Patent ID: 8783382

Claim:
A drill control system comprising: an uphole control device; and a downhole control device; wherein the uphole control device is configured to: transmit a reference trajectory to the downhole control device; and receive information about an actual trajectory from the downhole control device; and transmit control signals to the downhole device to control rotational speed of a drill bit based on information received from the downhole control device; and wherein the downhole control device is configured to: receive the reference trajectory from the uphole control device; calculate a confidence interval for the reference trajectory; reject disturbances in the actual trajectory which are considered noise; measure the actual trajectory; correct deviations between the reference trajectory and the actual trajectory exceeding the confidence interval; and transmit information about the actual trajectory to the uphole control device, wherein the uphole control device implements an uphole control loop and the downhole control device implements a downhole control loop, the uphole control loop having larger sampling intervals than the downhole control loop while monitoring the performance of the downhole control loop to facilitate drilling to a defined target.