Absolute time reference based control system for well construction automation

A system for controlling drilling unit apparatus, comprising:

• a plurality of drilling unit apparatus each operated by a corresponding controller, any one or more of the corresponding controllers in signal communication with at least one of (i) at least one sensor, the at least one sensor generating a signal related to an operating condition of the corresponding drilling unit apparatus and (ii) at least one other of the corresponding controllers to accept as input therefrom a signal related to an operating state of the corresponding drilling unit apparatus operated by the at least one other controller;
• a plurality of time reference signal receivers each in signal communication with a corresponding controller;
• and
• an absolute time reference signal transmitter in signal communication with each time reference signal receiver, wherein any one or more of the plurality of controllers operates the respective drilling apparatus in response to at least one of (i) the sensor signal and (ii) the signal from the at least one other controller.