Preconditions For Automatic Route Steering - Furuno FEA-2107-BB Operator's Manual

28.5.4

Preconditions for automatic route steering

General preconditions
The Goto WP and Goto Track modes can be activated when your ship is located inside a channel of a monitored
route.
The difference between actual heading and planned course to approach "To WP" must be less than the limit set in
the route steering parameters in order to initiate automatic route steering. For further details, see section 25.1.4
Navigation parameters setting.
Route steering requires activation of the Kalman filter. If you try to activate any of the route steering modes without
the filter, you get the alarm "2470 Disabled: Needs filter on".
If you try to activate any of the route steering modes without an independent speed source, you get the alarm "2490
Disabled: Needs log sensor". Route steering requires that you have at least either one log and position receiver or
two position receivers available and in use.
Alarm "2499 Disabled: Needs good Pos" appears when the filter did not have high-precision position sensor for
route steering, and position discrepancy limit between primary and secondary sensors is exceeded.
Alarm "2502 Disabled: Need higher Spd" appears when the speed used by the Kalman filter calculation is below
the limit set for track steering in the installation parameters.
It is recommended to activate the position discrepancy detector (i.e., set position discrepancy limit > 0). This lets the
Kalman filter exclude from position calculation a sensor that has large position discrepancy. This also influences the
Goto WP, Goto Track and Program track steering modes.
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If the position discrepancy limit is set very small (0.01 nm), the system will quickly alert you to the
discrepancy, but you may also experience frequent release of the alarm.
Goto track mode preconditions
Route steering with the Goto Track mode requires that you have at least one high-precision position receiver and
direct SOG/COG reference available and in use.
At least one high-precision position is available and in use when the permanent indication FILTER HIGH appears
at the upper right corner of the ECDIS display. DGPS, etc. are considered high-precision position receivers. Note
that a standard GPS or a DGPS without differential position available are not acceptable as high-precision position
receivers.
It is also required that the Speed Over Ground (SOG) reference is available either from position sensor(s) or bottom
track from a dual-axis log.
If any of the conditions described above is lost during the Goto Track mode, the system automatically activates the
Goto WP mode within 10 minutes and you get the alarm "2489 Route: Changed to Go to WP".
28. Steering with FURUNO Autopilot FAP-2000
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