Servo loop
From Glossary of Meteorology
servo loop
In general, an automatic feedback control system in which the controlled variable is mechanical position or any of its derivatives. In radar, it is a method for controlling the positioning of an antenna.
The servo loop control system, or servomechanism, employs an alignment error voltage to command the antenna to move to a position that will reduce the alignment error to zero. The system consists of a computer, amplifiers, filters, and motors that move the antenna about its vertical and horizontal axes.
