JPS5932600A - Horizon detector - 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 Field of the Invention The present invention relates to a horizon detection device for detecting the attitude of a three-axis stabilized satellite.

Conventional Structure and Problems Conventionally, the infrared detector of a horizon detection device used in a three-axis stabilized satellite has been an analog detector as shown in FIG. That is, an image 11 of the earth is formed from a satellite using an optical system (not shown), and the horizon 10 is detected by analog infrared detectors (13E, 13W, 133.13N) such as thermistors and thermomobiles installed in the north, south, east, west, and the like. so that it takes At this time, if you pay attention to one detector (for example, 13S), you can see the shaded area X that is looking at the earth 11, and the space 12
It is divided into the part (1-X) where you are looking at.

Now, the detector output when all the detectors see the earth (corresponds to x-1) is vE, and the detector output when all the detectors see the universe (corresponds to x-0) Let v6 be the output vx when the detector 13S-7JX is in the position shown in Fig.
).

The horizon position X can be determined by Similarly, the detectors 13E, 13W, and 13N are obtained, and the detector 13
When calculating the difference between the output of E and the output of the detector 13W, the east-west direction (
For example, the inclination in the roll axis direction can be calculated. Similarly, the inclination in the north-south direction (for example, pitch axis direction) is determined by the detectors 13S and 13N.

However, this method using an analog detector caused errors due to changes in infrared radiation intensity depending on the earth's seasons and latitude, and the temperature of the detector itself, making it difficult to accurately detect the horizon position. .

OBJECTS OF THE INVENTION The object of the present invention is to provide a highly accurate horizon detection device that is free from errors due to changes in infrared radiation intensity or changes in the temperature of the detector itself and has a relatively simple configuration.

Structure of the Invention The present invention uses a linear array sensor comprising a plurality of infrared detection elements as a linear area sensor that requires accuracy, and uses an analog sensor as a capture area sensor.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments will be described in detail with reference to the drawings. FIG. 2 shows an embodiment of the horizon detection device according to the present invention.

In FIG. 2, a detector 20 forms an image of the boundary between the earth 11 and the universe 12, that is, the horizon 10.

The detector 20 includes a linear array sensor 21 formed of a plurality of infrared detection elements 211, a scanning function element 24 such as a shift register for extracting the output of the element 211 with a conductor 212, and a space sensor 24 for reading out the output of the element 211. It consists of a capture area analog sensor 22 on the side and a capture area analog sensor 23 on the earth side.

As mentioned above, the absolute value of the output of an analog sensor changes depending on the temperature of the detector itself. However, if the sensor itself is composed of a large number of detector elements 211 as shown in Figure 3A, the output of the detector elements forming the image 11 of the Earth will be It is larger than that shown at b in the figure, which corresponds to 12, by an amount corresponding to the energy amount of the incident infrared rays (FIG. 3C). The outputs a and b of each element change depending on the temperature of the detector itself, but the difference signal C is determined by the difference between the incident energy of the earth and the universe, so it is constant and is shown in A of the same figure. horizon 10
If the image of is located somewhere within this linear array sensor element 211, it is possible to determine in which element 211 the boundary lies.

As mentioned above, compared to the conventional method of detecting the edge of the earth (horizon) using the absolute value of the output signal of an analog sensor, in the present invention, the temperature of the detector itself is not a problem. There is no need to control the temperature, and further subdivision of the detector elements has the effect of increasing accuracy accordingly. Note that analog sensors without temperature control may be used as the capture area sensors 22 and 23, which do not require much accuracy.

With this configuration, as shown in Figure 4,
When the attitude angle is taken on the X axis and the attitude error signal is taken on the y axis, the linear area d that requires accuracy is used. A type detector can be used.

Effects of the Invention Like the handle, the present invention is a horizon detection device that uses a linear array sensor consisting of a plurality of infrared detection elements as a linear area sensor and an analog sensor as a capture area sensor. The attitude of a three-axis stabilized satellite can always be detected with high precision and with a simple configuration regardless of temperature changes.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of a conventional horizon detection device, FIG. 2 is a conceptual diagram showing the configuration of a horizon detection device according to the present invention, and FIG. FIG. 4 is an operational characteristic diagram of the horizon detection device according to the present invention. 10...Horizon, 11...Earth, 12
...Space, 2o...Detector, 21...
... Linear array sensor, 22 ... Capture area analog sensor on the space side, 23 ... Capture area analog sensor on the earth side, 211 ... Elements of linear array sensor , 212... conductor, 24.
...Scanning functional element. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 1θ 3rd yJ lθ

Claims (1)

[Claims] A horizon detection device characterized in that it is equipped with a plurality of infrared detection elements or uses a near array sensor as a linear area sensor, and uses an analog sensor as a capture area sensor.