NavCom SF-3050 Rev.I - Manual (Page 190)

SF-3050 GNSS Product User Guide – Rev I
G-171
DGPS see Differential GPS.
Differential GPS (DGPS) a positioning procedure that uses two receivers, a rover at an
unknown location and a reference station at a known, fixed location. The reference
station computes corrections based on the actual and observed ranges to the satellites
being tracked. The coordinates of the unknown location can be computed with sub-meter
level precision by applying these corrections to the satellite data received by the rover.
Dilution of Precision (DOP) a class of measures of the magnitude of error in GPS
position fixes due to the orientation of the GPS satellites with respect to the GPS receiver.
There are several DOPs to measure different components of the error. Note: this is a
unitless value. see also PDOP.
DOP see Dilution of Precision.
DTE Data Terminal Equipment. See DCE.
dual-frequency a type of GPS receiver that uses both L1 and L2 signals from GPS
satellites. A dual-frequency receiver can compute more precise position fixes over longer
distances and under more adverse conditions because it compensates for ionospheric
delays. The SF-3050 is a multi-frequency GNSS receiver.
dynamic mode when a GPS receiver operates in dynamic mode, it assumes that it is in
motion and certain algorithms for GPS position fixing are enabled in order to calculate a
tighter position fix.
ECEF (Earth Centered Earth Fixed) a Cartesian coordinate system used for GPS,
sometimes known as a "conventional terrestrial" system.
EGNOS (European Geostationary Navigation Overlay Service) a European satellite
system used to augment the two military satellite navigation systems now operating, the
US GPS and Russian GLONASS systems.
elevation distance above or below Local Vertical Datum.
elevation mask the lowest elevation, in degrees, at which a receiver can track a satellite.
Measured from the horizon to zenith, 0º to 90º.
ellipsoid a mathematical figure approximating the E
arth’s surface, generated by rotating
an ellipse on its minor axis. GPS positions are computed relative to the WGS-84 ellipsoid.
An ellipsoid has a smooth surface, which does not match the earth’s geoidal surface
closely, so GPS altitude measurements can contain a large vertical error component.
Conventionally surveyed positions usually reference a geoid, which has an undulating
surface and approximates the earth’s surface more closely to minimize altitude errors.
epoch literally a period of time. This period of time is defined by the length of the said
period.
G1 carrier frequency the primary L-Band carrier used by GLONASS satellites to transmit
satellite data. The frequency is 1603.00MHz.
G2 carrier frequency the secondary L-Band carrier used by GLONASS satellites to
transmit satellite data. The frequency is 1247.00MHz.