Beam compensation is applied to a measured TS value to correct it for transducer directivity, that is to correct for the location of the target within the transducer beam pattern.
The following different methods are available for determining beam compensation.
The Simrad split beam method functions by determining the angular position of target within the beam, and calculating the beam compensation from that position. The beam compensation is calculated from a second order polynomial fit to an ideal function. See Simrad split-beam beam compensation and Split beam (method 1) for more information.
The BioSonics split beam method functions by determining the angular position of target within the beam, and calculating the beam compensation from that position. See BioSonics split-beam compensation for details.
The HTI split beam method functions by determining the angular position of target within the beam, and calculating the beam compensation from that position. The beam compensation is calculated from a fourth order polynomial that models the transducer's beam pattern. See HTI split-beam beam compensation for more information.
The dual beam method functions by determining the difference in target strength between two beams, one wide the other narrow. The difference in target strengths is attributed to a difference in the beam compensation (as the actual target strength of the target is independent of beam width). Echoview applies the narrow-beam beam compensation. See Dual-beam beam compensation and Dual beam (method 1) or Dual beam (method 2) for more information.
The Furuno split-beam method functions by determining the angular position of target within the beam, and calculating the beam compensation from that position. The beam compensation is a proprietary Furuno algorithm. For more information about the Furuno beam compensation model please contact Furuno.