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B-2 gps navigation problems – NorthStar Navigation Explorer 538i User Manual

Page 59

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Northstar Explorer 538i/538 Installation and Operation Manual

59

2-1 No GPS fix or long time to get fix at
startup:

a

May occur occasionally if the antenna does
not have a clear view of the sky. The satellite
positions are constantly changing.

b Antenna cable not connected to display unit.

c

Restart the GPS (see section 14-3).

2-2 Explorer GPS position different from true

position by more than 10 m (33 ft):

a

Explorer in simulate mode. Turn simulate
mode off (see section 14-12).

b The normal error in GPS position will exceed

10 m (33 ft) for about 5% of the time.

c

Under special circumstances the US
Department of Defence may introduce a
deliberate and changing error in the GPS
positions of up to 300 m (1000 ft).

2-3 Explorer position different from same

position on local charts:

a

Explorer in simulate mode. Turn simulate
mode off (see section 14-12).

b Incorrect chart datum. Select the correct

chart datum (see section 14-2).

c

Map shift has been applied wrongly. Clear map
shift, then reapply if necessary (see section 14-2).

2-4 Can not see boat on chart:

Press

to switch to centre on boat

mode (see section 3-2-1).

2-5 The time or date on satellite display is

wrong or off:

a

No GPS fix.

b In simulate mode. Turn simulate mode off

(see section 14-12).

c

Local time offset is wrong (see section 14-11).
The Local Time Offset must be changed
when daylight saving time starts or ends.

2-6 Autopilot not responding to Explorer; no
NMEA

output:

a

NMEA output disabled or the required NMEA
sentences are not turned on. Check NMEA
settings (see section 17-10).

b Check that the instrument is connected

correctly.

2-7 No DGPS fix or loss of DGPS fix:

a

To receive a DGPS fix, WAAS/EGNOS must be
enabled or an optional DGPS antenna fitted
(see section 7).

b With WAAS/EGNOS: Boat out of coverage

area (see section 7).

c

With WAAS: GPS antenna does not have a
clear view of the horizon towards the equator.

b With beacon DGPS: boat out of range of a

DGPS beacon.

B-2 GPS navigation problems

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