JPS6146798A - Controller for orbit of artificial satellite - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an orbit control device for a three-axis stabilizer artificial satellite flying in a geostationary orbit.

[Prior art]

Conventional orbit inclination angle control of this kind is determined at the orbit control station of two artificial satellites, and the thruster injection start time and injection time are transmitted from the ground station to the satellite based on the control date and time and control amount estimated from the determined values. This was carried out by firing thrusters according to commands. Therefore, the work of determining the orbit before control, creating control commands, sending commands, determining the orbit after control, and predicting the next control timing based on the determined value is not performed at the ground station during the satellite operation period. There was a drawback that it should not be done.

[Summary of the invention]

This invention was made with the aim of improving this drawback, and by equipping a satellite with a stellar sensor (hereinafter referred to as a Volaris sensor) that observes the North Star and a device that processes this sensor data, there is no need for instructions from a ground station. This project proposes an orbit control device for artificial satellites that can control the orbital inclination angle onboard.

[Embodiments of the invention]

1 and 2 show a schematic diagram of an artificial satellite on a geostationary orbit and components on the satellite body for explaining the present invention. In the figure, (1) is the Earth, (2) is the satellite's orbit, (3) is the equatorial station, (4a) is the satellite when it passes through the ascending node, and (4b) is when it is farthest north from the equatorial plane. (4C) is the satellite when it passes through the descending node.

(4d) is the satellite when it is farthest south from the equatorial plane, (5
) is the orbital inclination angle, (6) is the thruster attached to the − pitch axis side, and (7) is the thruster attached to the + pitch axis side.

(8) is the roll axis, (9) is the pitch axis, 00) is the yaw axis, (lla) is the data processor 1 that determines the position of the North Star on the Volaris sensor coordinates, (llb) is (lla)
2. A data processor that selects an injection thruster based on the position of the North Star determined in 2. and creates a signal instructing execution of injection. α
2 is a volaris sensor. Figure 3 shows the position of Polaris on the Volaris sensor coordinates. α3 in the figure).

Q4), Q51. [161 are (4a) and (+b) in FIG. 1, respectively.

(4c) and (4d) are the positions of the North Star on the Volaris sensor coordinates when the satellite is located. FIG. 4 shows the flow of signals between the components shown in FIG.

The attitude of the three-axis attitude control satellite is always controlled so that the yaw axis head is directed toward the center of the earth and the pitch axis (9) is perpendicular to the orbital plane. Therefore, if a volaris sensor is installed in one pitch axis direction of the satellite to be able to detect the Polaris, if the orbital inclination is 0 degrees, the center of the volaris sensor shown in Figure 3, that is, both the roll axis direction and the yaw axis direction, will be zero. You will sense the North Star in your position. However, if there is an orbital inclination angle (5) as shown in FIGS. 1 and 3.

Depending on the position of the orbit, the position at which the North Star is detected will rotate once per orbit. Using this, data processor 1
(Ha) determines the position of the North Star on the Volaris sensor coordinates and sends the data to the data processor 201b). Data processor 2 (nb) selects the thruster (6) on the one-pitch axis side when the sent data exists in the area from 061 in Fig. 3 clockwise through 03) to the circle. A signal is created to select the thruster (7) on the + pitch axis side when the signal exists in the area from (141 to 05 clockwise) to the scream. Furthermore, it is determined whether or not to eject the selected thruster depending on the position on the hysteresis loop shown in FIG. 5 of the signal from the data processor 1...a). In other words, when the position of the North Star on the Volaris sensor coordinates is outside the threshold value 1αη in FIG. 3, the threshold value 10 in FIG.
When it is on the right side of η, a thruster injection signal is sent to the thruster to drive the thruster and reduce the orbital inclination angle.

The thruster injection is stopped when the threshold value 2Q81 in FIG. 3 is smaller than the threshold value 2Q81 in FIG. 3, and when the threshold value 2Q8 in FIG.

If the position of the North Star exists between thresholds 2 and 1 while the thrusters are not injecting, the thruster will gradually approach threshold 1 and when threshold 1 is exceeded, the thrust will start again. As a result, the thruster ON and OFF are repeated according to the hysteresis loop shown in FIG. 5, and the orbital inclination angle is maintained between the value corresponding to threshold 1 and the value corresponding to threshold 2.

Thruster +61. If the +71 cannot be installed parallel to the pitch axis so as not to generate torque, install two or more thrusters in each of the -pitch axis and +pitch axis directions, and the combined thrust vector will generate torque. It is only necessary to attach the thrust force in the translational direction so that it can be sufficiently controlled by the attitude control system even if no thrust force is generated or one thrust force is generated.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to maintain the orbital inclination angle of an artificial satellite in a geostationary orbit within a set range. By using the thruster and data processing 2 that selects an injection thruster from the list and creates a signal instructing the start of injection execution, orbit inclination angle control can be performed without sending a control command from the ground station.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the position of an artificial satellite on its orbit and the direction of each axis, Figure 2 is a diagram for explaining the orbit control device for an artificial satellite according to the present invention, and Figure 3 is a diagram for explaining the satellite in orbit. Figure 4 is a diagram showing the connection and signal flow between the components shown in Figure 2. FIG. 2 is a diagram illustrating hysteresis logic used to determine whether thruster injection is ON or OFF. In the diagram, (1) is the earth, (2) is the orbit of the satellite, and (3)
is the equatorial plane, (4a) is the satellite when passing the diplomatic point,
(ab) is the satellite when it is farthest north from the equatorial plane, (
4C) is the satellite when passing the descending node, (5) is the orbital inclination, (6) is the thruster attached to the -hitchi axis side, and (7) is the orbital inclination angle.
) is the thruster attached to the + pitch axis side, (8) is the roll axis, (9) is the hit axis, 0ω is the yaw axis, (11a)
is the data processor 1□ (llb) is the data processor 2,0 is the Volaris sensor, 03) (14) Q5) 061 is the position of the North Star on the Volaris sensor coordinates. Note that the same or corresponding parts in FIG. 1 are designated by the same reference numerals.

Claims (1)

[Claims] A three-axis attitude control satellite in a geostationary orbit is equipped with a stellar sensor that observes Polaris in the -pitch axis direction, and two thrusters that generate thrust in the -pitch axis direction and +pitch axis direction, respectively, and the output of the stellar sensor is is processed to create a signal for controlling the injection of the two thrusters on and off, and the thruster injection is controlled by the signal to maintain the orbital inclination angle within a set range. An orbit control device for artificial satellites.