RPD System is a Rack Phase Differential monitoring system used in a jack-up Rig for precise recording of rack phase differences for all three legs of the jack-up rig. It gives accurate information of electronic and mechanical measurements to the operator for a controlled operation. It helps to avoid leg over stresses during jacking process. Among the three legs of a jack up rig each individual leg consists of three daisy wheel sensors for each chord. This adds to a total of nine for a single jack up rig.