engineering

1. Dr. AHMED, Wasiu Akande (Instructor)
EARTH STATION TECHNOLOGY
(SCM 704)
ARCSSTE-E’s PGD Program 2021/2022

2. Outline
An Overview of Satellite Earth Station Technology Subsystems;
Earth Station Design and Fabrication considerations;
Earth Station Standards;
Reliability of Earth Stations;
Operations and Maintenance of Earth Stations;
Rocket Launch Technology and Parking Orbits.

3. An Overview of Earth Station
 Major subsystems comprising in an Earth station include:
a. transmitter system b. receiver system c. antenna system d. tracking system
d. terrestrial interface equipment e. primary power f. test equipment
Types of Earth Station (based on the size of the dish antenna)
i. Fixed Satellite Service (FSS) Earth Stations
ii. Broadcast Satellite Service (BSS) Earth Stations
iii. Mobile Satellite Service (MSS) Earth Stations
Types of Earth Station (based upon their usage)
i. Single function stations
ii. Gateway stations
iii. Teleports

4. An Overview of Earth Station
Figure 3: Very Small Terminal (Transmit/Receive) Figure 4: Very Small Terminal (Receive)

5. Figure 5: Iridium System
An Overview of Earth Station

6. An Overview of Earth Station
 Satellite phone is the most commonly used mobile satellite service;
 It is a type of mobile that connects to satellites instead of terrestrial cellular sites;
 Mobile satellite services are provided both by the geostationary as well as low Earth
orbit satellites. Geostationary satellite based mobile services also suffer from noticeable
delay while making a telephone call or using data services;
 More so, geostationary satellite system is frequent absence of line-of-sight between the
satellite and the phone due to obstacles present in between the two;
 In the case of LEO satellite systems, an obstacle would block the satellite access only for
a short time until another satellite passes overhead;
 The major advantage of LEO satellites based communication system is worldwide
wireless coverage with no gaps;
 Iridium (66 satellite covers polar regions) and Globalstar (44 satellites with Inclination of
52o) are the two major LEO satellite systems offering mobile satellite services.

7. Outline
An Overview of Satellite Earth Station Technology Subsystems;
Earth Station Design and Fabrication considerations;
Earth Station Standards;
Reliability of Earth Stations;
Operations and Maintenance of Earth Stations;
Rocket Launch Technology and Parking Orbits.

8. Earth Station Architecture
Figure 6 :Block schematic arrangement of a generalized Earth station

9. Earth Station Architecture
Baseband Section
 performs the modulation/demodulation function with the specific
equipment required depending upon the modulation technique and the
method employed;
 It comprises of a digital modem and a time division multiplexer in the case
of a two-way digital communication link;
 terrestrial interface is connected to the input/output baseband section for
the terrestrial network;
 The connection maybe directly to the user in some applications and could
be a fibre-optic cable link or a microwave link or a combination of the two;
 An Earth station has support facilities such as tracking, control and
monitoring equipment, power supply with back-up and environmental
conditioning unit.

10. Earth Station Architecture
RF Section
 Mainly comprises of antenna subsystem, the up-converter and the high power
amplifier (HPA) in the up-link channel and the antenna subsystem, low noise
amplifier (LNA) and the down-converter in the down-link channel;
 It interfaces with the modem subsystem of the baseband section
 The up-converter in the up-link channel is to convert the baseband signal to the
desired frequency (amplified to the desired level) and fed to the feed system for
subsequent transmission to the intended satellite;
 A low noise amplifier amplifies the weak signals received by the antenna and
then down converted to the intermediate frequency level before it is fed to the
modem in the baseband section;
 The antenna feed system introduces the desired polarization, provides the
necessary aperture illumination and isolation between the transmitted and the
received signals