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Presented by:

DHARAMVEERRoll No. 48120802

PRESENTATIONON

OPTICAL SATELLITECOMMUNICATION

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Communication links between spacecrafts is an important element of spaceinfrastructure, particularly where suchlinks allow a major reduction in thenumber of earth stations needed toservice the system.

Introduction :

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SEVERAL TYPES OF SATELLITE

LEO

MEO GEO

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Originally proposed by Author C.Clarke

Circular orbit above the equator.Angular separation about 2

degree allows 180 satellites.Round trip time to satellite about

0.24 sec.

GEO

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EARLY SATELLITES

Relay - 4000 miles orbit

Telstar

Allowed Line transmission acrossthe Atlantic.

Syncom 2 - First Geosyndronoussatellite.

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LINK DESIGN OF SATELLITE

Wavelength and Polarization

Link Budgets for an asymmetric link

Pointing

Acquisition

Tracking

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DIRECT DETECTION OPTICALTERMINAL

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OVERVIEW OF THE SOUTTERMINAL

The SOUT terminal consists of two main

parts: a terminal head unit and a remote

electronics module (REM). The REM contains the

digital processing electronics for the pointing

acquisition and tracking (PAT) and terminal

control functions together with the

communications electronics.

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OPTICAL ANTENNA

The optical antenna comprises the telescope andcoarse pointing assembly. The CPA uses

stepping motors together with a conventional

spur gear and planetary gear. The total height ofthe optical antenna is a major contributor to the

height of the CPA above the platform which

affects LEO and GEO link.

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OPTICAL ANTENNA

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MAJOR PROBLEMS FORSATELLITES

Positioning in Orbit

Stability

Power

Communication

Harsh Environment

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THANK YOU