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

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.

TransmittedPulseLength

is the duration (s) of the transmitted pulse.

It is specified under TransmittedPulseLength 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.

TRFactor

where:

Wavelength

Linear Gain

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 transmitt 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.

See also

About the Echoview Data File Format
Echoview Data File Format files
Calibration settings for Echoview Data File Format data