SATCOM

Question 1

Describe Geostationary Orbit

Answer 1

The satellite appears stationary above the same point above the earth

Question 2

Describe what is meant by footprint

Answer 2

The area on the ground that the satellite covers

Question 3

Describe the problems when fitting SATCOM aerials to an aircraft

Answer 3

Satellite tracking- tracking circuits have to be used to ensure the aerial is pointing at the satellite

Aerial position- The location of the aerial must allow for continuous lock

Doppler shift- created by relative movement

Question 4

SATCOM advantages and disadvantage

Answer 4

Smaller aerials

More channels available

Less transmitter power

UHF and SHF are more suitable for wideband signals

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Expense

Question 5

Identify the main digital modulation techniques used in SATCOM?

Answer 5

Time Division Multiplexing

Frequency Hopping Spread Spectrum

Phase Shift Keying

Question 6

Geosynchronous orbit

Answer 6

Matches the rotation of the earth