This configuration represents the next level of complexity compared to the Minimised Basic and Basic systems for TBM guidance. The designed tunnel axis is defined as a 3D set of coordinates, typically as Northings (Y), Eastings (X) & Levels (Z), and stored in a DTA (Designed Tunnel Axis) file. In its simplest version, the laser is mounted for the best ‘line of sight’ view of the target unit along the side of the machine. The lasers global position, in the same frame of reference as the DTA, together with the vertical & horizontal angles associated with the beam are manually entered into the system.
Due to the more sophisticated mathematical approach used here, the entry level configuration described can be greatly enhanced with a wide range of options & upgrades, tailoring the equipment to meet the requirements made by more demanding projects.