JPS59195497A - Detection system of error of attitude 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 The present invention Fi relates to an attitude error detection method for an artificial satellite necessary for attitude control of an earth-orbiting satellite.

First, conventional yaw attitude detection of an artificial satellite will be explained using FIGS. 1 and 2.

In Figure 1, (1) is the earth, (21//'i orbit around the earth).

(3) is a satellite, (4) is a star Senna, +511riE-
axis, (6) is the stellar direction, (7) is the pitch axis, (8)/r
i shows the yaw axis angle error.

In Fig. 2, fl), (2L (31, (5L (
81ilt It's the same as Figure 1 C, (91 is the sun, α
0IIri is the orbital inclination angle, αD is the solar sensor, α2) is the sun direction, and (13H'j is the axial direction of the sensor.

Next, the operation will be explained. In FIG. 1, a special star sensor (4) is placed on the satellite to detect the yaw attitude error with reference to the direction of a star fixed in inertial space. In FIG. 2, one direction is determined at one point on the orbit in terms of orbit geometry, and deviations from that direction are detected by the solar sensor α1).

The method shown in FIG. 1 is a yaw attitude error detection method that is as good as 8 degrees and should be used in the first place (except when control is performed using the roll/yaw coupling effect of gyro stiffness).

The disadvantage is that a special star sensor is installed, which complicates the calculation of the space for star diagnosis.

The method shown in Figure 2 detects the yaw error at one point on the trajectory, but the drawback is that it becomes useless if the trajectory changes.

This invention was developed to improve the above points, and it is a method for detecting the attitude error of an artificial satellite that does not require complicated hardware and can detect the yaw attitude error even if the orbit changes. This is what we provide.

An embodiment of the present invention shown in FIG. 3 will be described below. In Figure 3 -C, (7) is the hit side J, HCd roll axis, (i, 51 Vi earth sensor a! Nobe, a6
) indicates the solar detection field of view.

Next, this operation will be explained.

The earth sensor field of view (15) has the roll and yaw attitude error detection function of the conventional earth sensor, and the sun detection part Q6+
The current J)
It has the function of detecting the position of the sun at an angle based on an arbitrary direction perpendicular to the direction of the sensor field of view. Yaw attitude error detection can be directly obtained from the angle obtained from the sun detector 1m. The principle will be explained below using FIGS. 4 and 5.

Figure 4 shows e r (1), (2L (91, (121
U is already in Figure 1.

As described in Figure 2, (Iη is the shaded area, u
al is the position immediately before entering the shade, 119) is immediately after entering the sunlight in Fig. 5 f7L (8), (91, (匈, 051. (161Fi Fig. 1, 2 and 3)
As stated in the figure, there is a shady part (1η) in the orbit, and just before that shade, there is a shady part (1η) in the orbit as shown in Fig. 4 (ta).
As shown in bJ, the sun appears in orbit (2) behind the earth (1), and immediately after the -1 shade, the sun appears in orbit (2) behind the earth (1) as shown in Figure 4 (C). The sun (9) appears.

As a result, if the yaw attitude error is zero, a thick 1st9) will appear on the roll axis as shown in Figure 5 (3) immediately after the 2nd shade, and if the yaw axis error angle (8) is no, it will appear counterclockwise from the roll axis. The sun (9) is shifted around by an angle of ε.
appears.

Therefore, in Fig. 3, if any direction perpendicular to the sensor field of view is selected as the positive direction of the roll axis, the yaw! l! III
The error angle (8) is the angular variation obtained from the solar detection section [IS.

As described above, according to the present invention, yaw attitude error can be detected efficiently even on a zero-bias momentum satellite on an orbit that has two periods of shade.

This has the effect of obviating the need for a star sensor and the complicated eight-domain quadrature associated with it as in the past.

Spread. According to the present invention, any orbit can be used as long as it has two periodic shades, so there is an advantage that there is no need to consider the geometrical elements of the orbit as in the past.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams showing a conventional method for detecting yaw attitude errors of artificial satellites, Figure 3 is a diagram showing the concept of an embodiment of the present invention, and Figures 4 and 5 are: FIG. 3 is a diagram for explaining the invention in detail. In the figure, (1) is the earth, (2) is the orbit around the earth, (3) is the satellite +41 iJ: stellar sensor, (5) is the yaw axis, (G
) is the stellar direction, (7) is the pitch axis, (8) is the yaw axis gravity angle, (9) is the thick 1 p u (Jr is the orbital inclination angle, α1
) is the sun sensor, u2) is the sun direction. (+3) is the sun sensor axis direction, (141 is the roll axis,
(151 is the earth sensor field of view, +i6+ is the sun detection part, a71 is the shaded area, a8) is the front position in the shade,
1 indicates the position immediately after entering sunlight and fC. In the two figures, the same parts are designated by the same reference numerals. Figure 1 × Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] The sun is on the orbital plane just before and after the shade. Taking advantage of the fact that the sun appears near the earth sensor's field of view, a sun detection unit is installed around the earth sensor's field of view to detect the position of the sun relative to the roll/pitch axis of the earth sensor. In contrast, an attitude error detection method for an artificial satellite is characterized in that the attitude error is detected by detecting the angle of appearance of the sun in the viewing direction.