A roll 
control system is provided for controlling a roll position of a boom rotatably coupled to a support frame, the boom comprising left and right wing sections (where the roll of the boom refers to a 
clockwise or counterclockwise rotation of said boom relative to the support frame). A roll control mechanism is configured for rotating the boom relative to the support frame in response to a roll 
control signal. 
Wing section position measuring apparatus is configured for producing a right wing 
signal correlatable to a distance between the right 
wing section and a right wing reference position and a left wing 
signal correlatable to a distance between the left 
wing section and a left wing reference position. Boom roll position measuring apparatus is configured for producing a boom roll 
signal correlatable to a roll position of the boom relative to a boom roll reference position. A controller is configured for: (i) identifying a 
wing section differential value and a boom roll value derived from the right and left wing signals and the boom roll signal, respectively; (ii) identifying a boom roll 
control error value derived from the wing section differential value and the boom roll value, the boom roll error control value being configured for deriving therefrom the roll 
control signal. Advantageously, the roll 
control system of the invention takes into account both the height differential (relative to a ground reference) between the left and right wings and the boom roll position relative to a neutral (reference) position.