Simrad NX40/45 Installation and Operation Manual
35
GPS worldwide navigation
The GPS system is 24 satellites orbiting the earth and
broadcasting position and time signals. The GPS receiver
analyses the signals from the closest satellites and
calculates exactly where it is on earth. The accuracy is
typically better than 10 m (33 ft) for 95% of the time.
GPS receiver (Optional)
Simrad GPS units have a sensitive 12-channel receiver,
which tracks signals from all GPS satellites visible
above the horizon and uses measurements from all
satellites more than 5° above the horizon to calculate
the position.
Each time a GPS receiver is turned on, it normally takes
about 50 seconds before it outputs the first position.
Under some circumstances it will take up to two minutes
or longer.
8-1 Satellite window
The satellite window has information about the GPS
satellites and GPS position.
To go to the satellite window
>
More
>
Satellite
The satellite window shows:
A Status of GPS antenna, for example
Acquiring
,
GPS fix
,
No GPS
. If the unit is in Simulate mode it
displays
Simulate
.
B Time and date from GPS satellites. Time is local time
(UTC [GMT] plus local offset
C HDOP: The error in the GPS position caused by
satellite geometry. A low value indicates a more
precise fix, a high value a less precise fix
D Signal strengths of up to twelve visible GPS satellites.
The higher the bar the stronger the signal
E Boat position
F Positions of visible GPS satellites:
Outer circle is horizon
Inner circle is 45° elevation
Center is directly above
North is at top of window
G If the boat is moving, COG is a line from center
Satellites
9
F
D
E
G
C
B
A
