This document describes the preliminary results in the implementation of a speed control system in a cartesian positioner used for improvised explosive devices (IEDs) and landmine detection with a ground penetration radar (GPR). The control is applied in a couple of servo-motors that allows the displacement of a measurement head in the cartesian positioner in GPR applications. Using an control system for the movement in each axis, the mechanical vibrations due the head's movements were reduced and the velocity response of the motors was smoothed.