
Principles of Operation
P/N 7010-0935
1-3
• GLONASS – the Global Navigation Satellite System maintained
and operated by the Russian Federation Ministry of Defense. For
information on the status of this system, visit the Coordinational
Scientific Information Center website.
• GALILEO – an upcoming global positioning system maintained
and operated by Galileo Industries, a joint venture of several
European space agencies/companies working closely with the
European Space Agency. Unlike GPS and GLONASS, this is a
civil endeavor and is currently in the development and validation
stage. For information on the status of this system, visit the
Galileo Industries website.
Despite numerous technical differences in the implementation of
these systems, satellite positioning systems have three essential
components:
• Space – GPS, GLONASS, and GALILEO satellites orbit
approximately 12,000 nautical miles above earth and are
equipped with a clock and radio. These satellites broadcast
ranging signals and various digital information (ephemerides,
almanacs, time&frequency corrections, etc.).
• Control – Ground stations located around the earth that monitor
the satellites and upload data, including clock corrections and
new ephemerides (satellite positions as a function of time), to
ensure the satellites transmit data properly.
• User – The community and military that use GNSS receivers to
calculate positions.
Calculating Absolute Positions
When calculating an absolute position, a stationary or moving
receiver determines its three-dimensional position with respect to the
origin of an Earth-Center Earth-Fixed coordinate system. To calculate
this position, the receiver measures the distance (called pseudoranges)
between it and at least four satellites. The measured pseudoranges are
corrected for clock differences (receiver and satellites) and signal
propagation delays due to atmospheric effects. The positions of the
satellites are computed from the ephemeris data transmitted to the
receiver in navigation messages. When using a single satellite system,
Net-G3A_OM_Book.book Page 3 Thursday, May 14, 2009 8:49 AM
Содержание Net-G3A
Страница 2: ...Net G3A_OM_Book book Page 2 Thursday May 14 2009 8 49 AM ...
Страница 4: ...ECO 3568 Net G3A_OM_Book book Page 2 Thursday May 14 2009 8 49 AM ...
Страница 34: ...Introduction NET G3A Operator s Manual Notes 1 22 Net G3A_OM_Book book Page 22 Thursday May 14 2009 8 49 AM ...
Страница 140: ...Warranty Terms NET G3A Operator s Manual Notes D 2 Net G3A_OM_Book book Page 2 Thursday May 14 2009 8 49 AM ...
Страница 145: ...Net G3A_OM_Book book Page 1 Thursday May 14 2009 8 49 AM ...