Bar check

This article explains a method for calibrating an echo sounder; the cashier's check is explained under check .

The Barcheck is a process for front-site calibration of surveying - sonar .

A so-called bar check plate (metal plate) on a steel cable under the sound transducer of the echo sounder device is lowered into the water. The respective distance to the bar check plate is marked on the steel cable in meter intervals. The distance from the water surface to the Barcheck plate is taken as the target depth and compared with the actually measured depth.

The transducer immersion depth is noticeable as a constant error, the speed of sound, which is dependent on temperature and salinity, has an effect as a percentage error. The greater the measured depth, the greater the absolute error caused by the deviating sound speed.