Lassen SQ, Справочное руководство

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Lassen SQ GPS Receiver 1 7 3
Glossary
Doppler shift
The apparent change in frequency of a received signal due to
the rate of change of the range between the transmitter and
receiver.
earth-centered
earth-fixed Cartesian coordinate system where the X direction is the
intersection of the prime meridian (Greenwich) with the
equator. The vectors rotate with the earth. Z is the direction of
the spin axis.
elevation angle The angle between the line of sight vector and the horizontal
plane.
elevation mask
angle A measure of the minimum elevation angle, above the
horizon, above which a GPS satellite must be located before
the signals from the satellite will be used to compute a GPS
location solution. Satellites below the elevation angle are
considered unusable. The elevation mask angle is used to
prevent the GPS receiver from computing position solutions
using satellites which are likely to be obscured by buildings
or mountains.
ellipsoid
In geodesy, unless otherwise specified, a mathematical figure
formed by revolving an ellipse about its minor axis. It is often
used interchangeably with spheroid. Two quantities define an
ellipsoid; these are usually given as the length of the
semimajor axis, a, and the flattening, f = (a - b)/a, where b is
the length of the semiminor axis.
ephemeris
A set of parameters that describe the satellite orbit very
accurately. It is used by the receiver to compute the position
of the satellite. This information is broadcast by the satellites.
epoch Measurement interval or data frequency, as in making
observations every 15 seconds. Loading data using 30-second
epochs means loading every other measurement.
firmware A set of software computer/processor instructions that are
permanently or semi-permanently resident in read-only
memory.