About target tracking

During normal operation, some echoes are clearly more interesting than others. In many situations specific echoes may be regarded as targets. To set up the ST90 system to provide such information, you can start target tracking.

The phrase target is used to identify an echo in the display presentation that you wish to act upon. The echo may be from a material item, a shallow, reef or rock, or from fish, fish schools or mammals. In most cases, the target will move and continuously change its position relative to your own vessel. You must decide which echoes that shall be classified as targets, and whether you shall start manual or automatic target tracking.

Once an echo has been provided with a marker in the display presentation it is regarded as an object.

In this context, the phrase track (noun) is used to define the movements of a target based on it geographical position, speed and direction (heading). A track is the output from a track algorithm implemented in a software program. A track is thus anything the ST90 is tracking either manually (through markers and user interaction) or automatically by the sonar (target tracking) on your initiative.

A target track permits the ST90 system to automatically control the tilt and bearing based on the movements of the chosen target. It locks on the target defined by its position, heading and speed. The bearing and tilt settings are automatically adjusted to follow the movements of the tracked target.

To start target tracking:

1. Place the cursor over the echo you wish to track.

2. Press Target Track on the Operating Panel.

   

or:

1. Place the cursor over the echo you wish to track.
2. Right-click to open the shortcut menu.
3. Select Initiate Track.

The tracked target is regarded as an object, and it is identified with a circle and two lines. The two lines reflect the size of the current tracking area. By default, a new manually initiated tracked object is automatically given priority status. The bearing line is automatically locked on the object to reflects its bearing.

The priority is identified with a "P". You can only give priority status to one object. If you start tracking a new target the first target will loose its priority. The same applies if you give priority to another marker. The tracking of the first target will however not stop, and the target marker is still shown.

Relevant information about the tracked object can be found in the bottom left corner of the view. To read this information in the view's bottom left corner, you must enable it on the Cursor Readout page. This page is located in the Display Options dialog box.

• Select Target Volume to present calculated area and volume of a tracked target or priority object.

• Select Target Track to present relevant information about a tracked target or priority object.

  • Bearing (The value relates to the ship's heading.)
  • Bearing
  • Range
  • Speed
  • Course
  • Depth

  The bearing and range values are relative to your vessel.

You can see this information in the bottom left corner of the view. If you think the text is small and hard to read, double-click on the text field. This will increase the text size.