JP2772777B2 - Sun tracking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sun mounted on an artificial satellite, which uses the sun as a light source and guides the sun's rays to an observation optical system in order to observe the spectrum of the sun's rays transmitted through the atmospheric layer surrounding the earth. It relates to a tracking device.

[0002]

2. Description of the Related Art As shown in FIG. 4, a conventional sun tracking device mounted on an artificial satellite has a movable reflecting mirror 13 that changes the direction of reflection of incident solar rays 16 by biaxial gimbals 13a and 13b.
A light splitter 32 such as a half mirror that divides the sunlight reflected by the movable reflecting mirror 13 into an observation optical path 17 and an optical path for tracking control 18 whose optical axis has been adjusted in advance, and a sunlight ray passing through the observation optical path 17 A Cassegrain telescope 11 that forms a solar surface by being incident thereon, a tracking sensor 12 that receives sunlight through a tracking control optical path 18 via a reflecting mirror 33, and a two-axis gimbal 13 a based on the output of the tracking sensor 12 , 13b to change the reflection direction of the movable reflecting mirror 13.

Further, as shown in FIG. 5, when the tracking of the sun is completed, the spectral observation field of view is limited almost at the center position of the solar surface 29 focused by the Cassegrain telescope 11, and the spectroscope or the like is used. A slit 15 is provided at the focal position of the Cassegrain telescope 11 so that the light can be incident on a spectrum observation device (not shown).

[0004] Next, the tracking operation of the conventional sun tracking device configured as described above will be described. As shown in FIG. 2, the artificial satellite 25 moves in the direction of the arrow along the satellite orbit 28, and the solar rays from the sun 27 at a certain level or more within the viewing angle of the tracking sensor 12 of the solar tracking device. When the incident point a is reached, a sun azimuth signal indicating the azimuth of the sun and a sun elevation angle signal indicating the elevation angle of the sun are output from the tracking sensor 12, so that the sun azimuth signal and the sun elevation angle signal are input. The gimbal control unit 14 controls the two-axis gimbal 13a, 13b based on these two signals,
Is adjusted to guide the sunlight to the optical axis center of the tracking sensor 12 (the optical axis center of the telescope 11).

[0005] Then, even when the artificial satellite 25 moves on the orbit 28 and the incident angle of the solar ray from the sun 27 changes, it continues to track the solar ray.

After the tracking is completed, the sun-tracking device receives the transmitted light transmitted through the atmospheric layer as at point a while the satellite 25 is moving, and transmits the transmitted light through the atmospheric layer as at point b. It can receive sunlight directly arriving without the need to observe the spectrum of the transmitted light through the spectroscope when receiving the transmitted light through the atmosphere. After the 100% light receiving state is calibrated, the solar tracking sequence is terminated, the outer space is forcibly observed, and the 0% light receiving state where no sunlight is incident is calibrated, and the spectrum of atmospheric transmitted light is observed. The data is being calibrated.

As shown in FIG. 5, a spectrum observation operation and a calibration operation in such a sun tracking apparatus have passed through a light beam of a fixed observation field determined by a slit image 30 in the sun surface 29, that is, a slit 15. It is based on light rays.

[0008]

However, in the conventional sun tracking device, the observation light path 17 and the tracking control light path 18 are adjusted in advance in the optical axis to track the sun rays 16, so that the sun surface 29 100% of the light receiving state is calibrated by using only the light rays in the specific slit image 30 within the slit image 30.
When black spots come and go inside, the amount of incident light (which becomes the light source of the spectroscope) becomes non-uniform, which may cause variations.

In order to improve the uniformity of the amount of incident light during the calibration operation in the 100% light receiving state, the solar surface
It is effective to sequentially move and observe the slit image 30 in 29.

However, in the conventional sun tracking device, the tracking sequence is stopped, and the two-axis gimbal 13a, 13b is driven within the range of the sun surface 29 from the tracking stop position to change the angle of the movable reflecting mirror 13 while slitting.・ By moving the image 30 and calibrating the 100% light receiving condition, the 2-axis gimbal
Since the position of the satellite changes during the command command to 13a and 13b and the sun surface 29 moves, the moving position of the slit image 30 with respect to the center of the sun matches the rotation angle of the gimbal 13a and 13b do not do.

When the position of the slit image is sequentially changed in several steps of operation, the position of the sun changes every moment.
The position of 30 is unknown.

In the calibration operation in the 100% light receiving state, it is necessary to clarify the position in the solar surface 29 with respect to the center of the sun as a reference, and the calibration operation in the 100% light receiving state is started again. In this case, the tracking sequence must be restarted, and the angles of the two-axis gimbals 13a and 13b must be reset in order to obtain a reference that is the center of the sun. In addition, two-axis gimbal
Since the time required for sending and receiving commands to 13a and 13b is so long that the movement of the sun cannot be ignored, it is possible to identify the field of view within a limited observation time, and observe all over the solar surface 29 for 100% It was difficult to calibrate the light receiving state.

The present invention has been conceived in order to solve the problems of such a conventional sun tracking apparatus, and performs a calibration operation of a 100% light receiving state performed by directly observing the sun rays, and a method of detecting the moving sun. It is an object of the present invention to provide a sun tracking device realized by using an in-plane scanning device that changes the angle of a tracking control optical path different from the tracking sun tracking control system.

[0014]

In order to achieve this object, a sun tracking apparatus according to the present invention comprises a movable reflecting mirror for changing the direction of reflection of incident sunlight, and a sun reflected by the movable reflecting mirror. A light splitting unit that splits a light beam into a first optical path and a second optical path, a telescope that forms a solar surface by focusing sunlight rays incident through the first optical path, and a telescope that is disposed at a focal position of the telescope. A slit for limiting the spectral observation field of view, an incident angle detecting means for detecting an incident angle of sunlight incident through the second optical path, and the movable based on an incident angle signal output from the incident angle detecting means. A tracking control system for controlling the reflection direction of the reflecting mirror, and changing the reflection direction of the movable reflecting mirror with the tracking control system by changing the optical axis of the second optical path so that the slit image of the slit is converted to the sun light. Inside It is constituted by the solar plane scanning means for scanning the.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a sun tracking apparatus according to the present invention comprises a movable reflecting mirror 13 for changing the direction of reflection of incident solar rays 16 by biaxial gimbals 13a and 13b, and a movable reflecting mirror. A piezo-driven light splitter 19 such as a half mirror for splitting the sunlight 16 reflected by 13 into an observation optical path 17 and an optical path for tracking control 18 whose optical axis is adjusted in advance, and an observation optical path.
A Cassegrain telescope 11 into which sunlight passing through 17 enters,
The slit 15 is disposed at the focal position of the Cassegrain telescope 11 and restricts a spectrum observation field of view and enters a spectrum observation device (not shown) such as a spectroscope. A tracking sensor 12 that enters through a reflecting mirror 20 and a gimbal controller 14 that controls the two-axis gimbals 13a and 13b based on the output of the tracking sensor 12 to change the reflecting direction of the movable reflecting mirror 13 are provided. .

Further, there is provided a piezo drive device 21 for applying a piezo drive voltage having a stepwise changing waveform as shown in FIG. 3C to the piezo drive light splitter 19 and the piezo drive reflection mirror 20. ing.

In the state where the deflection angle of the piezo drive light splitter 19 and the piezo drive reflection mirror 20 is set to zero without applying the piezo drive voltage, the optical axis of the observation optical path 17 and the light of the tracking control optical path 18 are changed. The optical axis is adjusted in advance so that the axis coincides with the axis.

Next, a tracking operation in the sun tracking device thus configured will be described. At the point a in FIG. 2, the spectrum observation of the transmitted light through the atmosphere while tracking the sun is performed in the same manner as in the conventional apparatus, and as shown in FIG. Spectral observations are made based on light rays that have passed through the field of view of the slit image 30 at the center of the surface 29.

When the satellite 25 reaches the point b in FIG. 2 while continuing the tracking of the sun, the satellite 25 receives the directly arriving sunlight without passing through the atmospheric layer.
Shift to the calibration operation sequence in the% light receiving state.

In the sequence of the calibration operation in the 100% light receiving state, the sun image 29 is scanned and observed by moving the slit image 31 vertically in the sun surface 29.

In order to scan the inside of the solar surface 29, the piezo driving device 21 changes the piezo driving light splitter 19 and the piezo driving reflecting mirror 20 stepwise as shown in the waveform diagram of FIG. Piezo drive voltages are applied, and the tracking control optical path 18 incident on the tracking sensor 12 is shifted by a deflection angle (+ nθ to + nθ).
(1θ, 0, −1θ to −nθ).

As described above, when the tracking control optical path 18 incident on the tracking sensor 12 is swung stepwise, the tracking sensor 12
Since the sun azimuth signal and the sun elevation / depression angle signal output from the camera change, the movable reflecting mirror 13 is a tracking sensor 12
Are controlled so that both the sun azimuth signal and the sun elevation / depression angle signal output by the controller become zero.

Therefore, the incident direction of the sunlight 16 reflected by the movable reflecting mirror 13 and incident on the Cassegrain telescope 11 changes in the same manner, so that the focused solar surface 29 is shown in FIG.
As shown by the dotted line in FIG. 3B, the slit image 31 is moved up and down. As a result, as shown by the dotted line in FIG.
Moves to scan the sun surface 29 over + nθ to −nθ.

In the embodiment of the present invention, the piezo driving light splitter 19 and the piezo driving reflecting mirror 20 are arranged in the tracking control optical path 18 so that the scanning range in the solar surface 29 is shared among them (+ nθ to + 1θ). And -1θ to -nθ).
That is, as shown in FIGS. 3A and 3B, the slit image 30 is shifted from top to bottom (from + nθ to −n) in the solar surface 29.
θ), the piezo drive light splitter 19 is set to + n
A Cassegrain type telescope is obtained by applying a piezo drive voltage so as to swing from θ to + 1θ to 0 and changing the piezo drive reflector 20 stepwise from 0 to -1θ to -θn. The incident angle of the sunlight 16 incident on 11 changes from + nθ to −nθ.

Usually, the deflection angle of the piezo drive element depends on the applied voltage, but is generally about 0.1 to 0.15 degrees.
In particular, when a high voltage is used in a space environment, a low-voltage driven piezo element of about 100 V is desired due to the danger of electric discharge and the like. It is effective to perform a scan inside.

In the above embodiment of the present invention, the configuration using the piezo-drive light splitter 19 and the piezo-drive reflector 20 has been described. ± 0 with respect to the optical axis of the observation optical path.
In the range of ± 0.125 degrees (approximately 25 degrees), a similar effect can be obtained by one piezo-drive reflecting mirror and a fixed reflecting mirror (the optical axis oscillates by 2θ if the mirror deflection angle is θ).

Further, m piezo-drive reflecting mirrors are provided, and n
By changing the reflection angle θ of the (n <m) reflecting mirrors in the same phase, the tracking optical path can be shifted by nθ, and the drive voltage of the piezo can be suppressed low.

Further, an optical sensor for arranging a beam splitter 22 in the observation optical path 17 to detect an incident angle of sunlight.
Change in angle of observation optical path 17 by entering into 23 (movement angle of slit image with respect to center of sunlight)
Can be directly monitored to determine the position of movement of the slit image.

[0029]

As is clear from the description based on the above embodiments of the present invention, according to the sun tracking apparatus of the present invention,
By controlling the sun tracking control system and the in-sun scanning control system that scans the sun surface and performs the calibration operation of 100% light receiving state by another control system, there is no transmission / reception of commands to the two-axis gimbal. The calibration operation of the 100% light receiving state can be performed in a limited time, and one or a plurality of movable reflecting mirrors in the tracking control optical path 18 can be swung at a small deflection angle, so that the center of the sun is set as a reference. The slit image can be moved in the sun.

Further, the beam arranged in the observation optical path
Splitter and optical sensor that detects the incident angle of sunlight
By providing 23, the movement position of the slit image can be specified.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a sun tracking device of the present invention,

FIG. 2 is a schematic diagram showing a sun tracking sequence at the artificial satellite in the first embodiment.

3 (a) and 3 (b) are views showing a slit image in the sun plane, FIG. 3 (b) is a waveform chart showing a relationship between a piezo voltage and a deflection angle of a piezo drive reflecting mirror,

FIG. 4 is a configuration diagram showing an example of a conventional sun tracking device;

FIG. 5 is a diagram showing a slit image in the solar surface at the time of spectrum observation and at the time of calibration operation of a 100% light receiving state in the conventional sun tracking device.

[Explanation of symbols]

 11 Cassegrain telescope 12 Tracking sensor 13a, 13b Biaxial gimbal 13 Movable reflector 14 Gimbal controller 15 Slit 16 Sunlight 17 First optical path (optical path for observation) 18 Second optical path (optical path for tracking control) 19 Piezo drive Beam splitter 20 Piezo drive reflector 21 Piezo drive 22 Reflector 23 Incident angle detection optical sensor 24 Earth 25 Satellite 26 Atmosphere layer 27 Sun 28 Satellite orbit 29 Sun surface 30 Spectrum observation field of view 31 Calibration operation of 100% light receiving condition Observation field of view 32 Beam splitter 33 Reflector

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-275511 (JP, A) JP-A-4-275510 (JP, A) JP-A-1-229216 (JP, A) 125305 (JP, U) Fully open 1988-120218 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02B 7/18 B64G 1/00 G01C 1/00 G01J 1/02

Claims (6)

(57) [Claims] A movable reflecting mirror for changing a direction of reflection of the incident sunlight; a light dividing means for dividing the sunlight reflected by the movable mirror into a first optical path and a second optical path; A telescope that forms a solar surface by focusing sunlight rays incident through the first optical path, a slit that limits a spectral observation field of view disposed at a focal position of the telescope, and a sun that enters through the second optical path. An incident angle detecting means for detecting an incident angle of a light beam, a tracking control system for controlling a reflection direction of the movable reflecting mirror based on an incident angle signal output from the incident angle detecting means, and a light in the second optical path. An in-plane scanning means for scanning a slit image of the slit in the sun plane by changing a reflection direction of the movable reflecting mirror by a tracking control system by swinging an axis. Satellite board Onboard sun tracking device. 2. The sun tracking apparatus according to claim 1, wherein the in-sun scanning means is a movable reflecting mirror driven by at least one piezo-electric element arranged in a second optical path. 3. The scanning device according to claim 1, wherein the in-sun scanning means is a light splitting means driven by a piezoelectric element.
A sun tracking device according to item 1. 4. The in-solar-plane scanning means comprises a movable reflecting mirror having a deflection angle θ driven by n piezo-electric elements.
2. The method according to claim 1, wherein the second optical path is swung at a deflection angle of 2n.theta. By simultaneously changing the number of movable reflecting mirrors.
A sun tracking device according to item 1. 5. The solar system according to claim 1, wherein the optical axes of the first optical path and the second optical path are adjusted to a reference position during spectrum observation and when the in-plane scanning unit is stopped. Tracking device. 6. The sun tracking device according to claim 1, further comprising an incident angle sensor disposed in the first optical path and detecting an incident angle of the sunlight at the time of the calibration operation.