Abstract: A system and method for checking and calibrating, if necessary, the orientation of a rotating laser beam as projected by a laser transmitter is provided. The laser transmitter is initially adjusted so that the rotating laser beam defines a plane which will be substantially horizontal if the transmitter is properly calibrated. A retroreflective target is positioned a predetermined distance from the transmitter. A known point on the transmitter is aligned in the direction of the retroreflective target. The laser beam is reflected from the retroreflective target back to the laser transmitter. A photodetecting system within the laser transmitter generates a signal representative of the position of the laser beam on the target. The laser transmitter is then rotated about a reference axis until the position of the laser beam on the target is determined with respect to each of the remaining coordinate axes.

Abstract: A system for distinguishing real target reflections from ghost target reflections for use in adjusting the orientation of a plane defined by a rotating laser beam from a laser transmitter is provided. One or more retroreflective targets are positioned in desired locations along a rotational arc to define the desired plane through which the laser beam is rotated. The laser beam rotates back and forth scanning for targets positioned along the rotational arc. The laser beam is reflected from the targets to the laser transmitter for processing. A plurality of detection zones are established within the rotational arc. The detection zones are associated with a direction of rotation of the laser beam so that the laser beam traverses a target prior to traversing a potential shiny surface which could cause a ghost target reflection. As the laser beam scans a target prior to a shiny surface, reflections received after a target reflection are ignored as being potentially invalid reflections.

Abstract: An autofocusing system for a laser transmitter is provided. A laser beam is swept across a target having a plurality of sections. The target includes a first reflective section and a second reflective section with a non-reflective section positioned therebetween. A photodetector detects a signal representative of the laser beam reflected from the target. The laser beam is focused by adjusting the focusing lens until a ratio of the duration of the non-reflective portion of the signal to the sum of the durations of the reflective portions of the signal is maximized.

Abstract: A system for adjusting the orientation of a plane defined by a rotating laser beam from a laser transmitter is provided. The laser beam is swept across one or more targets having a plurality of sections. The targets each include a first reflective section and a second reflective section with a non-reflective section positioned therebetween. The non-reflective section includes a portion which slopes across the reflective sections. A photodetector detects a signal representative of the laser beam reflected from each of the targets. The orientation of the laser beam is adjusted until the laser beam traverses the center of the target at which point the width of the first reflective section equals the width of the second reflective section. A processor calculates the distance or angle in which to adjust the laser transmitter so that the laser beam traverses the center of the target once the laser beam traverses the portion of the target including the sloped non-reflective section.