Furuno FCR-2107 Operator's Manual page 46

2. Radar Operation
Course-up mode
The course-up mode is an azimuth stabilized display in which a line connecting the center with the top of the display
indicates own ship's intended course (namely, own ship's previous heading just before this mode has been selected).
Target pips are painted at their measured distances and in their directions relative to the intended course, which is
maintained at the 0-degree position. The heading line moves in accordance with ship's yawing and course change.
This mode is useful for avoiding smearing of picture during course change.
Course-up mode
Head-up TB (True Bearing) mode
Radar echoes are shown in the same way as in the head-up mode. The difference from normal head-up presentation
lies in the orientation of the bearing scale. The bearing scale is heading sensor stabilized. That is, it rotates in
accordance with the heading sensor signal, enabling you to know own ship's heading at a glance.
This mode is available when the radar is interfaced with a gyro heading sensor. If the gyro heading sensor fails, the
bearing scale returns to the state of head-up mode.
North-up mode
The north-up mode paints target pips at their measured distances and in their true (heading sensor) directions from
own ship, north bearing maintained at the top of the screen. The heading line changes its direction according to the
ship's heading. Requires heading signal.
If the compass fails, the presentation mode changes to head-up and the north marker disappears. A failure of the
heading sensor input will cause the heading readout to disappear, and the message "No heading available" or "Gyro
error" (message in red) appears at the lower right corner of the screen.
North Marker
Heading Line
North-up mode
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