Xte Mode - Simrad ROBERTSON AP45 Instruction Manual

Page 2-6

XTE mode

00° ON TRACK
NAVIGATION
INFO DISPLAY
W AYPO INT 1
Heading =100°
ALARM
RESET
Steering through a route of waypoints with the AP45 allows you the total flexibility
for automatic waypoint sequencing, but combines the safety feature of requiring
operator acknowledge for course changes in excess of 10 degrees.
If the AP45 is connected to a Nav. receiver that does not transmit a message with
bearing to next waypoint, it will pick a XTE message and steer on Cross Track
Error only. In that case you have to revert to AUTO mode at each waypoint and
manually change set course to equal bearing to next waypoint and then select NAV
mode again.
When the AP45 steers using cross track error only, it corrects the set course in
order to keep the vessel on a straight track between two waypoints. Bearing
change at waypoints must be made manually by temporarily go to Auto mode -
change set course - and revert to Nav. mode.
Use the following procedure for XTE steering:
1. Enter the desired bearing line(s) to the Nav. receiver using the present position
and the first waypoint or destination. Distance between waypoints should be of
minimum 2-3 n.m. Otherwise there may not be sufficient time for the system to
calculate the XTE, and for the autopilot to alter the course and bring the vessel
onto the bearing line again.
2. Read the calculated bearing to waypoint from the Nav.receiver.
3. Select AUTO-mode on the AP45, and set the course to the waypoint showed on
the navigation receiver.
Before going to step 4, ensure that the XTE is within +/- 0.1 n.m. to avoid
hazardous course change when selecting NAV-mode.
4. Select NAV-mode on the AP45. The autopilot now automatically changes the
set course to reduce the Cross Track Error (XTE) to zero. The information
display shows the number of degrees the autopilot has changed the set course,
and the XTE in 1/100's of a nautical mile. Note that the display readout will be
delayed, depending upon the NAV. FILTER setting.
G PS satellite
04° XTE =R0.01NM
W AYPO INT 2
ACCEPT CHANGE?
Y: RESET N: AUTO
INFO DISPLAY
Note!
Simrad Robertson AS
Egersund - Norway
Robertson AP45 Autopilot
NAVIGATION
INFO DISPLAY
XTE W AYPO INT 3
New heading = 70°
R ESET 10MIN CHG 30°
NAVIGATION
INFO DISPLAY
COURSE DISPLAY
Operation