A global navigation satellite sensor system (GNSS) control system and method for irrigation and related applications is provided for a boom assembly with main and extension boom sections, which are hingedly connected and adapted for folding. The control system includes an antenna and a receiver connected to the antenna. A rover antenna is mounted on the boom extension section and is connected to the receiver. A processor receives GNSS positioning signals from the receiver and computes locations for the antennas, for which a vector indicating an attitude of the extension boom section can be computed. Various boom arrangements and field configurations are accommodated by alternative aspects of the control system.