Echoview Data File Format equations

Echoview Data File Format equations for Power to Sv and Power to TS.

Power

Received power (dB re 1W).

Power to Sv

EVD Power to Sv

Note: The term "-10 log10 ((SoundSpeed*PulseDuration)/2)" supports a SoundSpeed-Depth profile where available. See also: Using a sound speed profile.

Power to TS

EVD Power to TS

Where:

Pr

is the received Power (dB re 1W) of a sample.

Range

is the sample range (m).

It is derived from the sample thickness and the number of samples in the ping.

Sample thickness = (StopRange - StartRange)/SampleCount

Ping StopRange, StartRange and SampleCount are read from the file.

AbsorptionCoefficient

is the absorption coefficient in dB/m.

It is specified under AbsorptionCoefficient on the Calibration page of the Variable Properties dialog box.

SoundSpeed

is the speed of sound (m/s) in water.

It is specified under SoundSpeed on the Calibration page of the Variable Properties dialog box.

PulseDuration

is the duration (s) of the transmitted pulse.

It is specified under PulseDuration on the Calibration page of the Variable Properties dialog box.

TwoWayBeamAngle

is the Two way beam angle in dB re 1 steradian.

It is specified under TwoWayBeamAngle on the Calibration page of the Variable Properties dialog box.

TRFactor

is the transmit-receive factor (dB) for the transducer.

It is specified under TRFactor on the Calibration page of the Variable Properties dialog box. When TRFactor is unspecified, it can be calculated using the following equation.

where:

TransmittedPower is the transmitted power (W). It is specified under TransmittedPower on the Calibration page of the Variable Properties dialog box.

TransducerGain is the nominal gain (dB) for the transducer. It is specified under TransducerGain on the Calibration page of the Variable Properties dialog box.

Frequency is the frequency (Hz) of the transmit pulse. It is specified under Frequency on the Calibration page of the Variable Properties dialog box.

CalibrationOffsetSv

is a system/instrument constant for the Power to Sv equation that can be associated with hydroacoustic calibration.

It is specified under CalibrationOffsetSv on the Calibration page of the Variable Properties dialog box.

CalibrationOffsetTs

is a system/instrument constant for the Power to TS equation that can be associated with hydroacoustic calibration.

It is specified under CalibrationOffsetTs on the Calibration page of the Variable Properties dialog box.

Pr	is the received Power (dB re 1W) of a sample.
Range	is the sample range (m). It is derived from the sample thickness and the number of samples in the ping. Sample thickness = (StopRange - StartRange)/SampleCount Ping StopRange, StartRange and SampleCount are read from the file.
AbsorptionCoefficient	is the absorption coefficient in dB/m. It is specified under AbsorptionCoefficient on the Calibration page of the Variable Properties dialog box.
SoundSpeed	is the speed of sound (m/s) in water. It is specified under SoundSpeed on the Calibration page of the Variable Properties dialog box.
PulseDuration	is the duration (s) of the transmitted pulse. It is specified under PulseDuration on the Calibration page of the Variable Properties dialog box.
TwoWayBeamAngle	is the Two way beam angle in dB re 1 steradian. It is specified under TwoWayBeamAngle on the Calibration page of the Variable Properties dialog box.
TRFactor	is the transmit-receive factor (dB) for the transducer. It is specified under TRFactor on the Calibration page of the Variable Properties dialog box. When TRFactor is unspecified, it can be calculated using the following equation. where: TransmittedPower is the transmitted power (W). It is specified under TransmittedPower on the Calibration page of the Variable Properties dialog box. TransducerGain is the nominal gain (dB) for the transducer. It is specified under TransducerGain on the Calibration page of the Variable Properties dialog box. Frequency is the frequency (Hz) of the transmit pulse. It is specified under Frequency on the Calibration page of the Variable Properties dialog box.
CalibrationOffsetSv	is a system/instrument constant for the Power to Sv equation that can be associated with hydroacoustic calibration. It is specified under CalibrationOffsetSv on the Calibration page of the Variable Properties dialog box.
CalibrationOffsetTs	is a system/instrument constant for the Power to TS equation that can be associated with hydroacoustic calibration. It is specified under CalibrationOffsetTs on the Calibration page of the Variable Properties dialog box.