turned off to shorten the initial capture time. Radio waves can be captured.

Further, according to the present invention, since the voltage controlled oscillator and the channel switching circuit that can switch the channel frequency to be tracked are provided, when the tracking channel disappears, such as when the satellite fails. The channel can be changed easily.

[Brief description of drawings]

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

FIG. 2 is a plan view of the main antenna of the above.

FIG. 3 is a plan view of the horizontal angle antenna of the above.

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

5A and 5B are a plan view and a side view of the above tracking antenna device.

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

FIG. 7 is a diagram showing a locus of changes in DC voltage with respect to changes in the error angle in the above.

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

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

[Explanation of symbols]

 31 first planar antenna 32, 33 second planar antenna 34 receiving LNB 35 monopulse LNB unit 36 error angle detection unit 37, 38 third planar antenna 80 table

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaru Hashimoto 1048, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd. (72) Inventor, Yasuhiro Fujii 1048, Kadoma, Kadoma City, Osaka Matsushita Electric Works Co., Ltd.

Claims (6)

[Claims] 1. A first planar antenna for receiving satellite broadcasting or satellite communication, and a second planar antenna for detecting an elevation angle error angle provided on the same plane as this first planar antenna, First error angle detecting means for detecting an error angle in the elevation angle direction from the received wave of the second planar antenna, a third planar antenna for detecting an error angle in the horizontal direction, and a received wave of the third planar antenna. Second error angle detecting means for detecting a more horizontal error angle and a mechanism portion for driving the first planar antenna in the elevation direction are arranged on a table which rotates in the horizontal direction, and the third error angle detecting means is arranged. A tracking antenna device, in which a planar antenna is fixedly disposed on the table in the elevation direction. 2. The tracking antenna device according to claim 1, wherein one antenna element in the elevation direction of the third planar antenna is formed. 3. The tracking antenna device according to claim 1, further comprising a gyro that immediately shifts to horizontal tracking when the radio wave is cut off and instantly reacquires after the radio wave returns. 4. A direct-current servomotor 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 command voltage during radio wave tracking are provided. The tracking antenna device according to claim 1. 5. The tracking antenna device according to claim 1, further comprising a control means for reducing an initial acquisition time by searching from an elevation angle immediately before power-off at the time of initial acquisition. 6. The tracking antenna device according to claim 1, further comprising a voltage control oscillator and a channel switching circuit that can switch a channel frequency to be tracked.