NavCom SF-3040 Rev.F - Manual (Page 209)

SF-3040 Product User Guide
– Rev. F
Glossary-207
GMT see Greenwich Mean Time.
GNSS (Global Navigation Satellite System)
GPS see Global Positioning System.
GPS time is a measure of time. GPS time is based
on
UTC, but does not add periodic “leap seconds” to
correct for changes in the earth’s period of rotation.
As of September 2002, GPS time is 13 seconds
ahead of UTC.
Greenwich Mean Time (GMT) is the local time of the
0° meridian passing through Greenwich, England.
HAE see altitude and ellipsoid.
IODC (Issue of Data, Clock) indicates the issue
number of the data set and thereby provides the user
with a convenient means of detecting any change in
the correction parameters. The transmitted IODC will
be different from any value transmitted by the satellite
during the preceding seven days.
JPL Jet Propulsion Laboratory.
Kbps is the abbreviation for kilobits per second.
L-Band is the group of radio frequencies extending
from approximately 400MHz to approximately
1600MHz. The GPS carrier frequencies L1
(1575.4MHz) and L2 (1227.6 MHz) are in the L-Band
range.
L1 carrier frequency is the primary L-Band carrier
used by GPS satellites to transmit satellite data. The
frequency is 1575.42MHz. It is modulated by C/A
code, P-code, or Y-code, and a 50 bit/second
navigation message. The bandwidth of this signal is
1.023MHz.
L2 carrier frequency the secondary L-Band carrier
used by GPS satellites to transmit satellite data. The
frequency is 1227.6MHz. It is modulated by P-code,