The GRANIT® system operates by the use of an impact device, which creates a controlled tensile axial impulse that is transferred to the anchorage. The photography to the right shows the Universal Impact Device (UID) beside a rugged computer for field use. The hoses supply air to the impact device, in order to drive a piston that creates the impact. By varying the air pressure, the magnitude of the impacts can be controlled. The vibrational response of the system to this impact is measured by an accelerometer that is positioned on the impact device. The computer records the acceleration signal produced by the accelerometer, and performs the signal processing which is required for the neural network to diagnose the condition of the anchorage.