A/D

analog-to-digital

ADF

automatic direction finder

AF

audio frequencies

AGC

automatic gain control

AM

amplitude modulation

AMPS

Advanced Mobile Phone System

ANSI

American National Standards Institute

AR

axial ratio

ATC

air traffic control

ATCRBS

ATC radar beacon system

ATU

automatic tuning system

BER

bit error rate

BS

broadcast satellite

C/A

course acquisition

C/I

carrier-to-interference ratio

C/M

average power ratio of carrier to multipath wave

CAD

computer-aided design

CAT

computerized axial tomography

CBOCS

Comprehensive Bus Operation Control System

CCIR

International Committee on Radio

CDMA

code division multiple access

CFM

compounded frequency modulation

CIR

carrier-to-interference ratio

CNR

carrier-to-noise ratio

CONUS

continental United States

CPU

central processing unit

CRC

Communications Research Center

CW

continuous wave

D/U

desired-to-undesired signal strength ratio

DBS

direct broadcast satellite

DGPS

Differential GPS

DME

distance measuring equipment

DSRC

Dedicated Short Range Communication System

EGC

equal-gain combining

EIRP

equivalent isotropically radiated power

EM

electromagnetic

EMF

electromagnetic field

ENRI

Electronic and Navigation Research Institute

ERP

effective radiated power

ESTEC

European Space Research and Technology Center

ETC

Electronic Toll Collection System

ETS/V

Engineering Test Satellite-V

FDMA

frequency division multiple access

FDTD

finite difference time domain

FEC

forward error correction

FET

field-effect transistor

FM

frequency modulation

FSK

frequency shift keying

FSPL

free-space path loss

G/T

ratio of system gain to system noise temperature

GEO

geostationary earth orbiting

GLONAS(S)

global orbiting navigation satellite system

GMDSS

global maritime distress and safety system

GPS

global positioning satellite

GSM

Groupe Special Mobile

GTD

geometrical theory of diffraction

HEO

high earth orbit

HP

horizontally polarized

HPBW

half-power beamwidth