DFIU Digital Flight Instrument Unit
DFU Digital Function Unit
DFW Dallas Fort Worth Airport
DGNSS Differential Global Navigation Satellite System
DGPS Differential Global Positioning System
DGSS Data-link Ground System Standard
DH (1) Decision Height
(2) Dataflash Header
DI Data Interrupt
DIA Denver International Airport
DIAS DGPS Instrument Approach System
DID Data Item Description
DIP (1) Dual In line Package. The most common package
configuration for integrated circuits.
(2) Data Interrupt Program
DIR Director
Directed A DME operating mode that allows an FMCS to select
Mode one to five DME stations for interrogation.
DISCH Discharge
DITS Data Information Transfer System
DL Data Link
DLC Data Link Control Display Unit
DLGF Data Load Gateway Function
DLM Data Link Management Unit
DLODS Duct Leak and Overheat Detection
DLP Data Link Processor
DLS Data Load System
DLU Download Unit
DMA Direct Memory Access
DME Distance Measuring Equipment. A system that pro-
vides distance information from a ground station to
an aircraft.
DME/N Abbreviation for a DME normal system.
DME/P Abbreviation for a DME precision system.
DMM (1) Digital Multimeter
(2) Data Memory Module
DMS Debris Monitoring Sensor
DMU Data Management Unit
DOC Documentation
DOD Department of Defense
DOP Dilution of Precision
Doppler The change in frequency observed at the receiver
Effect when the transmitter and receiver are in motion rela
tive to each other.
DOT Department of Transportation
DOTS Dynamic Ocean Tracking System
Downlink The radio transmission path downward from the air-
craft to the earth.
DPR Dual Port RAM
DPSK Differential Phase Shift Keying
DRER Designated Radio Engineering Representative (FAA)
Drift Angle The angle between heading and track. It is due to the
effect of wind currents. Sometimes called the crab
angle.
DRMS Distance Root Mean Square
DRN Document Release Notice
DSARC Defense System Acquisition Review Cycle
DSB Double Side Band. An AM signal with the carrier
removed. Requires the same bandwidth as the AM
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