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User interface
Sonar views
Horizontal view
The Horizontal view presents the 360 degrees area around your vessel from a bird’s eye view. The current bearing is shown with a solid line pointing out from the vessel position.
Range / Range Rings / Variable Range Ring
The distance from the vessel symbol in the centre of the circle to the outer ring corresponds to the currently selected range.

About this manual
The purpose of this publication is to provide the descriptions, procedures and detailed parameter explanations required to allow for safe and efficient use of the ST90 system. The publication also provides you with a thorough understanding of the parameters and adjustments provided by the ST90 system.
Simrad ST90
Operating procedures
Maintenance procedures
User interface
- User interface familiarization
  By default, the display presentation covers the entire screen. The display presentation provided by the ST90 system consists of specific visual elements that work together. The visual elements provide you with the echo information you need, they help you to control the functionality needed to understand this information, and finally, they allow you to control the operational parameters.
- Top bar
- Replay bar description
  During replay, the dedicated replay bar is shown immediately under the top bar. The replay bar allows you to retrieve saved files, and to control the playback.
- Sonar views
  - Presentation modes
    All echoes offered by the ST90 system are shown in rectangular views. Combinations of these views are organized in presentation modes. Each presentation mode offered by the ST90 system provides a selection of views in a predefined pattern. You must first find the presentation mode that meets your operational requirements, then you can change the size of the individual views.
  - Horizontal view
    The Horizontal view presents the 360 degrees area around your vessel from a bird’s eye view. The current bearing is shown with a solid line pointing out from the vessel position.
    - Audio beam
      The solid bearing line in the Horizontal view controls the audio beam.
    - Bearing
      The current bearing is shown with a solid line pointing out from the vessel position. You can change the angle by means of the Bearing function on the Main menu. You can also select the bearing line and drag it sideways.
    - Bow marker
      The bow marker is shown as a dotted line drawn from the bow of the vessel symbol.
    - Compass cards
      Activate Compass Cards to place evenly spaced compass markers on the outer range ring in horizontal views.
    - Course line
      Course Line is located on the Visual Objects menu. This function displays a dotted line drawn from the bow of the vessel symbol. The line reflects your vessel’s current course.
    - Coverage plot
      In the Horizontal view, use Coverage Plot to visualize the area covered by the vertical beam. A circle is added to the Horizontal view presentation to indicate the size of the area.
    - Current vector / Current flow
      A current sensor can be connected to the ST90 system. This can for example be an acoustic Doppler current profiler (ADCP). The information from this sensor is presented in the applicable views.
    - Cursor
      The position (bearing and distance) and depth of the cursor's location is shown in the lower right corner of the view. The depth is calculated from the current tilt and the distance from the vessel.
    - Gain
      The current settings for range, gain and tilt are shown in the upper left corner of the view.
    - Gear symbol
      The gear symbol is a visual tool to keep track of your fishing gear. You can activate this function from the short-cut menu or use the dedicated button on the Operating Panel.
    - Inspection views
      The ST90 system offers three inspection beams. Each inspection beam is presented using an Inspection view. If you use several Inspection views, you can train and tilt the beams individually, and independent of the beams displayed in the other views.
    - Markers / Manual Track / Priority Marker
      One or more markers can be placed in the view to identify specific echoes. Markers are shown as small triangles. Once an echo has been provided with a marker in the display presentation it is regarded as an object.
    - Minute markers / History line
      In order to maintain a visual presentation of your vessel’s previous movements, you can draw these with a line. This line is drawn after the vessel symbol in the sonar views, and visualizes your past movements. We refer to this line as the History Line.
    - Plane view
      Certain presentation modes place the Plane and Horizontal views together. The Plane view presents the echo data in a horizontal sector ("fan"). The sector direction can be changed in both vertical and horizontal directions.
    - Range / Range Rings / Variable Range Ring
      The distance from the vessel symbol in the centre of the circle to the outer ring corresponds to the currently selected range.
    - Shortcut menu
      Right-click in the view to open the shortcut menu. The options on the shortcut menu are mainly related to markers.
    - 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.
    - Tilt
      The current settings for range, gain and tilt are shown in the upper left corner of the view.
    - Transducer position
      The top left corner of the view holds a small graphic presentation of the hull unit.
    - Horizontal TX Sector / Vertical TX Sector
      The Horizontal Tx Sector function allows you to control whether the system shall transmit acoustic energy into the water in omni (360°) or within a defined sector. The Vertical Tx Sector function is used to change the vertical opening angle in horizontal and vertical swaths.
    - User settings
      Any user setting selected on the Operating Panel is identified in the upper left corner of the Horizontal view.
  - Vertical view
    The Vertical view is oriented perpendicularly to the horizontal plane. The Vertical view shows you a "vertical slice" of the echo data. The direction of the vertical slice is indicated and controlled by the bearing line in the Horizontal view. The area covered by the vertical beam is shown as a triangle in the Horizontal view. The upper horizontal line in the view represents the water surface.
  - Inspection view
    The ST90 system offers three inspection beams. Each inspection beam is presented using an Inspection view. If you use several Inspection views, you can train and tilt the beams individually, and independent of the beams displayed in the other views. You can use the Inspection view to study single fish, schools and bottom conditions in detail.
  - Plane view
    The Plane view presents the echo data in a horizontal sector ("fan"). The sector direction can be changed in both vertical and horizontal directions.
  - Echogram view
    The Echogram view shows a time based history for a selected beam. Horizontal dotted lines show the depth intervals. The beam used to provide data is identified in the top left corner of the view.
  - Catch view
    Use the information in the Catch view to monitor the progress of the purse seine operation. The view does not offer any echo data.
  - 270 Vertical view
    The 270 Vertical view is designed for purse seining. The presentation combines a horizontal "bow up" presentation with a vertical slice.
- Using markers in the ST90 user interface
  Under normal use, the ST90 system presents several different echoes simultaneously. Some of these are clearly more interesting than others. It can be a challenging task to tell these echoes apart. It can also be hard to keep track of the different echoes as both echoes and your own vessel move. To ease the identification of these echoes you can use markers.
- Using target and position 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. A position track permits the ST90 system to automatically control the tilt and bearing based on the movements of your vessel.
- Informationpanes
- Bottom bar
  The bottom bar is located at the bottom of the display presentation and stretches from the left side to the right side. The tabs on the bottom bar allow you to choose presentation mode.
Menu system
Functions and dialog boxes
Concept descriptions
Technical specifications
The technical specifications summarize the main functional and operational characteristics of the ST90 system. They also provide information related to power requirements, physical properties and environmental conditions.
Datagram formats
The ST90 system can send and receive information to and from several different peripherals. All transmissions take place as datagrams with data sentences. Each datagram has a defined format and length.
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Range / Range Rings / Variable Range Ring

The distance from the vessel symbol in the centre of the circle to the outer ring corresponds to the currently selected range.

The current settings for range, gain and tilt are shown in the upper left corner of the view. Click on the text to make it larger. Click one more time to restore the original font size.

Range rings are a set of concentric circles labelled by distance from the vessel position. The selected range is divided into identical distances. The range rings are shown as dotted curves. Each ring has a range read-out. Use the Range Rings function to toggle the range rings On or Off.

Variable Range Ring adds an adjustable range ring to the view. The ring is shown as a dotted circle with its centre on the vessel symbol. The current range is shown next to the circle. To change the range, left-click on the circle and drag to requested diameter. You can use VRR Range to manually define a range. The variable range ring can be used for any type of distance measurement relative to the sonar.