Ex60 Power, Power to Sv and TS

Echoview extracts Power (dB re 1 W) raw variables from Ex60 data files.

Two raw variables derived from power data are also provided:

The Sv and TS values are calculated from the raw power data according to formulas below.

Notes:

Power

Power variables on the Filesets window represent the Recieved power (dB re 1W) read from the data file.

Calculation of Sv and TS

Sv and TS are obtained for range and power according to:

where:

R = the corrected range (m) - see TVG Range Correction

Pr = received power (dB re 1 W) - see Simrad EK numbers to Power.

Pt = transmitted power (W)

α = absorption coefficient (dB/m)

G0 = transducer peak gain (non-dimensional)

Echoview calculates G0 as 10^(G'0/10) where:

G'0 is the Transducer gain (dB re 1) entered under Ek60TransducerGain on the Calibration Page of the Variable Properties dialog box. This value should be the same for TS and Sv variables and equal to the Transducer gain specified under Ping (from file) of the Details dialog box.

λ = wavelength (m) = c/f

f = frequency (Hz) entered on the  Calibration Page of the Variable Properties dialog box.

c = sound speed (m/s) entered on the  Calibration Page of the Variable Properties dialog box.

τ = transmit pulse duration (s) - also known as the TransmittedPulseLength on the Calibration Page of the Variable Properties dialog box.

ψ = Equivalent Two-way beam angle (Steradians)

Echoview calculates ψ as 10^(Ψ/10), where:

Ψ is the Two-way beam angle (dB re 1 Steradian) entered on the Calibration Page of the Variable Properties dialog box.

Sa = Simrad correction factor (dB re 1m-1) determined during calibration of the Ex60. This is also used as a transducer constant in Sv to TS and TS to Sv conversion equations.

This represents the correction required to the Sv constant to harmonize the TS and NASC measurements.
The Sa correction value is entered on the Calibration page of the Variable Properties dialog box.

See also

Simrad EK numbers
EK500 Power to Sv and TS

Simrad Ex60 sample range calculation
Changes to Simrad Ex60 sample range calculation in Echoview