Research On Theodolite Automatic Targeting Technology

The electronic theodolite is a kind of high-precision angle measuring instrument and it has a lot of advantages,such as high accuracy,easy operation, facilitate to set station and non-contact measurement. It had achieved automatic reading and transmission of angle information with external devices and it’s an important part of industrial measuring system.The combination of electronic theodolite and angle electronic microscopic measurement technology had improved electronic theodolite’s angle resolution.The multi-theodolites based industrial measurement systems are widely used for geometric detection of large-scale industrial products. Currently, the most accurate theodolite has the uncertainty of0.5", and it can be driven by electronic motor to some direction, but even these top level theodolites can’t direct and recognize targets automatically. Because of the defects of artificial theodolite operation such as inefficiency, low accuracy etc.Especially in the field of industrial measurement,it will consume lots of time to menasure so many targets,what’s more,lasting of measurement time or station vibration will result in low precision.Therefore,the automatic targets directing and recognizing(ATD&R) will be the development direction for the next generation theodolites. There are three key technologies must be settled for ATD&R,i.e. auto-focusing, targets approximate position and automatic target recognizing.The extant total station instrument had realized automatic collimation by some special targets,angle coupling prism for example.but it isn’t applicable for electronic theodolite.In accordance with the second technical problem,a technology is presented here to settle the problem of targets approximate position. The Implementation of this technology is that a camera is mounted on the theodolite, then they are calibrated for the mutual coordinate systems parameter, before measurement, targets image ahead of the theodolite is captured, when the image coordinates of the targets are known by image characteristic recognizing technology, direction data of all the targets can be calculated. Theoretical derivation and experiments show that the presented method is effective to get the targets’approximate position,and meet the requirement of automatic target collimation of theodolite.Its automatic approximate collimation accuracy is better than0.4°.