ECE 5233 Satellite Communications
Prepared by:
Dr. Ivica Kostanic
Lecture 1: Introduction to Satellite Systems
(Sections 1.1-1.4)
Spring 2014
Florida Institute of technologies
Outline
Class overview
Configuration of a satellite systems
Elements of a satellite system
Types of satellite systems
Brief history of satellite communication
Florida Institute of technologies
Page 2
Satellite communication system
 Satellite system consists of
o Earth segment (traffic and control)
o Space segment
 Earth segment
o Service provider hub (ground)
o User terminals
 Space segment
o Satellite (s)
o Communication links to and from
satellites
1. Data center of the sat-com provider
2. Central hub (receives data stream and sends it toward satellite)
3. Satellite (receives data stream, amplifies and sends it back towards ground)
4. End user antenna – critical part (small size, high performance)
5. Modem – receives data stream
6. User end network – usually IP network
Florida Institute of technologies
Page 3
Ground segment
 Consists of earth stations
 Satellite network may have one or more earth stations
 Earth station may be transmit-receive or receive only
 Earth stations are connected to terrestrial networks (PSTN
for CS traffic or Internet for PS)
 Usually have very large antennas (up to 30m in diameter)
 Earth stations have high quality and redundant links to
terrestrial networks
Example of a Ku band
earth station antenna
Functional block diagram of an earth station
Florida Institute of technologies
Page 4
Space segment
 Satellite consist of
o Payload – used in communication
o Platform – facilitates operation of payload
 Payload
o Receive antenna
o Electronics for communication
o Transmit antenna
 Two types of satellites
Basics of “bent pipe” architecture
o “Bent pipes” (transparent)
o Regenerative (base band processing)
 Smallest assignable recourse
o Satellite transponder
o Satellite usually hosts multiple transponders
o Satellite usually operates in single band (although
there are some multiband satellites)
 Transmit antenna may be
o Single beam – one area of the Earth
o Multi beam – multiple areas of the Earth
Satellite with onboard processing
Florida Institute of technologies
Page 5
End user segment
 User stations
o Mobile stations (mobile terminals)
o VSAT terminals
o Gateways (connect space segment to
terrestrial networks)
 User equipment may
o Connect to user stations

Example: Satellite TV
o Integrate with user stations

Globstar satellite phones
Example: Satellite phone
 Heavily dependent on the end application
Marine satellite antennas
Satellite TV equipment
Florida Institute of technologies
Satellite on the move
Page 6
Types of satellite orbits
Constellation of
Globstar system
 Orbit height
o Low Earth Orbit (LEO)

Attitude 160-2,000km

Satellite speed ~ 8km/sec

Orbital period ~ 90 min

Example: Globstar, 48 satellites in six planes, 1413km
o Medium Earth Orbit (MEO)

Altitude 2,000km -35,786km

Satellite speed 8km/sec to 3 km/sec

Orbital period 2 to 24h

Example: GPS, 24 satellites in 6 planes, 20,200km
Constellation of
GPS system
o Geosynchronous orbit (GSO)

Altitude 35,768km

Satellite speed ~ 3km/sec

Non zero inclination

Orbital period 24 hours
o Geostationary orbit (GEO)

GSO satellite in zero inclination orbit
Florida Institute of technologies
Page 7
Satellite services
 Fixed satellite services (FSS)
o PTP or PTMP delivery of signal across the
Globe
 Mobile satellite services (MSS)
o Delivery of satellite signal to mobile platforms
(either terrestrial, marine or aeronautical)
 Broadcast satellite services (BSS)
o Broadcast of satellite signal (TV, radio)
 Navigation satellite services (NAV)
 Earth exploration services (ESS)
 Space research services (SRS)
 Space operations services (SOS)
 Radio determination satellite services
(RSS)
 Inter-satellite services (ISS)
Florida Institute of technologies
Page 8
Frequency bands used for sat-comm
 Satellites operate in microwave frequency range
 Two links
o Uplink – ground to satellite
o Downlink – satellite to ground
 Each link uses its own band
 Uplink operates on higher frequency
 Microwave frequency bands
o L band:
1-2GHz
o S band:
2-4GHz
o C band:
4-8GHz
o X band:
8-12GHz
o Ku band:
12-18GHz
o K band:
18-26.5GHz
o Ka band:
26.5-40GHz
 Majority of existing systems operate in C and Ku
 Higher frequencies
o More available spectrum
o Better antenna directivity
o Higher propagation losses
o More sophisticated technology
Frequency chart for communication
satellite services
Florida Institute of technologies
Page 9
Frequency management
 Responsibility of International
Telecommunication Union ITU
 Insures:
o
Non-interference condition between different
satellite systems
o
Fairness between nations in access to the
satellite frequencies
 Frequency allocation may be
o
exclusive for given service
o
shared between services
ITU Regions
 Service provisioning usually requires
consent of all countries within coverage
area of the satellite
 Frequency is usually allocated in pairs
o
One frequency for UL
o
One frequency for DL
 UL frequency is higher
Example: VIASAT license in
Ka band as of 2010
Florida Institute of technologies
Page 10
Beginnings of satellite communication
 Origins: Arthur Clarke’s article in Wireless World in 1945
 WW-II stimulated development of two key technologies
o
Microwave communication
o
Missile technology
 First satellite launched in 1957 by USSR
o
Sputnik, 83.6kg, LEO, atmospheric studies
o
Mission duration 3 months
 First commercial communication satellite 1967
o
Intelsat I - EarlyBird, 34.5kg, GEO, communication satellite
o
Coverage between US and Europe
o
Operated 4 years (deactivated in 1969)
o
Launched from KSC
o
Could handle 240 voice and 1 TV channel
o
Owned by Intelsat (52 countries)
Sputnik 1
Intelsat- EarlyBird
Florida Institute of technologies
Page 11
Development of satellite communication
 Imagination (1945-1960)
o
Early days of extensive scientific research
o
“Dreaming” of what is possible
 Privatization and private ventures (1990 – on)
 Innovation (1960-1970)
o
Establishment of governmental space exploration
agencies and international satellite consortia
o
Development of communication and rocket technology
o
First launches
o
Communication satellites become mainstream technology led
by private business
o
Leading applications: broadcast TV, data backhaul, mobile
communications in the air and on the sea, navigation, etc.
o
Future – integration of satellite technology with Internet
 Commercialization (1970-1980)
o
Satellite communication becomes commercial
technology
o
Applications: cross continental telephony and satellite TV
 Liberalization (1980-1990)
o
Transformation of international governmental consortia
o
Market led approach allowed private investments
o
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
Florida Institute of technologies
Page 12