Patent Grant
7663565
The present invention relates to a pedestal apparatus for stabilizing the attitude of a tracking antenna mounted at a moving object and a satellite antenna having the same; and, more particularly, to a pedestal apparatus having three axes for sustaining the attitude of the satellite antenna mounted at a moving object to face a target satellite although the moving object such as a ship is yawing, rolling or pitching.
An antenna is mounted at a moving object to receive and transmit a signal from and to a satellite. The antenna mounted at the moving object is controlled to track a target satellite while the moving object is moving. Since the antenna is vibrated by the motion of the moving object, the motion of the moving object is compensated to accurately control the antenna.
As conventional technology for compensating the motion of the moving object, a stabilized antenna system was introduced in U.S. Pat. No. 5,359,337. The conventional stabilized antenna system has an X1-Y-X2 mount structure having three axes, an X1 axis, a Y axis, and an X2 axis. The X1 axis is disposed in parallel to the moving direction of a moving object. The Y axis is disposed vertically to the X1 axis and moves with the X1 axis as a center when the X1 axis rotates. The X2 axis is disposed vertically to the Y axis and moves with the Y axis as a center when the Y axis rotates. Herein, the X2 axis is an electronic control axis that changes the directivity of neighbor antenna, compensates roll elements related to the rolling of the moving object by the rotation of X1 axis, and compensates pitch element related to the pitching of the moving object by the rotation of the Y axis and X2 axis.
As another conventional technology, a three-axis pedestal was introduced in U.S. Pat. No. 5,419,521. The conventional three-axis pedestal is suitable for mounting on a moving structure to provide a unit for obtaining rotational stabilization of an antenna about three mutually perpendicular axes. The pedestal includes a spindle unit, a cantilevered structural member, a pair of spaced apart co-axial bearings, a shaft, a structural beam and a structural unit. The centerline of the spindle unit defines a first pivot axis, and the spindle unit is rigidly attached to the moving structure. The cantilevered structural member includes one end mounted for pivoting motion about the first pivot axis of the spindle unit. The pair of spaced apart co-axial bearings is mounted on the other end of the cantilevered member so that the centerlines thereof define a second pivot axis perpendicular to and intersecting the first pivot axis. The bearings are located on the cantilevered member close to an upward extension of the first axis. The shaft is mounted in the pair of bearings for pivot motion about said second pivot axis. The structural beam is rigidly attached to the shaft. The beam carries a journal at each end thereof so that the centerlines of the journals define a third pivot axis. The third axis is perpendicular to the second pivot axis and nominally intersected the intersection point of the first and second pivot axes. The structural unit is mounted for pivot motion about said third pivot axis. The structural unit is rigidly attached to and supports the object for orbital motion about the common intersection point of each of the first, second and third axes.
However, the conventional pedestal apparatuses are not suitable for a moving object having a wide moving range. Also, it is not easy to control for stabilizing the attitude of a satellite tracking antenna, and it requests a high manufacturing cost.
It is, therefore, an object of the present invention to provide a pedestal apparatus, which is suitable for a moving object having a wide moving range, easily controlled for stabilizing the attitude of a satellite tracking antenna, requires a less manufacturing cost, has a durable structure and the structure of easy maintenance, and a satellite antenna having the same.
In accordance with one aspect of the present invention, there is provided a pedestal apparatus for stabilizing an attitude of a tracking antenna mounted at a moving object, the pedestal apparatus including: a fixing unit rigidly fixed at the moving object; a connecting unit disposed inside the fixing unit for forming a first rotating axis vertically to a surface of the fixing unit that is fixed at the moving object; a first rotation supporting unit having a bottom supporting member fixed at the fixing unit and a Y-shaped top supporting member bifurcated to two tines for rotating the tracking antenna around the first rotating axis; a second connecting unit connected to ends of two tines of the Y-shaped top supporting member for forming a second rotating axis; a second rotation supporting unit having both ends connected to the both ends of the second connecting unit for rotating the tracking antenna around the second rotating axis; a third connecting unit for forming a third rotating axis at a center of the second rotation supporting unit; and a supporting unit connected to the third connecting unit in a predetermined shape for supporting the tracking antenna, wherein the first, second and third rotating axes are not crossed one another.
In accordance with another aspect of the present invention, there is provided a satellite antenna mounted at a moving object, the antenna including: a radome for protecting the satellite antenna having a pedestal apparatus from an external environment; a vibration attenuating unit disposed at an outer bottom surface of the radome for absorbing vibration made by the moving object; and a pole connected to the moving object by being connected to the vibration attenuating unit, wherein the pedestal apparatus includes: a fixing unit rigidly fixed at the moving object; a connecting unit disposed inside the fixing unit for forming a first rotating axis vertically to a surface of the fixing unit that is fixed at the moving object; a first rotation supporting unit having a bottom supporting member fixed at the fixing unit and a Y-shaped top supporting member bifurcated to two tines for rotating the tracking antenna around the first rotating axis; a second connecting unit connected to ends of two tines of the Y-shaped top supporting member for forming a second rotating axis; a second rotation supporting unit having both ends connected to the both ends of the second connecting unit for rotating the tracking antenna around the second rotating axis; a third connecting unit for forming a third rotating axis at a center of the second rotation supporting unit; and a supporting unit connected to the third connecting unit in a predetermined shape for supporting the tracking antenna, wherein the first, second and third rotating axes are not crossed one another.
A pedestal apparatus and a satellite tracking antenna having the same in accordance with the present invention have following advantages.
The three-axis pedestal apparatus according to the present invention can stabilize the tracking antenna mounted at a moving object although the moving object is yawing, rolling and pitching.
By disposing a vibration attenuating unit between a radome and a pole connected to the moving object, the size of the radome is minimized, a manufacturing cost thereof is reduced and easy maintenance is allowed.
Furthermore, by disposing a driving unit at a sensor cage for an additional rotating axis, the sensor cage is enabled to constantly maintain a horizontal level although the target direction of the satellite tracking antenna is changed.
The above and other objects and features of the present invention will become apparent from the following description of the preferred embodiments given in conjunction with the accompanying drawings, in which:
Other objects and aspects of the invention will become apparent from the following description of the embodiments with reference to the accompanying drawings, which is set forth hereinafter.
As shown in
The first, second, and third rotating axes 130, 131 and 132 are not crossed one another when the extension line of the first rotating axis 130 is formed to be disposed at a center area of a rotating structure connected to the first rotating axis 130 in order not to cross with the extension lines of the second and the third rotating axes 131 and 132.
Meanwhile, the supporting unit includes a predetermined shaped first supporting member 115 connected to the third connecting unit 114, second supporting members 116 and 117 each of which is extended from the both ends of the first supporting member 115 for supporting the reflector antenna 120, and third supporting members 118 and 119 for holding the second supporting members 116 and 117 not to be separated.
Also, a supporting plate 107 is disposed at the bottom supporting member 106. Modules 108 and 109 such as an RF module or a power source module may be disposed at the supporting plate 107.
Furthermore, the centers of gravity of the rotating axes 130, 131 and 132 are present at corresponding rotating axes 130, 131 and 132, respectively, in the tracking antenna having the pedestal apparatus according to the present embodiment. That is, the centers of gravity for the antenna elements 105 to 120 which rotate around the first rotating axis 130 are present on the first rotating axis 130, the centers of gravity of the antenna elements 111 to 120 which rotate around the second rotating axis 131 are present on the second rotating axis 131, and the centers of gravity of the antenna elements 115 to 120 which rotate around the third rotating axis 132 are present on the third rotating axis 132.
Meanwhile,
The tracking antenna having the pedestal apparatus includes a radome including a top cover 103 and a bottom cover 102 to protect the tracking antenna from an external environment. A vibration attenuating unit 101 is disposed at the outer surface of the bottom cover 102 of the radome to absorb the vibration made by the moving object. The vibration attenuating unit 101 may be connected to a pole 100 connected to the moving object.
The pedestal apparatus according to the present embodiment further includes a sensor cage 142. The sensor cage includes a clinometer, an angle speedometer and an azimuth angle compass for measuring the motion of the tracking antenna made by yawing, rolling an pitching motion of the moving object in order to stabilize the attitude of the tracking antenna. The clinometer measures the angles of the rolling and pitching motion made by the tracking antenna. The angle speedometer measures the angle speed of yawing, rolling and pitching motion made by the tracking antenna. The azimuth angle compass measures an azimuth angle that the tracking antenna directs. The measurements from the clinometer, the angle speedometer and the azimuth angle compass are used to a control process for stabilizing the attitude of the tracking antenna.
Also, the sensor cage 142 is connected to a supporting unit supporting the tracking antenna and provides an additional elevation angle rotating axis 140 in parallel to the elevation angle rotating axis 131 of the pedestal apparatus. That is, the sensor cage 142 has a structure allowing itself to rotate around the additional elevation angle rotating axis 140. Furthermore, the sensor cage 142 includes a driving unit 144 for allowing the sensor cage 142 to rotate around the additional elevation angle rotating axis 140. The driving unit 144 includes a rod 143 for supporting the sensor cage 142 rotatably to the elevation angle rotating axis 140, a driven pulley 145 connected to the one end of the rod 143, a driving pulley 147 connected to a driving motor M and rotated by receiving power from the driving motor M, and a belt 146 for connecting the driving pulley 147 and the driven pulley 145 in order to transfer the rotating power of the driving pulley 147 to the driven pulley 145.
As shown in
The present application contains subject matter related to Korean patent application No. 2005-0099127, filed in the Korean Intellectual Property Office on Oct. 20, 2005, the entire contents of which is incorporated herein by reference.
While the present invention has been described with respect to certain preferred embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2005-0099127 | Oct 2005 | KR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/KR2006/003801 | 9/25/2006 | WO | 00 | 4/18/2008 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2007/046589 | 4/26/2007 | WO | A |
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| Number | Date | Country |
|---|---|---|
| 55-001781 | Jan 1980 | JP |
| 2002-0054179 | Jul 2002 | KR |
| 2004-0069685 | Aug 2004 | KR |
| Number | Date | Country | |
|---|---|---|---|
| 20080258988 A1 | Oct 2008 | US |
