Raymarine GPS Plotter - Manual (Page 88)

Chapter 4: Setting Up the GPS Plotter 4-11
Figure 4-2: GPS Status Screen
The GPS Navigation Status screen provides, for each tracked satellite,
the satellite number, a graphical signal strength bar and its current usage
status. Data for up to 12 satellites are shown.
Positional accuracy is dependent upon certain parameters; in particular
for GPS, the azimuth and elevation angles are used in a triangulation
process to calculate position. HDOP (Horizontal Dilution Of Position) is
a measure of this accuracy; a higher figure signifies greater error. In ideal
circumstances, the figure should be in the region of 1.0. The Fix Status
can indicate:
• FIX, where a satellite fix has been acquired.
• D-FIX, where a differential beacon fix has been acquired.
• SD-FIX, where a satellite differential fix has been acquired.
• NO FIX, where no fix can be acquired.
Fix Mode
Fix Mode provides selection of the method used to acquire a position fix.
➤
To select the required Fix Mode:
1. Press the FIX MODE soft key repeatedly to cycle through the available
modes.
i. Select GPS to calculate a fix using GPS data only.
ii. Select D to calculate a fix using Differential GPS data from an
external RTCM beacon receiver.
iii. Select SD to calculate a fix using Satellite Differential data, if
available.
2. Press CLEAR to exit.
D-GPS
SET UP
GPS STATUS
HDOP FIX STATUS
SAT SIGNAL STATUS
15
09
08
10
20
17
LOCKED
IN USE
IN USE
LOCKED
LOCKED
LOCKED
1.0 D-FIX
SAT SIGNAL STATUS
23
18
26
12
14
03
LOCKED
IN USE
IN USE
LOCKED
LOCKED
LOCKED
D5551_1
RESTART
GPS
FIX MODE
GPS D
SD
81171_4.BOOK Page 11 Thursday, November 29, 2001 11:34 AM