It is an optical instrument used in modern surveying. This instrument is a combination of an electronic theodolite (transit), an electronic distance measuring device (EDM) and software running on an external computer.

Features

The important features are:

• It is mounted on a tripod and leveled before use.
• It also consist of a mounting bracket that include aids for aiming the instrument.
• Most total stations use a purpose-built glass prism mounted on a pole of known height. This acts as the reflector for the EDM signal, and can measure distances out to a few kilometers.
• The prism is mounted so that its reflection point is aligned with the center of the pole on which it has been mounted.
• Most modern Total Station instruments measure angles by means of electro-optical scanning of extremely precise digital bar-codes etched on rotating glass cylinders or discs within the instrument.
• The instrument also includes a simple calculator to figure the location of points sighted. The calculator can perform the necessary trigonometric functions.
• These stations also include a data recorder, which reduce chances of error and eliminates manual data recording.

Working of Total Station

• With the help of trigonometry, the angles and distances may be used to calculate the coordinates of actual positions of surveyed points, or the position of the instrument from known points, in absolute terms.
• The data recorded by the instrument may be downloaded from the theodolite to a computer and application software will generate a map of the surveyed area.

Functions

They are very useful and perform many important functions. Some of them are:

• It helps to determine angles and distances from the instrument to points to be surveyed.
• The typical Total Station EDM can measure distances accurate to about 0.1 millimeter or 1/1000 foot.

Application

It is used in a wide variety of survey works. Some of its area of application are:

• Land Surveying
• Road Mapping
• Aerial photogrammetry
• Calibration Labs/Test Houses