engineering

1. AHMED Wasiu Akande (Instructor), Dr.
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. Earth Station Design Standards
 Two steps are involved: requirement specifications and cost effective
architecture;
 Type of service offered (Fixed satellite service, Broadcast satellite service or
Mobile satellite service);
 Mode of communication (telephony, data, television etc.);
 Base band quality at the destination;
 System capacity and reliability
 Major system parameters relevant to Earth station design include transmitter
EIRP (Effective Isotropic Radiated Power), receiver figure-of-merit (G/T ), system
noise and interference and allowable tracking error.
Requirement Specifications

4. Earth Station Design Standards
 When it comes to designing a satellite communication system, it is always
advisable to minimize the overall system costs (development as well as recurring
costs of the Earth and space segments);
 However, a trade-off is always possible to reduce cost (incurred cost on the Earth
station could be reduced by having a more expensive space segment);
 Resulting to designing less expensive user terminals and more expensive
satellites.
 Some technical and regulatory constraints trade-offs are outlined here:
i. Effective (or Equivalent) Isotropic Radiated Power (EIRP);
ii. Receiver Figure-of-merit (G/T )
Cost Effective Architecture
Key Performance Parameters

5. Earth Station Standards
Figure 1: Block schematic of VSAT remote terminal

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

7. Earth Station Design Optimization/Reliability
 The transmitter EIRP and receiver G/T together dictate the performance of the
communication system and therefore one can be traded off against the other
during the design optimization process;
 For a minimal cost Earth station, G/T should be minimized (higher EIRP in the
satellite or being able to afford a lower carrier-to noise ratio);
 For desired base band quality at the receiver, this can be achieved by using
modulation schemes that are more immune to noise. In the case of digital base
band, coding allows a further reduction in G/T .
(1)
Where C/No is the carrier-to-total noise power spectral density, EIRP is the satellite’s effective isotropic radiated power, Lp is
the path loss, Lm is the link margin and k is the Boltzmann constant (in dBs).

8. Earth Station Design Optimization/Reliability
 Antenna tracking requirements;
 Traffic handling capacity;
 Terrestrial interface requirements;
 International regulatory bodies like (ITU) and technical constraints that drive the
optimization process;
Example: put certain limitations on the transmitted EIRP of the FSS satellites sharing their frequ-
ency bands with terrestrial systems in order to allow them to co-exist. For applications such as
direct broadcast, mobile communications etc.
 The satellite EIRP is also limited by the DC power available on the satellite, maximum
power that can be generated by the high power amplifiers on board the satellite and
the practical constraints on the satellite antenna diameter limiting the antenna gain;
 Antenna size, the gain reduces with decrease in operational frequency. This answers
why, satellite EIRP limitation is more acute in L-band used for mobile communications;
 Then choose an optimum configuration of the antenna, high power amplifier and the
low noise amplifier to achieve the desired values.

9. Environmental and Site Considerations
Careful site selection can take care of the ill effects of some of these
factors:
1. External temperature and humidity;
2. Rainfall and snow;
3. wind conditions;
4. likelihood of Earth quakes;
5. corrosive conditions of the atmosphere;
6. Minimizing radio frequency interference (RFI) and electromagnetic interference
(EMI) is another requirement;
7. A clear line-of-sight to the satellites of interest;
8. Availability of sufficient space for the Earth station equipment, easy
transportation to the Earth station and reliable electrical power are the other
requirements.

10. THANKS FOR YOUR ATTENTION