SatCom Principles Flashcards
When used for communications,
a satélite acts as a repeater
What is the purpose of a communication satélite?
To relay the signal around the curve of the earth
Characteristics of a satélite:
.Self-contained communications system,
.Receives signals from earth and retransmits them using a transponder
.Creates a comms channel between the transmitter and receiver
Satélite components
1. Antennas
2. Transponders
3. The power system
4. Solar panels
5. Propulsion system
6. Fuel
Uses for comms satélites
1. Telephony
2. Television
3. Radio
4. Internet
5. Military applications
Antenna sub-system
. 2m uhf helix
. Shf
. Ehf
. Telemetry
. Tracking
. Command
What frequencies does satcom use?
A wide range of radio and microwave frequencies.
7 Benefits of Satcom
. Global
. Versatile
. Reliable
. Seamless
. Fast
. Expandable
. Flexible
Definition of an orbit:
An orbit is a regular, repeating, curved path that an object in space takes around another one due to gravity.
What happens if a satélite in orbit moves too slowly?
It falls to earth due to earths gravity.
What happens if a satélite in orbit moves too quickly?
It will escape earths gravitational pull and drift away.
Five different orbits:
GEO: Geostationary orbit
MEO: Medium Earth orbit
LEO: Low Earth Orbit
HAP: Hight Altitude Plane
LAP: Low Altitude Plane
Low Earth Orbit:
Altitude: 160 - 2000km
Speed: ~8 km/sec
Orbital Period: 90 mins
Low Earth Orbit Uses:
. Communication satélites such as Iridium
. Earth monitoring satélites:
Able to see surface of Earth more clearly
Able to traverse surface of Earth
. International Space Station
Space debris is LEO is an issue!
Advantages of LEO:
. Inexpensive
. Minimal transmission delay
. Maintainable
. Multiple applications
