Position measurement by laser beam

摘要: A laser beam from a source (20) is used to provide reference in space adjacent portion of structure movements which are monitored. The received by receiver (30). number targets (300) may be mounted move with parts the extending alongside path. Target constructions (Figs. 6-8) described allow for normal passage past target but enable position relative given measured intercepting beam. In variation (Fig. 13) civil engineering use, single selectively mountable one supports. Another 11) uses graduated mesh on impinges each alo transmitted through mesh. Dynamic movement part such as bridge attached question and comprising barred reflective assembly 3), fibre optic array 4) or sensing photo-diode 5). For use systems there also spatial filter 10), adapted precise re-positioning 9) dust excluding housing 12).