JPH0758853B2 - 3-axis control antenna device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a three-axis control antenna device, and particularly to tracking of a medium-altitude satellite passing through the vicinity of the zenith, which is provided with three axes of an azimuth axis, an elevation axis and an orthogonal elevation axis. The present invention relates to a three-axis control antenna device that can be easily operated.

[Conventional technology]

FIG. 3 (a) of the supporting directions of the omnidirectional antenna
The horizontal elevation axis 5 (E1) on a azimuth swivel that can rotate around a vertically fixed azimuth axis 3 (Az axis) as shown in Fig.
The Az-E1 mount method, in which the antenna is mounted so that the antenna can be rotated from horizontal to zenith about this elevation axis, is structurally most advantageous and is widely used. However, this method has a drawback that the rotational angular velocity around the azimuth axis becomes extremely large when tracking a satellite passing near the zenith. On the other hand, as shown in FIG. 3 (b), a horizontally fixed fixed shaft 20 (X axis) and a movable shaft 21 (Y axis) that rotates around the fixed shaft and is orthogonal to the fixed shaft 20 are provided. The XY mount provided does not hinder the tracking of satellites passing near the zenith, but has problems in tracking low elevation satellites and has a large supporting structure, and is not suitable for large antennas with a large diameter. .

As a method for solving the above problem, as shown in FIG. 3 (c), an orthogonal elevation axis orthogonal to the elevation axis is provided on the Az-E1 mount, and the antenna is limited around this orthogonal elevation axis. Japanese Patent Laid-Open No. 60-22803 proposes a drive control method in which there is a three-axis control antenna device which can be rotated only within the range, and the range of rotation about the orthogonal elevation axis can be reduced. When tracking a satellite passing near the zenith, this method drives the antenna in advance around the azimuth axis before the satellite reaches the maximum elevation angle. The rotatable range can be limited to half or less. FIG. 4 is a diagram showing this state, and FIG. 4 (a) shows the movement of each axis when the antenna starts to be driven around the azimuth axis after the satellite reaches the maximum elevation angle. The movement of each axis when the preceding drive is performed is shown in b). These figures represent the direction of the whole sky in polar coordinate format, and an enlarged view of the vicinity of the zenith. Radially drawn straight lines represent the same azimuth direction, and the center is the zenith direction. Also, each concentric circle represents the same elevation angle direction, and from Az 180 ° direction to Az 360 ° (0
This shows a satellite tracking in the direction of (). The heart-shaped locus in Fig. 4 (a) is a plot of the Az axis angle of the antenna and the E1 angle of the satellite. The tip of the vector written as E1 axis represents the E1 axis angle of the antenna.
The tip of the vector written Cross-E1 ahead of that is the satellite direction. The length of this Cross-E1 vector is Cross
-E1 axis angle is shown, and it is the fourth when the preceding drive is performed.
It can be seen that the length of the Cross-E1 vector in FIG. 6B is less than half that in FIG.

[Problems to be solved by the invention]

However, even with the above-described drive control method, the maximum rotational angular velocity required for rotation around the orthogonal elevation axis is more than the line-of-sight angular velocity of the satellite viewed from the antenna, which will be described later in detail. .

The object of the present invention is to make the antenna have a 90 ° elevation angle about the elevation axis.
(In this specification, the rotation angle display around the depression angle is used as the depression angle to distinguish it from the normal elevation angle, and the state in which the antenna is directed to the zenith when the rotation angle around the orthogonal depression and elevation axis is 0 ° is the depression angle. It is possible to provide a three-axis control antenna device capable of rotating up to about 180 ° beyond 180 °, and limiting the maximum rotation angular velocity about the orthogonal elevation axis to the line-of-sight angular velocity or less.

[Means for solving problems]

The three-axis control antenna device of the present invention comprises an azimuth swivel that can rotate around a vertically fixed azimuth axis, and an elevation that can rotate approximately 180 ° around an elevation axis horizontally provided on the azimuth swivel base. A rotary mount and a directional antenna mounted on the lift mount so that the mount can rotate within a limited angle range compared to the elevation rotation angle that is possible around the orthogonal lift axis that is orthogonal to the elevation axis. For satellites that pass through the zenith region above a certain fixed elevation angle, rotation around the depression / elevation axis is continuously performed over a depression / elevation angle of 90 °, and the azimuth axis is fixed or a predetermined small range. It is configured to rotate and track with.

[Action]

 The present invention will now be described in detail with reference to the drawings.

1 (a) and 1 (b) are vector diagrams showing changes in the rotation angle around the orthogonal elevation axis with respect to a satellite passing near the zenith. Figure 1 (a) shows the case of tracking a satellite that passes through the zenith at an angular velocity of 1.5 ° / sec from the azimuth angle of 0 ° to 180 °, and the black circles in the figure indicate the position of the satellite every second. ing. This satellite uses a conventional three-axis control antenna device whose movable range of depression and elevation is up to about 90 °.
In the case of tracking by the advance drive method described in Japanese Patent Publication No. 3, the azimuth angle becomes 90 ° when the satellite reaches the zenith, so that the maximum angular velocity is 10 ° around the azimuth axis from 9 seconds before reaching the zenith.
The tracking is carried out by driving in advance at / sec, but the loci of the antenna azimuth and elevation angle at this time are broken lines, and the rotation angle around the orthogonal depression and elevation axis is shown by the length of the arrow vector.

The locus shown by the broken line in FIG. 1 (a) corresponds to the locus of the tip of the vector spanning the E1 axis in FIG. Further, FIG. 1 shows a state of tracking a satellite passing from the direction of Az0 ° to the direction of Az180 °, which is opposite to the passing direction of FIG. The vector that was zero (point a) 9 seconds before reaching the zenith became the vector bc 1 second after that, and the length of ac corresponds to the angle of 1.5 ° that the satellite advances in 1 second, and bc> ac It can be seen from the figure that the angular velocity of the vertical and vertical axes is required to be 1.5 ° / sec or more of the angular velocity of the line of sight. In addition, the satellite passes through the zenith 1
Since the vector de seconds before is almost equal to the length of ze, it can be seen that when the satellite passes through the celestial apex, it must be rotated around the orthogonal elevation axis at almost the same speed as the line-of-sight angular velocity.

FIG. 7 shows the change in angle of each axis in the case of the tracking method proposed in Japanese Patent Laid-Open No. 60-22803. The time in FIG. 7 is negative before passing the zenith and zero when passing.

On the other hand, when tracking the same satellite with the three-axis control antenna device of the present invention that can rotate about 180 degrees about the elevation axis, it is a special example, but the azimuth angle is fixed at 0 degree and the orthogonal elevation axis angle is fixed. Is fixed at 0 ° and the elevation angle is 90 only around the elevation axis.
It can be tracked without rotating about the azimuth axis and the orthogonal elevation axis by rotating it beyond °. Next, as a general example, FIG. 1 (b) shows an example in which a satellite passing through a maximum elevation angle of 87 ° in the direction of azimuth angle of 90 ° is tracked by the three-axis control antenna device of the present invention. In the figure, at low elevation angle until azimuth angle reaches 10 °, normal tracking is performed with azimuth axis and depression angle,
When the azimuth angle reaches 10 °, the azimuth angle is fixed and the azimuth is tracked by the elevation and orthogonal elevation axes, and the maximum azimuth is 4 seconds from 2 seconds before the satellite reaches the maximum elevation angle to 2 seconds after it reaches the maximum elevation angle. The figure shows a case in which the azimuth angle is fixed at 5 ° / sec, which corresponds to 1/2 of the angular velocity, in the negative direction, and when the azimuth angle reaches −10 °, the azimuth angle is fixed and tracking is performed again. FIG. 5 shows the angle change of each axis in the case of FIG. 1 (b). The time in FIG. 5 is negative before passing the maximum elevation angle, and zero when passing. As is clear from this figure, the rotation angle around the orthogonal depression / elevation axis (Cross-E1)
Gradually increases, and gradually decreases again when the satellite passes the maximum elevation angle. Therefore, it can be seen that the rotational angular velocity around the orthogonal elevation axis may be smaller than the line-of-sight angular velocity of the satellite.

If the rotation angle around the orthogonal elevation axis is tilted from the time of capturing the satellite, the change in the rotation angle may be slower, and the rotation can be performed mainly by rotation around the elevation axis.
Fig. 6 shows the angle change of each axis when controlling so that the rotation angle around the orthogonal depression / elevation axis is constant. The azimuth angle (Az) is 0 ° and the orthogonal elevation / depression axis angle (Cross-E1) is It is almost fixed at 3 °.

The movement of each axis in FIGS. 5 to 7 is approximate, and in reality, the portion indicated by a straight line is a curve close to a straight line in a strict sense, and the polygonal corners are curved due to the limitation of angular acceleration. Changes to.

As described above, in the three-axis control antenna device of the present invention, the azimuth axis is fixed or fixed for tracking a satellite passing through the zenith above a certain elevation angle by setting the rotatable range about the elevation axis to approximately 180 °. It can be done by rotating within a small range. It is also clear that the maximum angular velocity of rotation about the orthogonal elevation axis can be set smaller than the line-of-sight angular velocity of the satellite.

〔Example〕

2 (a) and 2 (b) show a depression angle 0 of an embodiment of the present invention.
FIG. 3 is a side view in a state of 0 ° and a front view in a state of an elevation angle of 90 °. In FIGS. 2A and 2B, 1 is a support tower fixed to the ground, 2 is a vertical azimuth axis 3 supported by the indicator tower 1.
Azimuth swivel that can rotate about ± 270 ° around 4 is the elevation axis 5 that is installed horizontally on the azimuth swivel 2.
The elevation rotation platform that can rotate 180 ° and can direct the antenna from the horizontal direction to the opposite horizontal direction, 6 is this elevation rotation platform 4
This is an antenna mounted on the above so as to be rotatable ± 5 ° about an orthogonal elevation axis 7 provided orthogonal to the elevation axis 5.
Azimuth turning and elevation rotation are performed via a large gear 8 fixed to the support tower 1 and a semicircular large gear 9 attached to the elevation rotation mount 4, respectively, but rotation around the orthogonal elevation axis is linear. It is performed by a screw jack 10 that expands and contracts.

If the maximum angular velocity for azimuth turning is 10 ° / sec and the maximum angular velocity for elevation / lowering is 5 ° / sec, for satellites with a line-of-sight angular velocity of 1.5 ° / sec, the normal Az −E1
Similar to the case of the mount, it can be tracked without rotation around the orthogonal elevation axis. On the other hand, as for the satellite whose maximum elevation angle exceeds 85 °, it can be tracked by performing elevation / depression rotation of 0 to 180 ° as described above, and the satellite of 80 to 85 ° is described in the above-mentioned JP-A-60-22803. If the tracking method is adopted, the maximum rotational angular velocity about the orthogonal elevation axis is about half of the line-of-sight angular velocity of 0.8 ° / sec, which is sufficient for tracking (Fig. 8 shows JP-A-60-2.
2 is a vector diagram showing a change in rotation angle of a rotation angle around an orthogonal depression / elevation axis when a satellite passing through a maximum elevation angle of 85 ° is tracked by the tracking method described in Japanese Patent No. 2803. It will be easily understood by comparing the length of the vector in this figure with FIG. 1 (a)), and the mechanical design and the design of the drive device have great advantages.

The above embodiment shows the case where the azimuth swivel base is mounted on the support tower fixed to the ground via bearings, but a trapezoidal frame is installed via the wheels on the circular rail on which the azimuth swivel base is laid on the ground. It can also be a structure. Also, the rotatable range around the orthogonal elevation axis is set to ± 5 °, and
Although the example in which the prior drive system described in the publication is adopted is shown, it does not matter even if the prior drive system is not used together with the rotatable range being ± 10 °.

〔The invention's effect〕

As described in detail above, according to the three-axis control antenna device of the present invention, the rotatable range around the orthogonal elevation axis can be limited, the rotational angular velocity can be set lower than the line-of-sight angular velocity of the satellite, and the azimuth axis is fixed. Alternatively, there is an effect that it can be rotated and tracked within a small range, which is advantageous in the design of the structure and the drive device.

In particular, there is a tendency to use a higher frequency for transmitting a lot of information, and the antenna RF beam width becomes sharp, so that high tracking accuracy is required. According to the three-axis control antenna device of the present invention, it is possible to suppress the change in speed during tracking and provide an excellent effect of achieving high tracking accuracy.

[Brief description of drawings]

FIGS. 1 (a) and 1 (b) are vector diagrams showing changes in the rotation angle around the orthogonal elevation axis in the case of tracking a satellite passing near the zenith, and FIGS. 2 (a) and 2 (b) show the present invention. It is a side view and a front view of one example. Figure 3 (a), (b)
And (c) are explanatory views of various antenna supporting methods (mounting methods), and FIGS. 4 (a) and 4 (b) are vector diagrams for explaining the tracking method proposed in JP-A-60-22803,
The figure is an explanatory view of the angle change of each axis at the time of tracking by the method of FIG. 1 (b), and FIG. 6 shows the angle change of each axis when controlling so that the rotation angle around the orthogonal elevation axis is constant. Explanatory diagram, FIG. 7 is an explanatory diagram of the angle change of each axis by the tracking system proposed in Japanese Patent Laid-Open No. 60-22803, and FIG.
With the tracking method proposed in JP 22803, the maximum elevation angle is 8
FIG. 6 is a vector diagram showing a change in rotation angle around a perpendicular depression / elevation axis when tracking a satellite passing through 5 °. DESCRIPTION OF SYMBOLS 1 ... Support tower, 2 ... Azimuth swivel base, 3 ... Azimuth axis, 4 ... Depression rotation platform, 5 ... Depression axis, 6 ... Antenna, 7 ... Orthogonal elevation axis,
8,9… Large gear, 10… Screw jack.

Claims (1)

[Claims] 1. An azimuth revolving base which can rotate around a vertically fixed azimuth axis, and a elevation revolving gantry which is horizontally provided on the azimuth revolving base and which can rotate about 180 ° around an elevation / rear axis. A directional antenna mounted on the elevation / rotation platform so as to be able to rotate within a limited angle range compared to the elevation / rotation angle possible about the orthogonal depression / elevation axis orthogonal to the elevation / depression axis, and a predetermined fixed amount. For satellites that pass through the zenith region above the elevation angle, the rotation around the depression / elevation axis is continuously performed over a depression / elevation angle of 90 °, and the azimuth axis is fixed or rotated within a predetermined small range. A three-axis control antenna device characterized by being tracked.