Directional drilling control devices and methods

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.