| The Total Station (TST) is one of the widely used | | | | application software the results could be analyzed |
| electronic or optical instrument in modern saving. | | | | and generated and corresponding map of the |
| It has been used by many people such as | | | | surveyed location could be developed. |
| archaeologists (to record excavations) | | | | More sophisticated TST has Global Navigational |
| police,(crime scene investigations or private | | | | Satellite System (GNSS or GPS) which can |
| accidents), insurance companies and other | | | | measure very accurately (few meters) the |
| numerous surveying applications. If you examine | | | | latitude, longitude and altitude of given location or |
| the total station, you will notice that its an | | | | of a point. The advantage is having GNSS is, it |
| electronic theodolite (transit type) coupled with an | | | | does not require line of sight measuring points. |
| electronic distance meter (EDM) which can be | | | | However, the GNSS has poor accuracy in |
| used for distance measurement of particular land | | | | measuring along vertical axis without long |
| area. | | | | occupation periods. Whereas TST allows high |
| There are many TST models available in the | | | | precision measurements along the vertical axis. |
| market. For example, certain TST models have | | | | Hence, combining both these technologies (TST |
| internal electronic data storage facility which can | | | | & GNSS or GPS), much faster and accurate |
| easily record horizontal and vertical distances, | | | | data can be collected from wide survey area. |
| horizontal and vertical angle measurements. | | | | The latest TST instruments measure angles using |
| Similarly, some models have hand held, | | | | electro-optical scanning facility incorporated in it. |
| computerized external data collectors which can | | | | For example, the extremely precise digital |
| record data on the field. Depending on the | | | | bar-codes etched on rotating glass cylinders or |
| sophistication of the model the price of TST | | | | discs have been provided in the TST instrument. |
| instruments vary from low price to very high | | | | These types of highly sophisticated and high |
| price. | | | | quality total stations have the capability of |
| Using TST, usually, distances and angles are | | | | measuring angles up to 0.5 arc-second accuracy |
| measured (reference to the total station) to | | | | when compared with inexpensive total stations |
| points under survey, and the corresponding | | | | that can usually measure angles up to an |
| coordinates (X, Y, and Z or north, east and | | | | accuracy of 5 or 10 arc-seconds. |
| elevation) of the surveyed points are derived | | | | TST uses modulated microwave or infrared |
| (reference to the total station position) using | | | | carrier signal ( emitted by a small solid-state |
| trigonometry or triangulation methods. Also, the | | | | emitter) sent along the instrument's optical path, |
| total station works on line of sight observations. | | | | and reflected by a prism reflector kept at the |
| Thus it has to be set up over an established point | | | | point under survey. The returning signal is |
| or with line of sight to two or several known | | | | received by the onboard computer of the TST |
| points. The main important attribute of TST is | | | | and processed to determine the distance of that |
| that it can be combined with a computer. In other | | | | particular point. Most of TST instruments can |
| words, data can be transfered from the TST to | | | | measure distance up to accuracy of 3 millimeters |
| a computer and later using the appropriate | | | | or one-thousandth of a feet. |