ComNav 1101 - Advanced Operations; Navigation Interface and NAV Mode

ComNav 1101 Autopilot
Introduction
Once your Autopilot is functioning properly in AUTOPILOT mode, and
you have completed all of the Setup and Sea Trials in the Getting
Started and Basic Operations sections, you are ready to use
NAV mode.
The 1101 Autopilot has the capability to use steering information
from an external NMEA device such as a GPS, DGPS, Loran,
Chartplotter, or suitably equipped computer. This allows the vessel
to steer to a waypoint destination or along a route of waypoints.
In NAV mode the Autopilot uses its own compass as its primary
source of heading for course keeping while the data received from
the external device is used to calculate the commanded heading to
direct the vessel to the destination waypoint.
7. Advanced Operations
7 - 1 ADVANCED OPERATIONS
Navigation Interface
The 1101 autopilot may be interfaced to navigation devices capable
of transmitting autopilot sentences in NMEA 0183 format. Four
types of information from the NMEA data provided by the navigation
device are used by the autopilot:
- Vessel Speed is used if the autopilot is set to automatically
switch between FAST and SLOW steering parameters. See
Section 6Basic Operations for more information on this
feature. Vessel speed can be taken from NMEA 0183 sentence
types VTG (recommended), VHW, or VBW.
- Bearing to Destination. The best performance will be obtained
if Bearing to Waypoint is used, but Bearing (from) Origin to
Destination (BOD) will be selected if bearing to waypoint is not
available. The commanded bearing can be taken from NMEA
sentences APB (recommended), APA, RMA together with RMB,
RMC together with RMB, BOD, or HSC. WBD, a proprietary
sentence from Northstar Lorans, may also be used.
- Cross Track Error (XTE) is the perpendicular distance from the
track and the direction to steer to get back on track. Cross
track error can be taken from APB (recommended), APA, RMA
together with RMB, RMC together with RMB, or XTE.
- Waypoint Arrival Status. This will cause the audible alarm to
sound and the message Waypoint Arrival to be displayed on
the autopilot when the vessel enters the arrival circle around