GNSS Flashcards
What is the gps type made by Russia?
Glonass
What is the gps type made by China?
Beidou
What is the gps type made by EU?
Galileo (not in service)
What does GNSS stand for?
Global Navigation Satellite Systems
Explain space segment?
24 satellites ( 7 reserves) Configure in 6 orbital planes 12 hour orbit 20.2 km Alt Onboard Atomic clocks
Survivability
Accuracy
Coverage
Explain control segment?
Master control station
10 monitoring stations
Monitoring satellites
What does NAVSTAR stand for?
Navigation Satellite Timing And Ranging
Gps
What does multilateration mean?
Measurement of the difference in distance 2 or more known and unknown locations.
What does GPS work on?
Time and distance
What are the two satellite radio frequencies?
L1 and L2
Explain L1 radio frequency?
Coarse Acquisition code (CA)
Navigation message
Explain L2 radio frequency?
Precise code ( P(Y) ) (Encrypted) Navigation message
How long does a P(Y) code last for?
35 days
What does a Navigation message contain?
Ephermeris (Satellite location)
Almanac ( forecast of satellite location) bus timetable!
Sat clock corrections
GPS requires a minimum of how many fixes?
4
X, Y, Z and time
What are the main errors in GPS?
Receiver clock (time)
What is the least accurate GPS fix?
Height
Most GPS fixes can be corrected. Which one can not?
Trapasphere (environment)
What can interfere with GPS reception?
Weather Electrical cables/ underground High powered radars Large bodies of water Iso containers Barbwire fences
What are the two GPS positioning services divided into?
Standard positioning Services (SPS)
Precise Positioning services
PPS
What are GPS fixes accurate to?
SPS +- 30m
PPS +- 11.1m
What does DAGR stand for?
Defence Advanced GPS Receiver
What is the gps type made by USA?
Navstar