About calibration settings

Calibration settings are values that are used to achieve calibrated data within an acoustic variable.

Calibration model

Echoview's calibration model takes calibration settings from data, uses default settings where none are available and modifies calibration settings using an ECS file. To achieve calibrated data for quantitative analysis, you must verify and correct calibration settings especially when the Message box flags the use of default values or when you know there are incorrect settings recorded with your data. Refer to calibration workflow for more information.

Note: An ECS file may affect multiple EV files or multiple variables. For more information refer to Echoview Calibration Supplement files.

Echoview calibration setting values

Echoview calibration settings are displayed on the Calibration page of the Variable Properties dialog box. Data file values that have been used since the data was loaded or the ECS file was added, saved or removed are displayed in black text. Default values that have been used are displayed in orange text. Data file or ECS values that have been read but not used are displayed in grey text.

Calibration setting values can be changed by using an ECS file, that is added to a fileset through the Calibration section of the Filesets window. Refer to Echoview calibration supplement files for information about the grammar and syntax of ECS files. Echoview can auto-generate an ECS file based on the calculations performed with your data. You can then Copy-Paste calibration setting information to it from the:

Most settings on the calibration pages are used for calculating data point values and data point ranges and must therefore be correctly set for each variable to achieve meaningful displays and analyses. For information on recording calibration settings with exports see Exporting Data.

Settings on the Calibration page of the Variable Properties dialog box are directly associated with the data within the variable. The selection of a transducer and the properties of the transducer used to collect your data should be defined prior to entering calibration settings. See About transducer geometry.

Notes:

A summary of how the calibration settings are used for the variables in each data set is available on the following pages:

Additional uses of calibration settings

Some calibration settings are used for purposes other than calculating the data point values or ranges.

Calculations affected by specific calibration settings are:

The tables below describe which calibration settings affect these calculations. If you intend using TVG, background noise analysis variables, corrected schools analysis variables, beam volume sum or single targets the calibration settings listed must be entered correctly for the specified variables.

Note: The tables apply to both raw and virtual variables from data logged with any echosounder.

Sv variables

Setting

Affects

Calibration page of Variable Properties dialog box

AbsorptionCoefficient

Background noise analysis variables.
Time-varied thresholds.

TwoWayBeamAngle

Beam volume sum

TransmittedPulseLength

Corrected schools analysis variables.

Sample thickness.

SoundSpeed

Sample thickness.

SimradDraftLogging (where available)

Corrected schools analysis variables.

Frequency

Frequency Response graph.

MajorAxis3dBBeamAngle

MinorAxis3dBBeamAngle

Multibeam bottom detections export (Athwartship).

 

WedgeVolumeBeamAngle

Wedge volume sampled algorithm (when you want to override the Major-axis 3 dB beam angle).

MinorAxis3dBBeamAngle

Corrected schools analysis variables.

TS variables

Setting

Affects

Calibration page of Variable Properties dialog box

AbsorptionCoefficient

Time-varied thresholds

SoundSpeed

Sample thickness.

TransmittedPulseLength

Virtual variables created by single target detection operators using the PLDL and normalised pulse length.

Single target and target length variables

Setting

Affects

Calibration page of Variable Properties dialog box

TransmittedPulseLength

Single target display thickness1

Virtual variables created by single target detection operators using the PLDL and normalized pulse length.

Sample thickness.

SoundSpeed

Single target display thickness1

Sample thickness.

SamplingFrequency

Sample thickness.

TwoWayBeamAngle

Beam volume sum2

MajorAxis3dBBeamAngle

MinorAxis3dBBeamAngle

Beam compensation of single targets detected in Echoview.
3D Single targets graph beam rings.

1 Except for virtual variables in the Single target manipulation operators group. The Single target display thickness for these virtual variables is inherited from the first operand.

2 Except for Target length variables, where the calculation of Beam volume sum is not supported.

See also

About entering calibration settings
Using Echoview in the calibration process
Calibration settings for virtual variables
About time varied gain