Choosing a calibration offset for Sv to TS and TS to Sv conversion

The choice of transducer constants is of particular relevance in determining the accuracy of the TS to Sv and Sv to TS operators.

If you need to choose a transducer constant as part of your echosounder calibration process, see Using Echoview in the calibration process.

Simrad Ex500 data

Simrad Ex500 echosounders associate one gain with Sv data and another with TS data (the Sv Gain and TS Gain respectively).

The transducer constant to use in converting:

from Sv to TS  is (TS Gain - Sv Gain)
from TS to Sv  is (Sv Gain - TS Gain)

See EK500 Power to Sv and TS and Sv to TS and TS to Sv for the underlying formulae.

Simrad Ex60 data

Simrad Ex60 echosounders associate:

• one gain with Sv data (Sv Gain (dB) = Transducer Gain(dB) + Sa correction(dB))
• one gain with TS data (TS gain (dB) = Transducer Gain(dB))

The transducer constants to use in converting

from Sv to TS is (2 × Sa correction)
from TS to Sv is (-2 × Sa correction)

See Ex60 Power to Sv and TS and Sv to TS and TS to Sv for the underlying formulae.

Other data

To the best of our knowledge, generally no transducer constant is required for TS/Sv conversion with Sv and TS data derived from echosounders other than the Simrad Ex500 and Simrad Ex60. However, if you have used different transducer constant values for the parent TS and Sv variables, you may have to consider the impact of that on subsequent TS/Sv conversions with the data.

Separate transducer constants CalibrationOffsetTs and CalibrationOffsetSv are available for BioSonics data.

Where transducer constants are unavailable for your data and you have both Sv and TS data, you may be able to estimate and specify the Calibration difference offset.

See Sv to TS and TS to Sv for the general conversion equations.

See also

Calibration settings for Sv to TS and TS to Sv virtual variables
Sv to TS
TS to Sv
Using Echoview in the calibration process