SL869x-V2 Family Product User Guide
1VV0301175 Rev. 9 Page 87 of 93 2021-07-15
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.
Please refer to Local Ephemeris prediction data and Server-based
Ephemeris prediction data
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. Please refer to Ephemeris.
BeiDou (BDS) -
formerly
COMPASS
The Chinese GNSS, currently being expanded towards full
operational capability.
A cold start occurs when a receiver begins operation with unknown
position, time, and ephemeris data, typically when it is powered up
or restarted after a period on inactivity. Almanac information may
be used to identify previously visible satellites and their
approximate positions. Please refer to 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.
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. Please refer to Almanac.
Electro-Static Discharge
Large, momentary, unwanted electrical currents that can cause
damage to electronic equipment.
The European GNSS currently being built by the European Union
(EU) and European Space Agency (ESA).
Geometric Dilution of Precision
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