Kongsberg Simrad SN90 Reference Manual page 409

Track History
When you start a target track, a dedicated marker is used to identify the object
you are tracking. Each marker is shown as a small circle with or without a short
identifying text. In most cases, the target will move and continuously change its
position relative to your own vessel. When enabled,
history line after each tracked target. The line identifies the previous positions of
the target. This allows you to manually predict its current heading.
Estimated Track Area
This is an "on/off" switch. To keep track of the targets you can use target markers
and/or start target tracking. The tracked target is regarded as an object, and it is
identified with a circle and two lines. When target tracking is activated, bearing
and tilt are automatically adjusted to follow the movements of the tracked target.
Relevant information about the tracked object can be found in the bottom left
corner of the view. The information includes the location, speed, course and depth
of the target, as well as an estimate of its area and volume. The area is provided in
m 2 while the volume is presented as weight in metric tons.
The area and volume information is calculated from selected beams in the
Horizontal view. Due to the noise, acoustic conditions and varying echo strength
the size of the tracked target may change from one ping to the next. This will
cause the area and volume information to change accordingly. Use the
function to visualize the area estimated by the tracking function. The
Track Area
Estimated Track Area
polygon is a lot larger or smaller than the echo in the view, you can assume that the
area and/or volume information may be inaccurate.
Speed Vector
This is an "on/off" switch.
of the tracked target. The prediction is based on target's current movements.
The estimate is limited to one minute. The information is provided with a line
indicating the target's course. The length of the line reflects its speed.
Bow Marker
This is an "on/off" switch. This function displays a dotted line drawn from the
bow of the vessel symbol. The line reflects your vessel's current heading. Do not
confuse this line with the bearing line.
Current Vector
This is an "on/off" switch. The
direction of the water current under your vessel. One or more arrow are drawn
to or from the vessel symbol to indicate the properties of the sea currents. The
direction of the arrows indicate the direction of the water currents. The length of
the arrows reflects their speeds. Multiple arrows are used if the sensor presents
information from more than one layer. A numerical readout of the current vector
data is provided in the top right corner of the Horizontal view.
381294/E
function draws a polygon to enclose the target. If this
shows you the predicted course and speed
Speed Vector
Current Vector
draws a position
Track History
function shows you the speed and
Menu system
Estimated
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