A total station or total station theodolite is an electronic/optical instrument used for surveying and building construction. It is an electronic transit theodolite integrated with electronic distance measurement (EDM) to measure both vertical and horizontal angles and the slope distance from the instrument to a particular point, and an on-board computer to collect data and perform triangulation and position resection and intersection calculations.
Robotic or motorized total stations allow the operator to control the instrument from a distance via remote control. In theory, this eliminates the need for an assistant staff member, as the operator holds the retroreflector and controls the total station from the observed point. In practice, however, an assistant surveyor is often needed when the surveying is being conducted in busy areas such as on a public carriageway or construction site. This is to prevent people from disrupting the total station as they walk past, which would necessitate resetting the tripod and re-establishing a baseline. Additionally, an assistant surveyor discourages opportunistic theft, which is not uncommon due to the value of the instrument. If all else fails, most total stations have serial numbers. In the United States the National Society of Professional Surveyors hosts a registry of stolen equipment which can be checked by institutions that service surveying equipment to prevent stolen instruments from circulating. These motorized total stations can also be used in automated setups known as "automated motorized total station".
