C-Nav 2050, User Manual

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2050 User Guide
Glossary-67
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 B).
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 transmitters.
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 set of corrections for the GPS satellites, which are
valid for the Americas region. They incorporate satellite orbit and clock corrections.
WAD GPS ( 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 .