A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for

surveying Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial two-dimensional or three-dimensional positions of points and the distances and angles between them. A land surveying professional is ca ...

and

building construction Construction is a general term meaning the art and science to form objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009 and com ...

. It is an electronic transit

theodolite A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and i ...

integrated with

electronic distance measurement Length measurement, distance measurement, or range measurement (ranging) refers to the many ways in which length, distance, or range can be measured. The most commonly used approaches are the rulers, followed by transit-time methods and the int ...

(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 In trigonometry and geometry, triangulation is the process of determining the location of a point by forming triangles to the point from known points. Applications In surveying Specifically in surveying, triangulation involves only angle me ...

calculations.

Robotic Robotics is an interdisciplinarity, interdisciplinary branch of computer science and engineering. Robotics involves design, construction, operation, and use of robots. The goal of robotics is to design machines that can help and assist human ...

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 A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that reflects radiation (usually light) back to its source with minimum scattering. This works at a wide range of angle of incidence, unlike a planar mirror, ...

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 neccesitate 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. These motorized total stations can also be used in automated setups known as Automated Motorized Total Station (AMTS).

Function

Angle measurement

Most 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 best quality total stations are capable of measuring angles to 0.5

arc-second A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The na ...

. Inexpensive "construction grade" total stations can generally measure angles to 5 or 10 arc-seconds.

Distance measurement

Measurement of distance is accomplished with a modulated

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

carrier signal, generated by a small solid-state emitter within the instrument's optical path, and reflected by a prism reflector or the object under survey. The modulation pattern in the returning signal is read and interpreted by the computer in the total station. The distance is determined by emitting and receiving multiple frequencies, and determining the integer number of

wavelengths In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tro ...

to the target for each

frequency Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...

. Most total stations use purpose-built glass

prism (surveying) A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that reflects radiation (usually light) back to its source with minimum scattering. This works at a wide range of angle of incidence, unlike a planar mirror, ...

reflectors for the EDM signal. A typical total station can measure distances up to with an accuracy of about ± 2 parts per million.''Leica Flexline TS02/06/09''
(2008). Leica Geosystems. See datasheet for model TS06 (PDF). Retrieved 27 August 2009 Reflectorless total stations can measure distances to any object that is reasonably light in color, up to a few hundred

meters The metre (British spelling) or meter (American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure"), symbol m, is the primary unit of length in the International System of Units (SI), though its prefi ...

Coordinate measurement

The coordinates of an unknown point relative to a known coordinate can be determined using the total station as long as a direct line of sight can be established between the two points. Angles and distances are measured from the total station to points under survey, and the

coordinate In geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine the position of the points or other geometric elements on a manifold such as Euclidean space. The order of the coordinates is sign ...

s (X, Y, and Z; or easting, northing, and

elevation The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § Vert ...

) of surveyed points relative to the total station position are calculated using

trigonometry Trigonometry () is a branch of mathematics that studies relationships between side lengths and angles of triangles. The field emerged in the Hellenistic world during the 3rd century BC from applications of geometry to astronomical studies. T ...

and

. To determine an absolute location, a total station requires line of sight observations and can be set up over a known point or with line of sight to 2 or more points with known location, called

free stationing In surveying, free stationing (also known as resection) is a method of determining a location of one unknown point in relation to known points. There is a zero point of reference called a total station. The instrument can be freely positioned so th ...

. For this reason, some total stations also have a

Global Navigation Satellite System A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high pre ...

receiver and do not require a direct line of sight to determine coordinates. However, GNSS measurements may require longer occupation periods and offer relatively poor accuracy in the vertical axis.

Data processing

Some models include internal electronic data storage to record distance, horizontal angle, and vertical angle measured, while other models are equipped to write these measurements to an external

data collector In the UK electricity system, a data collector (DC) is responsible for determining the amount of electricity supplied so that the customer can be correctly billed. Half-hourly For half-hourly metered supplies, the half-hourly data collector (H ...

, such as a hand-held computer. When data is downloaded from a total station onto a computer, application software can be used to compute results and generate a

map A map is a symbolic depiction emphasizing relationships between elements of some space, such as objects, regions, or themes. Many maps are static, fixed to paper or some other durable medium, while others are dynamic or interactive. Although ...

of the surveyed area. The newest generation of total stations can also show the map on the touch-screen of the instrument immediately after measuring the points.

Applications

Total stations are mainly used by

land surveyor Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial two-dimensional or three-dimensional positions of points and the distances and angles between them. A land surveying professional is ca ...

s and

civil engineers This list of civil engineers is a list of notable people who have been trained in or have practiced civil engineering. A B C D E F G H I J K L M N O P Q R S T U ...

, either to record features as in topographic surveying or to set out features (such as roads, houses or boundaries). They are also used by archaeologists to record excavations and by police, crime scene investigators, private accident reconstructionists and insurance companies to take measurements of scenes.

Mining

Total stations are the primary survey instrument used in

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic via ...

surveying. A total station is used to record the absolute location of the tunnel walls, ceilings (backs), and floors as the drifts of an underground mine are driven. The recorded data are then downloaded into a

CAD program Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve co ...

, and compared to the designed layout of the tunnel. The survey party installs control stations at regular intervals. These are small steel plugs installed in pairs in holes drilled into walls or the back. For wall stations, two plugs are installed in opposite walls, forming a line perpendicular to the drift. For back stations, two plugs are installed in the back, forming a line parallel to the drift. A set of plugs can be used to locate the total station set up in a drift or tunnel by processing measurements to the plugs by intersection and resection.

Mechanical and electrical construction

Total stations have become the highest standard for most forms of construction layout. They are most often used in the X and Y axis to lay out the locations of penetrations out of the underground utilities into the foundation, between floors of a structure, as well as roofing penetrations. Because more commercial and industrial construction jobs have become centered around

building information modeling Building information modeling (BIM) is a process supported by various tools, technologies and contracts involving the generation and management of digital representations of physical and functional characteristics of places. Building informatio ...

(BIM), the coordinates for almost every pipe, conduit, duct and hanger support are available with digital precision. The application of communicating a virtual model to a tangible construction potentially eliminates labor costs related to moving poorly measured systems, as well as time spent laying out these systems in the midst of a full blown construction job in progress.

Meteorology

Meteorologists A meteorologist is a scientist who studies and works in the field of meteorology aiming to understand or predict Earth's atmospheric phenomena including the weather. Those who study meteorological phenomena are meteorologists in research, while t ...

also use total stations to track

weather balloon A weather balloon, also known as sounding balloon, is a balloon (specifically a type of high-altitude balloon) that carries instruments aloft to send back information on atmospheric pressure, temperature, humidity and wind speed by means of a ...

s for determining upper-level winds. With the average ascent rate of the weather balloon known or assumed, the change in azimuth and elevation readings provided by the total station as it tracks the weather balloon over time are used to compute the wind speed and direction at different altitudes. Additionally, the total station is used to track ceiling balloons to determine the height of cloud layers. Such upper-level wind data is often used for aviation weather forecasting and rocket launches.

Instrument manufacturers

Carl Zeiss Carl Zeiss (; 11 September 1816 – 3 December 1888) was a German scientific instrument maker, optician and businessman. In 1846 he founded his workshop, which is still in business as Carl Zeiss AG. Zeiss gathered a group of gifted practica ...

(historical) * GeoMax, part of

Hexagon AB Hexagon AB is a publicly listed global information technology company specializing in hardware and software digital reality that was founded in 1992 and headquartered in Stockholm, Sweden. Hexagon's B share is listed on the list of large companie ...

Hewlett Packard The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company headquartered in Palo Alto, California. HP developed and provided a wide variety of hardware components ...

(historical) *

Hilti Corporation Hilti Corporation (Hilti Aktiengesellschaft or Hilti AG, also known as Hilti Group) is a Liechtensteiner multinational company that develops, manufactures, and markets products for the construction, building maintenance, energy and manufactur ...

Nikon (, ; ), also known just as Nikon, is a Japanese multinational corporation headquartered in Tokyo, Japan, specializing in optics and imaging products. The companies held by Nikon form the Nikon Group. Nikon's products include cameras, camera ...

, part of Trimble *

Leica Geosystems Leica Geosystems (formerly known as Wild Heerbrugg or just Wild) based in eastern Switzerland produces products and systems for surveying and geographical measurement (geomatics). Its products employ a variety of technologies including GPS sat ...

, part of Hexagon AB * North Group LTD (historical) *

Sokkia {{Infobox company, name = Sokkia Co., Ltd. , type = Public K.K. , foundation = 1920 , location = Atsugi, Kanagawa, Japan , key_people = Jin Ito , industry = High precision instruments for construction, ...

, part of Topcon * TI Asahi Co. Ltd, sold under the

Pentax is a brand name used primarily by the Japanese multinational imaging and electronics company Ricoh for DSLR cameras, lenses, sport optics (including binoculars and rifle scopes), and CCTV optics. The Pentax brand is also used by Hoya Corporation ...

brand *

Topcon is a Japanese manufacturer of optical equipment for ophthalmology and surveying. History September 1932—TOPCON was established based on the surveying instruments division of K. Hattori & Co., Ltd. (currently SEIKO HOLDINGS CORPORATION) in or ...

* Trimble Navigation Ltd. * Wild Heerbrugg AG (historical), part of Leica Geosystems * Stonex (company)

References

External links

Using a Total Station

Total Station Manual with Laser Scanner Function

Online computation of total station measurements
{{DEFAULTSORT:Total Station Civil engineering Construction surveying Geodesy Optical instruments Surveying instruments