NavCom SF-3050 Rev.A - Manual (Page 167)

SF-3050 User Guide – Rev A
Glossary-165
SBAS (Satellite Based Augmentation System) this
is a more general term, which encompasses WAAS,
StarFire and EGNOS type corrections.
Selective Availability (S/A) is the deliberate
degradation of the GPS signal by encrypting the P-
ock. When the US
e signal contains
accurate by
is a measure of a
arFire equipped
endix C).
, or demodulate making
smitted
r
code and dithering the satellite cl
Department of Defense uses S/A, th
errors, which can cause positions to be in
as much as 100 meters.
Signal-to-Noise Ratio (SNR)
satellite’s signal strength.
single-frequency is a type of receiver that only uses
the L1 GPS signal. There is no compensation for
ionospheric effects.
SNR see signal-to-noise Ratio.
StarFire a set of real-time global orbit and clock
corrections for GPS satellites. St
receivers are capable of real-time decimeter
positioning
(see App
Spread Spectrum Radio (SSR) a radio that uses
wide band, noise like (pseudo-noise) signals that are
hard to detect, intercept, jam
any data transmitted secure. Because spread
spectrum signals are so wide, they can be tran
at much lower spectral power density (Watts pe
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.
USB Universal Serial Bus.