JPS60248498A - Earth sensor - 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 earth sensor used, for example, in an antenna pointing spindle control unit of a spin-stabilized attitude control communication satellite.

[Prior art]

FIG. 1 is a sectional view showing a conventional earth sensor.

In the figure, (1) is an optical lens, and (2, is an optical filter).

(3) is a bolometer, (4) is an electronic circuit, (51 is a housing, and (6) is a mounting base provided on the bottom surface of this housing.

In addition, α is the center axis L of the earth sensor (inside the i-Gakushin!
The shaft) is at an angle with the mounting surface.

The conventional earth sensor is constructed as described above, and the radiation light (infrared i) from the earth is focused by the optical lens (1).
Only the light in the infrared band is extracted by the optical filter (2).

The infrared rays absorbed by this extraction are input to the bolometer (3), and after being converted into electric power, the electronic circuit (4) is amplified.
After the waveform has been shaped, it is sent to the attitude control device.

In communication satellites with spin-stabilized attitude control system,
The above earth sensor has a mounting angle of +α (earth sensor A)
And, the -α one (Earth sensor B) is fidgeting with the installation. Figure 2 (However, A) shows the scanning plane of Earth sensor A.
(B) is the scanning surface of the earth sensor B) As shown in K, the plane is scanned ±4° from the lower surface of the equator of the earth E, and as shown in Figure 3, the output signal corresponding to the earth width G is sent to the attitude control device. It is designed to be sent to Also, if the sun or September is observed in the viewing angle of either earth sensor,
Tanu cannot output accurate earth 1mk.

It has a redundant configuration in which it switches to the remaining sensors.

In addition, in FIGS. 2 and 3, C is the rotation axis.

SP is the spin axis, N is the north pole, S is the south pole, T is the spin period, and t is time.

However, using all the earth sensors configured as above,
4Q ■ When a star antenna directional king axis control session is performed.

Fluctuations in the earth station received signal level, as shown in Figure 4, are frequently reported before and after the satellite's negative time period, which occurs 88 days a year around the Spring and Autumn calendar.

Figure 4 V (in Figure 4 V, the horizontal axis is time t, the vertical axis is the level (dB)', and tBr is the negative time period.The reasons for this are shown in Figure 5 and Figure 6 Kongo). I will explain.

No. 51 I(a) to (C) are diagrams showing the positional relationship of the sun, the earth, and the satellite before and after the negative time period. Figure 5 (a) V? −
Leave it behind.

(7) is the sun, (8) is the earth, (91 is the artificial satellite.-!

W is the true width of the Earth, W' is the apparent width of the Earth in Figure 5 1(b) before the eclipse, and W'' is the apparent width of the Earth in Figure 5 (C1) after the eclipse. (I1. (OL is the second
It is the same as the figure, (c) is the equator, N is the north pole, and S is the south pole.

Ota. Figure 6 shows all the earth sensor output signals before and after the eclipse. Figure 6 (a) shows before the eclipse, and Figure 6 (bl shows after the eclipse). As shown in Figure 5,
When the Earth is viewed from a satellite in geostationary orbit, the sun will be located on the Earth's equatorial plane.

Therefore, since the scanning plane of the conventional earth sensor is about ±4°, the radiation energy of the above-mentioned thick III light is inputted to the earth sensor as an interference radiation wave, especially.

Before and after the negative time period, the apparent width of the Earth W
' and W'' become larger than the true earth width W. Therefore, the output signal from the earth sensor is as shown in Fig. 6 (
As shown in a) and (b), it is no longer possible to output a signal corresponding to the true width of the earth, and when the signal is input to the attitude control device, incorrect antenna raw white main axis control is performed, resulting in earth station reception. It had the disadvantage of causing noise level fluctuations, which in turn affected the quality of the single line. Also, with conventional earth sensors, two sensors are installed in the +α and -α directions.

Regarding interference as shown in FIGS. 4 and 5,
Since the interference source is located in the middle of the +α and -α direction earth sensors, it affects both earth sensors equally,
As mentioned above, there is also the drawback that it is not possible to use a method of switching one of the earth sensors to prevent interference.

[Summary of the invention]

This invention was made with the aim of alleviating these drawbacks, and by providing a slit between the optical lens of the earth sensor and the optical filter, solar radiation generated before and after the negative time period of the Spring and Autumn Festival can be reduced. We propose an earth sensor that can eliminate shadows.

[Embodiment of the Invention] FIG. 1 is a cross-sectional view showing an embodiment of the invention.
) to (6) are completely the same as the above-mentioned conventional device. 0
1 is a slit with a circular hole centered in the middle lb axis of the optical lens (1). This embodiment shows a case where it is installed between the slit all-optical lens i11 and the optical filter +21.

The earth sensor is configured as described above.

First of all, the radiation waves that entered the optical lens F11 from outside the wild bird can be filtered out through the slit +l0IK, so the bolometer (
3) It shall not have any influence on VC.

Therefore, even if the positional relationship between the sun and Earth's 9 artificial satellites becomes as shown in Figure 5 before and after the negative time period of the Spring and Autumn Festival, the slit 001 will prevent the effects of radiation waves from the sun from being detected by the holometer (3). Because it can be eliminated before the
The electronic circuit (4) outputs the normal characteristics shown in FIG. 3.

Note that in the above embodiment, the slit 001 is an optical lens (1
) and the round filter +2'l, but this slit tl [n is the round filter (2'l).
) and the holometer (3), or between the optical lens (II and the optical filter (21) and the optical filter (2) and the tobolometer (3), the same effect as above can be obtained. Needless to say.

〔Effect of the invention〕

As explained above, this invention uses a simple structure of a round lens thread and a bolometer's I'll K slit cable to reduce the shadows of solar radiation waves that occur before and after the eclipse period during the spring and autumnal equinox periods. It has the effect of eliminating

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the structure of a conventional earth sensor. Figure 2 is a box diagram showing the relationship between the scanned image of the earth sensor and the earth's equatorial plane, Figure 3 is a waveform diagram of the output signal from the earth sensor, and Figure 4 is a diagram of the relationship between the earth sensor's scan image and the earth's equatorial plane. Figure 7 showing the fluctuations in the received signal level of the earth station that occur,
Figure 5 is a diagram showing the relationship between the sun and the Earth 1 satellite in VC before and after the eclipse. Figure 6 shows the waveform of the output signal of a conventional earth sensor before and after the eclipse period.1. Is Figure 7 an example of this? FIG. 3 is a cross-sectional view of the earth sensor shown in FIG. In the figures, ill is an optical lens, (21 is an optical filter, (3) is a holometer, (4) is a Tomoko circuit, (5 is a body donation, and (61 is a mounting base.) In each figure, the same reference numerals are the same. Dimensions indicate the corresponding parts. Agent Masuo Oiwa Figure 1 Figure 2 Figure 3 Figure 5 (Q) S Figure 6 to Figure 7

Claims (1)

[Scope of Claims] (1) An optical lens system that collects radiation waves from the earth; an optical filter that extracts light and sound in the infrared band of the radiation waves collected by the optical lens system; A bolometer for converting into an infrared radiation signal extracted by a filter, an electronic circuit for amplifying and shaping the electrical signal from the bolometer, and outputting all the information of the width of the earth, and for housing all of the above components. An earth sensor comprising a housing, characterized in that a slit with a circular hole centered on the central axis of the optical lens system is provided between the optical lens system and the holometer. (Earth sensor according to claim f11, which is characterized in that a 21 slit is provided between the optical filter and the holometer. The earth sensor according to claim 11, characterized in that the earth sensor is provided between.