JP2751850B2 - Optical antenna for satellite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical antenna mounted on a satellite for transmitting and receiving an optical signal in an optical communication between satellites, and more particularly to a positional deviation in a direction of an optical axis between a main reflecting mirror and a sub-reflecting mirror. The present invention relates to a detection structure for detecting an inclination of a sub-reflector and the like.

[0002]

2. Description of the Related Art Conventionally, as an optical antenna of this type, a main reflecting mirror and an opposing sub-reflecting mirror are coaxially mounted and supported by a support so as to be adjustable. the tubular member is mounted on the sub-reflecting mirror penetrating, by Rukoto permeability of the target color appears on the received portion of the laser beam are attached to both ends of the cylindrical body, such as inclination and eccentricity of the sub-reflecting mirror Cassegrain-type antennas that can be adjusted easily and quickly have been proposed. An optical antenna of this type is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-269.
No. 504, for example.

[0003]

However, this type of optical antenna has the following problems when used as an optical antenna mounted on a satellite. Measures the positional deviation in the optical axis direction between the main reflecting mirror and the sub-reflecting mirror in an orbital environment (deviation in the direction perpendicular to the optical axis) and the inclination of the sub-reflecting mirror (angular inclination of the optical axis) Does not have the ability to In addition, in order to achieve a high antenna gain, it is necessary to grasp the deviation between the main reflector and the sub-reflector in orbit. Further, it is impossible to correct the influence of the alignment of the transmission and reception beams due to the inclination of the sub-reflector on the orbit.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a satellite mounting system capable of detecting a positional shift and a tilt between a main reflecting mirror and a sub-reflecting mirror. An optical antenna is provided.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, an optical antenna for a satellite according to the present invention has a main reflecting mirror having a light reflecting surface and an opening in the center, and the main reflecting mirror. A sub-reflection mirror opposed to the optical axis of the sub-reflection mirror, a support for supporting and fixing the main reflection mirror and the sub-reflection mirror with a predetermined space therebetween, and a plurality of mirrors axially symmetric around the peripheral edge of the sub-reflection mirror An attached first reference light source, and a plurality of divided lights which are disposed coaxially with the opening of the main reflecting mirror and receive the first reference light emitted from the first reference light source. A photodetector having a detection sensor and a level difference between output voltages output from the respective photodetection sensors of the photodetector are arithmetically processed to perform positional deviation and subdivision in the optical axis direction between the main reflecting mirror and the sub-reflecting mirror. And an angle detection processing circuit for calculating the inclination of the reflecting mirror.

According to another aspect of the present invention, there is provided a satellite-mounted optical antenna having a correction means for correcting the alignment of the photodetector on the optical axis between the opening of the main reflector and the photodetector. is there. According to another aspect of the present invention, in the above-mentioned configuration, the correction means is disposed coaxially with the opening of the main reflecting mirror and is provided with a first reference light source.
And a second reference light source disposed on the optical axis of the half prism and emitting the second reference light to the photodetector .

[0007]

According to the present invention, the periphery of the sub-reflector is axially symmetric.
The reference light emitted from a plurality of first reference light sources attached to the light source passes through an opening provided at the center of the main reflection surface, and is incident on a photodetector having a plurality of divided photodetection sensors. The output voltage output from each light detection sensor of the detector is arithmetically processed by an angle detection processing circuit to calculate a positional shift between the main reflecting mirror and the sub-reflecting mirror in the optical axis direction and a tilt of the sub-reflecting mirror.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram illustrating the configuration of an embodiment of an optical antenna for onboard satellites according to the present invention. In FIG. 1, reference numeral 1 denotes a main reflecting mirror having a light reflecting surface and an opening 1a at the center, 2 denotes a sub-reflecting mirror opposed to the focal position of the main reflecting mirror 1, and 3 denotes a main reflecting mirror arranged to face. A support in which the mirror 1 and the sub-reflector 2 are supported and fixed at a predetermined interval;
Reference light sources 4 and 5 are mounted on the periphery of the sub-reflecting mirror 2 axisymmetrically and fixed and emit a light beam at a stable level.
Reference numeral 6 denotes a half prism disposed on the back side of the main reflecting mirror 1 coaxially with the opening 1a.

Reference numeral 7 denotes an internal optical system which is disposed on the same optical axis as the half prism 6 and transmits and receives a light beam to and from the main reflecting mirror 1. The reference light source 9 is disposed on the same optical axis that connects the half prism 6 and the reference light source 8, and the four-element light detector 9 has a light-receiving surface. Each area a (first elephant), b (second elephant), c divided into four radially
Photoelectric conversion sensors 9a, 9b, 9c and 9d are formed on (third elephant) and d (third elephant), respectively.

[0010] Reference numeral 10 designates input of each output Sa, Sb, Sc, Sd output from each photoelectric conversion sensor 9a, 9b, 9c, 9d output from the four-element photodetector 9, and performs arithmetic processing. This is an angle detection processing circuit that calculates the deviation between the main reflecting mirror 1 and the sub-reflecting mirror 2 and the inclination of the sub-reflecting mirror 2. In addition,
The half prism 6, the internal optical system 7, the reference light source 8, the four-dimensional element photodetector 9, and the angle detection processing circuit 10
Although not shown, it has a structure arranged in the optical antenna.

In such a configuration, the reference light source 4 and the reference light having a stable level emitted from the reference light source 5 provided at the peripheral portion of the sub-reflector 2 are provided at the center of the main reflector 1. The light passes through the opening 1a and is incident on the light incident surface of the half prism 6, and is refracted by the half prism 6 and divided into four regions a, b, and
The light enters the photoelectric conversion sensors 9a, 9b, 9c, 9d of c and d, respectively.

As a result, each of the photoelectric conversion sensors 9a, 9
b, 9c and 9d output outputs Sa, Sb, Sc and Sd, respectively, corresponding to the incident light beam.
a, Sb, Sc, and Sd are input to the angle detection processing circuit 10. The angle detection processing circuit 10 determines whether each input S
Each output voltage corresponding to a, Sb, Sc, Sd is V
Assuming that a, Vb, Vc, and Vd, V1 = Va + Vb-Vc-Vd V2 = Va-Vb-Vc + Vd, and the sign of the voltage V1 and the voltage V2 is determined to obtain a reference as shown in Table 1 below. Detect the position of light.

[0013]

[Table 1]

For example, when the reference light source 4 is turned on, FIG.
In (a), (b) and (c), as shown in case 1, case 2 and case 3, the spot-shaped reference light indicated by a black circle is applied to each photoelectric conversion sensor 9a, 9b, 9c of the four-element photodetector 9. , 9d
Is irradiated. In this case, the reference light source 4 is as follows: Case 1: V1> 0, V2 ケ ー ス 0 Case 2: V1 ≒ 0, V2> 0 Case 3: V1> 0, V2> 0, corresponding to the position shown in FIG. I understand that there is. Therefore, by observing the change in the image of the reference light, a positional shift between the main reflecting mirror 1 and the sub-reflecting mirror 2 in the optical axis direction and an inclination of the sub-reflecting mirror 2 can be detected.

Similarly, by turning on the reference light source 5 attached to the other peripheral portion of the sub-reflecting mirror 2, the reference light source 5 is provided in the same manner as described above: Case 1: V1 <0, V2 ≒ 0 Case 2: V1 < 0, V2> 0 Case 3: V1 <0, V2> 0, which is understood to correspond to the position shown in FIG. Therefore, by observing the change in the image of the reference light, it is possible to detect the positional deviation between the main reflecting mirror 1 and the sub-reflecting mirror 2 in the optical axis direction and the inclination of the sub-reflecting mirror 2, and to obtain the results of both. Utilization can improve detection accuracy.

Further, by turning on the reference light source 8 disposed in the optical antenna, the reference light source 8 is provided in the same manner as described above: Case 1: V1 ≒ 0, V2 ≒ 0 Case 2: V1 ≒ 0, V2 ≒ 0 Case 3 : V1 ≒ 0, V2> 0, and it can be seen that they correspond to the positions shown in FIG. Therefore, by observing the change in the image of the reference light, the inclination of the four-element photodetector 9 itself can be measured.
By using the result to correct the above-described measurement result, detection accuracy can be improved.

For example, assuming that a state where no positional displacement in the optical axis direction occurs is a case 1 in FIG.
In such a case, since the position of the spot of the reference light source 8 is not shifted, it is estimated that the entire sub-reflecting mirror 2 is shifted in the direction corresponding to the region d. In case 3, since the spots of the three reference light sources 4, 5, and 8 are shifted by the same amount in the same direction, it can be estimated that only the four-element photodetector 9 is shifted.

In the above-described embodiment, the case where the half prism 6 and the reference light source 8 are provided on the optical axis between the opening 1a of the main reflecting mirror 1 and the photodetector 9 has been described. Is not limited to this configuration,
By disposing the photodetector 9 on the same optical axis as the opening 1a of the main reflecting mirror 1, the alignment of the photodetector 9 cannot be corrected, but the optical axis between the main reflecting mirror 1 and the sub-reflecting mirror 2 cannot be corrected. The positional deviation in the direction and the inclination of the sub-reflecting mirror 2 can be detected.

In the above-described embodiment, as a means for correcting the alignment of the photodetector, a half which is disposed coaxially with the opening of the main reflecting mirror and receives the first reference light of the first reference light source. The case has been described in which the prism is constituted by the prism and the second reference light source which is disposed on the optical axis of the half prism and emits the second reference light to the photodetector. However, the present invention is limited to this structure. Instead, it may be constituted only by a second reference light source for introducing the second reference light to the optical axis of the photodetector, and an optical system combining a second reference light source and a lens may be used. Even if it is used, it is needless to say that almost the same effect as described above can be obtained.

[0020]

As described above, according to the present invention,
It is extremely excellent that an on-board antenna with a detection function that can detect the positional deviation in the optical axis direction between the main reflector and the sub-reflector in the orbital environment and the inclination of the sub-reflector can be realized. The effect is obtained.

According to the present invention, in orbit,
The position deviation in the optical axis direction between the main reflecting mirror and the sub-reflecting mirror and the inclination of the sub-reflecting mirror can be grasped. It is possible to obtain a very excellent effect that the antenna can be oriented and a high antenna gain can be secured.

Further, according to the present invention, an extremely excellent effect is obtained that the influence of the alignment of the transmitted and received light due to the inclination of the sub-reflector on the track can be corrected.

Further, according to the present invention, the alignment of the photodetector itself can be corrected by providing the correction means on the optical axis between the opening of the main reflector and the photodetector. The accuracy of the measurement of the misalignment with the sub-reflector can be improved, and the change in the signal level when the second reference light from the second reference light source is received is periodically measured. This is an extremely excellent effect that the secular change of the internal optical system can be detected.

Further, according to the present invention, by providing a plurality of first reference light sources at the peripheral edge of the sub-reflector, even if deterioration occurs due to an on-orbit failure, it is possible to perform redundant switching, and measurement can be performed. An extremely excellent effect that continuity can be maintained is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration according to an embodiment of a satellite-mounted optical antenna according to the present invention.

FIG. 2 is a diagram showing an example of image formation of a reference light source in the four-element photodetector of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main reflection mirror, 1a ... Aperture, 2 ... Sub reflection mirror, 3 ... Support, 4 ... Reference light source, 5 ... Reference light source, 6 ... Half prism, 7 ... Internal optical system, 8 ... Reference light source, 9 ... 4 elements Source photodetector, 9a: photoelectric conversion sensor, 9b: photoelectric conversion sensor, 9
c: photoelectric conversion sensor, 9d: photoelectric conversion sensor, 10: angle detection processing circuit.

Claims (3)

(57) [Claims] A main reflecting mirror having a light reflecting surface and an opening at a central portion; a sub-reflecting mirror opposed to an optical axis of the main reflecting mirror; a main reflecting mirror and a sub-reflecting mirror; A plurality of first reference light sources attached axially symmetrically to the periphery of the sub-reflector ; and a plurality of first reference light sources mounted on the periphery of the sub-reflector, and disposed on the optical axis of the main reflector. A plurality of divided light detection sensors for receiving the first reference light emitted from the first reference light source, and a level of an output voltage output from each light detection sensor of the light detector An angle detection processing circuit that calculates a difference between the main reflecting mirror and the sub-reflecting mirror in the optical axis direction and calculates a tilt of the sub-reflecting mirror by calculating the difference. Optical antenna. 2. The light for mounting on a satellite according to claim 1, wherein a correction means for correcting the alignment of the photodetector is provided on an optical axis between the opening of the main reflecting mirror and the photodetector. antenna. 3. The half prism according to claim 2, wherein the correcting means is provided coaxially with an opening of the main reflecting mirror, and receives the first reference light of the first reference light source, and the half prism. A second reference light source disposed on an optical axis of the prism and emitting a second reference light to the photodetector;