METHOD AND APPARATUS FOR POSITIONING CONSTRUCTION MACHINERY

摘要

A construction machine (such as a piling rig) is correctly positioned on a work site by (a) providing the machine with a mast (5) having a nominally vertical axis passing through the centre of operation of the machine at ground level; (b) providing a satellite navigation system receiver (preferably a high-precision GPS P-code receiver) and locating its antenna (11) on the said axis at the top of the mast; (c) providing means (12) for determining the displacement of the mast from its nominal vertical position; (d) obtaining output readings from the said navigation system receiver when the displacement is less than a predetermined limit (which may be reduced as the target position is approached); and (e) positioning the machine manually or automatically in response to those output readings. If output readings are obtained when the displacement is outside the chosen limit, they are distinguished from usable positioning readings, for example by dimming or changing the colour of the display.