Raymarine gS Series, Installation And Operation Instructions Manual, Page: 26 / 208

7.1 GPS Check
Checking GPS operation
You can check that the GPS is functioning correctly using the
chart application.
1. Select the Chart page.
2. Check the screen.
With the chart displayed, you should see:
Your boat position (indicates a GPS fix) . Your current
position is represented by a boat symbol or solid circle. Your
position is also displayed in the data bar under VES POS.
A solid circle on the chart indicates that neither heading nor
Course Over Ground (COG) data is available.
Note: Raymarine recommends that you check the displayed
vessel position in the chart application against your actual
proximity to a known charted object. GPS receivers typically
have an accuracy of between 5 and 15 m.
Note: A GPS Status screen is available within the Setup
menu of Raymarine multifunction displays. This provides
satellite signal strength and other relevant information.
GPS setup
The GPS setup options enable you to configure a GPS receiver.
The Global Positioning System (GPS) is used to position your
vessel on the chart. You can set up your GPS receiver and
check its status from the GPS Status option in the
System
Settings menu. For each tracked satellite, the screen provides
the following information:
• Satellite number.
• Signal strength bar.
• Status.
• Azimuth angle.
• Elevation angle.
• A sky-view to show the position of tracked satellites.
D12204-1
6 1
4
2
3
5
Item Description
1 Sky view — a visual representation of the position of tracked
satellites.
2 Satellite status — displays the signal strength and status of
each satellite identified in the sky view diagram on the left of
the screen. The colored bars have the following meanings:
• Grey = searching for satellite.
• Green = satellite in use.
• Orange = tracking satellite.
3 Horizontal Dilution of Position (HDOP) — a measure of
GPS accuracy, calculated from a number of factors including
satellite geometry, system errors in the data transmission and
system errors in the GPS receiver. A higher figure signifies
a greater positional error. A typical GPS receiver has an
accuracy of between 5 and 15 m. As an example, assuming
a GPS receiver error of 5 m, an HDOP of 2 would represent
an error of approximately 15 m. Please remember that even
a very low HDOP figure is NO guarantee that your GPS
receiver is providing an accurate position. If in doubt, check
the displayed vessel position in the chart application against
your actual proximity to a known charted object.
Estimated Horizontal Position Error (EHPE) — a measure
of GPS accuracy, this indicates that your position is within a
circle radius of the stated size 67% of the time.
4 Fix status — indicates the actual mode the GPS receiver is
reporting (No Fix, Fix, D Fix or SD Fix).
5 Mode — the mode currently selected by the GPS receiver.
6 Datum — The GPS receiver's datum setting affects the
accuracy of the vessel position information displayed in
the chart application. In order for your GPS receiver and
multifunction display to correlate accurately with your paper
charts, they must be using the same datum.
The accuracy of the GPS receiver depends on the parameters
detailed above, especially the azimuth and elevation angles
which are used in triangulation to calculate your position.
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gS Series