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Operating procedures
Using the markers and tracking features
Measuring the size of a school relative to the purse seine
Estimating the size of a school can sometimes be challenging. A single circle marker can be placed in the display presentation. The circle is drawn with the same diameter as your purse. By means of the circle you can see the size of the school relative to your purse.

Purpose
Document information
About this manual
The purpose of this publication is to provide the descriptions and procedures required to allow for efficient use of the ST90 system. The manual does not contain detailed information about functions, dialog boxes and operating parameters.
Simrad ST90
Operating procedures
- Getting started
- Choosing operating mode and key transmit parameters
- Controlling the gain and range settings
- Using the markers and tracking features
  - Starting a position track
    A position track permits the ST90 system to automatically control the tilt and bearing based on the movements of your vessel.
  - Starting a target track
    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.
  - Placing a new marker
    One or more markers can be placed in the view to identify specific echoes. Each marker is shown as a small triangle with or without a short identifying label.
  - Deleting a marker
    There are several ways to delete a single marker. You can use the shortcut menu, or select Delete in the Objects menu. You can also use the Operating Panel.
  - Deleting multiple markers
    There are several ways to delete multiple markers simultaneously.
  - Measuring the size of a school relative to the purse seine
    Estimating the size of a school can sometimes be challenging. A single circle marker can be placed in the display presentation. The circle is drawn with the same diameter as your purse. By means of the circle you can see the size of the school relative to your purse.
  - Using visual aids during the purse seine catch phase
    The gear symbol is provided as a tool to help you plan and shoot the purse seine. The symbol is intended to be used in a structured sequence that starts when you plan to shoot the purse seine.
  - Selecting a geographical area for accurate target tracking
    When you have an echo you wish to track, the tracking functionality places a geographical area around the object. An invisible area - the tracking area - is created as an acquisition area. In order for the ST90 system to find and lock on the intended target, it needs to be kept within this tracking area. If the intended target falls outside the area, the tracking can not be started.
  - Defining the physical size of the tracking area
    When you have an echo you wish to track, the tracking functionality places a geographical area around the object. An invisible area - the tracking area - is created as an acquisition area. In order for the ST90 system to find and lock on the intended target, it needs to be kept within this tracking area. If the intended target falls outside the area, the tracking can not be started. Use the Tracking Area Setup dialog box to define or change the physical size of the tracking area.
  - Choosing the fishing gear in use
    By defining the type of fishing gear you are using, the ST90 system may provide more accurate visual presentations. The Fishing Gear function allows you to define the size of your trawl or purse seine.
  - Changing the fishing gear properties to match your own equipment
    Use the Fishing Gear Setup dialog box to change the fishing gear properties to match your own equipment.
- Improving the recognition of fish and schools using receiver filters
- Recording and replaying echo data
- Recording and exporting processed echo data
- Capturing the display presentation in image and video files
- Setting up presentation modes and views
- Defining the visual information in the sonar views
- Defining settings related to user preferences and individual customizing
- Saving, retrieving and maintaining user settings
- Defining the user-selected features on the Operating Panel
- Exporting sensor data, marker positions and technical information
User interface
Menu system
Functions and dialog boxes
The functions and dialog boxes provided in the ST90 user interface are not described in this publication.
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.
Copyright

Measuring the size of a school relative to the purse seine

Estimating the size of a school can sometimes be challenging. A single circle marker can be placed in the display presentation. The circle is drawn with the same diameter as your purse. By means of the circle you can see the size of the school relative to your purse.

To provide an accurate visual presentation, the ST90 system needs to know the size of your gear.

The Fishing Gear function allows you to define the size of your trawl or purse seine. This function is opened from the Setup menu.

You can only add one circle marker to the display presentation.

Procedure

Position the cursor where you wish to place the circle marker.
Press Circle Marker on the Operating Panel.
or:
Right-click and select Place Circle Marker on the shortcut menu.
The size and location of the marker is defined by the choices you have made with the Fishing Gear function.

To delete the circle marker, press Circle Marker on the Operating Panel, or right-click to select Remove Circle Marker on the shortcut menu.