An excavator 3D integrated laser and radio positioning guidance system (10, 70), Ex_3D_ILRPGS, for a excavator; wherein said excavator further comprises: a frame comprising a cab member horizontally pivoted about a tread member, a boom (36, 100) pivotally mounted at a proximal end to said cab member by a first pivot means, a stick pivotally mounted at a proximal end to a distal end of said boom (36, 100) by a second pivot means, and a bucket (40, 83) pivotally mounted at a proximal end to a distal end of said stick (38, 102) by a third pivot means; wherein a distal end of said bucket (40, 83) defines a cutting edge (30, 82) which is used to excavate dirt in response to movement of said bucket (40, 83) towards said frame; said Ex_3D_ILRPGS (10, 70) comprising: a mobile radio positioning system receiver (12, 96) configured to obtain a set of 3D coordinates measurements of said excavator by making a plurality of measurements; a bucket-to-machine-body positioning system (16, 18, 98) configured to obtain position coordinates of said boom (36, 100), said stick (38, 102) and said bucket (40, 83) of said excavator; a laser detector (24, 78) configured to receive at least one laser beam (26, 74, 76) and configured to provide a set of local vertical coordinate measurements with a substantially high accuracy by making a plurality of measurements; and an on-board navigational system (28, 80) configured to: select a weight function configured to assign a 3D weight function to said set of 3D coordinates measurements obtained by said mobile radio positioning system receiver (12, 96) and to assign a vertical weight function to said set of local vertical coordinate measurements obtained by said laser detector (24, 78); integrate said set of 3D coordinates measurements of said excavator with said 3D weight function, said position coordinates of said boom (36, 100), said stick (38, 102) and said bucket (40, 83) of said excavator obtained by said bucket-to-machine-body positioning system (16, 18, 98), and said set of local vertical coordinate measurements with the vertical weight function; and guide said cutting edge (30, 82) of said bucket (40, 83) of said excavator with substantially high vertical accuracy. a mobile radio positioning system receiver (12, 96) configured to obtain a set of 3D coordinates measurements of said excavator by making a plurality of measurements; a bucket-to-machine-body positioning system (16, 18, 98) configured to obtain position coordinates of said boom (36, 100), said stick (38, 102) and said bucket (40, 83) of said excavator; a laser detector (24, 78) configured to receive at least one laser beam (26, 74, 76) and configured to provide a set of local vertical coordinate measurements with a substantially high accuracy by making a plurality of measurements; and an on-board navigational system (28, 80) configured to: select a weight function configured to assign a 3D weight function to said set of 3D coordinates measurements obtained by said mobile radio positioning system receiver (12, 96) and to assign a vertical weight function to said set of local vertical coordinate measurements obtained by said laser detector (24, 78); integrate said set of 3D coordinates measurements of said excavator with said 3D weight function, said position coordinates of said boom (36, 100), said stick (38, 102) and said bucket (40, 83) of said excavator obtained by said bucket-to-machine-body positioning system (16, 18, 98), and said set of local vertical coordinate measurements with the vertical weight function; and guide said cutting edge (30, 82) of said bucket (40, 83) of said excavator with substantially high vertical accuracy. select a weight function configured to assign a 3D weight function to said set of 3D coordinates measurements obtained by said mobile radio positioning system receiver (12, 96) and to assign a vertical weight function to said set of local vertical coordinate measurements obtained by said laser detector (24, 78); integrate said set of 3D coordinates measurements of said excavator with said 3D weight function, said position coordinates of said boom (36, 100), said stick (38, 102) and said bucket (40, 83) of said excavator obtained by said bucket-to-machine-body positioning system (16, 18, 98), and said set of local vertical coordinate measurements with the vertical weight function; and guide said cutting edge (30, 82) of said bucket (40, 83) of said excavator with substantially high vertical accuracy.