Simrad SL 30, Manual

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SL 30/35 Hull Sonar Operators Manual 974-25007001/2.0
Menu and Software Description Page 4.15
Kongsberg Simrad Mesotech Ltd.
Port Coquitlam, BC - Canada
To calculate a sound velocity based on temperature and salinity estimates or
measurements:
•
In the Configuration Menu, select Parameters
•
Click on the Sound Velocity tab to open the Parameters | Sound Velocity dialog
box
•
In the Calculate from Temperature, Salinity, Depth box, enter estimates of
water Temperature , Salinity and Depth of the sonar head.
Note: Salinity of pure fresh water is near 0 ppm, salinity of sea water is typically
between 30 and 40 ppm. Brackish or mixed fresh and salt water will be somewhere
in between.
•
Click the Calculate button. The calculated value will be entered automatically in
the Value to be Used box
•
Click the OK button
4.19 HOW TO INTERPRET THE SONAR IMAGE
4.19.1 The Color Palette
The sonar image is a map of the echo returns over the scanned area. A sequence
of colors is used to show the relative strengths of the returns. Several colour
schemes or image palettes are available. Most of them use darker colors to indicate
weak returns and brighter, lighter colors to indicate the stronger returns.
4.19.2 Bright Spots
Bright spots in the image indicate strong sonar targets. Generally, this indicates a
hard, highly reflective surface.
4.19.3 Dark Spots
Dark spots in the image indicate either areas of low reflectivity (soft areas) or
possibly an acoustic shadow zone behind a target.