Calibration names used by transducer specific raw variables

Calibration setting name

Help file terminology

Default value

Units

ICES CRR No. 326

Term, Symbol, and Units

(Refer to Demer et al. 2015)

ApplyCalibrationCorrection

(Apply Simrad) Calibration correction

Default value is ApplyCalibrationCorrection = false.

Used with:

• Sample Sv and TS variables (V and P telegrams) logged with Ex500
• Simrad echogram and echo trace (Q and E telegrams) variables logged with Ex500
• Sample Sv and TS variables (V and P telegrams) logged with Ex60
• Simrad echogram and echo trace variables (Q and E telegrams) logged with Ex60

false

Bandwidth

Effective transmit bandwidth used by certain operators (e.g., Interval analysis – Calibration) and some HTI data workflows. It may be read from some HTI files or set by the user. Not used for Simrad raw-variable calibration in Echoview; for EK/EX systems see SimradBandwidth.

kHz

CalibrationOffset

Generic calibration offset used by operators (distinct from format-specific offsets such as CalibrationOffsetSv or CalibrationOffsetTs).

0

dB

CalibrationOffsetUnspecifieddB

Generic calibration offset (dB) used by operators such as Interval analysis – Calibration when a format-specific offset isn’t available.

0

dB

EcholistenerEchosounderConstant

Used explicitly by EchoListener data files.

300

MajorAxisAngleOffset

Refer to MinorAxisAngleOffset.

0

°

Transducer beamwidth offset   α0   °

MajorAxisAngleSensitivity

Simrad defines Angle Sensitivity as a parameter that is used in the conversion of the raw angle samples into mechanical degrees for fore-and-aft and athwartship directions. It represents the ratio of electrical degrees to mechanical degrees for the current transducer. This ratio is not used with single beam transducers, and the value is set to 0.

There may be an Angle Sensitivity for the Major-axis and/or the Minor-axis angles.

See also: Beam angles

Used by:

• Ek500 Sv and TS from Power (W telegrams) and B telegrams logged with Ex500
• Ek500 Sample Sv and TS variables (V and P telegrams) logged with Ex60
• Ek60 angular position raw variables
• ME70 angular position raw variables

21.9

Transducer angle sensitivity (electric/geometric)   Λα

MinorAxisAngleOffset

Simrad defines Angle Offset as the offset angle from the acoustical axis. The value is estimated during calibration. If no calibration takes place, the value 0 is used. There may be an Angle Offset for the Major-axis and/or the Minor-axis angles.

See also: Beam angles

0

°

Transducer beamwidth offset   β0   °

MinorAxisAngleSensitivity

Simrad defines Angle Sensitivity as a parameter that is used in the conversion of the raw angle samples into mechanical degrees for fore-and-aft and athwartship directions. It represents the ratio of electrical degrees to mechanical degrees for the current transducer. This ratio is not used with single beam transducers, and the value is set to 0.

There may be an Angle Sensitivity for the Major-axis and/or the Minor-axis angles.

See also: Beam angles

Used by:

• Ek500 Sv and TS from Power (W telegrams) and B telegrams logged with Ex500
• Ek500 Sample Sv and TS variables (V and P telegrams) logged with Ex60
• Ek60 angular position raw variables
• ME70 angular position raw variables

21.9

Transducer angle sensitivity (electric/geometric)   Λβ

SaCorrectionFactor

Sa correction

The Sa correction factor is determined during calibration (e.g., Simrad Ex60, Simrad EK80 CW). Echoview will also read this value from an ECS file, which is useful if users apply calibration results post-survey or via Calibration Assistant.

A deprecated alias is EK60SaCorrection.

0

dB

SamplingFrequency

Sampling frequency

The Sampling frequency, together with the SoundSpeed and TransmittedPulseDuration, is used to calculate the sample thickness.

kHz

SimradBandwidth

The Simrad Bandwidth is used to determine the value of filter corrections in the EK500 Power to Sv or TS calculation. Values include: Unknown, Auto, Narrow and Wide.

Unknown

SimradSampleResolution

Sample resolution

10

cm

SimradStartSampleRange

Start sample range

0

m

TransducerGain

The recorded transducer-specific gain that is used in Simrad Ek60 Power to Sv and TS algorithms.

Note: A deprecated alias is Ek60TransducerGain.

26.5

dB

On-axis gain   G0   dB re 1

TransducerImpedance

Generic transducer impedance referenced by operators such as Interval analysis – Calibration. For EK80 specifics, see TransceiverImpedance and TransducerImpedanceTableWideband in the Simrad EK80 section.

Ω

TvgRangeCoefficient

TVG range coefficient

20

WedgeVolumeBeamAngle

Wedge-geometry equivalent of two-way beam angle for beams that approximate a wedge; used by operators where applicable.

dB re 1 sr

Calibration setting name

Help file terminology

Default value

Units

ICES CRR No. 326

Term, Symbol, and Units

(Refer to Demer et al. 2015)

AbsorptionCoefficientLogging

Logging value for the Absorption coefficient.

0.01

dB m-1

Ek5SvGain

Ek5 Sv gain

Used in EK500 Power to Sv and TS - to calculate the transducer peak gain.

26.5

dB

On-axis gain   G0   dB re 1

Ek5SvGainLogging

Logging value for the Ek5SvGain.

26.5

dB

Ek5TSGain

Ek5 TS gain

Used in EK500 Power to Sv and TS - to calculate the transducer peak gain.

26.5

dB

On-axis gain   G0   dB re 1

Ek5TSGainLogging

Logging value for the Ek5TSGain.

26.5

dB

PulseDurationLogging

Logging value for the pulse duration.

A deprecated alias is TransmittedPulseLengthLogging.

1

ms

SimradDraftLogging

Logging value for the Simrad Draft for Simrad Sv and TS variables based on Q telegrams and single target variables based on E telegrams and only when these variables include a logged draft.

We strongly recommend logging data with transducer depth set to 0 and using Echoview's transducer geometry to model the draft.

Note: There may be slight differences in single target or fish track exported analyses when comparing the analyses pre and post Echoview 5.

0

m

SimradPulseLength

The Simrad Pulse length is used to determine the value of filter corrections in the Ek500 Power to Sv or TS calculation. Values include: Unknown, Short, Medium, Long.

Unknown

SoundSpeedLogging

Logging value for the Sound speed.

1500

m s-1

TransmittedPower

Transmitted power

2000

W

TransmittedPowerLogging

Logging value for the Transmitted power.

2000

W

TwoWayBeamAngleLogging

Logging value for the Two-way beam angle.

-20.6

dB re 1 sr

WavelengthLogging

Logging value for the Wavelength.

0.0394737

m

Wavelength

Wavelength

0.0394737

m

Calibration setting name

Help file terminology

Default value

Units

ICES CRR No. 326

Term, Symbol, and Units

(Refer to Demer et al. 2015)

AzfpDetectionSlope

Value for a read from an associated AZFP .XML or .cfg file if it is present in the data folder.

0.0227

V dB-1

AzfpEchoLevelMax

Value for ELmaxread from an associated AZFP .XML or .cfg file if it is present in the data folder.

128.3

dB

AzfpTransmitVoltage

91.9

V

Transmit voltage   uet   V

AzfpTransmitVoltageResponse

Value for TVR read from an associated AZFP .XML or .cfg file if it is present in the data folder.

172.3

dB

CalibrationOffsetSv

A setting for an AZFP Sv calibration offset constant.

0

dB

CalibrationOffsetTs

A setting for an AZFP TS calibration offset constant.

0

dB

SoundSpeed

SoundSpeed may be read from an associated AZFP .XML or .cfg file if it is present in the data folder.

1500

m s-1

Water sound speed   cw   m s-1

TwoWayBeamAngle

TwoWayBeamAngle may be read from an associated AZFP .XML or .cfg file if it is present in the data folder.

-20.600000

dB re 1 sr

Equivalent two-way beam angle   Ψ   dB re 1 sr

Calibration setting name

Help file terminology

Default value

Units

ICES CRR No. 326

Term, Symbol, and Units

(Refer to Demer et al. 2015)

CalibrationOffsetSv

A setting for the BioSonics Sv transducer constant that can be used in the BioSonics Sv equation.

0

dB

CalibrationOffsetTs

A setting for the BioSonics TS transducer constant that can be used in the BioSonics TS equation.

0

dB

Dt4PowerSetting

BioSonics power setting

Note: Post-Echoview 3.00 the calibration setting Dt4PowerSetting is used and the Calibration offset setting is set to zero. Pre-Echoview 3.00 the Calibration offset setting was used to represent the BioSonics PS (Power setting) value - Echoview was unable to read the BioSonics PS at that time.

0

dB

ReceiveSensitivity

DT4 Receive sensitivity (RS) read from the data file and used in BioSonics DT4 Sv and TS equations.

dB

SourceLevel

DT4 Source level (SL) read from the data file and used in BioSonics DT4 Sv and TS equations.

dB

Source level SL dB re 1 μPa at r0 (the reference range)

Calibration setting name

Help file terminology

Default value

Units

CalibrationOffsetSv

An offset value used in the Echoview Data File Format Power to Sv equation.

0

dB

CalibrationOffsetTs

An offset used in the Echoview Data File Format Power to Sv equation.

0

dB

Calibration setting name

Help file terminology

Default value

Units

ICES CRR No. 326

Term, Symbol, and Units

(Refer to Demer et al. 2015)

GainCorrection

GainCorrection is read from the data file and used to calculate the received power for Version 2 data.

0.000

dB

MajorAxis3dbBeamAngle

MajorAxis3dbBeamAngle

MajorAxis3dbBeamAngle is assigned the value for beamwidth_receive_major read from the data file.

7.10

°

Transducer beamwidth   α-3 dB   °

MajorAxis3dbBeamAngleTransmit

FCV-38 instrument information about the major axis 3 dB angle transmit value. It is not used in the calculation of the raw variables but may be of use elsewhere.

°

MajorAxisAngleSensitivity

MajorAxisAngleSensitivity is read from the data file and used to calculate angular position angles.

MinorAxis3dbBeamAngle

MinorAxis3dbBeamAngle

MinorAxis3dbBeamAngle is assigned the value for beamwidth_receive_minor read from the data file.

7.10

°

Transducer beamwidth   β-3 dB   °

MinorAxis3dbBeamAngleTransmit

FCV-38 instrument information about the minor axis 3 dB angle transmit value. It is not used in the calculation of the raw variables but may be of use elsewhere.

°

MinorAxisAngleSensitivity

MinorAxisAngleSensitivity is read from the data file and used to calculate angular position angles.

PulseDuration

PulseDuration

The FCV-38 effective PulseDuration is read from the data file, and used to calculate Sv.

1.000

ms

Pulse duration   τ   s

TransmitReceiveCoefficient

TransmitReceiveCoefficient read from Furuno FCV-38 *.nc Version 2 data files and used to calculate the received power.

0

dB

TransmittedPower

Transmitted power

The Furuno TransmittedPower (W) is read from the data file.

2000

W

Transmit acoustic power   pat   W

TwoWayBeamAngle

Two-way beam angle

The TwoWayBeamAngle is read from the data file and used to calculate the Sv.

-20.6

dB re 1 sr

Equivalent two-way beam angle   Ψ   dB re 1 sr

Calibration setting name

Help file terminology

Default value

Units

ICES CRR No. 326

Term, Symbol, and Units

(Refer to Demer et al. 2015)

AbsorptionCoefficient

Absorption coefficient

The absorption coefficient read from an absorption coefficient-frequency table recorded in the Furuno FSV-25 data file.

Where a frequency is between two frequencies in the table, Echoview linearly interpolates for the absorption coefficient. If a frequency is outside of the tabled frequencies, the absorption coefficient used is of the closest table frequency.

0.010

dB m-1

Absorption coefficient   αa   dB m-1

Frequency

Frequency

Frequency determined from transmit_frequency_start and transmit_frequency_stop data read from the file.

• Where transmit_frequency_start is not present in the data file, Frequency is not displayed as a calibration setting.
• Where transmit_frequency_start and transmit_frequency_stop are present in the data file and their values are unequal, the calibration setting - Frequency is assigned the average of the two values.
• Where only a transmit_frequency_start value is present in the data file, Frequency is assigned the transmit_frequency_start value.

38

kHz

Acoustic frequency   f   Hz

GainCorrection

GainCorrection is determined during the calibration process. This factor accounts for differences between the theoretical response and the observed response during calibration.

0.0000

dB

MajorAxis3dbBeamAngle

MajorAxis3dbBeamAngle

MajorAxis3dbBeamAngle is assigned the value for beamwidth_receive_major of Beam 0, read from the Furuno FSV-25 data file.

7.10

°

Transducer beamwidth   α-3 dB   °

MinorAxis3dbBeamAngle

MinorAxis3dbBeamAngle

MinorAxis3dbBeamAngle is assigned the value for beamwidth_receive_minor of Beam 0, read from the Furuno FSV-25 data file.

7.10

°

Transducer beamwidth   β-3 dB   °

PulseDuration

PulseDuration

The pulse duration read from the Furuno FSV-25 data file.

1.000

ms

Pulse duration   τ   s

ReceiveSensitivity

Receive sensitivity read from the Furuno FSV-25 data file.

-48.8

dB

Sound speed

The sound speed read from the Furuno FSV-25 data file.

1500

m s-1

Water sound speed   cw   m s-1

SourceLevel

Source level read from the Furuno FSV-25 data file.

205.6

dB

Source level   SL   dB re 1 μPa at r0 (the reference range)

TvgRangeCorrection

TvgRangeCorrection

Can be used to calculate Furuno FSV-25 Sv and TS values.

Standard

TwoWayBeamAngle

Two-way beam angle

The TwoWayBeamAngle is calculated using values for sound speed, frequency and transducer radius read from the Furuno FSV-25 data file.

-20.6

dB re 1 sr

Equivalent two-way beam angle   Ψ   dB re 1 sr

Calibration setting name

Help file terminology

Default value

Units

ICES CRR No. 326

Term, Symbol, and Units

(Refer to Demer et al. 2015)

AbsorptionCoefficient

Absorption coefficient

The absorption coefficient read from the Furuno FSV-30 (Research version) data file.

0.010

dB m-1

Absorption coefficient   αa   dB m-1

Frequency

The frequency is read from the Furuno FSV-30 (Research version) data file.

38

kHz

Acoustic frequency   f   Hz

MajorAxis3dbBeamAngle

Echoview evaluates the H-mode MajorAxis3dbBeamAngle value when Furuno FSV-30 (Research version) angle and angle weight data are recorded in the file.

The MajorAxis3dbBeamAngle is equivalent to Furuno FSV-30 (Research version) beamwidth_receive_major. The equations are specific to Furuno FSV-30 (Research version) data.

MajorAxis3dbBeamAngle may be used for the calculation of TwoWayBeamAngle.

7.10

°

Transducer beamwidth   α-3 dB   °

MinorAxis3dbBeamAngle

Echoview evaluates the H-mode MinorAxis3dbBeamAngle value when Furuno FSV-30 (Research version) angle and angle weight data are recorded in the file.

The MinorAxis3dbBeamAngle is equivalent to Furuno FSV-30 (Research version) beamwidth_receive_minor. The equations are specific to Furuno FSV-30 (Research version) data.

MinorAxis3dbBeamAngle may be used for the calculation of TwoWayBeamAngle.

7.10

°

Transducer beamwidth   β-3 dB   °

MinorAxis3dbBeamAngleTransmit

Echoview evaluates the H-mode MinorAxis3dbBeamAngleTransmit value when Furuno FSV 30 (Research version) angle and angle weight data are recorded in the file.

MinorAxis3dbBeamAngleTransmit is equivalent to Furuno FSV-30 (Research version) beamwidth_transmit_minor. The equations are specific to Furuno FSV-30 (Research version) data.

MinorAxis3dbBeamAngleTransmit may be used for the calculation of TwoWayBeamAngle.

7.10

°

PulseDuration

PulseDuration

The pulse duration read from the Furuno FSV-30 (Research version) data file.

1.000

ms

Pulse duration   τ   s

Sound speed

1500

m s-1

Water sound speed   cw   m s-1

SourceLevel

Source level is read from the Furuno FSV-30 (Research version) data file.

205.6

dB

Source level   SL   dB re 1 μPa at r0 (the reference range)

TvgRangeCorrection

TvgRangeCorrection

Standard

TwoWayBeamAngle

Two-way beam angle

The TwoWayBeamAngle is read from the Furuno FSV-30 (Research version) data file.

For H-mode Sv data, where MajorAxis3dbBeamAngle, MinorAxis3dbBeamAngle and MinorAxis3dbBeamAngleTransmit data are available in the data file, the TwoWayBeamAngle is calculated.

-20.6

dB re 1 sr

Equivalent two-way beam angle   Ψ   dB re 1 sr

Calibration setting name

Help file terminology

Default value

Units

ICES CRR No. 326

Term, Symbol, and Units

(Refer to Demer et al. 2015)

BeamPatternFactor

This is the Beam_Pattern_Factor used in the HTI sample data to Sv, TS and angular position equations.

0.016

dB

ChirpBandwidth

0

kHz

HtiAequip

Aequip. Used by HTI version 0.0 .INT files (you will need to calculate the value for Aequip).

For other HTI file types Aequip-related calculations are handled by Echoview.

See also HTI integrated data: Notes.

1.00E-06

MajorAxisAngleRatio

MinorAxisAngleRatio

This is the Vertical ratio used in the HTI sample data to Sv, TS and angular position equations.

ReceiverGain20Log

This is the Receiver_Gain_20_Log read from a *.smp file, where settings and data are stored together, and is used as Receiver_Gain in the HTI sample data to Sv, TS and angular position equations.

Where a *.cfg file accompanies a *.smp file, this is the Receiver_Gain read from the *.cfg file and used in the HTI sample data to Sv, TS and angular position equations.

ReceiverGain40Log

This is the Receiver_Gain_40_Log read from a *.smp file, where settings and data are stored together, and used as Receiver_Gain in the HTI sample data to Sv, TS and angular position equations.

Where a *.cfg file accompanies a *.smp file, this is the Receiver_Gain read from the *.cfg file and used in the HTI sample data to Sv, TS and angular position equations.

SamplingFrequency

44.1

kHz

SoundSpeed

SoundSpeed can be read from version 1.06 SMP files. Other HTI data file types may not record SoundSpeed or may record it in associated *.cfg or *.cal files.

1500

m s-1

Water sound speed   cw   m s-1

SourceLevel

This is the Source_level_n used in the HTI sample data to Sv, TS and angular position equations.

205.6

dB

Source level   SL   dB re 1 μPa at r0 (the reference range)

ThroughSystemGain20Log

This is the Log_20 Through System Gain used in the HTI sample data to Sv, TS and angular position equations.

-151

ThroughSystemGain40Log

This is the Log_40 Through System Gain used in the HTI sample data to Sv, TS and angular position equations.

-171

TvgCrossover20Log

This is the Tvg_Crossover used in the HTI sample data to Sv, TS and angular position equations.

-11.2

TvgGain20Log

This is read from a *.smp file, where settings and data are stored together, and used as Tvg_Gain in the HTI sample data to Sv, TS and angular position equations.

Where a *.cfg file accompanies a *.smp file, this is the Tvg_Gain read from the *.cfg file and used in the HTI sample data to Sv, TS and angular position equations.

20.98

dB

TvgGain40Log

This is read from a *.smp file, where settings and data are stored together, and used as Tvg_Gain in the HTI sample data to Sv, TS and angular position equations.

Where a *.cfg file accompanies a *.smp file, this is the Tvg_Gain read from the *.cfg file and used in the HTI sample data to Sv, TS and angular position equations.

20.98

dB

Calibration setting name

Help file terminology

Default value

Units

ICES CRR No. 326

Term, Symbol, and Units

(Refer to Demer et al. 2015)

AbsorptionCoefficient

Absorption coefficient

The absorption coefficient recorded in the *.nc file.

0.010

dB m-1

Absorption coefficient   αa   dB m-1

EffectivePulseDuration

The EffectivePulseDuration recorded in the *.nc file for wideband data.

1.000

ms

Effective pulse duration   τeff   s

Frequency

Frequency

The frequency recorded in the *.nc file.

38

kHz

Acoustic frequency   f   Hz

MajorAxis3dbBeamAngle

MajorAxis3dbBeamAngle

Physical MajorAxis3dbBeamAngle recorded in the *.nc file.

7.10

°

Transducer beamwidth   α-3 dB   °

MajorAxis3dbBeamAngleTransmit

MajorAxis3dbBeamAngleTransmit

Value recorded in the *.nc file,

7.10

°

MajorAxisAngleSensitivity

Based on the ICES SONAR-netCDF4 split-aperture beam handling when physical arrival angles are recorded; treated as a ratio.

1.0

MinorAxis3dbBeamAngle

MinorAxis3dbBeamAngle

Physical MinorAxis3dbBeamAngle recorded in the *.nc file.

7.10

°

Transducer beamwidth   β-3 dB   °

MinorAxis3dbBeamAngleTransmit

MinorAxis3dbBeamAngleTransmit

Value recorded in the *.nc file,

7.10

°

Transducer beamwidth   β-3 dB   °

MinorAxisAngleSensitivity

Based on the ICES SONAR-netCDF4 split-aperture beam handling when physical arrival angles are recorded; treated as a ratio.

1.0

PulseDuration

PulseDuration

The pulse duration read from the *.nc file.

1.000

ms

Pulse duration   τ   s

Sound speed

The sound speed read from the *.nc file. Affects the calculation for sample ranges.

1500

m s-1

Water sound speed   cw   m s-1

TransmitReceiveCoefficient

The TransmitReceiveCoefficient recorded in the *.nc file.

0

dB

TvgRangeCorrection

TvgRangeCorrection

Standard

Calibration setting name

Help file terminology

Default value

Units

ICES CRR No. 326

Term, Symbol, and Units

(Refer to Demer et al. 2015)

AbsorptionCoefficient

An AbsorptionCoefficient is calculated when AbsorptionDepth, Salinity, Temperature, Acidity, Frequency and SoundSpeed are available. The equation used is described by  Francois & Garrison (1982). The calculated AbsorptionCoefficient value is not displayed on the Calibration page of the Variable Properties dialog box but is displayed in the Calibration section of the Details dialog box.

You can override the calculated value by specifying an AbsorptionCoefficient value in an ECS file or you can recalculate the AbsorptionCoefficient by specifying different environmental values in an ECS file.

Values read from the ECS file and used by the variable are displayed in the Calibration page and the Details dialog box.

0.01

dB m-1

Absorption coefficient   αa   dB m-1

AbsorptionDepth

The AbsorptionDepth is calculated from Pressure, Salinity, Temperature and Acidity values read from the data file.

250

m

PulseDuration

The Nortek configured transmit length read from the data file.

1

ms

Pulse duration   τ   s

SoundSpeed

The Nortek nominal sound speed is 1500 m s-1 and it is used to calculate the sample range. To modify the sound speed use an ECS file.

1500

m s-1

Water sound speed   cw   m s-1

TransmittedPower

The TransmittedPower is read from the PL value recorded in the data file.

2000

W

Transmit acoustic power   pat   W

Calibration setting name

Help file terminology

Default value

Units

HarpAdcCorrectionX

• Split-beam TS calibration setting
• ADC correction X-axis

2048

HarpAdcCorrectionY

• Split-beam TS calibration setting
• ADC correction Y-axis

1990

HarpChannelGain

Channel gain (dB)

40

dB

HarpPdcCorrectionX

• Split-beam TS calibration setting
• PDC correction X-axis

400

HarpPdcCorrectionY

• Split-beam TS calibration setting
• PDC correction Y-axis

960

HarpPdiCorrectionX

• Split-beam TS calibration setting
• PDI correction X-axis

-139700

HarpPdiCorrectionY

• Split-beam TS calibration setting
• PDI correction Y-axis

-129700

HarpPhaseAngleCorrectionX

• Split-beam TS calibration setting
• Phase angle correction X-axis

2049

HarpPhaseAngleCorrectionY

• Split-beam TS calibration setting
• Phase angle correction Y-axis

1991

HarpSourceLevel

Source level (dB)

215

dB

HarpStaticGain

Static gain (G1) (dB)

-112

dB

Calibration setting name

Default value

Units

SM2000BeamsToForm

A beamforming calibration setting that specifies the Number of beams to form.

128

SM2000HeadType

SM2000 Transducer head setting for the Head type (deg).

Typical Head values:

None

SM2000Radius

SM2000 Transducer head setting for the Head Radius (m).

0

m

SM2000Sector

A beamforming calibration setting that specifies the Sector.

Note: Another beamforming setting is Sound speed (a common calibration setting).

120

°

SM2000Spacing

SM2000 Transducer head setting for the Head spacing (deg).

0

°

Calibration setting name

Help file terminology

Default value

Units

ICES CRR No. 326

Term, Symbol, and Units

(Refer to Demer et al. 2015)

AbsorptionCoefficient

CW and FM variables may use a calculated value for AbsorptionCoefficient based on environmental data read from the file. Environmental data includes water Temperature, Salinity, Acidity, AbsorptionDepth, SoundSpeed and Frequency. The equation used is described by Francois & Garrison (1982).

The calculated value is not displayed on the Calibration page of the Variable Properties dialog box, but is displayed under the Calibration section on the Details dialog box.

The calculated value can be overridden by specifying an AbsorptionCoefficient value in an ECS file, or can be recalculated by specifying other values for the environmental quantities via an ECS file. Values read from the ECS file and used by the variable are displayed in the Calibration page and the Details dialog box.

FM variables may also make use of a table of absorption coefficients with AbsorptionCoefficientTableWideband.

0.01

dB m-1

Absorption coefficient   αa   dB m-1

AbsorptionCoefficientTableWideband

A space or semicolon-separated sequence of AbsorptionCoefficient values, used in conjunction with the frequencies in FrequencyTableWideband.

Echoview computes the relative position of the given frequency between the closest entries in FrequencyTableWideband. Then for the (positionally) corresponding absorption coefficients in AbsorptionCoefficientTableWideband, it derives an interpolated value for the AbsorptionCoefficient.

AbsorptionDepth

Read from EK80 data file and used as depth in the Francois & Garrison (1982) equation.

The Francois & Garrison (1982) equation calculates the absorption coefficient using acidity, temperature and salinity, frequency and depth.

250

m

Acidity

The acidity or pH read from EK80 data file. See Common calibration names: Acidity.

The Francois & Garrison (1982) equation calculates the absorption coefficient using acidity, temperature and salinity, frequency and depth.

8.0

pH

CtdDepthProfile

Depth-keyed profile of CTD quantities (temperature, salinity, acidity/pH) used for depth-dependent absorption or sound-speed modeling when provided via ECS.

— (profile)

EffectivePulseDuration

The EffectivePulseDuration is calculated using the EK80 matched filter. EffectivePulseDuration is used in the calculation of continuous wave Sv and wideband Sv raw variables and may be modified using an ECS file.

For EK80 CW data recorded as non-complex data, the EffectivePulseDuration may be calculated using the TransceiverSamplingFrequency.

A deprecated alias is EffectivePulseLength.

1

ms

Effective pulse duration   τeff   s

EquivalentTwoWayBeamAngleTableWideband

A sequence of TwoWayBeamAngle values, used in conjunction with the frequencies in FrequencyTableWideband.

Echoview computes the relative position of the given frequency between the closest entries in FrequencyTableWideband. Then for the (positionally) corresponding two-way beam angle in EquivalentTwoWayBeamAngleTableWideband, it derives an interpolated TwoWayBeamAngle.

dB re 1 sr

Frequency

Frequency read from the EK80 data file. Used by EK80 CW and FM calculations where a scalar frequency is required.

kHz

Acoustic frequency  f Hz

FrequencyEnd

Wideband end frequency.

38

kHz

FrequencyStart

Wideband start frequency.

38

kHz

FrequencyTableWideband

Simrad frequency-dependent Frequency read from an instrument calibrated EK80 data file. FrequencyTableWideband frequency values at array positions are correlated with associated wideband table array data.

See Common calibration names: FrequencyTableWideband and Array position and element number note.

Hz

GainTableWideband

Simrad frequency-dependent Gain read from an instrument calibrated EK80 data file.

Array values/interpolated values are used in place of the TransducerGain.

See Common calibration names: GainTableWideband and Array position and element number note.

dB

MajorAxis3dbBeamAngle

MajorAxis3dbBeamAngle read from file or supplied via ECS for use in EK80 beam geometry.

°

Transducer beamwidth  α-3 dB °

MajorAxisAngleOffset

MajorAxisAngleOffset used to convert raw angle samples to mechanical degrees.

0

°

MajorAxisAngleOffsetTableWideband

Simrad frequency-dependent AngleOffsetAthwartship read from an instrument calibrated EK80 data file.

See Common calibration names: MajorAxisAngleOffsetTableWideband and Array position and element number note.

°

MajorAxisAngleSensitivity

Ratio of electrical to mechanical degrees for the major axis; not used for single-beam transducers.

21.9

Transducer angle sensitivity (electric/geometric)  Λα

MajorAxisBeamWidthTableWideband

Simrad frequency-dependent BeamWidthAthwartship read from an instrument calibrated EK80 data file.

Array values/interpolated values are used in place of the MajorAxis3dbBeamAngle.

See Common calibration names: MajorAxisBeamWidthTableWideband and Array position and element number note.

°

MinorAxis3dbBeamAngle

MinorAxis3dbBeamAngle read from file or supplied via ECS for use in EK80 beam geometry.

°

Transducer beamwidth  β-3 dB °

MinorAxisAngleOffset

MinorAxisAngleOffset used to convert raw angle samples to mechanical degrees.

0

°

MinorAxisAngleOffsetTableWideband

Simrad frequency-dependent AngleOffsetAlongship read from an instrument calibrated EK80 data file.

See Common calibration names: MinorAxisAngleOffsetTableWideband and Array position and element number note.

°

MinorAxisAngleSensitivity

Ratio of electrical to mechanical degrees for the minor axis; not used for single-beam transducers.

21.9

Transducer angle sensitivity (electric/geometric)  Λβ

MinorAxisBeamWidthTableWideband

Simrad frequency-dependent BeamWidthAlongship read from an instrument calibrated EK80 data file.

Array values/interpolated values are used in place of the MinorAxis3dbBeamAngle.

See Common calibration names: MinorAxisBeamWidthTableWideband and Array position and element number note.

°

NumberOfTransducerSegments

The NumberOfTransducerSegments is read from data files recorded from wideband transceivers. It records the number of transducer segments for the beam. The value is used in the calculation of EK80 received power.

• 4 is the value for a split beam transducer
• 3 is the value for a 3 segment transducer
• 2 is the value for a 2 segment transducer
• 1 is the value for a single beam transducer

PulseCompressedEffectivePulseDuration

The PulseCompressedEffectivePulseDuration is calculated using the EK80 auto-correlated matched filter. PulseCompressedEffectivePulseDuration is used in the calculation of pulse compressed wideband Sv raw variables and Single target detection - wideband virtual variables and may be modified using an ECS file.

A deprecated alias is PulseCompressedEffectivePulseLength.

1

ms

PulseDuration

Simrad EK80 data files may record PulseDuration values under alternative names.

A deprecated alias is TransmittedPulseLength.

1

ms

Pulse duration   τ   s

PulseDurationLookupKey

A space or semicolon-separated sequence of PulseDuration values used in conjunction with PulseDurationLookupSaCorrection or PulseDurationLookupTransducerGain. Can be used in an ECS file to handle pings from a survey with different pulse durations.

This setting is available to Simrad Ex60 and Simrad CW and wideband systems.

ms

PulseDurationLookupSaCorrection

A space or semicolon-separated sequence of SaCorrection values.

Echoview uses the PulseDurationLookupSaCorrection value corresponding to the PulseDurationLookupKey that matches PulseDuration to within 1%. Otherwise it uses the default Sa correction.

This setting is available to Simrad Ex60 and Simrad EK80 CW systems.

dB

PulseDurationLookupTransducerGain

A space or semicolon-separated sequence of TransducerGain values.

Echoview uses the PulseDurationLookupTransducerGain value corresponding to the PulseDurationLookupKey that matches PulseDuration to within 1%. Otherwise it uses the default transducer gain.

This setting is available to Simrad Ex60 and Simrad EK80 CW and wideband systems.

dB

SaCorrectionFactor

SaCorrectionFactor is read from EK80 CW data when present and may also be supplied via an ECS file (e.g., when users apply calibration results post-survey).

The factor represents the correction required to the Sv constant to harmonize TS and Sa (NASC) measurements.

A deprecated alias is EK60SaCorrection.

0

dB

Salinity

Read from the EK80 data file. See Common calibration names: Salinity.

The Francois & Garrison (1982) equation calculates the absorption coefficient using acidity, temperature and salinity, frequency and depth.

32

ppt
(parts per thousand)

Water salinity   sw   psu (practical salinity unit)

SamplingFrequency

Read from the EK80 data file. See Sampling frequency.

44.1

kHz

SoundSpeed

Sound speed read from file or supplied via ECS; affects sample range and wavelength.

1500

m s-1

Water sound speed  cw m s-1

SoundSpeedProfile

Depth-keyed sound speed profile used to refine range/wavelength calculations when provided via ECS.

m s-1 (vs depth)

Temperature

Read from the EK80 data file. See Common calibration names: Temperature.

The Francois & Garrison (1982) equation calculates the absorption coefficient using acidity, temperature and salinity, frequency and depth.

10

°C

Water temperature   tw   °C

This is the Simrad transceiver impedance recorded under the Transceiver element of the data file. This impedance represents the internal electrical resistance of the WBT unit and is used for the calculation of received power.

Note: Some versions of EK80 files may not record an impedance under the Transceiver element. In such cases a value of 1000 Ohms is used. Please contact Simrad for further information.

1000

Ω

TransceiverSamplingFrequency

TransceiverSamplingFrequency may be read from the EK80 data file. It may be recorded when data is saved as non-complex data at reduced sampling rate or a reduced file size. TransceiverSamplingFrequency is used to calculate the decimated sampling frequency and the EffectivePulseDuration.

Note: An instrument-specific TransceiverSamplingFrequency may be used when RxSampleFrequency is not present in the data file.

1500

kHz

TransducerGain

26.5

dB

On-axis gain   G0   dB re 1

TransducerImpedance

Electrical impedance of the transducer at the operating frequency. Used by Interval analysis – Calibration.

1000

Ω

This is a Simrad transducer impedance. The EK80 Calibration XML file can record a frequency-dependent array under the Impedance element. Echoview also reads such data, when it is present in an EK80 .raw file. However, Echoview does not use the data for EK80 calculations. The calibration setting is hidden but is available to ECS files and EVD files for the sake of completeness.

See also ECS and EVD issue for TransducerImpedanceTableWideband.

1000

Ω

TransducerModeActive

Determined from Channelmode read from the EK80 data file.

TransducerModeActive is true for active ping data (Channelmode=0).

TransducerModeActive is false for passive ping data (Channelmode=1).

An example is to filter active or passive pings (refer to the Glossary) with the Calibration subset operator by setting limits around the Channelmode value.

True

TransmittedPower

Read from the EK80 data file. See Transmitted power.

2000

W

TvgRangeCorrection

TvgRangeCorrection

Set to Simrad EK80, which applies a half pulse-length correction to Sv only.

Simrad EK80

TwoWayBeamAngle

TwoWayBeamAngle

Two-way beam angle is read from the file and is used in the calculation of Sv.

Additionally, for FM variables, you can customize the two-way beam angle with EquivalentTwoWayBeamAngleTableWideband.

-21

dB re 1 sr

Equivalent two-way beam angle Ψ dB re 1 sr

WedgeVolumeBeamAngle

Wedge-geometry equivalent of two-way beam angle for transducers/beamforming modes that produce wedge-shaped beams. Used in Sv calculations where applicable. May be read from file or supplied via ECS.

dB re 1 sr

Calibration setting name

Help file terminology

Default value

Units

SaCorrectionFactor

If present, read from file or supplied via ECS; harmonizes TS and Sa (NASC) measurements.

0

dB

TransducerGain

Recorded transducer-specific gain used in Ex60 Power to Sv/TS.

26.5

dB

TwoWayBeamAngle

Two-way beam angle read from file or supplied via ECS; used in Ex60 Power to Sv/TS.

-20.6

dB re 1 sr

Calibration setting name

Default value

Units

ICES CRR No. 326

Term, Symbol, and Units

(Refer to Demer et al. 2015)

AbsorptionCoefficient

Absorption coefficient

Absorption coefficient is used in the calculation of Sv and TS with respect to the netCDF4 convention.

0.01

dB m-1

Absorption coefficient   αa   dB m-1

1.000

ms

Effective pulse duration   τeff   s

Frequency

Frequency read from file.

38.0

kHz

Acoustic frequency   f   Hz

FrequencyEnd

End frequency read from file and used in the calculation of wavelength.

38.0

kHz

FrequencyStart

Start frequency read from file and used in the calculation of wavelength.

38.0

kHz

MajorAxis3dbBeamAngle

MajorAxis3dbBeamAngle

7.10

°

Transducer beamwidth   α-3 dB   °

MajorAxis3dbBeamAngleTransmit

Major-axis component of the transmitted cone angle (aka Tilt). Tilt angle is used in the calculation of Sv and TS.

7.10

°

MinorAxis3dbBeamAngle

MinorAxis3dbBeamAngle

7.10

°

Transducer beamwidth   β-3 dB   °

MinorAxis3dbBeamAngleTransmit

Minor-axis component of the transmitted cone angle (aka Tilt). Tilt angle is used in the calculation of Sv and TS.

7.10

°

PulseDuration

PulseDuration

Nominal transmit duration is read from the data file and may be used in the calculation of Sv when EffectivePulseDuration is unavailable.

1.000

ms

Pulse duration   τ   s

SoundSpeed

SoundSpeed

Sound speed is used in the calculation of Sv and TS.

1500

m s-1

Water sound speed   cw   m s-1

SourceLevel

Transducer source level read from the file.

205.6

dB

Source level   SL   dB re 1 μPa at r0 (the reference range)

TransducerGain

Transducer gain is read from the file and used in the calculation of Sv and TS.

26.5

dB

On-axis gain   G0   dB re 1

TransmittedPower

Transmit power read from the file used in the calculation of Sv and TS.

2000

W

Transmit acoustic power   pat   W

TvgRangeCorrection

TvgRangeCorrection

TvgRangeCorrection is assigned as Standard.

Standard

-

TwoWayBeamAngle

TwoWayBeamAngle

Two-way beam angle is read from the file and is used in the calculation of Sv.

-20.6

dB re 1 sr

Equivalent two-way beam angle Ψ dB re 1 sr

Calibration setting name

Default value

Units

ICES CRR No. 326

Term, Symbol, and Units

(Refer to Demer et al. 2015)

AbsorptionDepth

Read from MS70 data file and used as depth in the Francois & Garrison (1982) equation.

The Francois & Garrison (1982) equation calculates the absorption coefficient using acidity, temperature and salinity, frequency and depth.

250

m

Calibration setting name

Help file terminology

Default value

Units

CalibrationOffsetSv

A setting that can offset the Sv value. It may be useful when you need to adjust the Sv value for calibration sphere procedures or for Sv to TS conversions.

0

dB

CalibrationOffsetTs

A setting that can offset the TS value. It may be useful when you need to adjust the TS value for calibration sphere procedures or for TS to Sv conversions.

0

dB

KaijoTRFactor

T/R factor

62.8

SonicArrayCenterDistance

Sonic KFC-6000/KSE-300 coefficient for the distance between array centers. It is used in the calculation of Sonic KFC-6000/KSE-300 angles.

2.0

SonicTransducerRadiusCoefficient

Sonic KFC-6000/KSE-300 coefficient used with Sonic split-beam beam compensation. The coefficient is a function of the transducer radius and wavelength.

3.5

TRFactor

Sonic KFC-6000/KSE-300 T/R factor.

62.8