NavCom SF-3040 Rev.F - Manual (Page 207)

SF-3040 Product User Guide
– Rev. F
Glossary-205
dual-frequency is a type of GNSS receiver that uses
both L1 and L2 signals from GNSS 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-3040 is a dual-frequency
receiver.
dynamic mode when a GNSS receiver operates in
dynamic mode, it assumes that it is in motion and
certain algorithms for GNSS position fixing are
enabled in order to calculate a tighter position fix.
EGNOS (European Geostationary Navigation
Overlay Service) a European satellite system used
to augment the two military satellite navigation
systems now operating: the U.S. GPS and the
Russian GLONASS.
elevation is the distance above or below the Local
Vertical Datum.
elevation mask is the lowest elevation, in degrees, at
which a receiver can track a satellite; it is measured
from the horizon to zenith, 0º to 90º.
ellipsoid is a mathematical figure approximating the
earth’s surface, generated by rotating an ellipse on its
minor axis. GNSS 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 GNSS 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 is literally a period of time. This period of time
is defined by the length of the period.