If the communication takes place between any two earth stations through a satellite, then it is called as satellite communication. In this communication, electromagnetic waves are used as carrier signals. Introduction Need for communication Satellite Communication How a satellite works Frequency Band of a satellite communication Kepler’s Laws Earth Orbit satellites ● Geosynchronous Earth Orbit ● Medium Earth Orbit ● Low Earth Orbit Subsystems ● Space Subsystem  AOC Subsystem  TTCM Subsystem  Power and Antenna Subsystems  Transponders ● Earth Subsystem  Transmitter  Receiver  Earth Station Antenna  Tracking Subsystem Multiple Access Techniques ● FDMA (Frequency Division Multiple Access) ● TDMA (Time Division Multiple Access) ● CDMA (Code Division Multiple Access) Satellite Communication Services ● One-way satellite communication link service ● Two-way satellite communication link service Global Positioning System ● GPS codes and services ● GPS receiver Advantages Disadvantages Application Bibliography Conclusion

1. SATELLITE
COMMUNICATION
Debasish Dutta
ddmasterdon@gmail.com

2. INTRODUCTION
 If the communication takes place
between any two earth stations
through a satellite, then it is called as
satellite communication.
 The first satellite to relay
communications was Pioneer 1, an
intended lunar probe.
 India launched its first artificial satellite
named Aryabhata in 1975.

3. NEED FOR COMMUNICATION
Sender
Channel
Receiver
Due the necessity of exchange of some
information, means of communication exist.

4. SATELLITE COMMUNICATION
A satellite is a smaller object that
revolves around a larger object in
space.
The communication takes place
between any two earth stations
through a satellite, then it is called as
satellite communication.
Here, electromagnetic waves are used
as carrier signals.

5. NEED FOR SATELLITE COMMUNICATION
Ground wave propagation
 Frequencies up to 2MHz
Sky wave propagation
 Frequency 2-30 MHz
Maximum hop distance is
limited to 1500KM only

6. HOW A SATELLITE WORKS
 A microwave repeater station in space
 A repeater is a circuit, which increases the
strength of the received signal and then
transmits it.
 Satellite's footprint is the area which
receives a signal of useful strength from
the satellite.
 Area of coverage is more than that of
terrestrial systems
 More bandwidth and broadcasting
possibilities

7. FREQUENCY BAND OF A SATELLITE
COMMUNICATION

8. KEPLER’S LAW
 Kepler’s !st Law
 Kepler’s 2nd Law
 Kepler’s 3rd Law
 Geosynchronous Earth Orbit Satellites
(GEO)
 Medium Earth Orbit Satellites (MEO)
 Low Earth Orbit Satellites (LEO)
EARTH ORBIT
SATELLITES

9. SUBSYSTEMS
The main operations of a
satellite communications are
orbit controlling, altitude of
satellite, monitoring and
controlling of other
subsystems.
 space segment
 earth segment.

10. SPACE
SUBSYSTEM
AOC Subsystem
TTCM Subsystem
Power Subsystem
Antenna Subsystem
Transponders

11. TRANSPONDER
Duplexer
Low Noise Amplifier
Carrier Processor
Power Amplifier
Transponder performs the
function of
Both transmitter and
receiver(responder)
• Bent Pipe Transponders
• Regenerative Transponders

12. EARTH
SUBSYSTE
M
Transmitter
Receiver
Earth Station
Antenna
Tracking Subsystem

13. MULTIPLE ACCESS TECHNIQUES

14. FDMA
• FDMA allots a different sub-
band of frequency to each
different user to access the
network.
• If FDMA is not in use, the
channel is left idle instead of
allotting to the other users.
• FDMA is implemented in
Narrowband systems and it is
less complex than TDMA.

15. TDMA
• TDMA shares a single carrier
frequency with several users
where each users makes use of
non-overlapping time slots.
• Data transmission in TDMA is
not continuous, but occurs in
bursts. Hence hands off
process is simpler.
• TDMA uses different time slots
for transmission and reception
thus duplexers are not
required.

16. CDMA
• In CDMA every user uses the
full available spectrum instead
of getting allotted by separate
frequency.
• CDMA is much recommended
for voice and data
communications.
• While multiple codes occupy
the same channel in CDMA, the
users having same code can
communicate with each other.
• CDMA offers more air-space
capacity than TDMA.

17. SATELLITE COMMUNICATION SERVICES

18. ONE-WAY SATELLITE
COMMUNICATION LINK SERVICE
Provides both point to point
connectivity and point to multi
point connectivity.
• Broadcasting satellite services like
Radio, TV and Internet services.
• Space operations services like
Telemetry, Tracking and
Commanding services.
• Radio determination satellite
service like Position location
service.

19. TWO-WAY SATELLITE
COMMUNICATION LINK SERVICE
Provides only point to point
connectivity
• Fixed satellite services like
Telephone, Fax and Data of high
bit rate services.
• Mobile satellite services like
Land mobile, Maritime and
Aero mobile communication
services.

20. GLOBAL POSITIONING SYSTEM
• a navigation system based on
satellite comm
• used in positioning,
navigation, monitoring and
surveying applications
• real time positioning and
timing synchronization

21. GPS CODES AND SERVICES
GPS Services
Precise Positioning Service
(PPS)
Standard Positioning Service
(SPS
GPS Codes
• Coarse Acquisition code
or C/A code
• Precise code or P code

22. GPS RECEIVER

23. ADVANTAGES
Flexibility
Ease in installing new
circuits
Distances are easily
covered
Broadcasting possibilities
DISADVANTAGES
The initial costs such as
segment and launch
costs are too high.
Congestion of
frequencies
Interference and
propagation

24. APPLICATIONS
Voice communications
Research and
development sector
Military applications
Navigations
TV broadcasting
In Radio
broadcasting
Internet
applications
data transfer
GPS applications
Internet surfing

25. CONCLUSION
We could say satellite communication brought a
big revolution in communication process