Basics Flashcards
Position
Location for a vehicle/observer, specified by three independent (orthogonal) coordinates that are referenced to a specified coordinate system.
Navigation
Determination of the position and velocity of a vehicle from measurements made on-board the vehicle
Timing
GPS time
Who provides common grid references
NGA World Geodetic System (WGS)
WGS-84
World Geodetic System established in 1984 that establishes 3-dimensional coordinate reference frame for establishing latitude, longitude and heights for navigation, positioning and targeting for the DoD, IC, NATO, International Hydrographic Office and the International Civil Aviation Organization
GPS Segments
Monitor/Uplink Stations, Space Segment, Control Segment, User Segment
Navstar GPS Operational Constellation (number of operational satellites, ans max number supportable)
The NAVSTAR/GPS operational constellation comprises a minimum of 24 satellites in semi-synchronous orbit, with the system designed to support up to 32
Orbit Period
11 hours 58 minutes
Orbit Altitude
10,898 nautical miles
Solar Day (definition)
Time effect of 1 day of earth motion as fraction of annual orbit period; the time it takes for a celestial object to rotate once in relation to the star it is orbiting
Solar Day
3 mins 56.5 sec
Sidereal Day (definition)
time between two consecutive transits of the First Point of Aries. It represents the time taken by the earth to rotate on its axis relative to the stars,
Sidereal Day
23 hrs. 56 mins. 3.5 secs
GPS Navigation Services
Standard Positioning Service (SPS) and Precise Positioning Service (PPS)
Standard Positioning Service (SPS)
Civil users, some military users, C/A code on L1
Precise Positioning Service (PPS)
Military users with more stringent requirements
C/A codes and P(Y) codes on L1
P(Y) codes on L2
