Abstract: A laser referenced control system for maintaining sequence and correcting the deflections of a moving irrigation pipe includes a laser positioned on a reference coordinate against which the irrigation program sequence and the motion of the pipe are taken. In typical use the pipe is supported on powered wheeled carriages which move across the irrigated terrain at a predetermined rate and it is these wheeled carriages that are controlled according to the deviation of the end of the pipe relative the laser optical axis. This deviation is measured in a fore and aft plane by a phototransducer array to provide the control inputs to the carriages, the vertical terrain undulations being compensated by way of a laser alignment servosystem. In this manner the vertical changes in pipe alignment are taken out, the only correction being made in the plane of translation.

Abstract: The present disclosure entails a program controlled multi-loop system for providing even distribution of irrigating water over normally square plots. More specifically the disclosure includes control loops connected to a center post irrigation system which control the advance rate, the flow rate, select an end gun nozzle, and select the elevation of the end gun under program control to provide even coverage. In this manner a telescopically extended system of the type described in our prior U.S. Pat. No. 4,033,508 is improved to both insure even irrigation and full coverage of corners.