Telit Wireless Solutions SL876Q5-A, Руководство пользователя

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SL876Q5-A Product User Guide
1VV0301333 Rev. 2
Page 62 of 68
2017-06-27
16. GLOSSARY AND ACRONYMS
AGPS
Assisted (or Aided) GPS
AGPS provides ephemeris data to the receiver to allow faster cold start
times than would be possible using only broadcast data.
This extended ephemeris data could be either server-generated or locally-
generated.
See Local Ephemeris prediction data and Server-based Ephemeris
prediction data
Almanac
A reduced-precision set of orbital parameters for the entire GPS
constellation that allows calculation of approximate satellite positions and
velocities. The almanac may be used by a receiver to determine satellite
visibility as an aid during acquisition of satellite signals. The almanac is
updated weekly by the Master Control Station. See Ephemeris.
BeiDou (BDS / formerly
COMPASS)
The Chinese GNSS, currently being expanded towards full operational
capability.
Cold Start
A cold start occurs when a receiver begins operation with unknown
position, time, and ephemeris data, typically when it is powered up after a
period on inactivity. Almanac information may be used to identify
previously visible satellites and their approximate positions. See Restart.
Cold Start Acquisition
Sensitivity
The lowest signal level at which a GNSS receiver is able to reliably acquire
satellite signals and calculate a navigation solution from a Cold Start. Cold
start acquisition sensitivity is limited by the data decoding threshold of the
satellite messages.
EGNOS
European Geostationary Navigation Overlay Service
The European SBAS system.
Ephemeris
(plural ephemerides)
A set of precise orbital parameters that is used by a GNSS receiver to
calculate satellite position and velocity. The satellite position is then used
to calculate the navigation solution. Ephemeris data is updated frequently
(normally every 2 hours for GPS) to maintain the accuracy of the position
calculation. See Almanac.
ESD:
Electro-Static Discharge
Large, momentary, unwanted electrical currents that can cause damage to
electronic equipment.
GAGAN
The Indian SBAS system.
Galileo
The European GNSS currently being built by the European Union (EU) and
European Space Agency (ESA).
GDOP
Geometric Dilution of Precision
A factor used to describe the effect of satellite geometry on the accuracy
of the time and position solution of a GNSS receiver. A lower value of
GDOP indicates a smaller error in the solution. Related factors include
PDOP, HDOP, VDOP and TDOP.
GLONASS
ГЛОбальная НАвигационная Спутниковая Система
GLObal'naya NAvigatsionnaya Sputnikovaya Sistema
(Global Navigation Satellite System)
The Russian GNSS, which is operated by the Russian Aerospace Defense
Forces
GNSS
Global Navigation Satellite System
Generic term for a satellite-based navigation system with global coverage.
The current or planned systems are: GPS, GLONASS, BDS, and Galileo.