NavCom SF-3040 Rev.F - Manual (Page 215)

SF-3040 Product User Guide
– Rev. F
Glossary-213
the navigation (.YYn) file,
meteorological (.YYm) files; where YY indicates
the last two digits of the year the data was
collected.
rover any mobile GPS receiver and field computer
collecting data in the field. A rov
ing receiver’s position
can be differentially corrected relative to a stationary
reference GPS receiver or by using GPS orbit and
clock corrections from a SBAS such as StarFire

.
roving receiver see rover.
RTCM (Radio Technical Commission for Maritime
Services) a standard format for Differential GPS
corrections used to transmit corrections from a base
station to rovers. RTCM allows both real-time
kinematic (RTK) data collection and post-processed
differential data collection. RTCM SC-104 (RTCM
Special Committee 104) is the most commonly used
version of RTCM message.
RTK see Real-time kinematic.
RTG Real Time GIPSY, a processing technique
developed by NASA’s Jet Propulsion Laboratory to
provide a single set of real time global corrections for
the GPS satellites.
S/A see Selective Availability.
SBAS (Satellite Based Augmentation System) this
is a more general term, which encompasses
StarFire™, WAAS, EGNOS, MSAS, and GAGAN
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.