Raw variables derived from HTI data files
This page describes the variables that Echoview can derive from HTI data files. The following abbreviations are used:
s = the sequence number (see HTI operators manual for definition)
p = the sampling period (see HTI operators manual for definition)
m = the mux port number (see HTI operators manual for definition)
.smp files
Echoview derives raw variables using the 12kHz sampling rate used in *.smp files and denotes them with the general name sample pings. In addition, Echoview will also derive raw variables using the HTI 48 kHz interpolation algorithm and denote them by the general name 48 kHz interpolated pings.
Echoview can derive the following raw variables from .smp files:
-
Sv sample pings (SsPp MXm)
-
TS sample pings (SsPp MXm)
-
angular position sample pings (SsPp MXm)
-
Sv 48 kHz interpolated pings (SsPp MXm)
-
TS 48 kHz interpolated pings (SsPp MXm)
-
angular position 48 kHz interpolated pings (SsPp MXm)
-
position GPS fixes
Warning: Echoview supports the HTI 12kHz sampling rate that is used in *.smp files. Using the Nyquist-Shannon sampling theorem, the 12kHz sampling rate supports a minimum pulse length of 4/12000=0.33 ms. Analysis of such short pulses requires resampling to at least 24 kHz to minimize errors in target detection and pulse height (TS) and length estimation. As resampling was not implemented in Echoview at that time Echoview Software recommended a minimum pulse length of 0.66 ms. Under the 12kHz regime, single target detection variables derived from .smp files with shorter pulse lengths may be suitable for fish tracking and fish counting where it is acceptable to have errors in the pulse height (TS) and pulse length.
.bot files
Echoview can derive the following variable from .bot files:
-
position GPS fixes
.raw files
Echoview can derive the following raw variable from .raw files:
-
single target detections raw echo pings (SsPp MXm)
A new variable is created for each unique combination of sequence number (s) and period number (p) independent of the mux port (m) which was used. See HTI Data files for further information.
.int files
Echoview can derive the following raw variable from .int files:
- Sv integrated pings (SsPp MXm)
A new variable is created for each unique combination of sequence number (s) and period number (p) independent of the mux port (m) which was used. See HTI Data files for further information.
See also
Calibrating HTI data
Adding HTI sample files to an Echoview fileset