102824549 comm satellite ppt bbb

7/27/2019 102824549 Comm Satellite Ppt Bbb

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APAPER PRESENTATION

ON

BYM.RASHMI &G.SWATHI

SREE VIDYANIKETHAN ENGINEERINGCOLLEGE

TIRUPATHI


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INTRODUCTION The demand for high-capacity wireless services

is bringing increasing challenges, especially fordelivery of the last mile .

The need for line of-sight propagation pathsrepresents a constraint unless very largenumber of base-stations are employed.

An emerging solution is offered by high-altitude

platforms (HAPs) . HAPs operate in the stratosphere at altitudes of

up to 22 km to provide communication facilities.


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It causes high latency (signal delay) . limited signal penetration through buildings . Any upgrade requires the launch of an entire new

constellation. Takes 3-4 years to deploy the entire system. high infrastructure cost . We cannot shift capacities, and also the dead zones

are quite common. A complex and expensive installation and network

management is needed. Network building requires literally hundreds of towers.

LIMITATIONS OFSATELLITES


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ALTERNATIVE TO SATELLITES-HAPS

Single aerial platform can replace a large number of

terrestrial masts , associated costs, environmentalimpacts. High elevation angle compared to terrestrial base

stations A visibility of around 200 Km at 5 Deg elevation

Replaces large number of terrestrial base stations Offer much lower path loss than satellites - better by ~

34 dB for LEO satellites and ~ 66 dB for GEO satellites. HAPs has assigned frequency bands in 47/48 GHz and

28 GHz bands

Site acquisition problems are also eliminated, togetherwith installation & maintenance costs.

Types of HAPs: Manned plane Unmanned airship Unmanned plane Out of these we use airships for communication purpose.


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AIRSHIP or DIRIGIBLE is a type of aerostat that can be

steered and propelled through air using rudders andpropellers and other thrust mechanisms

PrinciplE

Airship operate on the principle ofarchimedes

Bodies submerged in to a fluid receive a lifting force which isequal to mass of displaced fluid

AIRSHIPS


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The airship has a pressurized

semi-rigid hull of ellipsoidal shapewith an overall length of nearly 200m. I

Internal bags filled with the buoyant

helium gas. Two air ballonets are installed

inside the hull to keep the airship ata required attitude.

For a load balance to the liftingforce , catenary curtains areconnected to a lower rigid keel

Propulsive propellers are mounted

on both the stem and stern . Tail win s are installed on rear end.


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ENERGY STORAGE

Lightweight solar cells in the form oflarge flexible sheets, which may weightypically well under 400g/m2 cover theupper surfaces of the airship.

During the day, power is stored inregenerative solar fuel cells, whichprovides all the power requirements atnight.

The performance and ageing of thefuel cells determine the achievablemission duration.


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GROUND HANDLING, LAUNCH AND RECOVERY

Launch and recovery is perhapsthe most difficult phase of airshipflight.

One important factor is the real estaterequired

This will depend on the size of theairship, its controllability and type oflaunch.The number of airships required tobe moored at any one site would alsoaffect the acreage.Many companies are planning largefleets but the build, launch andrecoveries will need to be scheduled

to optimize the ground area and


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The Airborne Relay Communications (ARC)System is the name of an airship platform planned

by the US Company Platforms WirelessInternational.The ARC system is designed to operate at loweraltitudes, 3 to 10.5 km. originally known as

Aerostats.

INNOVATONS IN AIRSHIPS


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Platforms Wireless International is developing a systemwhich provides fixed wireless broadband as well as

mobile services to areas of 55 to 225 km diameter persystem and servicing up to 1'500'000 subscribers .

ARC system is not using solar cells. Electricity issupplied to the payload via a 2.5 cm thick cable.

It also incorporates a fiber-optic cable link that connectsthe airborne base stations to the rest of the network.

A no-fly zone must also be created so other aircrafts donot fly intom the airship or its cable.


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SPECIFICATIO

NS

TERRESTRIAL

WIRELESS

SYSTEM

AIRSHIP

TECHNOLOGI

ES

SATELLITE

SYSTEMS

HEIGHT OVERGROUNDLEVEL

5-250 KM 3-22 KM 500-36000 KM

LIFETIME Up to 15 years Up to 5 years Up to 15 years

COVERAGE Only land &shore possible Land & seapossible Land & seapossible

ESTIMATEDCOST OFINFRASTRUCTURE

varies >$50 million >$200 million

REMARKS *Maintenancepossible*number oftransmitters

necessary

*maintenance&redeployment ispossible

*unsolvedpower problems

*high launchingcosts*well known &Proven

technlogies


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conclusionsatellite systems have capacity limitations and

high installation costs

Hence, airships can be used as a low costalternative for communication satellites for deliveryof future broadband wireless communications.


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102824549 comm satellite ppt bbb

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