bab xii pengembangan mutakhir teknologi dan aplikasi satelit

8/13/2019 BAB XII Pengembangan Mutakhir Teknologi Dan Aplikasi Satelit

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FAKULTAS ELEKTRO & KOMUNIKASI

Some of New Satellite

Applications and

Technological Advancements


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FAKULTAS ELEKTRO & KOMUNIKASI 3

1. Direct to The Home (DTH)

Satellite Broadcasting

DTH systems are designed to transmit entertainmentTV programming to home receiving Earth terminals(home receivers). This is a natural extension of TVdistribution by satellite, utilizing the area-coverageand single service provider features of the

technology. DTH systems, also called Direct Broadcast Satellite,

employ either the BSS allocations, which areintended for this use, or the FSS allocations as one ofa number of possible applications.


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DTH Architecture


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Major elements of DTH system

1. DTH satellites in GEO (one or more): Spacecraft construction

Launch services;

Launch and on-orbit insurance.

2. TT&C:

Controls the space segment and monitors spacecraft health;

Verifies that transmissions to satellite do not causeinterference;

Provided by satellite operator (usually a separate company);

Limited communication required between DTH networkoperator and satellite operator.


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Major elements of DTH system

3. Broadcast center: Originates, acquires, and transmits program

material;

Generally centralized, with no or limited backup;

Part of conditional access system.

4. Customer service:

Billing and customer turn-on-off;

Customer assistance.


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Digital DTH transmission system,

(based on the DVB-S model)


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High-Power DTH Satellite Systems

High EIRP, typically 63 dBW; Fixed-frequency plan with 23-MHz transponders;

At least one satellite with five channels per country;

Circular polarization (left and right hand);

Fixed orbital spacing between satellites:

3 minimum separation;

9 for co-frequency assignments.

Satellites that serve different countries are colocatedwhere possible;

Maximum spacecraft reflector size of about 2m; Elliptical beams without shaping;

Mandated radiation levels into other countries.


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High-Power DTH Receiver

Dish size no smaller than 0.9m (0.45 typicaltoday);

Receiver noise figure no lower than 9 dB (10

dB typical today);

Relatively poor cross-polarization ability;

Relatively poor angular discrimination


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Comparison of DTH Systems

Around the World


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DIRECTV Broadcasting Center in

Castle Rock, CO


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TELKOMVISION SATELLITE TV

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2. Satellite Radio Broadcast

It delivers a multiplexed combination of several audio programchannels transmitted directly to automobile receivers, portableradios, and homes using special frequency allocations in theregion of L- and S-bands. S-DARS overcomes the rangelimitation of terrestrial FM radio broadcasting and providesquality of sound comparable to other digital formats such as MP-

3 and possibly CD. WorldSpace pioneered the concept of broadcasting a radio

service from space and launched Afristar, their first operatingsatellite, in October 1998. then followed by XM Satellite Radio inthe United States in March 2001and Sirius Satellite Radio.


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FAKULTAS ELEKTRO & KOMUNIKASI14

Basic architecture of a satellite digital

audio radio service (S-DARS)


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2.1. The WorldSpace

The WorldSpace system is built on the premise of serving the needypopulations of the world, as divided into three regions: Africa and theMiddle East (AfriStar), Asia and the Pacific Rim (AsiaStar), and Centraland South America (CaribStar).


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World space radio receiver

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System configuration in each region

The space segment: the satellite and its associated TT&Cfacilities needed to control the satellite;

The broadcast segment: the studios and feeder link systems touplink the programming to the space segment;

The radio segment: the individual receivers used by the public;

The mission segment: to control and monitor the broadcast

segment and the satellite payload. it is composed ofCommunication System Monitoring which receives all signalstransmitted by the satellite, controls the quality of the link interms of bit error rate, and controls the mapping of the programswith what is expected.


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General block diagram of the

WorldSpace communications payload


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Radio receiver block diagram and example of

WorldSpace receiver from Sony


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2.2. Sirius Satellite Radio

Sirius Satellite Radio is a commercial radio broadcasting company

using non GEO, headquartered in New York City. Sirius provide aprogramming package within a total of about 5 Mbps comprising 100audio channels, half of which are music and half of which are talkradio. Using advanced digital recording systems, the music may beassembled off-line for later playback and without advertising. Thetalk formats include standard services like Fox News Channel and

CNN along with a variety of shows to appeal across a spectrum ofinterests.

The satellite and network control functions are also provided in NewYork using automation onboard the spacecraft as well as withincomputers at the headquarters. Tracking, telemetry, and commandstations are located near the equator in Quito, Ecuador, and Utive,Panama; these locations see the entire orbit and each have twoantennas to allow for one spare across the system to maintaincoverage.


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Sirius orbital configuration


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The Sirius orbital ground track allows the three satellites to be visible above

North Americaat least two satellites are visible at any one time. TT&C

stations are located near the equator to provide continuous view of the three

satellites


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Sirius satellite fully deployed

Si i i i l d


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Sirius communications payload

block diagram

Si i S DARS d li


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Sirius S-DARS delivery system

architecture

T i l Si i i


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Typical Sirius receiver

block diagram

B i Li k B d t f Si i


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Basic Link Budget for Sirius

Satellite Radio


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Antenna Technology(Mobile Broadcasting Corporation of Japan)

Sk Fi di it d i t ll ti


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SkyFi radio unit and installation

options, by Delphi Electronics.


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The End

bab xii pengembangan mutakhir teknologi dan aplikasi satelit

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