NavCom SF-3050 Rev.B - Manual (Page 199)

SF-3050 User Guide – Rev B
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-
code and dithering the satellite clock. When the US
Department of Defense uses S/A, the signal contains
errors, which can cause positions to be inaccurate by
as much as 100 meters.
Signal-to-Noise Ratio (SNR) is a measure of a
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. StarFire equipped
receivers are capable of real-time decimeter
positioning
(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.
USB Universal Serial Bus.
Glossary-197