JPH04256107A - Inter-satellite laser communication catching/tracking device - Google Patents

Abstract

PURPOSE:To obtain the catching/tracking device of a simple structure by using a hologram scanner to catch and track the laser light beams for the inter- satellite laser communication. CONSTITUTION:An optical antenna 1 condenses a received beam 2 and also narrows the spreading angle of a transmitted beam 3 to direct the beam 3 with high accuracy. The beam 2 is condensed by the antenna 1 and then inputted to a detector 7 through a hologram scanner 4, a half mirror 5 and a lens 6. The output of the detector 7 is inputted to a signal processing circuit 8. Then the incident direction of the beam 2 is calculated. If this incident direction is shifted from the prescribed direction, a control circuit 9 revolves the scanner 4 to change the direction of the beam 2. Thus the prescribed incident direction is secured for the beam 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acquisition and tracking device for inter-satellite laser communications.

0002

2. Description of the Related Art A conventional acquisition and tracking device for inter-satellite laser communication controls the pointing direction of a laser beam by moving a mirror using a mirror drive mechanism 11, as shown in FIG. The mirror drive mechanism 11 changes the angle of the mirror using a motor or a piezoelectric element.

0003

SUMMARY OF THE INVENTION The conventional acquisition and tracking device for inter-satellite laser communication described above has a drawback in that the mirror drive resolution is low when a motor is used for the mirror drive mechanism.

[0004] Furthermore, when using a piezoelectric element, there is a drawback in mechanical properties that the piezoelectric element is weak against bending and tension.

Furthermore, since the path of the laser beam is controlled by reflection from a mirror, there is also the drawback that it is susceptible to thermal distortion and contamination of the mirror.

[0006]

[Means for Solving the Problems] The acquisition and tracking device for inter-satellite laser communication of the present invention includes an optical antenna, a photodetector into which a received beam focused by the optical antenna is input, the photodetector and the optical It includes a hologram scanner disposed between the antenna and a control means for rotating the hologram scanner based on the output of the photodetector.

[0007]Furthermore, the acquisition and tracking device for intersatellite laser communication of the present invention is constructed by disposing a half mirror that transmits the received beam and reflects the transmitted beam between the hologram scanner and the photodetector. It's okay.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

In FIG. 1, an optical antenna 1 condenses a receiving beam 2 and narrows the spread angle of a transmitting beam 3 to direct it with high precision. The received beam 2 is focused by an optical antenna 1, passes through a hologram scanner 4, and is input to a detector 7 via a half mirror 5 and a lens 6. The output of the detector 7 is input to the signal processing circuit 8, and the receiving beam 2 is
The direction of incidence of is calculated. If the direction of incidence deviates from the predetermined direction, the control circuit 9 rotates the hologram scanner 4 to change the direction of the receiving beam 2 so that it becomes the predetermined direction of incidence.

The transmission beam 3 outputted by the laser light source 10 passes through the half mirror 5 in the opposite direction to the reception beam 2, that is, passes through the half mirror 5 and the hologram scanner 4, and is output from the optical antenna 1.

Note that the directional resolution of the laser beam by the hologram scanner 4 is determined by the diffraction pattern of the hologram scanner 4, so the resolution can be increased by selecting the diffraction pattern.

[0013]

As described above, the present invention uses a hologram scanner to capture and track a laser beam for intersatellite laser communication, thereby providing a capture and tracking device for intersatellite laser communication with a simple structure.

Furthermore, by selecting the diffraction pattern of the hologram scanner, it is possible to freely select the directional resolution.

Furthermore, since the hologram scanner is fundamentally resistant to contamination, it is possible to reduce the influence of contamination on the laser beam directing section.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a block diagram of a conventional acquisition and tracking device for inter-satellite laser communication.

[Explanation of symbols]

1 Optical antenna 2 Receive beam 3 Transmission beam 4 Hologram scanner 5 Half mirror 7 Detector 8 Signal processing circuit 9 Control circuit

Claims (2)

[Claims] 1. An optical antenna, a photodetector into which a received beam focused by the optical antenna is input, a hologram scanner disposed between the photodetector and the optical antenna, and a hologram scanner arranged between the optical antenna and the optical antenna. 1. An acquisition and tracking device for inter-satellite laser communication, comprising a control means that rotates based on the output of a detector. 2. A half mirror that transmits the received beam and reflects the transmitted beam is disposed between the hologram scanner and the photodetector.
The acquisition and tracking device for intersatellite laser communication described above.