Simrad omnisonar netCDF Type 1 equations

Echoview Simrad omnisonar netCDF Sv and TS equations are based on the Type 1 equations according to the netCDF4 convention that in turn bases the Type 1 equations on the work of Macaulay et al (2016). Contact Simrad for further details.

See also Multibeam calibration settings for Omnisonar netCDF (.nc).

where:

TS (dB re 1m2) is the target strength.

Sv (dB re 1m-1) is the volume backscatter strength.

Pr (W) is linearly proportional to the received complex power.

r (m) is the range between the transducer and the target or sample.

where:

c (ms-1) is the sound speed is read from the file and displayed as the SoundSpeed on the Calibration page of the Variable Properties dialog box.

dt (s) is the time between recorded samples is read from file.

i is the sample number.

t0 (s) is the time offset read from file.

α (dB/m) is the speed of sound in water read from file and displayed as AbsorptionCoefficient on the Calibration page of the Variable Properties dialog box.

Pt (W) is the transmit power read from file and displayed as TransmittedPower on the Calibration page of the Variable Properties dialog box.

λ (m) is the acoustic wavelength.

where:

FrequencyEnd (kHz) and FrequencyStart (kHz) are read from file and displayed on the Calibration page of the Variable Properties dialog box.

G (dB) is the transducer gain read from file and displayed as TransducerGain on the Calibration page of the Variable Properties dialog box.

γ (degrees) is the tilt of the transmitted beam (cone), evaluated from from beam angles read from file.

ψ (dB re 1sr) is the equivalent beam angle read from file and displayed as TwoWayBeamAngle on the Calibration page of the Variable Properties dialog box.

τe (s) is the effective pulse duration and is displayed as EffectivePulseDuration on the Calibration page of the Variable Properties dialog box. When EffectivePulseDuration is unavailable, the PulseDuration is used for Sv calculations.