Definition

The European Space Agency (ESA) has programmes underway to place Satellites carrying optical terminals in GEO orbit within the next decade. The first is the ARTEMIS technology demonstration satellite which carries both microwave and SILEX (Semiconductor Laser Intro satellite Link Experiment) optical interorbit communications terminal. SILEX employs direct detection and GaAIAs diode laser technology; the optical antenna is a 25cm diameter reflecting telescope.

The SILEX GEO terminal is capable of receiving data modulated on to ....etc

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ABSTRACT
Satellite crosslinks generally require narrower bandwidths for
increased power concentration. We can increase the power concentration
by increasing the cross page link frequency with the same size antenna. But
the source technology and the modulation hardware required at these
higher frequency bands are still in the development stage. Use of
optical frequencies will help to overcome this problem with the
availability of feasible light sources and the existence of ....etc

[:=Read Full Message Here=:]

Definition

The European Space Agency (ESA) has programmes underway to place Satellites carrying optical terminals in GEO orbit within the next decade. The first is the ARTEMIS technology demonstration satellite which carries both microwave and SILEX (Semiconductor Laser Intro satellite Link Experiment) optical interorbit communications terminal. SILEX employs direct detection and GaAIAs diode laser technology; the optical antenna is a 25cm diameter reflecting telescope.

The SILEX GEO terminal is capable of receiving data modulated on to ....etc

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The beginning of new millenium sees an important milestone in military aviation communication with the introduction of the first Super-High-Frequency (SHF) airborne satellite communication (Satcom) terminals, which are due to enter service on Nimrod maritime reconnaissance aircraft (MRA4). Satcom terminals using the Ultra-High-Frequency (UHF) band have been fitted to larger aircrafts for a number of years. Although relatively simple to install and comparatively inexpensive, UHF satcoms(240-270 & 290-320 MHz bands) suffers from very limited capa ....etc

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CHAPTER 1
INTRODUCTION

Communication links between space crafts is an important element of space infrastructure, particularly where such links allow a major reduction in the number of earth stations needed to service the system. An example of an inter orbit page link for relaying data from LEO space craft to ground is shown in the figure below



Interorbit page link for relating data from LEO spacecraft to ground

Fig. 1
Inter orbit page link for relaying data from LEO space craft to ground.


The above figure represents a ....etc

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....etc

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xyz xffgyh fghgdf fghvff fggbhhh fggg... ....etc

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ABSTRACT
Satellite crosslinks generally require narrower bandwidths for increased power concentration. We can increase the power concentration by increasing the cross page link frequency with the same size antenna. But the source technology and the modulation hardware required at these higher frequency bands are still in the development stage. Use of optical frequencies will help to overcome this problem with the availability of feasible light sources and the existence of eff ....etc

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ABSTRACT
This paper outlines some of the techniques being developed to provide affordable, reliable satellite communications suitable for a wide range of military aircraft, from agile platforms such as jets and helicopters to surveillance, tanker and transport aircraft. It also gives an overview of airborne SHF (Super High Frequency) and also EHF (Extremely High Frequency) satcom techniques. Although presently used UHF (Ultra High Frequency) satellite communication are relatively simple to install and comparatively inexpensive, suffer from ....etc

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Abstract
LEO is Low Earth Orbit satellite.It circulates on a lower orbit in a shorter period . Additionally LEO systems try to ensure a high elevation for every spot of the earth to provide a highquality communication page link . The networks will play an important role in the evolving information infrastructure . It provides communication with shorter endto- end delays and e_ciency frequency usages . Some problems need to be solved before LEO satellite system can be successfully deployed . One of these problems is handover management . Even ....etc

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