Furuno FSV-25 Sv and TS equations

Echoview Furuno FSV-25 Sv and TS equations are based on the Type 2 equations according to the netCDF4 convention. Contact Furuno Electric Co., Ltd for further details.

See also Multibeam calibration settings for Furuno FSV-25 *.nc data files.

TS

where:

TS
is the Target strength (dB)

A
is read from the data file and is linearly proportional to the amplitude of the received echo.

r
is the range (m) from the transducer to the ping sample

where:

c is the sound speed (ms-1) read from the data file. It is represented by SoundSpeed on the Calibration page of the Variable Properties dialog box.

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

i is the sample number i ∈ [0, n-1] where n is the number of samples in a ping.

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

α
is the absorption coefficient (dB/m) read from the data file. It is represented by AbsoprtionCoefficient on the Calibration page of the Variable Properties dialog box.

SL
is source level (dB re 1µPa at 1 m) read from the data file. It is represented by SourceLevel on the Calibration page of the Variable Properties dialog box.

K
is receiver sensitivity (dB re 1/µPa) read from the data file. It is represented by ReceiverSensitivity on the Calibration page of the Variable Properties dialog box.

ΔG
is Gain correction (dB) is determined during the calibration process. It is represented by GainCorrection on the Calibration page of the Variable Properties dialog box.

GT
is Time-varied gain, GT (dB), is given at each sample number i.

Note: SL and K may depend on tilt angle of the beam for transmitting and receiving.

Sv

where:

Sv
is the mean volume backscattering strength (dB)

A, r, α, c, SL, K, ΔG, GT
See descriptions under TS equation definitions for details.

R
is the corrected sample range (m), it accounts for the time-variad-gain effect on the echo shape.

R= r - r0, where r0 = (cτe)/4

τe
is the effective pulse duration (seconds) read from the file. It is represented by PulseDuration on the Calibration page of the Variable Properties dialog box.

ψ
is the TwoWayBeamAngle (Steradian) read from the data file. It is represented by TwoWayBeamAngle on the Calibration page of the Variable Properties dialog box.

Ψ dB = 10log ψ

TS	is the Target strength (dB)
A	is read from the data file and is linearly proportional to the amplitude of the received echo.
r	is the range (m) from the transducer to the ping sample where: c is the sound speed (ms-1) read from the data file. It is represented by SoundSpeed on the Calibration page of the Variable Properties dialog box. dt is the time (s) between recorded samples read from the data file. i is the sample number i ∈ [0, n-1] where n is the number of samples in a ping. t0 is the sample time offset (s) read from the data file.
α	is the absorption coefficient (dB/m) read from the data file. It is represented by AbsoprtionCoefficient on the Calibration page of the Variable Properties dialog box.
SL	is source level (dB re 1µPa at 1 m) read from the data file. It is represented by SourceLevel on the Calibration page of the Variable Properties dialog box.
K	is receiver sensitivity (dB re 1/µPa) read from the data file. It is represented by ReceiverSensitivity on the Calibration page of the Variable Properties dialog box.
ΔG	is Gain correction (dB) is determined during the calibration process. It is represented by GainCorrection on the Calibration page of the Variable Properties dialog box.
GT	is Time-varied gain, GT (dB), is given at each sample number i.

Sv	is the mean volume backscattering strength (dB)
A, r, α, c, SL, K, ΔG, GT	See descriptions under TS equation definitions for details.
R	is the corrected sample range (m), it accounts for the time-variad-gain effect on the echo shape. R= r - r0, where r0 = (cτe)/4
τe	is the effective pulse duration (seconds) read from the file. It is represented by PulseDuration on the Calibration page of the Variable Properties dialog box.
ψ	is the TwoWayBeamAngle (Steradian) read from the data file. It is represented by TwoWayBeamAngle on the Calibration page of the Variable Properties dialog box. Ψ dB = 10log ψ