2a Flashcards
What is the purpose of the GPS
Position, altitude, speed, precision time
How many satellites provide navigational data to nav sets
27
The satellites are arranged in how many rings
6
How often do the satellites orbit the earth
Twice a day
This segment is used to track satellites. It monitors and controls satellite orbit
Ground control segment
The ground control segment updates satellite NAV message every ______ hrs? 
24
This segment receives satellite RF signals: Link 1 & Link 2
Calculates 3D position, 3D speed, precise time data
User segment
The satellites transmit on two L-Band frequencies-
L1= \_\_\_\_\_MHz L2= \_\_\_\_\_MHz
L1= 1575.42, L2= 1227.60
This describes the orbital planes of ALL satellites
Almanac data
This is data that tells the GPS receiver where EACH satellite should be at any time throughout the day
Ephemeris Data
The satellite transmits 2 coded signals-One per millisecond.
On L1 only
Civilian and military
GPS can easily lock onto and acquire it
PRN course acquisition code
This broadcast’s on one frequency, Civilians use this
Standard positioning service SPS
This is used for the military only
Precision code
When the P code becomes encrypted it becomes the ___ code?
Y
The P code is transmitted on the L1 and L2. It is for military only. What is the term for this called?
Precise positioning service PPS
This code is used in place of the P code for anti-spoofing
Y code
This type of delay is predictable, include in Almanac Data
Tropospheric Delay
This type of delay is unpredictable, measure phase shift of L1 & L2 “P” code
Ionospheric Delay
When a receiver clock is not perfectly synchronized with a satellite clock, what is is it called?
Navigation set clock error
The term for: Denial of full accuracy
Selective availability
Searches for satellites based on almanac data
Signal acquisition
This is stored in critical memory
Almanac data
Where is Epheremis data displayed
Figure of merit
What is the principle of operation for GPS
Satellite ranging, to accurately provide position data.
How many satellites are necessary for aircraft position- Latitude, longitude, altitude
Three
What satellite corrects NAV set clock error
The fourth one
How many elements does an antenna for a GPS contain?

7 elements
1 reference, 6 aux elements
