JPS58148927A - Earth sensor for artificial satellite attitude control - Google Patents

Abstract

PURPOSE:To increase common designed parts, by equipping >=4 infrared detectors having optical axes slanting at a prescribed angle to a center line, and fitting a detachable reflecting mirror which has reflecting surfaces at an angle corresponding to the altitude of a low-altitude artificial satellite. CONSTITUTION:An earth sensor is equipped with >=4 infrared sensors 31 arranged having optical axes slanting at the prescribed angle to the center line. Namely, the infrared detectors 31 are provided to a housing 33 for <=4 channels and the optical axis of the infrared detector for each channel slants inward or outward at thetaH=8.7 deg. to the center line. Then, the reflecting mirror 38 having reflecting surfaces at the angle corresponding to the altitude of the low-altitude artificial satellite is fitted detachably to increase parts which are designed in common regardless of the altitude; and conversion between still high altitude and low altitude is performed freely by the attachment and detachment of the reflecting mirror to obtain great effect to economy and reliability improvement.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a non-scan type earth sensor for detecting and controlling the attitude of a satellite using a three-axis stabilizer.

As shown in No. 1 Na, if the artificial satellite is a geostatic satellite, its altitude Fi is 35,800 km, and the viewing angle looking at the earth 1 from the 1-person L satellite 2 is 1764°. On the other hand, in the case of a low-altitude satellite, its altitude is between 300 Km and 2,000 Km.
7j It becomes a wide angle of 125.4 degrees.

Therefore, in the case of a horn spin type three-axis stable satellite and a non-scan type earth sensor, in order to detect the four horizons of the earth (north, south, east, west, and I have to do it. The non-scanning earth sensor is equipped with at least four sensors so that it can reliably detect the edge of the earth even when the satellite is in the correct attitude as shown in Figure 2a, or when it is swaying in either direction as shown in figure b. Channel infrared detector 21, 22゜23
．． 24 is mounted on a manned satellite and detects the position of the edge of the earth, thereby measuring the attitude of the incoming satellite with respect to the earth 21. Infrared detectors 22, 23, 2 of each channel
4.25 in advance.

It must be placed precisely so that it captures the edge of the earth. For this reason, conventionally multiple infrared optical systems were set up according to the altitude of the satellite, but it was extremely difficult to install a large number of infrared optical systems accurately and with high precision.

The present invention was made in order to eliminate these drawbacks. Basically, the structure is designed for static IF altitude, and by simply attaching a reflector, it can be assembled as a low altitude earth sensor. This will be explained in detail below with reference to the drawings.

FIGS. 3a and 3b are a sectional view and a plan view when the earth sensor according to the present invention is used for an advanced manned satellite. In the figure, numeral 31 denotes an infrared detection element, which is installed in four parts 39 provided in the housing 33. 32 is an infrared lens, and the infrared detection element 31 and the infrared lens 32 constitute an infrared detector. The infrared detector is provided with four or more channels for the housing, and the optical axis of the infrared detector in the valley channel is θH = 8.7 inside or outside of the center line.
It is installed so that it is tilted. The figure shows a case where it is tilted inward. This angle is preferably set to 8.7° and 0.1°, taking into consideration alignment accuracy, etc.

Reference numeral 34 denotes an electronic equipment section and a power supply section, the specific configurations of which are well known and directly related to the present invention, so a detailed description thereof will be omitted. 36
is the anti-IN mirror mounting screw hole. In this configuration, the optical axis of the infrared detector is used as an earth sensor for an urban satellite located at an altitude of 35,800 km with an angle of θ=8.7° relative to the center line.

For use as a low-altitude satellite, as shown in FIG. 4, a reflector 38 is attached to the configuration shown in FIG. 3. Anti-1! The f-mirror 38 has at least 4
It has two reflective surfaces on its outer surface, and is fixed to the screw hole 35 with a screw 4o.

Since the installation of the reflecting mirror 38 must be carried out with high precision, the surface area of the mounting surface of the mirror and the mounting surface of the holder should be well adjusted, and a thin plate 37 for fine adjustment should be placed between each car with three valleys. Install it on the mounting screw part and check the mounting angle with the alignment note mirror 36 to ensure accurate mounting. The h-position angle is θ in the figure.
, = 62.7°, and the altitude is 80°.
0 and 77L for low altitude satellites. In this case, the mounting angle θm of the reflecting mirror is defined as 90 minus the angle formed by the center line and the perpendicular to the mirror surface, and is expressed as 0m"(θL-fly)/2 --- (1), and the reflection The angles θ and n between the perpendicular of the mirror and the optical axis of the incident infrared light from the low-altitude satellite are θL4θ1 θ −90°−□ − (2) n−2.

Note that the optical axis of the valley channel is relative to the center line.

If the angle is 87 to the outside, that is, if the infrared detector is placed 4 tilted so as to open outward, then θ. '-(θL10M)/2 (3)
. θshi−θ□ θ1n−=9Q−□ (4). .

θ,. If we compare θin with θin, it becomes clear that θ,. is smaller, so the angle θll28.7° for static altitude is tilted inward from the center line.The force of the configuration in Figures 3 and 4 is
The area of the reflecting mirror can be reduced.

In this way, the earth sensor according to the present invention can easily be equipped with an It has the feature of being able to assemble earth sensors for low-altitude satellites, and this feature increases the number of parts that can be commonly designed regardless of the altitude. It can be freely converted to both low-altitude and low-altitude use, resulting in significant improvements in economy and reliability.

In addition, if you prepare multiple reflectors with different angles for low-altitude satellites, you can freely convert them to use for low-altitude incoming satellites at various altitudes. Note that the earth sensor requires an infrared detection system with at least 4 channels, but infrared detection with 6 channels, 8 channels, or more channels can be used as a redundant system to improve accuracy and reliability. In this case, the structure according to the present invention can be constructed, and the effect thereof will not be reduced in any way.

[Brief explanation of the drawing]

Figures 1a and b show static altitude and low altitude (8ooicm).
Figure 2 a and b are diagrams showing the relationship between the human satellite and the earth in ).
Figures 3a and 3b are diagrams showing an example of the earth as seen from an artificial satellite and an infrared detector field of view. Cross-sectional view and plan view when
d is a cross-sectional view and a plan view when the geosensor is used as an earth sensor for a low-altitude incoming satellite. 31.・Infrared detection element, 32.・Infrared lens, 3
3... Housing, 34... Electronic equipment section and power supply section, 3
6..., IX mirror mounting screw hole, 36... Alinocytoscope, 37... Thin root for fine adjustment, 38...
・JX elbow mirror, 39・・4 parts, 40 screws. Name of agent: Patent attorney Masao Nakao and 1 other person 1st
Figure fθ) (b) Ca2 (b) Figure 3

Claims (2)

[Claims] (1) 4 with the haze axis tilted at a predetermined angle with respect to the center line
Earth sensor for manned satellite attitude control (incorporated) characterized by being equipped with more than one infrared detector and detachably attached to a reflector having a reflecting surface with an angle corresponding to the altitude of the low-height oddball satellite. . (2) The earth sensor for attitude control of a man-made satellite according to claim 1, wherein the light receiving part of the infrared detector is inclined inward toward the center line.