Automated system for joining at least two portions of a chassis, comprising; • at least one actuation device adapted to move at least one portion in the space with three degrees of freedom; • a central control unit for controlling each actuation device as a function of a plurality of data obtained through a plurality of sensors; said plurality of sensors can continuously determine, on each chassis portion, a plurality of key points (A, B, C) which are univocal for each portion; said central control unit, depending on the data obtained from said plurality of sensors, activates said at least one actuation device in order to bring near and connect said at least two portions, while monitoring, through said plurality of sensors, the relative position between said plurality of key points (A, B, C) of said portions and the absolute position of said portions in the space; said system is adapted to join at least two sections of a fuselage of an aircraft; each actuation device comprises at least one column for supporting and moving at least one section, comprising at least one support or arm for moving said section with three degrees of freedom; said at least one column can be extended, in an automatic manner, along a vertical axis and can move on adapted first guides along a second axis, perpendicular to said vertical axis; said plurality of sensors comprise at least one laser meter for measuring the position of the various key points (A, B, C) and the relative and absolute distances of the same key points (A, B, C). characterized in that each laser meter is movable, being associated with at least one carriage that slides on at least one second guide arranged along a second axis. • at least one actuation device adapted to move at least one portion in the space with three degrees of freedom; • a central control unit for controlling each actuation device as a function of a plurality of data obtained through a plurality of sensors; said plurality of sensors can continuously determine, on each chassis portion, a plurality of key points (A, B, C) which are univocal for each portion; said central control unit, depending on the data obtained from said plurality of sensors, activates said at least one actuation device in order to bring near and connect said at least two portions, while monitoring, through said plurality of sensors, the relative position between said plurality of key points (A, B, C) of said portions and the absolute position of said portions in the space; said system is adapted to join at least two sections of a fuselage of an aircraft; each actuation device comprises at least one column for supporting and moving at least one section, comprising at least one support or arm for moving said section with three degrees of freedom; said at least one column can be extended, in an automatic manner, along a vertical axis and can move on adapted first guides along a second axis, perpendicular to said vertical axis; said plurality of sensors comprise at least one laser meter for measuring the position of the various key points (A, B, C) and the relative and absolute distances of the same key points (A, B, C). characterized in that each laser meter is movable, being associated with at least one carriage that slides on at least one second guide arranged along a second axis.