Calibration settings for SciFish 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 SciFish 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 datapoint values or ranges, others may be used during analysis or display of the data. The tables below show which settings are used for calculating datapoint 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.

Note: The (red) default values on the Calibration pages are for illustration purposes only and have not been read from your data file. Read About calibration settings for further information.

Table legend:

P	Setting is used in calculating datapoint values or ranges as indicated by the column heading.
	Setting is not used in calculating datapoint 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

Sv, TS and angular position raw variables

Settings	Sv raw pings	TS raw pings	Angular positions raw pings	All acoustic variables
Settings	Datapoint values			Datapoint range
Calibration page of Variable Properties dialog box
AbsorptionCoefficient	P	P
SoundSpeed	P	P		P
TransmittedPower	P	P
TwoWayBeamAngle	P
Ek60TransducerGain	P	P
SimradSaCorrection	P
TransmittedPulseLength	P
Frequency	P	P
MajorAxis3dBBeamAngle
MinorAxis3dBBeamAngle
MinorAxisAngleOffset			P
MajorAxisAngleOffset			P
TvgRangeCorrection +	P	P
From data file
Sample interval				P
MajorAxisAngleSensitivity			P
MinorAxisAngleSensitivity			P

Most of these values can be obtained from the Information dialog box in Echoview.

About TVG range correction

In Echoview you may apply, to data from the SciFish broadband sonar, a correction to the time-varied gain calculated for each sample point to compensate for electronic delays in filter circuits (in Sv and TS variables). If applied, the time-varied gain applied at each sample depth, when calculating Sv or TS from power, is calculated using a corrected range, rather than the actual range to the sample. As an example See EK60 Power to Sv and TS for further details. The reason for this type of range correction is discussed in About Time Varied Gain and in Simmonds and MacLennan pp. 118.

If range correction is not applied, the time-varied gain, applied in calculating Sv or TS, is calculated using the range of each sample.

Note: If you are using TS data and intending to use one of the method 2 operators to detect single targets on that data you should be aware that these operators apply a TVG range correction of 2 samples and it is advised not to apply one to the TS data.

Calibration settings for SciFish data

Sv, TS and angular position raw variables

About TVG range correction

See also