Raymarine Raystar 112 User Manual - Chapter 3: Operation
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Chapter 3: Operation
Chapter 3: Operation
3.1 COLD Start (Initial Start-up)
Your GPS is set up for fully Automatic operation when it leaves the
factory. All you need to do is turn the unit ON.
When power is applied to the Raystar 112 for the very first time, the GPS
sensor has to locate and identify three or more satellites before
determining the vessel’s actual L/L position. The sensor’s memories
contain pre-programmed profiles of each satellite’s signal coding. So it
becomes a matter of sampling the incoming GPS signals and
comparing the profiles until the signal coding matches. Unfortunately,
this process (similiar to matching fingerprints) is both time consuming
and complex. It can take up to 10 minutes before the unit completes
satellite identification and calculates the first position.
If you are using one of Raytheon’s GPS display units, the operator can
aid the GPS sensor in its satellite search by entering specific initialization
information concerning ship’s position, date, and time. The time required
for obtaining the initial position fix can be reduced to approximately 1 to 3
minutes once the sensor has received this initialization data.
After the sensor has completed this initial search and determined its
location, the sensor will remember the L/L position in memory. The next
time you use the unit, the only thing you’ll have to do is turn the unit ON.
In a few minutes your position will be displayed.
This will occur as long as the ship remains within approximately 100
NMof the L/L position where the unit was turned OFF. If the vessel has
been moved a substantial distance from the last saved position and the
GPS sensor is then powered up, the unit may again go through the Cold
Start routine. The time to acquire the satellites and get your position can
be reduced by re-entering your new L/L position, date, and time
information.
3.2 Geodetic Datum
The normal Geodetic datum used by the Raystar 112 sensor is
WGS-84.
Mariners can/may find considerable errors (up to 200 m) in plotting own
ship’s position if their charts were created using one type of geodetic