HTI split-beam beam compensation

Setting

Description

HTI beam pattern factor coefficients

Displays the Beam pattern factor coefficients for a fourth-order polynomial fit to an ideal beam pattern.

You can enter the  coefficients yourself or Echoview can read the coefficients from the data files for the first suitable HTI variable found, when Set HTI coefficients from file is selected.

Note: Entering your own polynomial coefficients may have a dramatic effect on target strength. HTI recommend using the coefficients supplied with each transducer. (pers .comm HTI management)

The following coefficients are offered:

Vertical coefficients for the minor-axis beam pattern factor

Horizontal coefficients for the major-axis beam pattern factor

Set HTI coefficients from file

When selected, Echoview reads the coefficients from data file for the first suitable HTI variable found.

Clear

Sets all beam pattern coefficients to zero.

α

is the measured minor-axis angle of the target echo (degrees)

β

is the measured major-axis angle of the target echo (degrees)

TS(0,0)

is the TS derived from received power measurements - valid at α=0, β=0 (dB re 1 m2) - see uncompensated_TS

TS(α,β)

is the TS predicted for a target at position α, β in the beam (dB re 1 m2) - see compensated_TS

B(α,β)

is the beam compensation function (dB). This identical to CorrHTISplitBeam

is the beam pattern factor in the plane of the minor-axis (dB)

Where:

Where:

α	=	Minor-axis angle of the peak amplitude for the detected single target (mechanical degrees) Note: The angular position variable (made up of minor-axis and major-axis angles) is derived from values read from the HTI data file.
av	=	is zero.
bv	=	Parameter 225 from the first HTI data file found when you select Set HTI coefficients from file on the Single Target Detection page of the Variable Properties dialog box. - OR - The value for b entered under the Vertical HTI beam pattern factor coefficients section on the Single Target Detection page of the Variable Properties dialog box.
cv	=	Parameter 226 from the first HTI data file found when you select Set HTI coefficients from file on the Single Target Detection page of the Variable Properties dialog box. - OR - The value for c entered under the Vertical HTI beam pattern factor coefficients section on the Single Target Detection page of the Variable Properties dialog box.
dv	=	Parameter 227 from the first HTI data file found when you select Set HTI coefficients from file on the Single Target Detection page of the Variable Properties dialog box. - OR - The value for d entered under the Vertical HTI beam pattern factor coefficients section on the Single Target Detection page of the Variable Properties dialog box.
ev	=	Parameter 228 from the first HTI data file found when you select Set HTI coefficients from file on the Single Target Detection page of the Variable Properties dialog box. - OR - The value for e entered under the Vertical HTI beam pattern factor coefficients section on the Single Target Detection page of the Variable Properties dialog box.

 

is the beam pattern factor in the plane of the major-axis (dB)

Where:

Where:

β	=	Major-axis angle of the peak amplitude for the detected single target (mechanical degrees) Note: The angular position variable (made up of minor-axis and major-axis angles) is derived from values read from the HTI data file.
ah	=	is zero.
bh	=	Parameter 230 from the first HTI data file found when you select Set HTI coefficients from file on the Single Target Detection page of the Variable Properties dialog box. - OR - The value for b entered under the Horizontal HTI beam pattern factor coefficients section on the Single Target Detection page of the Variable Properties dialog box.
ch	=	Parameter 231 from the first HTI data file found when you select Set HTI coefficients from file on the Single Target Detection page of the Variable Properties dialog box. - OR - The value for c entered under the Horizontal HTI beam pattern factor coefficients section on the Single Target Detection page of the Variable Properties dialog box.
dh	=	Parameter 232 from the first HTI data file found when you select Set HTI coefficients from file on the Single Target Detection page of the Variable Properties dialog box. - OR - The value for d entered under the Horizontal HTI beam pattern factor coefficients section on the Single Target Detection page of the Variable Properties dialog box.
eh	=	Parameter 233 from the first HTI data file found when you select Set HTI coefficients from file on the Single Target Detection page of the Variable Properties dialog box. - OR - The value for e entered under the Horizontal HTI beam pattern factor coefficients section on the Single Target Detection page of the Variable Properties dialog box.