JPS61133733A - Antenna direction control method for artificial satellite - Google Patents

Abstract

PURPOSE:To irradiate a radio wave from a communication antenna to a prescribed position with high accuracy by detecting a relative drive angle between a satellite and >=2 communication antennas having an antenna driver and using the detection signal to detect a yaw angle error of the artificial satellite thereby correcting the attitude of the satellite. CONSTITUTION:The angle between the satellite main body 1 and communication antennas 3a, 3b is measured by an antenna driver provided with an angle detection mechanism while the communication antennas 3a, 3b trace beacon stations 6a, 6b to detect the attitude error of the existing satellite. That is, when the attitude of the satellite is set as a prescribed value, and when the two communication antennas track the beacon stations, the angle to the satellite main body 1 has a specific value. Thus, when the angle detection mechanism has a value different from the specific value, the difference is interpreted that there is an error in the attitude of the satellite. Thus, the invention method uses an earth sensor to eliminate the roll shaft and pitch shaft error of the attitude of the satellite main body 1, the yaw axis error is read from the angle between the communication antennas 3a, 3b and the satellite main body 1 and the error is eliminated from the attitude control of the satellite main body 1.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to an artificial satellite equipped with a communication antenna equipped with an antenna drive control system that operates in a geostationary orbit, and which transmits radio waves from the communication antenna to the earth. The present invention relates to an antenna pointing control method for accurately irradiating a predetermined position.

[Prior art]

In most spin-type artificial satellites that have been used in large numbers in the past, one communication antenna only has a degree of freedom around the rotation of the satellite's spin axis, so in order to improve the pointing accuracy of one communication antenna, Directivity was improved by reducing the attitude stability of the satellite itself and the fluctuations caused by rotation.

Later, even in the three-axis attitude stabilized satellites that came into use, the communication antenna was fixed to the satellite body. This resulted in improved directional accuracy.

However, as the communication range required for communication satellites is limited to narrow areas, the pointing precision required for directional antennas becomes even higher. between the antenna sliding mechanism (A
ntenna Pointing Me chani
sm), and the communication antenna is equipped with a RIF sensor such as a monopulse type, and in addition to controlling the attitude of the satellite itself, the antenna is directed in a certain direction on the earth by the tracking ability of the antenna drive control system. Antenna Pointing Control
), it is possible to further improve pointing accuracy.

FIG. 1 shows a communication satellite equipped with a communication antenna having a conventional RF sensor. (1) is the main body of a three-axis attitude-stable artificial satellite in geostationary orbit.

(2) is an antenna drive control device, and (3) is a communication antenna.

(4) is the specific irradiation area on the earth that is irradiated by the communication antenna (3), and (5) is the antenna pattern that can be irradiated with radiated power equal to or higher than the level formed by the communication antenna (3). What I drew above, (
6) is a beacon station placed in a specific irradiation area (4) and used for angular tracking of the satellite's onboard antenna;
) is the R built in the beacon station (6) and the communication antenna.
A line connecting the Hu11 direction of the F sensor, (8) is the equator, (9
) is the point directly below the satellite projected onto the equator, and α[ is the earth.

FIG. 2 shows the relationship between the pointing direction of the communication antenna, the tracking direction of the RF sensor, and the antenna fist pattern.

In Fig. 2, αυ is the mechanical part of the -order radiator of the communication antenna (3), a'; a is the primary radiator for angle tracking,
Alpha Ken has multiple communication radiators.

Generally, the primary radiator (12) for angle tracking and the secondary radiator (a3) for communication are fixed to the mechanical part I of the primary radiator.

I is the reflector of the communication antenna (3) used for both angle tracking and communication, (l!9 is the communication antenna) center of the turn (5), and (le is the main directional axis of the communication antenna). This is the line connecting the center of the antenna pattern (15). Since the mutual solid angle relationship of the above-mentioned -order radiator α3.a3 is fixed by the mechanism part I of the primary radiator, the antenna pattern (5) is located in a specific direction of the line (7).αη is xm that creates local coordinates on the earth centered on the beacon station (6), the exposure is the Y axis, and the convergence 3 is the center of the coordinates and the antenna pattern. A straight line CII connecting the center α9 is an angle formed by the Y-axis αg and the antenna pattern direction line a9.

That is, when the mechanical part συ of the primary radiator has a specific value on the geostationary orbit, the center αS of the nine communication antenna working patterns exists uniquely in the direction of a specific angle when viewed from the beacon station coordinates.

Assuming that there is no error in the attitude of the main body (1) of the artificial satellite, if the line (7) points towards the beacon station (6), the mechanical part αυ of the -order radiator is fixed to the satellite in advance, so Communication antenna pattern (
5) is oriented as specified. However, in the case of ordinary artificial satellites, there is an attitude error, and the error around the yaw axis is particularly large.

Figure 3 shows the roll and pitch of the satellite body (1).

Beacon station (6) at 7 o'clock when there is no error in the attitude of the yaw axis.
This figure shows a state in which the main body (1) of one artificial satellite is rotated around the yaw axis with the communication antenna (3) pointing. QID is the latitudinal axis of coordinates centered on the point directly below (9), @ is the longitudinal axis, ■ is the rotation angle of the yaw axis, (
) is the position of line (7) on the earth after the yaw axis has rotated,
(c) is the antenna pattern that has been moved as the yaw axis rotates, and (1) is the line connecting the direct point (9) and the beacon station (6).

L is a line connecting the center of the coordinates and the center of the antenna pattern. In reality, if an error occurs around the yaw axis, the main antenna orientation axis of the communication antenna 9 (3) will track the beacon station (6) using the angular degree tracking control mechanism.

In this way, the communication antenna (
3) Azimuth angle (Az angle) + elevation angle (
E! (L angle) C, it will have a value different from the value when there is no yaw angle error. Therefore, the antenna angle mechanism is based on the Az angle and I
J, by changing the angle the line (7) becomes the beacon station (
6) Orient in a direction.

However, since the movement of the antenna pattern (c) due to this pointing direction control is a parallel movement on Fig. 3,
A predetermined specific radiation area (4) will not be irradiated correctly.

In other words, if there is an error around the yaw axis in the main body (1) of the artificial satellite, even if it is equipped with an antenna drive control system, the correct communication antenna pattern (5) cannot be obtained unless the error around the yaw axis is corrected. irradiation is not possible (...For this reason, it is necessary to detect errors around the yaw axis.As mentioned above,
2 for cases where there is an error around the yaw axis and cases where there is no error.
Az angle and J between the main body of the satellite (1) and the antenna drive mechanism (2).

Since there is a difference in angle, it is possible to detect this angle and detect errors around the yaw axis. It is possible to correct the yaw angle of the main body (1) of the satellite based on the detected error around the yaw axis. however.

This method is based on the premise that the yaw axis is correctly directed to the point directly below the satellite, that is, the roll angle and pitch angle of the nine satellites are both controlled to zero. If there is an error in the roll angle or pitch angle, the yaw angle detected and controlled by the above method has a drawback in that the error is accompanied by that error.

[Summary of the invention]

The present invention was made with the aim of improving such drawbacks, and detects the relative drive angle of two or more communication antennas with the satellite, each having an antenna drive device, and uses the detection signal to detect the yaw of the artificial satellite. By detecting angular errors and correcting the satellite's attitude.

An object of the present invention is to provide an antenna pointing control method for an artificial satellite that can irradiate radio waves from a communication antenna to a predetermined position where mis<predetermined position.

[Embodiments of the invention]

FIG. 4 is a diagram showing an embodiment of the present invention.

In Figure 4, (1) is the main body of the satellite, (2a)
is the first antenna drive device, (2b) is the second antenna drive device, (!+a) is the first communication antenna,
(3b) is the first communication antenna, (4) is the specific irradiation area on the earth that is irradiated by the communication antenna, and (5)
is the antenna pattern, (sa) (sb) is the first antenna pattern placed within the specific illumination area (4). Second beacon station, (
9) is the direct point, C1l is the earth, '(7a) is the first beacon station (6a) and the first communication antenna (3a)
) is the line connecting the Null direction of the RF sensor incorporated in the second beacon station (6b) and the Hu11 of the RF sensor incorporated in the second communication antenna (3b).
It is a line connecting the directions. In this configuration, there are two antenna drive control systems and two beacon stations in the specific irradiation area (4), with lines (7a) and (7) for each antenna drive control system.
b) shows a state in which communication antennas (3a) and (3b) are tracking beacon stations (6a) and (6b). Under general circumstances, the attitude of the satellite body (1) may be in a state in which there is an error from a predetermined attitude angle. Even in such a case, the 9 communication antennas (6a) and (3b) will point toward the beacon station (Sa) (6b), but if there is an attitude error, the antenna pattern will point to a predetermined point on the earth. Therefore, it is necessary to remove the attitude error. Therefore, in this invention, an antenna drive device equipped with an angle detection mechanism is used to connect the satellite main body (1) and the communication antenna (
The angle formed between 6a) and (sb) is the communication antenna (3
Measurements are taken while the satellites a) and (3b) are tracking the beacon stations (6a) and (6b) to detect the current attitude error of the satellite.

In other words, if the attitude of the satellite is set to a predetermined value (.), then when the two communication antennas are tracking the beacon station, the angle they make with the satellite body (1) will have a unique value. Therefore, when the angle detection mechanism reaches a value different from this unique value, this difference can be interpreted as an error in the satellite's attitude.

This will be explained below using pattern movement and the like.

Figure 5 shows the antenna pattern when there is no error in the roll and pitch axes of the satellite (there is an error around the yaw axis), and the R1 sensor of the first communication antenna (3a) The RF sensor of the second communication antenna (5b) tracks the second beacon station (6b).
) shows how the antenna pattern is projected onto the Earth while tracking the Earth. In Figure 5, (
5a) is the projection of the antenna pattern rotated around the first Bikotsu station (6a) onto the earth; (sb) is the projection of the antenna pattern on the earth
This is a projection onto the earth of the antenna pattern rotated around the beacon station (6b).

Attitude control of the satellite itself is normally carried out by detecting its own attitude using an earth-based sensor.This sensor can easily detect attitude information around the roll and pitch axes, but it is difficult to control the attitude around the yaw axis. Errors have the property of being difficult to detect.For this reason, there are methods that use solar sensors other than earth sensors, but in this system, which has one communication antenna,
Using this information is very effective. I explained using Figure 4 that posture errors can be detected using this method.
As shown in Fig. 5 to explain the movement of the actual pattern, the attitude of the satellite main body fil is such that errors in the roll axis and pitch axis are detected and removed by the earth sensor, so 5a) and (5b) in a misaligned putter are mostly caused by errors in the yaw axis. Therefore, this method uses the earth sensor to remove roll and pitch axis errors in the attitude of the satellite body (1), and 9 communication antennas (3).
This is an attitude control method that reads the yaw axis error from the angle between a) and (3b) and the satellite body (1), and removes this error by controlling the attitude of the satellite body (1).

FIG. 6 shows a block diagram of an antenna drive control system according to the present invention. In Fig. 6, @ is the direction of arrival of the beacon, @ is the RF sensor and power supply unit, @ is the RF multiplier signal field is the tracking receiver, C1υ is the error output of the tracking receiver, (to) is the antenna drive control circuit, and C (3 is an interface signal with the attitude control system, C341 is an antenna drive signal, (to) is an antenna drive mechanism, (to) is an angle detector.

(9) is the angle signal between the antenna and the satellite.

When an angular error is detected between the direction of arrival of the beacon @ and the Hu11 direction of the RF sensor and power supply section (toward), the RIF sensor and power supply section (2) detect the angular error.

The RF signal of the detected angle error is converted into an error output 6υ of the azimuth angle and the elevation angle by the tracking receiver ω, and is input to the antenna drive control circuit (to).

The antenna drive control circuit (to) performs conversion according to the constants of the control system and outputs an antenna drive signal, and the antenna drive mechanism (to) is driven according to the signal, so that the Nu11 direction of the RP sensor is directed to the arrival of the beacon. controlled to face the direction. The angle between the antenna and the satellite is detected by the angle detector (to) and sent as an angle signal (9) to the antenna drive control circuit (
to). The antenna drive control system has an interface with the attitude control system and telemetry system, and receives the detected angle signal (
2) etc. are output to other systems as interface signals (to).

Although FIG. 6 shows the drive control system for the first communication antenna, the drive control system for the second communication antenna is also the same as that shown in FIG.

〔Effect of the invention〕

When two antennas are mounted on a satellite like this, an RIF sensor is attached to each antenna.

When the RF sensor is tracking each beacon station,
By reading the angle between the antenna drive mechanism and the satellite body, the satellite's yaw angle error can be read independently of the satellite's roll angle and pitch angle errors, so the satellite's attitude can be corrected based on this signal. This makes it possible for communication antennas mounted on satellites to irradiate radio waves to predetermined locations with high precision.

Of course, it goes without saying that even when two or more communication antennas are mounted, similar attitude errors can be detected.

[Brief explanation of the drawing]

Figure 1 is a diagram of a conventional antenna drive control system. Figure 2 is a diagram showing the relationship between the communication antenna and the antenna pattern of the antenna drive control system projected onto the earth and the beacon station, and Figure 3 is the projection of the antenna pattern when the satellite has no attitude error. Fig. 4 is a drawing showing an embodiment of the present invention, and Fig. 5 (8) shows how the configuration shown in Fig. 4 changes when rotated around the yaw axis. When. FIG. 6, which is a diagram showing how the antenna pattern rotates, is a block diagram of the antenna drive control system. In the figure, (1) is the main body of the satellite, (2aX2b)
is the first. Second antenna driving device, (5a) (5b)
are the first and second communication antennas, and (6a) and (6b) are the first and second communication antennas. The second beacon station, αυ, is the mechanical part of the primary radiator, α
2 is a primary radiator for angle tracking, and α3 is a primary radiator for communication. (to) is the RIP sensor and power feeding unit, C11 is the tracking receiver, (to) is the antenna drive control circuit, and (to) is the antenna drive mechanism. (to) is an angle detector. Note that the same or corresponding parts in FIG. 9 are designated by the same reference numerals.

Claims (1)

[Claims] A communication antenna mounted on an artificial satellite irradiates multiple earth stations located far apart from each other within the communication range on the earth, and radio waves from the earth station installed on the artificial satellite are used to drive the antenna. Multiple antenna patterns for controlled tracking and antennas used for communication
A plurality of communication antennas having a fixed azimuth relationship with the pattern, and an angle detector for detecting relative azimuth angles and elevation angles between the plurality of communication antennas and the artificial satellite. , the plurality of communication antennas angle-track the radio waves of the different earth stations, and the yaw angle of the artificial satellite is detected by one or both of the azimuth angle and the elevation angle detected by the plurality of angle detectors. and controlling the pointing direction of a communication antenna using the detection signal.