Novel Method for Spatial Angle Measurement Based on Rotating Planar Laser Beams

Spatial angle measurement,especially the measurement of horizontal and vertical angle,is a basic method used for industrial large-scale coordinate measurement.As main equipments in use,both theodolites and laser trackers can provide very high accuracy for spatial angle measurement.However,their industrial applications are limited by low level of automation and poor parallelism.For the purpose of improving measurement efficiency,a lot of studies have been conducted and several alternative methods have been proposed.Unfortunately,all these means are either low precision or too expensive.In this paper,a novel method of spatial angle measurement based on two rotating planar laser beams is proposed and demonstrated.Photoelectric receivers placed on measured points are used to receive the rotating planner laser signals transmitted by laser transmitters.The scanning time intervals of laser planes were measured,and then measured point's horizontal/vertical angles can be calculated.Laser plane's angle parameters are utilized to establish the abstract geometric model of transmitter.Calculating formulas of receiver's horizontal/vertical angles have been derived.Measurement equations' solvability conditions and judgment method of imaginary solutions are also presented after analyzing.Proposed method for spatial angle measurement is experimentally verified through a platform consisting of one laser transmitter and one optical receiver.The transmitters used in new method are only responsible for providing rotating light plane signals carrying angle information.Receivers automatically measure scanning time of laser planes and upload data to the workstation to calculate horizontal angle and vertical angle.Simultaneous measurement of multiple receivers can be realized since there is no human intervention in measurement process.Spatial angle measurement result indicates that the repeatable accuracy of new method is better than 10".Proposed method can improve measurement's automation degree and speed while ensuring measurement accuracy.