Echoview can derive the following raw variables from DIDSON .ddf data files.
Unspecified dB frames
Sv dB frames
position GPS fixes
pitch data
roll data
heading data
The unspecified dB frames variable contains signal intensities from 0 to 90 dB as stored in the DIDSON data file. The Sv frames variable contains Sv data derived for these intensities as described in Multibeam Magnitudes to Sv. You must enter calibration settings for the Sv frames variable before using this variable for quantitative analyses.