Total station Instruments , or Electronic Total Station, is a high technology measuring instrument integrating light, machine and electricity. It is a surveying and mapping instrument system which integrates horizontal angle, vertical angle, distance (oblique distance, horizontal distance) and height difference measurement function. Compared with the optical theodolite, the electronic theodolite will change the optical dial to the photoelectric scanning dial, and replace the manual optical micrometer reading to record and display automatically, so that the angle measuring operation is simplified, and the reading error can be avoided. As a result of its one placement instrument, all measurement work on the station can be completed, so it is called the total station. It is widely used in the field of precision engineering measurement or deformation monitoring, such as large and underground construction and underground tunnel construction.
The difference between total station and optical theodolite lies in the dial reading and display system. The horizontal disc and vertical dial of optical theodolite and their reading devices are measured by angles (coded disc) or two identical grating discs and reading sensors. According to the accuracy of the angle measurement, it can be divided into 0.5 ", 1", 2 ", 3", 5 ", 7" and so on.