JP2002120798A - On-satellite direction controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate support by overseas agencies needed heretofore for securing a channel when using an omnidirectional antenna for controlling the orbit of a lunar orbiter, etc. SOLUTION: A direction controller 2 faces a satellite body 1 and is connected to a support 6 via a boom 8. The support 6 and the boom 8 are integrally displaced according to the position of the satellite body 1. In the direction controller 2, a moving part 3 of the directional antenna is freely rotationally connected to a support 7 via support 4, and the support 7 is freely rotationally connected to a support 5. A power supply horn is attached to a top 9 though not shown in the figure, and it constitutes the directional antenna together with the moving part 3. The moving part 3 is supported by the support 4 or 5 at the center of gravity in such a manner that only little friction is caused. The position of the satellite body 1 does not influence the position of the moving part 3. Consequently, the directional antenna is oriented in a constant direction in inertia space even when controlling the position/orbit of the satellite body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pointing control device for mounting on a satellite, and more particularly to a pointing control device for mounting on a satellite which controls a pointing direction of an antenna mounted on a satellite.

[0002]

2. Description of the Related Art There are various types of artificial satellites.
NE) "orbiting satellites orbiting the moon. When transmitting lunar observation data to earth ground stations, the lunar orbiting satellite uses a high-gain antenna to secure a line with the ground stations. Since the high-gain antenna has a narrow beam width, it is necessary to control the directional direction for directing to the earth.

In the case of the lunar orbiting satellite SELENE, the directivity of this high gain antenna is controlled by two antenna driving motors attached in the azimuth and elevation directions. Further, the lunar orbiting satellite SELENE has a lunar orientation in a steady state, and it is necessary to always control the direction of the antenna. The trajectory control is to be performed periodically. Therefore, in the case of the lunar orbiting satellite SELENE, the pointing direction of the antenna is always controlled in a predetermined direction even when the attitude changes, and when the attitude changes during the orbit control, the directional antenna is directed to the ground station. Because it is difficult, it is necessary to switch to another omnidirectional antenna during orbit control.

[0004]

In the conventional directional control device described above, when an omnidirectional antenna is used during orbit control, a large-sized antenna larger than a ground station antenna of the Japan Space Development Agency of Japan is used to secure a line. It is necessary to use an antenna, and for this reason, it is necessary to use a ground station of an overseas organization such as NASA or European ESA having a large antenna.

[0005] The present invention has been made in view of the above points,
It is an object of the present invention to provide a pointing control device for mounting on a satellite capable of controlling the pointing direction of an antenna without receiving the support of an overseas organization even during attitude control or orbit control of the satellite body.

Another object of the present invention is to obtain better observation data by another device by controlling only the direction of a desired device without affecting the direction of the other device. An object of the present invention is to provide a pointing control device for mounting on a satellite.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is a directional control device for controlling the directional direction of a controlled object mounted on an artificial satellite. A first holding unit that is movably held with little friction at the center of gravity, a second holding unit that holds the first holding unit fixed to the artificial satellite body, and a pointing direction of the controlled object is desired. Moving means for moving the movable portion so as to make the direction, and the attitude variation of the artificial satellite body and the movement of the movable portion are made substantially independent.

According to the present invention, when the attitude of the artificial satellite body fluctuates, the second holding means moves and the first holding means moves accordingly. However, even if the first holding means moves, the movable part is almost moved. Since the satellite is held in a fixed direction, the attitude change of the satellite main body and the movement of the movable part can be made almost independent.

Here, the controlled object is a directional antenna, and the movable portion is hemispherical or an observation data acquisition sensor. When the directional antenna is to be controlled, two first and second holding means and two movable means are provided, one each facing the artificial satellite body at 180 degrees. Therefore, since the directional antenna moves 360 degrees, the blind spot can be eliminated.

Further, the movable means comprises an X-axis reaction wheel and a Y-axis reaction wheel provided in the movable part, and a control means for electrically controlling these reaction wheels. I do. Here, the control means is a small wireless device that controls the rotation of the X-axis reaction wheel and the Y-axis reaction wheel based on the pointing control signal sent from the satellite main body. It is desirable because it can.

An antenna driving mechanism for moving the direction of a parabolic antenna in a hemispherical shape has been known (Japanese Patent Laid-Open No. 1-260903). Are not disclosed at all.

[0012]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of an embodiment of a pointing control device for mounting an artificial satellite according to the present invention, and FIG. 2 is a six-view diagram of an embodiment of a pointing control device for mounting an artificial satellite according to the present invention. As shown in FIGS. 1 and 2, the pointing control device 2 of the present embodiment is an example in which the control target is a directional antenna, and is connected to an arched support 6 via a boom 8 to the satellite main body 1. The support 6 and the boom 8
Are displaced integrally according to the attitude of the artificial satellite body 1.

Further, the directional control device 2 includes a hemispherical movable portion 3 of a directional antenna, a support 4 having a circular support 7.
The support 7 is rotatably connected to the support 5. Further, one ends of four linear members are fixed to the movable portion 3, and the other ends of the four linear members are connected to form a vertex 9. Although not shown, a feeding horn (not shown) is attached to the apex 9 and constitutes a high-gain directional antenna together with the movable portion 3.

As a result, the movable part 3 and the four linear members are displaced integrally, but displaced independently of the artificial satellite body 1, the boom 8 and the support 6. The movable part 3 is supported by supports 4 and 5 at the center of gravity in a manner with very little friction, and the attitude of the artificial satellite body 1 does not affect the attitude of the movable part 3. Therefore, even at the time of attitude control / orbit control of the artificial satellite body 1, the pointing direction of the directional antenna is directed in a fixed direction in the inertial space, and is hardly affected by the attitude change of the artificial satellite body 1.

As shown in FIG. 3, an X-axis reaction wheel 11, a Y-axis reaction wheel 12, a small wireless device 13, and the like are provided in the movable portion 3. By controlling the rotation of the X-axis reaction wheel 11 and the rotation of the Y-axis reaction wheel 12, respectively,
, That is, the antenna pointing direction can be controlled independently of the attitude of the artificial satellite body 1. In addition, the small wireless device 13
The electrical connection between the satellite main body 1 and the antenna other than the electric power is performed. This is to make the movement of the movable section 3 as smooth as possible.

In FIG. 1, a directional antenna as a directional control device 2 is provided on one side surface of the artificial satellite 1 via a boom 8, but actually, as shown in FIG. Are provided opposite each other by 180 degrees.

Next, the operation of the embodiment of the present invention will be described with reference to FIG. As shown in FIG. 4, two high-gain directional antennas, which are the directivity control devices described with reference to FIGS. 1 to 3, are opposed to each other by 180 degrees with respect to the satellite main body 1 as shown by 2a and 2b. It is provided to form an artificial satellite. This artificial satellite orbits the orbit of the moon 15 and transmits observation data of the moon 15 to a ground station on the earth 16. Here, the directional antennas 2a and 2b
Are all oriented in the same direction, as shown in FIG.

Here, the distance between the earth 16 and the moon 15 is about 3
80,000 km, satellite body 1 and directional antenna 2
The orbit altitude of the lunar orbit satellites a and 2b is at most 10,000 km, and the direction of the ground station viewed from the lunar orbit may be considered as a substantially constant direction in the inertial space. Therefore, if the attitude control of the artificial satellite is not performed at all, the directional antennas 2a and 2b always point almost in the direction of the ground station, and the communication line can be maintained.

However, if the attitude of the satellite is controlled in order to orient the lunar observation device in the lunar direction, if the directional antenna is fixed to the satellite main body 1, the directional antenna will be terrestrial. Stops pointing in the station direction. Usually, in such a case, the directional antenna is controlled by using an on-board electronic device to control a motor for driving the antenna, and the directional direction of the directional antenna is controlled. Control of the sexual antenna.

However, according to the present embodiment, since the movements of the directional antennas 2a and 2b and the movement of the artificial satellite body 1 are substantially independent, even if the attitude of the artificial satellite body 1 fluctuates, the pointing Since the directional directions of the directional antennas 2a and 2b do not change, they remain in the direction of the ground station, so that a communication line with the ground station is secured even during the attitude control of the satellite, the orbit control, and immediately thereafter. You can continue.

The directional directions of the directional antennas 2a and 2b are substantially hemispherical, and when the attitude is rotated by 180 degrees or more, the directional directions cannot be controlled completely. However, FIG.
As shown in (2), since the directional antennas 2a and 2b are attached to the artificial satellite body 1 so as to face each other by 180 degrees, it is possible to secure a 360-degree directivity direction,
It can always point in the direction of the ground station.

By the way, when the directional antennas 2a and 2b are switched to point to another terrestrial station at a different location as the terrestrial station to which the directional antennas 2a and 2b are directed,
If the movements of the directional antennas 2a and 2b are not completely independent of each other, for example, to cancel accumulated errors, it is necessary to control the directional directions of the directional antennas 2a and 2b.

In this case, the direction of the antenna can be controlled by controlling the rotation of the movable portion 3 in a desired direction by the X-axis reaction wheel 11 and the Y-axis reaction wheel 12 shown in FIG. At this time, the command of the pointing direction is transmitted from the artificial satellite body 1 to the small receiver 13 in the movable unit 3 by radio, and the small receiver 1
3 controls the rotation of the reaction wheels 11 and 12 (the amount of rotation, the direction of rotation, etc.). However, power in the movable section 3 is supplied through the antenna movable supports 4 and 5.

As described above, according to the present embodiment, since the directional antenna including the movable portion 3 and the like is directed in a fixed direction in the inertial space without being affected by the attitude of the artificial satellite body 1, the artificial satellite A line with the ground station can be secured during or just after attitude control and orbit control, and there is no need to use an omni-directional antenna during orbit control. Can be unnecessary. When the direction of the antenna is controlled, it does not affect the attitude of the satellite main body 1, so that, for example, the direction of the sensor attached to the satellite main body 1 is not affected. Thus, better observation data can be obtained.

In the above embodiment, the antenna mounted on the artificial satellite has been described. However, the present invention is not limited to this. For example, the controlled object may be applied to a sensor or the like other than the antenna. It is possible. When the present invention is applied to a sensor that needs to maintain a directivity direction on an inertial space, without being affected by the attitude of the satellite body,
The directional direction of the sensor can be controlled to be substantially constant.
In addition, the present invention can be applied to artificial satellites other than lunar orbiting satellites.

[0026]

As described above, according to the present invention,
Since the attitude change of the satellite body and the movement of the movable part can be made almost independent, it is possible to communicate with the ground station without performing complicated pointing control even during or immediately after the attitude control / orbit control of the satellite body. The wireless communication link between the satellites can be maintained, so that it is not necessary to use an omni-directional antenna during orbit control, and therefore, there is no need to support an overseas organization.

Further, according to the present invention, even when the directional control of the desired controlled object is variably controlled, the attitude of the artificial satellite body is not affected. Good observation data can be obtained without affecting the directivity direction of the sensor or the like.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of an embodiment of the present invention.

FIG. 2 is a six-view drawing of an embodiment of the present invention.

FIG. 3 is a diagram showing an example of an internal configuration of a main part of one embodiment of the present invention.

FIG. 4 is a diagram illustrating an example of a communication system to which the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Artificial satellite main body 2 Direction control device 2a, 2b Directional antenna 3 Movable part 4, 5 Antenna movable support 6, 7 Support 8 Boom 11 X-axis reaction wheel in movable part 12 Y-axis reaction wheel in movable part 13 Small radio 15 Moon 16 Earth

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01Q 1/28 H01Q 1/28 3/08 3/08

Claims (6)

[Claims] 1. A pointing control device for controlling a pointing direction of a controlled object mounted on an artificial satellite, wherein the movable portion of the controlled object is rotatably held in a state of low friction at a center of gravity. A first holding means for fixing the first holding means to an artificial satellite main body;
Holding means, and movable means for moving the movable portion so that the directional direction of the controlled object is a desired direction,
A pointing control device for mounting on a satellite, wherein the attitude change of the satellite body and the movement of the movable part are substantially independent. 2. The pointing control device according to claim 1, wherein the controlled object is a directional antenna, and the movable portion is hemispherical. 3. The pointing control device according to claim 1, wherein the controlled object is an observation data acquisition sensor. 4. The apparatus according to claim 1, wherein the first and second holding means and the movable means are provided two each, one each at 180 ° opposite to the main body of the artificial satellite. The pointing control device for mounting on an artificial satellite according to claim 2. 5. The apparatus according to claim 1, wherein the movable means includes an X-axis reaction wheel and a Y-axis reaction wheel provided in the movable portion, and control means for electrically controlling the reaction wheels. The pointing control device for mounting on an artificial satellite according to claim 1. 6. The small radio device according to claim 1, wherein the control unit controls rotation of the X-axis reaction wheel and the Y-axis reaction wheel based on a pointing control signal sent from the artificial satellite body. 5. The pointing control device for mounting on an artificial satellite according to 5.