GPS Receiver User Manual

Copernicus GPS Receiver 59
OPERATING MODES 4
Saving Almanac, Ephemeris and Position to Flash Memory
The Almanac, Ephemeris, and recent Position data contained in RAM is
automatically saved to Flash memory.
Graceful Shutdown
The Graceful Shutdown command is issued using TSIP packet 0xC0 or NMEA
command RT with the store RAM to flash flag enabled. The reset type will depend on
the Graceful Shutdown command parameters. On start-up, the unit will use the
almanac, ephemeris, and position from RAM first. If RAM is not available, the unit
will use the almanac from the Flash Memory.
SBAS
The Satellite Based Augmentation System (SBAS) includes implementation of the
current standard for WAAS and the European Geostationary Navigation Overlay
Service (EGNOS) operated by the European Space Agency and other compatible
systems that will come online in the future.
WAAS
Wide Area Augmentation System (WAAS) is an extremely accurate navigation
system developed for civil aviation by the Federal Aviation Administration (FAA).
The system augments GPS to provide the additional accuracy, integrity, and
availability necessary to enable users to rely on GPS for all phases of flight for all
qualified airports within the WAAS coverage area.
The worst-case accuracy is within 7.6 meters of the true position 95% of the time.
This is achieved via a network of ground stations located throughout North America,
which monitor and measure the GPS signal. Measurements from the reference
stations are routed to two master stations, which generate and send the correction
messages to geostationary satellites. Those satellites broadcast the correction
messages back to Earth, where WAAS-enabled GPS receivers apply the corrections to
their computed GPS position.
Number of channels
The Copernicus GPS Receiver tracks one WAAS satellite at a time. When acquiring
and tracking a WAAS satellite, one tracking channel is set aside for this purpose,
leaving eleven tracking channels which are used for the GPS satellites.