sistem komunikasi satelit

SISTEM KOMUNIKASI SATELIT
BAB I
PENDAHULUAN
Topik:
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Overview Arsitektur komunikasi Satelit
Implementasi komunikasi satelit dalam kehidupan sehari-hari
Pengaruh komunikasi satelit terhadap sendi-sendi kehidupan modern
Overview sejarah komunikasi satelit
Overview Regulasi ITU-R
Obyektif Perkuliahan
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Mengenalkan kembali dan memahami blok diagram sistem
komunikasi dan mekanisme kerjanya
Mengenal dan memahami sejarah perkembangan komunikasi
satelit, evolusi, dan implementasi serta regulasi dan
pengaruhnya.
Referensi :
1. Bruce R. Elbert, “Satellite Communications Handbook”, 2nd
Ed., Artech House, 2004
2. Dennis Roddy, “Satellite Communications”, 3rd Ed., Mc
Graw Hill, 2001.
3. G. Maral & M. Bousquet, “ Satellite Communications
Systems, Technology, and Application,” 3 rd Ed., John Wiley
& Son, 2002.
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Arsitektur Komunikasi Satelit
Segmen Angkasa
Downlink
Uplink
TT&C
SB TX
SB RX
Master Station
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Arsitektur Komunikasi Satelit
• Segmen Angkasa:
– Struktur / Bus
– Payload
– Power Supply
– Kontrol temperatur
– Kontrol attitude dan orbit
– Sistem propulsi
– Telemetry, Tracking, & Command (TT&C)
• Segmen Bumi:
– User Terminal, SB Master, dan Jaringan.
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Jenis Spaceraft
Spinning Stabilized Satellite, misalnya
Palapa A, Measat, etc
3-axis Stabilized Satellite, misalnya
Telkom-1, Thuraya (UEA), etc
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Komponen Dasar Link Satelit
SB Receive
SB Transmit
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Tipe Orbit
• Equatorial, polar, dan inclined orbit.
• GEO (35,378 km), MEO (5000 km – 12.000 km), dan LEO (300km –
2000km).
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Tinggi Orbit dan delay
• Delay merupakan
parameter penting yang
menentukan kinerja link
komunikasi.
• Periode orbit akan
menentukan jenis
komunikasi satelit, dan
juga konstelasi terkait
dengan desain cakupan
komunikasi.
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Konstelasi Satelit
• Untuk cakupan Global
biasanya dibutuhkan banyak
satelit yang ditempatkan
dalam beberapa bidang
orbit, dan spasi antar satelit
ditentukan.
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Bentuk Cakupan Satelit
• Global beam, spot beam, dan shaped beam
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Frequency Bands
Band
Frequency
Range
Total Bandwidth
General Application
L
1 to 2 GHz
1 GHz
Mobile satellite service (MSS)
S
2 to 4 GHz
2 GHz
MSS, NASA, deep space research
C
4 to 8 GHz
4 GHz
Fixed satellite service (FSS)
X
8 to 12.5 GHz
4.5 GHz
FSS military, terrestrial earth
exploration, meteorological
satellites
Ku
12.5 to 18 GHz
5.5 GHz
FSS, broadcast satellite service
(BSS)
K
18 to 26.5 GHz
8.5 GHz
BSS, FSS
Ka
26.5 to 40 GHz
13.5 GHz
FSS
General Applications
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Mobile Satellite Service (MSS): Is a satellite system which uses portable terrestrial terminals.
MSS terminals may be mounted on a ship, an airplane, an automobile or may even be
carried by an individual. The most promising application of Mobile Satellite Service is
portable satellite telephones which will enable phone service anywhere on the globe.
Another application is global positioning systems (GPS)
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Fixed Satellite Services (FSS): Broadcast feed used between TV networks. Main application is
on National Cable Channels supplied to the TV head station
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Broadcast Satellite Service(BSS): This is also known as Direct Broadcast Satellite.
communications satellite that transmits to small DBS satellite dishes (usually 18" to 24" in
diameter). DBS technology is used for DTH-oriented (Direct-To-Home) satellite tv services,
such as DirecTV, Dish Network, and Sky Angel in the United States, ExpressVu in Canada, and
Sky Digital in the UK.
Regulasi dan Koordinasi Frekuensi
• Regulasi slot orbit , terutama GEO, dan
frekuensi secara internasional dilakukan oleh
ITU-R.
• Karena tiap negara berhak mengklaim wilayah
udara (space) diatasnya, maka harus dilakukan
koordinasi untuk filing orbit dan alokasi
frekuensi supaya tidak terjadi overlaping dan
interferensi.
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Objektif Regulasi ITU-R
• To facilitate equitable access to and rational use of the natural
resource of the radio-frequency spectrum and the
geostationary-satellite orbit;
• To ensure the availability and protection from harmful
interference of the frequencies provided for distress and safety
purposes;
• To assist in the prevention or resolution of cases of harmful
interference between the radio services of different
administrations;
• To facilitate the efficient and effective operation of all
radiocommunication services;
• To provide and, where necessary, regulate new applications of
radiocommunication technology.
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Pembagian Alokasi Spektrum ITU
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Definisi Layanan dan Alokasi Frekuensi
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Definisi Layanan dan Alokasi Frekuensi
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Satelit di Orbit GEO (mid-1990)
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Aplikasi Komunikasi Satelit
Sambungan Telepon Internasional
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Telepon dan Data
• Dial-up voice, fax, dan data di multiplex dan diolah
(dikompresi) sebelum diinputkan ke modem satelit.
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Direct Broadcasting Services (DBS)
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Fungsi Satelit pada TV Broadcasting
• Distribusi Point-to-multipoint programTV dari
studio ke stasiun broadcast lokal;
• Transmisi Point-to-point liputan/siaran langsung
ke studio (alternatively, from one studio to
another studio);
• Distribusi Point-to-multipoint program cable TV
dari studio ke cable TV lokal
• Distribusi Point-to-multipoint program cable TV
dan/atau jaringan TV langsung dari studio ke
customer (i.e., DTH-direct to home).
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Keberhasilan DTH-DBS Dipengaruhi Oleh
Faktor-Faktor:
• Ukuran Antena RX: makin kecil ukuran antena, makin mudah di
instal dan murah. Dewasa ini ukuran antena TVRO berkisar
antara 35 cm – 80 cm, dan harga sekitar $100 (Rp 1 jt)
termasuk set top box.
• Peralatan simple dan mudah dioperasikan.
• Satu antena RX bisa di gunakan bersama-sama (sharing) untuk
beberapa user/TV.
• Jumlah transponder yang bisa dibawa oleh Satelit meningkat
(umumnya sekitar 32 Transponder)
• Jumlah kanal per transponder umumnya 2 kanal TV analog dan
10 kanal TV Digital. Dengan teknik kompresi yang makin baik,
jumlah kanal TV digital bisa ditingkatkan
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VSAT Network
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Perangkat VSAT
• VSAT untuk broadband communications.
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Direct Audio Broadcasting (DAB)
WorldSpace Receiver
Basic arsitektur DAB
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Intersatelit Link (ISL)
• Ilustrasi laser intersatellite link oleh satellite Artemis.
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Keunggulan Komunikasi Satelit
• Cakupan yang luas: satu negara, region, ataupun
satu benua
• Bandwith yang tersedia cukup lebar;
• Independen dari infrastruktur terrestrial;
• instalasi jaringan segmen bumi yang cepat;
• Biaya relatif rendah per site;
• Karakteristik layanan yang seragam;
• Layanan total hanya dari satu provider;
• Layanan mobile/wireless yang independen
terhadap lokasi.
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Kelemahan Komunikasi Satelit
• Up Front Cost tinggi: Contoh untuk Satelit GEO: Spacecraft,
Ground Segment & Launch = US $ 200 jt, Asuransi : $ 50 jt.
• Distance insensitive: Biaya komunikasi untuk jarak pendek
maupun jauh relatif sama.
• Hanya ekonomis jika jumlah User besar dan kapasitas
digunakan secara intensif.
• Delay propagasi besar.
• Rentan terhadap pengaruh armosfir, dll
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Overview Sejarah
Komunikasi Satelit
• 1957: Sputnik diluncurkan (USSR)
• 1964: INTELSAT (International Telecommunications Satellite dibentuk beranggota-kan
140 negara.
• 1975: Anik untuk Komunikasi domestik Canada
• 1976: SKSD Palapa (Palapa-A).
• 1999: Telkom-1 diluncurkan.
• 2005: Telkom-2
• 2012: Telkom-3  Gagal mencapai orbit
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Beginnings of satellite
communication
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Origins: Arthur Clarke’s article in Wireless World in 1945
WW-II stimulated development of two key technologies
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First satellite launched in 1957 by USSR
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Microwave communication
Missile technology
Sputnik, 83.6kg, LEO, atmospheric studies
Mission duration 3 months
First commercial communication satellite 1967
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Intelsat I - EarlyBird, 34.5kg, GEO, communication satellite
Coverage between US and Europe
Operated 4 years (deactivated in 1969)
Launched from KSC
Could handle 240 voice and 1 TV channel
Owned by Intelsat (52 countries)
Intelsat- EarlyBird
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Sputnik 1
Development of satellite
communication
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Imagination (1945-1960)
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Innovation (1960-1970)
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Establishment of governmental space exploration agencies
and international satellite consortia
Development of communication and rocket technology
First launches
Privatization and private ventures (1990 – on)
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Communication satellites become mainstream technology led by
private business
Leading applications: broadcast TV, data backhaul, mobile
communications in the air and on the sea, navigation, etc.
Future – integration of satellite technology with Internet
Commercialization (1970-1980)
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Early days of extensive scientific research
“Dreaming” of what is possible
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Satellite communication becomes commercial technology
Applications: cross continental telephony and satellite TV
Liberalization (1980-1990)
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Transformation of international governmental consortia
Market led approach allowed private investments
Regulatory framework changes that allowed all of the
transformations to take place
Satellite applications
(values in B$)
History channel documentary: Satellites – how they work
https://www.youtube.com/watch?v=eYUxkSFCKZQ
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Soal-soal
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Sebutkan jenis konstelasi satelit
Apa hubungan antara delay dengan ketinggian satelit?
Apa yang dimaksudt distance insentive?
Sebutkan type orbit
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