Apollo 65 - Manual (Page 307)

FDE: The Fault Detection and Exclusion column
refers to the ability to identify and exclude a faulty
satellite and still have suitable satellite geometry at
that position.
FF: Final Approach Fix. A code appended to a
waypoint in the database that may not appear on a
published map.
Fix: A geographical location determined by either
visual reference or by electronic navigation aids.
Flight Time: Flight Time shows the elapsed time in
hours and minutes (00:00 to 99:59) from departure. If
the Flight Timer is not started the value will be
replaced with dashes. The Flight Timer options are
set in the System Functions (see page 8).
Flight Plan: A series of two or more waypoints.
G GDOP: Geometric Dilution of Precision. The
relationship between errors in receiver position and
time and in satellite range.
Global Positioning System (GPS): Also known as
NAVSTAR. A constellation of satellites launched by the
U.S. Department of Defense into six orbit lanes (four
satellites per plane) at an altitude of 10,898 nm above the
earth.
Greenwich Mean Time (GMT): See Universal Time
Coordinate (UTC).
Ground (GRND): Ground communication
frequency
Ground Speed (GS): Speed of travel across the
ground. In aviation, the relation between ground
speed and air speed is affected by the prevailing
winds.
H HDOP: Horizontal Dilution of Precision. See
Dilution Of Precision.
15-5
Glossary