Course: The planned direction of travel in a
horizontal plane.
Course Deviation: A measurement of distance left
or right from the desired course of travel.
Course Deviation Indicator (CDI): A graphic
indicator of course deviation typically shown as a
graduated horizontal bar with an icon indicating the
deviation distance left or right of course.
Common Traffic Advisory Frequency (CTAF)
D
Database: A collection of data structured in such a
way as to allow quick and convenient access to any
particular record or records. The Apollo GX55
contains a built-in database of waypoints and
waypoint information. Users may add waypoints to
this database.
Degree: 1/360th of a circle.
Departure: The first waypoint in the active route.
Desired Track (DTK): The desired course of
navigation between a point of origin and a
destination waypoint.
Destination: The last waypoint in the active route.
Dilution of Precision (DOP): A merit value for the
calculated
position
based
on
the
geometrical
configuration of the satellites used; 3 is considered
good, greater than 7 is considered poor. Also called
Precision Dilution of Precision or PDOP.
Direct-To: The function or procedure that directs
you from your present position to the designated TO
waypoint.
Distance: A measure of interval in space. Also
referred to as range.
Glossary of Navigation Terms
152