Throughout the years, a surveyor’s tool of choice in determining property lines and building sites was the optical transit. However the electronic theodolite began to replace the optical transit in the 1970’s due to its ability to measure angles more accurately. By the early 1980’s a new instrument of choice came about called “total stations.” Total stations are integrated with electronic distance meters (EDMs) which enables them to read distances far more accurately compared to previous instruments. Then in late 1990, Dandryd Sweden introduced the first “robotic total station” called the Geodimeter. The Geodimeter added automatic tracking and radio communication to data collectors at the “target” or pole. For the first time, a surveyor was not required at the site of the instrument, only a person was required at the site of the “target”. This has allowed reducing the sizes of survey crews.

Today there are three companies that manufacture these robotic total stations. These companies include Trimble, Leica, and Topcon. Total robotic total stations were once a tool only used by surveyors but are more commonly being used today by contractor and construction businesses.

How Total Robotic Stations Work
Although each robotic total station has its own benefits and features, all of the elements for each manufacturer are the same. Each station is servo-motor-driven which means they have the ability to measure angles both in the X & Y (horizontal planes) and in the Z (elevation axis). All measurements are very accurate and precise and usually measure within 3 seconds of accuracy or less.

Electronic distance meters (EDMs) are found in robotic total station just as they are present in total stations. By laser technology or infrared sensors, EDMs are able to measure the distance from the station to its target within millimeters accuracy. The target found within the station involves a prism that reflects light back to the instrument. This light determines a remote measurement and is reported through radio communication to the electronic data collector. This process is also known as telemetry. The use of these prisms, servomotors, and infrared technology allow for robotic total stations to search for and lock onto targets automatically. This unique feature enables surveyors to easily move the station around jobsites without losing targets.

Manufacturers provide computer software for their robotic total stations which allow easy downloads for survey crews to update coordinate information. Coordinate information is often provided from computer-aided drafting (CAD) files which are downloaded from office computers, ASCII files, PCMCIA cards (flash cards), or entered manually into the instrument.
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