GS GNSS/RNAV Flashcards
How many satellites does the system have?
24
How many orbital planes are there?
6
How long does it take a satellite to orbit?
11 hours and 56 minutes
How many orbits can a satellite do per day?
2
How high do the satellites orbit?
20200km
How fast do satellites travel?
11340km/h
What is the Space Segment?
The satellites
What is the Control Segment?
5 monitoring stations around the world close to the equator.
Where is the master control station?
Colarado Springs
What is the User Segment?
Receivers.
What are the two navigation radio signals satellites send?
L1 and L2
What is the L1 signal?
1575.42MHz - Civilian Course Acquisition (C/A)
What is the L2 signal?
1227.6MHz - Precision Code (P Code) military use
How many satellites do we need for a 3D fix?
4
How many satellites do we need for RAIM?
5
How many satellites do we need for RAIM and FDE
6
How many less satellites do we need if we have barometric aiding?
1 less
What grid does the Navstar GPS use?
WGS84
What is in the pseudorandom code?
Satellite Time, Ephemeris Data and Almanac Data
What is Ephemeris Data?
A precise position and velocity of the satellite in orbit
What is Almanac Data?
Information about where the satellite should be in its orbit and other satellites in their orbits for the next 4 hours.
What is the effect of the ionosphere on the radio waves?
Slows them down.
How much error can selective availability inflict?
100m
How much error will a billionth of a second result in?
1 foot
What is the 4th satellite used for?
Time and Position fixing
Is a high GDOP good or bad?
Bad
Are spread out satellites going to produce a high or low GDOP?
Low
What is the HIL for enroute mode?
+-2nm
What is the HIL for terminal mode?
+-1nm
What is the HIL for approach mode?
+-0.3nm
What is the CDI for enroute mode?
+-5nm
What is the CDI for terminal mode?
+-1nm
What is the CDI for approach mode?
+-0.3nm
