Satelite Principles Flashcards
What is asynchronous orbit?
Satellite is going the other way than earths orbit
What do you use a asmith card for?
Bearing & elevation
What is a syncromes orbit?
Satellite stayes in the same place in the sky
What is the night of a geo orbit?
22223miles or 35,756km
What is the hight of leo orbit?
80 - 1200
What are military satellites orbit?
Geostationary syncrones orbit
Disadvantage and advantages of geostationary orbit?
Less drag / fewer satellites / provides constant coverage
Propagation loss / can’t provide polar coverage
What kind of orbit would you expect to find a GPS satellite in?
Asynchronous orbit
Name one disadvantage and one adavtage of LEO satellite?
Closer to earth - need less power, increasingly used for mobile comms, ideal for surveillance / photos.
Requires constellation of satellites for constant coverage, susceptible to drag
Explain what is meant by a broad beam footprint?
Wide down print from satellite
Explain spot beam?
Narrow down print from satellite
What is the approx frequency range of commercial satellite communication systems such as INMARSAT, IRIDIUM, THURAYA etc?
1525 to 1660 MHz ish L band
List the types of satellite communication / system we use in the group?
GPS, Thuraya, INMARSAT (GAN), INMARSAT (BGAN), iridium, military satcom, military tacsat
What is the approx frequency range of military strategic satellites communication systems such as UK/PSC501/3/4 & DAGGER/TALON etc?
7.25 to 8.4 Ghz
Which 2 generations of sky net satellites are used by UK military today?
Skynet 4 & 5
List the four INMARSAT GAN OCEAN REGIONS.
Pacific Ocean region
Atlantic Ocean region west
Atlantic Ocean region east
Indian Ocean region
What freq does NAVSTAR GPS system operate?
1575.42 MHz
What kind of orbit would you expect to find a IRIDUIM satellite?
Asynchronous
How many LES(land earth stations) does the Inmarsat network have?
29
What is the satellite downlink coverage area called?
Footprint
What is the approx frequency range of military tactical satellite communication systems such as AN/PRC117F, 148 etc? (To the nearest 50 MHz)
240 - 320 MHz
What are the six application for satellites? What are they used for?
Meteorological Broadcast Navigation Scientific Phot surveillance Communication
What is transmission delay?
The time is taken for a signal to trace between two SGS via a satellite
What does SGS stand for?
Satellite ground station
LES?
Land earth station
Military satcom bearers?
Dagger talon
Vsat
Sweedish
SANTAM
