Satellite Communications Flashcards
What are the 2 Types of Satellite?
Natural
Man made
Purpose of Satellite communications?
Communications
Research
Observations
Weather
Navigation
What equals worldwide Radio/Television communication system?
3 Satellites spaced 120 degrees apart
Travelling west to east
Principles of satellite communications?
Power
Satellite
Transmit
Recieve
Line of Sight(LOS)
Frequency bands?
UHF-300Mhz-3Ghz
SHF-3Ghz-30Ghz
3 segments a satellite system can be divided down into?
Space segment
Earth segment
Control segment
What are the three main hazards presented by SatComms
Radio Frequency(RF)
Electrical
Deployment
Uplink
7.9-8.4Ghz
Downlink
7.25-7.75Ghz
What does Azimuth and Elevation mean
Horizontal & Up/Down
Advantages of SatComms
Quick set-up
World-wide communications
Versatile
Remote locations
Disadvantages of SatComms
Planning, Development & Deployment
Life-span of fuel
Network of satellites needed
Cost
2 Types of Satellite Network?
Simple
Complex
Expand on Complex Satellite Network
multiple satellites are needed, examples:
- GPS
- Broadcasting
- Communications
What are the 3 Types of Orbit?
Polar
Synchronous
Sub-synchronous
What are the 2 examples of Synchronous Orbit?
Low Earth Orbits(LEO)
Medium Earth Orbit(MEO)
What are the 2 examples of Sub-synchronous Orbit?
Geostationary
Geosynchronous
Expand on Synchronous Orbit?
-Takes __Hrs __Mins __Secs to orbit around the Earth
-Maintains altitude of __k or __miles
-Requiring __ satellites __ degrees apart at an angle of __
Expand on Geostationary
Coincides with equatorial plane
Expand on Geosynchronous
Does not coincide with equatorial plane, but at an incline to it
What are the 4 Monitoring & Control points
Beacon
Locking on
Tracking
Monitoring
What are the 4 Coverages
Global
Regional Wide - 1800km
Regional Narrow - 1350km
Theatre - 600Km
What are the 4 antenna types?
Gregorian
Axial or Front-feed
Off-Axis or Offset-feed
Cassegrain
The System is divided into 7 Major Subsystems, what are they?
Users
Baseband
Transmitter
Clock
Receiver
Antenna
Power
Monitoring & Control
What does the Transmitting Station Comprise of?
Multiplexer
Modem
Upconverter – Clock
Solid State Power Amplifier
Duplex
Bandpass Filter
Waveguide
Reflector
What does the Receiving Station Comprise of?
Reflector
Waveguide
Duplex
Bandpass Filter(BPF)
High Noise Amplifier(HNA)
Down Converter (X-L)
*Beacon RX & Antenna Ctrl Unit
Modem
Multiplexer
Where are the 2 main uk ground satellites
oakhanger
colerne
