Calibration settings for Simrad EK80 data

This page describes the settings, necessary to an Echoview calculation, on the Calibration page of the Variable Properties dialog box for acoustic variables derived from EK80 raw data files and Kongsberg EA640 raw data files.

We recommend you assess the suitability of the settings available on the Calibration pages for each acoustic variable. Some settings will be used to calculate data point values or ranges, others may be used during analysis or display of the data. The tables below show which settings are used for calculating data point values and ranges and which are used for other calculations. The tables also detail the parameters that are read from the data file and used to calculate range values.

Quantitative calculation/analysis requires calibrated data which is achieved using correct calibration setting values (rather than default values). An ECS file enables you to modify calibration settings for variables in a fileset.

Changes in calibration settings used for range calculations may shift ping data in the depth dimension but will not automatically adjust the position of regions and lines. You should review any existing regions and lines to ensure they are still valid. For more information refer to Range calculation effects on regions and lines.

Notes:

Table legend:

Y

Setting is used in calculating data point values or ranges as indicated by the column heading.

 

Setting is not used in calculating data point values (when green background) or ranges (when blue background) but may be used for other purposes, see Additional uses of Calibration settings

 

Setting is not available for this variable

Power, Sv, TS and angular position raw variables

The following raw variables are derived from data recorded with the Simrad EK80 echosounder configured to transmit a "continuous wave" pulse.

Settings

Data point values

Data point range

Power dB pings

Sv pings

TS pings

Angular positions pings

All acoustic variables

Calibration page of Variable Properties dialog box

AbsorptionCoefficient**

Y

Y

Y

Y

 

AbsorptionDepth

Y

Y

Y

Y

  

Acidity

Y

Y

Y 

Y 

 

EffectivePulseLength

 

Y

 

 

 

EK60SaCorrection

 

Y

 

 

 

Frequency

Y

Y

Y

Y

 

FrequencyEnd

Y

Y

Y

Y 

 

FrequencyStart

Y

Y 

Y 

 

MajorAxisAngleOffset

Y

Y

Y

Y

 

MajorAxisAngleSensitivity

Y

Y

Y

  

MajorAxis3dbBeamAngle

 

 

 

 

  

MinorAxisAngleOffset

Y

Y

Y

Y

 

MinorAxisAngleSensitivity

Y

Y

Y

 

MinorAxis3dbBeamAngle

 

 

 

 

  

NumberOfTransducerSegments

Y

Y

  

PulseCompressedEffectivePulseLength

 

 

 

 

 

Salinity

Y

Y

Y 

Y 

 

SamplingFrequency

 

 

 

 

 

SoundSpeed

Y

Y

Y

Y

Y

Temperature

Y

Y 

Y

Y

 

TransceiverImpedance

Y

Y

Y

Y

 

TransceiverSamplingFrequency*

Y

Y

Y

Y

 

TransducerGain

Y

Y

Y

Y

 

TransmittedPower

Y

Y

Y

Y

  

TransmittedPulseLength

Y

Y

 

TvgRangeCorrection +

Y

Y

Y

Y 

 

TwoWayBeamAngle

Y

Y

  

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

** EK80 single frequency (CW) variables use a calculated value for AbsorptionCoefficient based on environmental data read from the file. The calculated value may be overridden by an AbsorptionCoefficient specified in an ECS file.

About TVG range correction

The Simrad EK80 applies a correction to the time-varied gain calculated for each sample point to compensate for electronic delays in filter circuits (in Sv variables). If applied, the time-varied gain applied at each sample depth, when calculating Sv from power, is calculated using a corrected range, rather than the actual range to the sample. The reason for this type of range correction is discussed in Simmonds and MacLennan pp. 118 and on the page About Time Varied Gain.

If range correction is not applied, the time-varied gain, applied in calculating Sv, is calculated using the range of each sample. The magnitude of the correction applied is specified by the SimradEK80 algorithm. No correction is applied to TS.

Power dB, Sv, TS, and angular position wideband pings variables

Power dB, Sv, TS and angular position pulse compressed wideband pings variables

The following raw variables are derived from data recorded with the Simrad EK80 echosounder configured to transmit a chirp pulse.

Settings

Data point values for wideband pings

Data point range

Power dB

Power dB pulse compressed

Sv

Sv pulse compressed

TS

TS pulse compressed

Angular positions

Angular positions pulse compressed

All acoustic variables

Calibration page of Variable Properties dialog box

AbsorptionDepth

Y

Y

Y

Y

 

EffectivePulseLength

 

Wideband Sv only

 

 

  

Acidity

Y

Y

Y

Y  

  

MinorAxisAngleOffsetTableWideband *

 

 

 

  

 

MajorAxisAngleOffsetTableWideband *

 

 

 

 

 

MinorAxisBeamWidthTableWideband *

 

 

 

 

 

MajorAxisBeamWidthTableWideband *

 

 

 

 

 

EffectivePulseLength

 

 

 

  

 

Frequency

Y

Y

Y

Y  

 

FrequencyTableWideband *

Y

Y

Y

Y  

 

FrequencyEnd

Y

Y

Y

Y

 

FrequencyStart

Y

Y

Y

Y

 

GainTableWideband *

Y

Y

Y

 

MajorAxis3dbBeamAngle

 

 

 

 

  

MajorAxisAngleOffset

Y

Y

Y

  

MajorAxisAngleSensitivity

Y

Y

Y

  

MinorAxis3dbBeamAngle

 

 

 

 

 

MinorAxisAngleOffset

Y

Y

Y

Y

 

MinorAxisAngleSensitivity

Y

Y

Y

Y

  

NumberOfTransducerSegments

Y

Y

Y

  

PulseCompressedEffectivePulseLength

 

Pulse compressed wideband Sv only

   

  

  

Salinity

Y

Y

Y   

Y  

  

SamplingFrequency

Y

Y

Y

Y

 

SoundSpeed

Y

Y

Y

Y

Y

Temperature

Y

Y

Y

Y

 

TransceiverImpedance

Y

Y

Y

   

TransceiverSamplingFrequency

 

 

 

   

TransducerGain

Y

Y

Y

Y

 

TransmittedPower

Y

Y

Y

Y

 

TransmittedPulseLength

Y

Y

Y

Y

 

TvgRangeCorrection +

Y

Y

Y

Y

 

TwoWayBeamAngle

Y

Y

Y

Y

 

* TableWideband Array and element number note.

See also

About calibration settings
Entering calibration settings
Simrad data files
Raw variables derived from EK80 data
About transmitted pulse