Patent Description:
Devices for transmitting and receiving radio waves through antennas are known in the relevant area. A typical device is configured to have an azimuth axis (AZ axis) that substantially coincides with a zenith line joining the device provided on a reference plane with a zenith. While an antenna of this device tracks an object (e.g., satellite) that transmits and receives radio waves on a field of view FOV, the antenna needs to rotate relatively rapidly when an orientation axis thereof is in a region close to the zenith, rather than when in the other regions within the field of view. Accordingly, a relatively large capacity of power source is required to control the rotation velocity of the antenna while the orientation axis of the antenna is in a region close to the zenith. This phenomenon occurs when the azimuth axis coincides with the zenith line and is generally called the keyhole effect. In consideration of the foregoing, various types of devices are being developed to use a relatively small capacity of power source. For example, a pedestal for tracking an antenna is disclosed in <CIT>. The pedestal disclosed in the publication is configured to be capable of three-axis driving for stabilizing the pointing of a mobile antenna. Such a three-axis driving pedestal requires a complex structure to implement high degrees of freedom.

<CIT> and <CIT> and <CIT>, which belongs to the state of the art under Article <NUM>(<NUM>) EPC, disclose pedestals with inclined azimuth axes.

<CIT> and <CIT> disclose supporters with inclined rotation axes.

An aspect provides a pedestal configured to use a relatively small capacity of power source through a simple structure while stably tracking a target that transmits and receives radio waves and to use a small capacity of power source at the same time removing a section showing a sharp rise of a drive velocity in a region within a field of view through a structure for avoiding the keyhole effect.

According to an aspect, there is provided a pedestal including a supporter having an azimuth axis and a pivot on the azimuth axis, and a tracker connected to the pivot and configured to track an object within a field of view, wherein the azimuth axis is tilted with respect to a reference plane on which the supporter is installed in a direction away from a zenith line joining the pivot with a zenith within the field of view, and a tilt angle between the azimuth axis and the reference plane is set to correspond to an orbital angle of the object, wherein the supporter includes a first supporter installed on the reference plane and having an inclined surface that is inclined with respect to the reference plane, and a second supporter installed on the inclined surface and having the azimuth axis and the pivot.

The tracker has an orientation axis, where the tilt angle may be set such that a singularity point at which the orientation axis of the tracker coincides with the azimuth axis is present in a vicinity of the field of view or outside the field of view.

The supporter may have a fixed rotation with respect to the reference plane.

The tracker may be configured to rotate independently with respect to each of the azimuth axis and the pivot.

The pedestal may further include a cable connecting the first supporter and the tracker, where space may be provided between the first supporter and the tracker to sufficiently receive the cable so as to prevent interference between the cable and the tracker and a twist of the cable while the tracker rotates with respect to the pivot.

The cable may be placed on a same side of the tracker and the first supporter.

The cable may be prevented from wrapping while the tracker rotates with respect to the pivot.

The cable may have a slack configuration while the tracker rotates with respect to the pivot in a first direction, and have a taut configuration while the tracker rotates with respect to the pivot in a second direction which is opposite to the first direction.

According to example embodiments, a pedestal may have an azimuth axis that is tilted to the outside of a determined field of view and thus, prevent the keyhole effect while being driven within the field of view.

According to example embodiments, a pedestal may be configured to require no rapid adjustment of a rotation velocity of an antenna while an orientation axis thereof passes through a region close to a zenith.

According to example embodiments, a pedestal may require relatively low power to rotate an antenna and thus, reduce a capacity of a power source that is used.

According to example embodiments, a pedestal may be configured in a relatively simple structure to lower the overall weight.

The effects of the pedestal are not limited to the above-mentioned effects, and other unmentioned effects can be clearly understood from the above description by those having ordinary skill in the technical field to which the present disclosure pertains.

Hereinafter, example embodiments will be described in detail with reference to the illustrative drawings. Regarding the reference numerals assigned to the components in the drawings, it should be noted that the same components will be designated by the same reference numerals, wherever possible, even though they are shown in different drawings. Further, in the following description of the present example embodiments, a detailed description of publicly known configurations or functions incorporated herein will be omitted when it is determined that the detailed description obscures the subject matters of the present example embodiments.

In addition, the terms first, second, A, B, (a), and (b) may be used to describe constituent elements of the example embodiments. These terms are used only for the purpose of discriminating one constituent element from another constituent element, and the nature, the sequences, or the orders of the constituent elements are not limited by the terms. When one constituent element is described as being "connected", "coupled", or "attached" to another constituent element, it should be understood that one constituent element can be connected or attached directly to another constituent element, and an intervening constituent element can also be "connected", "coupled", or "attached" to the constituent elements.

The constituent element, which has the same common function as the constituent element included in any one example embodiment, will be described by using the same name in other example embodiments. Unless disclosed to the contrary, the configuration disclosed in any one example embodiment may be applied to other example embodiments, and the specific description of the repeated configuration will be omitted.

<FIG> schematically illustrates an example of the use of a pedestal according to an example embodiment.

Referring to <FIG>, a pedestal <NUM> according to an example embodiment operates to have an orientation axis OT track an object O on a system <NUM> where the pedestal <NUM> is used. Here, the object O may include, for example, an artificial satellite that transmits and receives radio waves.

The pedestal <NUM> has an elevational axis EL, which is a main axis, and a tilted azimuth axis TAZ, where the orientation axis OT of the pedestal <NUM> is configured to rotate independently with respect to the elevational axis EL and the tilted azimuth axis TAZ.

A field of view FOV refers to a working range in which the orientation axis OT of the pedestal <NUM> may track the object O. The field of view FOV is determined based on a range of rotation of the orientation axis OT with respect to the elevational axis EL and the tilted azimuth axis TAZ. For example, the field of view FOV may generally have a conical shape about the position of the pedestal <NUM>.

A zenith ZP refers to a point at which an extension line perpendicular to a reference plane GD on which the pedestal <NUM> is installed meets the field of view. Here, the extension line perpendicular to the reference plane GD is defined as a zenith line ZL.

The object O moves along a set orbit on the field of view FOV. Here, an orbital plane including the orbit of the object O and a reference point on the reference plane GD on which the pedestal <NUM> is positioned is defined. An orbital angle is defined as an angle θ formed by the orbital plane and a vertical plane VP that passes through the zenith ZP and is perpendicular to the reference plane GD. A tilt angle of the tilted azimuth axis TAZ with respect to the reference plane GD is set to correspond to the orbital angle so as to stably track the object O within the field of view FOV.

<FIG> is a conceptual diagram to describe a singularity point of a pedestal according to an example embodiment.

Referring to <FIG>, the pedestal <NUM> according to an example embodiment may include a tracker <NUM> having an orientation axis OT that tracks an object. The tracker <NUM> may rotate with respect to the elevational axis EL about the pivot, and rotate with respect to the tilted azimuth axis TAZ independently from the rotation with respect to the elevational axis.

The singularity point SP is defined as a point on a celestial body on which the orientation axis OT of the tracker <NUM> coincides with the tilted azimuth axis TAZ. While an object O passes through a region in the vicinity of the singularity point SP, a radical change in the rotation direction and/or the rotation velocity of the tracker <NUM> that tracks the object O, the so-called keyhole effect, may occur. In this case, a power source needs to have a large capacity to drive the tracker <NUM> having the rotation direction and/or the rotation velocity that changes rapidly, and a large structural rigidness of the pedestal <NUM> may be required accordingly to support the large-capacity power source. Thus, the singularity point SP may not be present at the center of the field of view where an object O is mainly tracked, but in the vicinity of the field of view or preferably outside the field of view.

<FIG> are conceptual diagrams to describe a relationship between a size of a field of view and a tilt angle and a positional change of a singularity point with respect to a change in the tilt angle, the tilt angle of an azimuth axis of a pedestal with respect to a reference plane on which the pedestal is installed, according to an example embodiment.

Referring to <FIG>, a conventional pedestal 10a may have an azimuth axis AZ that is perpendicular to a reference plane GD and coincides with a zenith line ZL. In this example embodiment, a singularity point SP may be positioned on the zenith line ZL. When an object being tracked by the tracker <NUM> passes through the singularity point SP, the rotation direction and/or the rotation velocity of the tracker <NUM> may change radically in the vicinity of the singularity point SP based on the azimuth axis AZ.

Referring to <FIG>, pedestals 10b, 10c, 10d, and 10e according to example embodiments may have azimuth axes AZs that are tilted with respect to the reference plane GD about <NUM> degrees, about <NUM> degrees, about <NUM> degrees, and about <NUM> degrees, respectively. Sequentially from the example embodiment of <FIG> to the example embodiment of <FIG>, the singularity point SP positioned on the tilted azimuth axis TAZ is further away from the zenith line ZL, and the size of the field of view FOV further increases.

The pedestals 10b, 10c, 10d, and 10e having the tilted azimuth axes TAZs of which the tilt angles with respect to the reference plane GD are greater than <NUM> degrees may be less likely to experience the keyhole effect within the field of view FOV than the pedestal 10a having the azimuth axis AZ that coincides with the zenith line ZL, operate using a relatively small capacity of a power source in terms of driving efficiency, and require a reduced structural rigidness to support the power source.

<FIG> is a perspective view schematically illustrating a structure of a pedestal according to an example embodiment, and <FIG> is an exploded perspective view schematically illustrating the structure of the pedestal of <FIG>.

Referring to <FIG> and <FIG>, the pedestal <NUM> according to an example embodiment may include a first supporter <NUM>, a second supporter <NUM>, and the tracker <NUM>. In this example embodiment, the second supporter <NUM> is configured to have a tilted azimuth axis TAZ of about <NUM> degrees with respect to a reference plane on which the first supporter <NUM> is installed.

The first supporter <NUM> is installed on the reference plane and configured to support the second supporter <NUM> and the tracker <NUM>. The first supporter <NUM> may include a first frame <NUM> having an inclined surface on which the second supporter <NUM> is installed and a first driver <NUM> positioned opposite to the second supporter <NUM> based on the inclined surface of the first frame <NUM> and coupled to a bearing assembly <NUM> of the second supporter <NUM>. A drive shaft of the first driver <NUM> coincides with the tilted azimuth axis TAZ of the pedestal <NUM>. The second supporter <NUM> is configured to rotate with respect to the tilted azimuth axis TAZ in response to the drive of the first driver <NUM>.

The second supporter <NUM> is installed on the first supporter <NUM> and configured to support the tracker <NUM>. The second supporter <NUM> is configured to rotate with respect to the drive shaft of the first driver <NUM>, that is, the tilted azimuth axis TAZ of the pedestal <NUM>. The second supporter <NUM> may include a second frame <NUM>, a second driver <NUM>, a first balancer <NUM>, nuts 128a and 128b, and the bearing assembly <NUM>.

The second frame <NUM> may include a first arm <NUM> and a second arm <NUM>. The first arm <NUM> may extend in a first direction to enclose the tracker <NUM>, and the second arm <NUM> may extend in a second direction to enclose the tracker <NUM>. The first arm <NUM> and the second arm <NUM> may be positioned opposite to each other based on the tracker <NUM>. A proximal portion of the first arm <NUM> and a proximal portion of the second arm <NUM> may be coupled to each other. The bearing assembly <NUM> may be installed provided in the proximal portion of the first arm <NUM> and the proximal portion of the second arm <NUM> that are coupled to each other. A first slot <NUM> may be formed in the extension direction of the first arm <NUM> at an end portion of the first arm <NUM>, and a second slot <NUM> may be formed in the extension direction of the second arm <NUM> at an end portion of the second arm <NUM>.

The second driver <NUM> may be coupled to the second frame <NUM> and the tracker <NUM> so that a drive shaft thereof coincides with the elevational axis EL. In a detailed example embodiment, the drive shaft of the second driver <NUM> may pass through the first nut 128a, be inserted into the first slot <NUM> at the end portion of the first arm <NUM> such that the first nut 128a is positioned between the second driver <NUM> and the first arm <NUM>, and be coupled to a first shaft <NUM> provided in a third frame <NUM> of the tracker <NUM>.

The first balancer <NUM> may be positioned opposite to the second driver <NUM> based on the second frame <NUM> in consideration of the weight of the second driver <NUM>. In a detailed example embodiment, the first balancer <NUM> may be coupled to the end portion of the second arm <NUM> such that the second nut 128b is positioned between the first balancer <NUM> and the second arm <NUM>.

Alternatively, the second driver <NUM> may be inserted into the second slot <NUM> provided at the end portion of the second arm <NUM> and coupled to a second shaft <NUM> provided in the third frame <NUM> of the tracker <NUM>, where the second shaft <NUM> is positioned opposite to the first shaft <NUM> based on the third frame. In this example embodiment, the first balancer <NUM> may be coupled to the end portion of the first arm <NUM>.

The bearing assembly <NUM> may be installed in the proximal portion of the first arm <NUM> and the proximal portion of the second arm <NUM> and coupled to the drive shaft of the first driver <NUM>. In the example embodiment shown, an inner race of the bearing assembly <NUM> is fixed, while an outer race thereof is configured to rotate. In an alternative example embodiment not shown, the inner race of the bearing assembly <NUM> rotates, while the outer race thereof is fixed.

The tracker <NUM> is configured to track an object (e.g., satellite) on the field of view. The tracker <NUM> may include a reflecting body <NUM>, a feed horn <NUM> positioned at the center of the reflecting body <NUM>, a transmitting/receiving device <NUM> communicating radio wave information with the feed horn <NUM>, the third frame <NUM> installed on a rear surface of the reflecting body <NUM>, a fourth frame <NUM> coupled to the third frame <NUM> and configured to enclose the transmitting/receiving device <NUM> along with the third frame <NUM>, and a second balancer <NUM> positioned opposite to the reflecting body <NUM> based on the transmitting/receiving device <NUM>. The weight of the second balancer <NUM> may be set in consideration of the weight of the transmitting/receiving device <NUM> and the weight of the fourth frame <NUM>.

The third frame <NUM> and the fourth frame <NUM> may each include arms extending in both directions, where end portions of the arms of the third frame <NUM> may be coupled to corresponding end portions of the arms of the fourth frame <NUM>, respectively. The first shaft <NUM> and the second shaft <NUM> to which the second driver <NUM> is to be coupled may be installed respectively in the end portion of the arm of the third frame <NUM> and the end portion of the arm of the fourth frame <NUM> that are coupled to each other. The reflecting body <NUM> of the tracker <NUM> may be configured to rotate with respect to the elevational axis EL in response to the operation of the second driver <NUM> coupled to the first shaft <NUM> or the second shaft <NUM>.

In one example embodiment, the first supporter <NUM> may have a fixed rotation with respect to the reference plane. In this example embodiment, the pedestal <NUM> does not rotate against an axis perpendicular to the reference plane. The pedestal <NUM> according to this example embodiment follows a dual-axis drive method where the tracker <NUM> rotates independently with respect to two axes, the elevational axis EL and the tilted azimuth axis TAZ.

<FIG> is a side view schematically illustrating a configuration of a cable connecting a supporter and a tracker in a pedestal according to an example embodiment, <FIG> is a side view schematically illustrating a configuration of the cable when the tracker in the pedestal rotates in a direction toward a reference plane according to an example embodiment, and <FIG> is a side view schematically illustrating a configuration of the cable when the tracker in the pedestal rotates in a direction away from the reference plane according to an example embodiment.

Referring to <FIG>, the pedestal <NUM> according to an example embodiment may further include a cable <NUM> connecting the first supporter <NUM> and the tracker <NUM>. Ends of the cable <NUM> may be clamped to the first supporter <NUM> and the tracker <NUM>. In this example embodiment, the cable <NUM> may be positioned in a slack configuration in space between the first supporter <NUM> and the tracker <NUM> so as to prevent a twist of the cable <NUM> itself and interference resulting from the operation of the tracker <NUM>. In a preferable example embodiment, the cable <NUM> may be placed on the same side (for example, on the left side when viewed based on <FIG>) of the first supporter <NUM> and the tracker <NUM>.

In an example, the cable <NUM> may include a cable. In an example, the cable <NUM> may have any suitable length to maintain the slack configuration. In an example, the cable <NUM> may include any suitable elastic material.

Referring to <FIG>, when the tracker <NUM> rotates downward about the elevational axis EL, the cable <NUM> may maintain a substantially slack configuration not to be twisted. Referring to <FIG>, when the tracker <NUM> rotates upward about the elevational axis EL, the cable <NUM> may maintain a substantially taut configuration not to be twisted.

As described above, such configurations of the cable <NUM> have structurally simple advantages in helping to prevent a twist of the cable <NUM> itself and interference resulting from the operation of the tracker <NUM> and requiring no separate mechanism for wrapping of the cable <NUM>.

Referring to <FIG> and <FIG>, a pedestal <NUM> according to an example embodiment may include a first supporter <NUM>, a second supporter <NUM>, and a tracker <NUM>. In this example embodiment, the second supporter <NUM> is configured to have a tilted azimuth axis TAZ of about <NUM> degrees with respect to a reference plane on which the first supporter <NUM> is installed.

The first supporter <NUM> may include a spacer <NUM> including a plurality of feet extending radially, and a first frame <NUM> installed on the spacer <NUM>, having a hole through which the second supporter <NUM> is rotatably coupled thereto, and configured to support the second supporter <NUM>. The hole in the first frame <NUM> may be provided to be aligned with the tilted azimuth axis TAZ of the pedestal <NUM> and a drive shaft of a first driver (not shown).

The second supporter <NUM> may include a second frame <NUM>, and the second frame <NUM> may include a first arm <NUM> having a first slot <NUM> and a second arm <NUM> having a second slot <NUM>. The first arm <NUM> and the second arm <NUM> may have portions that extend substantially in parallel.

The tracker <NUM> may include a reflecting body <NUM>, a feed horn <NUM>, a transmitting/receiving device <NUM>, and a third frame <NUM>. The third frame <NUM> may have a housing shape to receiving the transmitting/receiving device <NUM>. A first shaft <NUM> may be provided on at least one side surface of the third frame <NUM> such that a second driver (not shown) may be coupled thereto through the first slot <NUM>.

As described above, considering the need to change the structure of a pedestal as a tilt angle formed by an azimuth axis with respect to a reference plane changes, a simpler one out of several structures of pedestals having a tilted azimuth axis with respect to a reference plane may be selected in many aspects (e.g., the aspect of structural rigidness, the aspect of driving efficiency of pedestal, and the like).

Claim 1:
A pedestal comprising:
a supporter (<NUM>, <NUM>) having an azimuth axis (TAZ) and a pivot on the azimuth axis (TAZ); and
a tracker (<NUM>) connected to the pivot and configured to track an object (O) within a field of view (FOV),
wherein the azimuth axis (TAZ) is tilted with respect to a reference plane (GD) on which the supporter (<NUM>, <NUM>) is installed in a direction away from a zenith line (ZL) joining the pivot with a zenith (ZP) within the field of view (FOV), and the pedestal (<NUM>) is configured to set a tilt angle between the azimuth axis (TAZ) and the reference plane (GD) to correspond to an orbital angle of the object (O),
characterized in that the supporter (<NUM>, <NUM>) comprises:
a first supporter (<NUM>) installed on the reference plane (GD) and having an inclined surface that is inclined with respect to the reference plane (GD); and
a second supporter (<NUM>) installed on the inclined surface and having the azimuth axis (TAZ) and the pivot.