JP2842963B2 - Mobile 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 mobile antenna device mounted on a mobile body for satellite communication, satellite broadcasting, and the like.

[0002]

2. Description of the Related Art In order to perform satellite communication, satellite broadcasting, and the like,
An antenna device for capturing the satellite is required. For example, in a maritime satellite communication system, a ship earth station is configured using an antenna device that is controlled to always capture a satellite.

[0003] Further, when an antenna device for satellite communication and satellite broadcasting is mounted on a mobile body, it is necessary to always be able to capture the satellite irrespective of the swing of the mobile body. This operation, that is, swing compensation, is realized by driving a plurality of mechanical axes constituting the antenna device or by switching the beam position of the array antenna.

FIG. 3 shows various configurations of a conventionally known antenna mount. The direction of the beam of the antenna is indicated by an arrow in the figure, and the beam direction can be controlled by rotating the antenna about each axis shown in the figure.

Among these mounts, FIG. 3A shows a so-called Az-El mount, and FIG.
3 shows an XY mount, FIG. 3C shows an X-Az-El mount, and FIG. 3D shows an XY-Az-El mount. Az is the axis that rotates the antenna around the azimuth, El is the axis that rotates the antenna around the elevation, X is the axis that rotates the antenna around the bow, for example, Y is the axis that rotates the antenna around the direction orthogonal to X. is there.

Among these mounts, the XY-Az-El mount shown in FIG. 3D is suitable for swing compensation. This mount can realize a swing compensation accuracy of about 1 to 2 degrees which is better than other mounts.

[0007]

However, XY-Az
-The El mount has a four-axis configuration, has a complicated axis configuration, and is not easily designed mechanically. In addition, the size and cost of the apparatus are increased.

An object of the present invention is to solve such a problem, and an object of the present invention is to realize good swing compensation accuracy with a smaller number of shafts.

[0009]

In order to achieve such an object, the present invention provides an antenna, a mechanical Az axis,
Trapezoidal rotating part rotatable about the Az axis of
Support pillars that are erected diagonally upward from
Supported by the antenna and rotatable around it
A mount having a supporting mechanical El axis;
In a mobile object antenna device mounted on a mobile object, A
The position of the center line of the El axis as viewed from the center line of the z axis
Position that is shifted to the opposite side from the standing position of the support column
The support column and the El axis are arranged, and the center line of the El axis is
The radius of the trajectory drawn by the top of the antenna with the rotation around the center
However, it is larger than the radius of the locus drawn by the lower end of the antenna
The antenna is supported by the axis of the antenna El .

According to a second aspect of the present invention, the antenna and its peripheral members are arranged and the posture of the supporting column is set so that the center of gravity of the device is on the center line of the Az axis.

According to a third aspect of the present invention, the antenna and its peripheral members are arranged so as to maintain a weight balance around the El axis.

[0012]

According to the present invention, the antenna is supported forward by the support column. Accordingly, the driving range around the elevation angle of the antenna is expanded, and the beam direction of the antenna can be changed from below the horizontal plane to the elevation angle exceeding the zenith. Thus, gimbal lock can be prevented with a small number of axes, and pointing error can be reduced. In particular, swing compensation at a low elevation angle can be suitably realized. Further, since the antenna is biased supported above, the antenna and the device lower part of the member is Ru to <br/> rather kuna conflict.

According to a second aspect of the present invention, the arrangement of the antenna and its peripheral members and the setting of the posture of the support column allow for
The center of gravity of the device is set on the center line of the Az axis. As a result, driving of the Az axis is facilitated, and a small motor can be used.

In the third aspect, the antenna and its peripheral members are arranged so that the weight balance around the El axis is maintained. As a result, the driving of the El axis becomes easy, and a small motor can be used.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the actual configuration of a mobile antenna apparatus according to an embodiment of the present invention. In this figure, (a) is a front view, and (b) is a side view.

In this embodiment, the mount is Az-E
lMount. That is, an Az axis 12 and an El axis 14 are provided as axes for rotating the antenna 10. The Az axis 12 moves the antenna 10 around the azimuth,
The l-axis 14 is an axis for rotating around an elevation angle.

The Az axis 12 is connected to an Az axis motor 16 by a belt 18. Therefore, the Az axis motor 1
When the 6 rotates, the rotating unit 20 to which the Az-axis motor 16 is fixed rotates around the Az-axis 12, and accordingly, the antenna 10 also rotates around the Az-axis 12. Similarly, El
The shaft 14 is connected to an El-axis motor 22 by a belt 24. When the El-axis motor 22 rotates, the El-axis 14 rotates, and the antenna 10 to which the El-axis 14 is fixed is mounted.
Also rotate. The rotation angle of the Az axis 12 is detected by the Az axis angle detector 26, and the rotation angle of the El axis 14 is detected by the El axis angle detector 28, and is servo-controlled as described later. The Az axis angle detector 26 has a configuration having a rotation stopper.

The El-axis motor 22 is fixed to a support column 30 that extends obliquely above the rotating section 20. The support column 30 has such a length and inclination that the position of the El axis 14 protrudes forward by a small distance Δl from the center line of the Az axis 12. This distance Δl is determined by the antenna 10
The setting is made so as not to compete with, or block, the rotating unit 20 when rotating about the axis 14. Further, the support column 30
Is set to be behind the center line of the Az axis 12.

An antenna support 32 and an RF unit 34 are arranged around the El axis 14 in addition to the antenna 10. The RF unit 34 is a circuit for amplifying the reception output of the antenna 10 configured as a planar antenna with low noise. The antenna support 32 functions as a weight for maintaining a weight balance around the El axis 14. Further, the antenna 10 is displaced upward in the figure by Δl with respect to the El axis 14. As a result, competition and blocking between the antenna 10 and the rotating unit 20 are reduced, and a radome (cover of the entire apparatus) not shown is also reduced. Further, the antenna 10, the antenna support 32, and the RF unit 34 are arranged so as to balance with the center of gravity of the support column 30, that is, such that the center of gravity of the entire antenna device is on the center line of the Az axis 12.

A control section for servo-controlling the attitude of the antenna 10 by driving the Az-axis motor 16 and the El-axis motor 22 is disposed on a support column 30 (not shown). Becomes Power is supplied to each member from the power supply unit 36. The support column 30 includes the rotating unit 20.
Is separable from

As described above, according to this embodiment, the support column 3
Since 0 is tilted forward and Δl is set appropriately, each member can be arranged so that the center of gravity of the apparatus is on the Az axis 12, and A
The z-axis motor 16 can be downsized. Further, since the weight balance around the El axis 14 is ensured, the El axis motor 2
2 can also be miniaturized. Further, since the support column 30 is tilted forward and the antenna 10 is moved upward by Δl,
Mechanical conflict i.e. <br/> blocking the antenna 10 and the member on the rotating portion 20 can proof Gukoto.

Further, in this embodiment, the rotation range of the antenna 10 in the elevation direction can be expanded. For example, the beam direction of the antenna 10 can be the direction of −20 ° with respect to the horizontal plane at the lowest elevation angle, and can be 55 ° beyond the zenith on the high elevation angle side. Therefore, Az-E
The problem of gimbal lock and the problem of pointing error generally occurring in the l-mount can be reduced, and more suitable swing compensation can be realized.

When the antenna 10 is configured as a phased array antenna capable of switching the beam position around an axis (cross El axis) orthogonal to the El axis 14, errors near the time difference point (zenith direction) are more preferable. Can be reduced to

FIG. 2 is a schematic block diagram showing a circuit configuration when such a phased array antenna is used as the antenna 10. The circuit shown in the figure includes an antenna 10, a mechanical axis driving unit 38, an azimuth / elevation angle input unit 40,
It comprises a control amount calculation unit 42, a swing detection unit 44, and an antenna output processing unit 46.

Among them, the mechanical axis driving section 38 includes the Az axis motor 16 and the El axis motor 22, the Az axis angle detector 26 and the El axis angle
This is a configuration including means for controlling the axis motor 16 and the El axis motor 22. That is, the control target of the attitude of the antenna 10 is input (AZ and EL in the figure), and the Az axis angle detector 2
The Az-axis motor 16 and the El-axis motor 22 are controlled so that the attitude of the antenna 10 matches the control target while applying servo using the outputs of the 6 and El-axis angle detectors 28.

The control targets are the azimuth / elevation angle input unit 4
0 and the control amount calculation unit 42. The control amount calculation unit 42 inputs the elevation angle and the relative azimuth of the satellite to be tracked from the azimuth / elevation angle input unit 40, and provides the control target of the El axis 14 to the mechanical axis drive unit 38 based on these. at the same time,
The control amount calculation unit 42 controls the cross El
Give control target around axis. This is given as a signal for controlling the phase shifter of the antenna 10. Azimuth / elevation angle input unit 4
0, while inputting the azimuth of the moving object on which the antenna is mounted from a device such as a gyro compass, searches for the elevation angle and relative azimuth of the satellite while monitoring the carrier detection signal (CD), and raises the elevation angle of the satellite to be tracked. And the relative bearing. Further, a step track of the elevation angle and the azimuth is executed. The relative azimuth of the satellite obtained by the azimuth / elevation angle input unit 40 can be used as a control target of the Az axis 12 as it is.

The antenna output processing unit 46 includes the antenna 10
Is a circuit for processing the output of the RF unit 3 shown in FIG.
4 etc. are included. The antenna output processing unit 46 detects the presence or absence of a carrier in the output of the antenna 10 and outputs a CD. In addition, a small angle having a sign (+/-) for increasing the reception level of the antenna 10 is output for the step track.

The swing detecting means 44 detects a swing applied to the moving body, for example, a pitch and a roll in the case of a ship, and supplies them to the control amount calculating section 42. The control amount calculation unit 42 appropriately corrects and sets the control target of the attitude and the beam position of the antenna 10 according to the detected swing amount, and controls the control amount so that the antenna 10 appropriately tracks the satellite despite the swing. Is calculated.

The present invention is not limited to such a circuit configuration.

[0031]

As described above, according to the present invention,
By supporting the antenna forward by the support column, the driving range around the elevation angle of the antenna is widened, and the pointing error can be reduced with a small number of axes. In particular, swing compensation at a low elevation angle can be suitably realized. Further, since the antenna is biased supported above, the antenna and the device lower part of the member is less likely to conflict.

According to the second aspect, the center of gravity of the device is A
Since the setting is made on the center line of the z-axis, the driving of the Az-axis is facilitated, and a small motor can be used.

According to the third aspect, since the weight balance around the El axis is maintained, the driving of the El axis is facilitated and a small motor can be used.

[Brief description of the drawings]

1A and 1B are a front view and a side view showing a configuration of an antenna device for a mobile object according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a circuit configuration according to the embodiment.

FIG. 3 is a diagram showing a general antenna mount.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Antenna 12 Az axis 14 El axis 16 Az axis motor 22 El axis motor 26 Az axis angle detector 28 El axis angle detector 30 Support column 32 Antenna support 34 RF part

Continuation of the front page (56) References JP-A-2-94801 (JP, A) JP-A-60-163504 (JP, A) JP-A-62-64007 (JP, U)

Claims (3)

(57) [Claims] 1. An antenna, a mechanical Az axis, and an Az axis
A trapezoidal rotating part that can rotate around an axis,
Support pillars that stand upward and
To support the antenna rotatably around it.
And a mount having a mechanical El axis, wherein the position of the center line of the El axis is a rotating part when viewed from the center line of the Az axis.
At the position opposite to the standing position of the support column at
The supporting column and the El axis are arranged so that the antenna is rotated above the center line of the El axis.
The radius of the locus drawn by the end is half of the locus drawn by the lower end of the antenna.
An antenna device for a mobile object, wherein an antenna is supported on an El axis so as to be larger than a diameter . 2. The mobile antenna device according to claim 1, wherein the antenna and its peripheral members are arranged and the posture of the supporting column is set such that the center of gravity of the device is on the center line of the Az axis. Mobile device antenna device. 3. The antenna device for a mobile object according to claim 1, wherein the antenna and its peripheral members are arranged so as to maintain a weight balance around the El axis.