NavCom SF-2040 Rev.F - Manual (Page 92)

SF-2040 User Guide – Rev. F
Glossary-90
(see Appendix C).
Spread Spectrum Radio (SSR) a radio that uses
wide band, noise like (pseudo-noise) signals that are
hard to detect, intercept, jam, or demodulate making
any data transmitted secure. Because spread
spectrum signals are so wide, they can be transmitted
at much lower spectral power density (Watts per
Hertz), than narrow band signals.
SV (Space Vehicle) a GPS satellite.
Universal Time Coordinated (UTC) a time standard
maintained by the US Naval Observatory, based on
local solar mean time at the Greenwich meridian.
GPS time is based on UTC.
UTC see Universal Time Coordinated.
WAAS (Wide Area Augmentation System) a US
satellite system that provides a set of corrections for
the GPS satellites, which are valid for the North
American region. They incorporate satellite orbit and
clock corrections.
WADGPS (Wide Area Differential GPS) a set of
corrections for the GPS satellites, which are valid for
a wide geographic area.
WGS-84 (World Geodetic System 1984) the current
standard datum for global positioning and surveying.
The WGS-84 is based on the GRS-80 ellipsoid.
Y-code the name given to encrypted P-code when
the U.S. Department of Defense uses selective
availability.