Total stations are surveying instruments that combine an electronic theodolite, electronic distance meter, and on-board computer. They allow users to measure horizontal and vertical angles as well as slope distances to calculate coordinates. Modern total stations can store thousands of data points, perform computations, and transfer data remotely via memory cards or wireless connections. They have largely replaced standalone theodolites and distance meters due to greater accuracy, automation, and data processing capabilities. Total stations find wide application in civil engineering, mining, accident reconstruction, and other fields requiring precise spatial measurements and positioning.

1. TOTAL STATION AND ITS APPLICATION TO CIVIL ENGINEERING Mrs. RESHMA L. PATEL Lecturer, Civil Engineering Department, Birla Vishvakarma Mahavidyalaya

2. Introduction Current State of the Art in Surveying:- There can be little doubt that the single most important technological development in recent years has been the computer. It has affected almost every facet of what most of us do in our daily lives, regardless of our field of endeavor. But computers have especially impacted the technical areas of practice. In surveying and mapping, they have completely changed the way data are collected, computations are made, maps and other products are developed and than disseminated to users.

3. Current State of the Art in Surveying (cont) :- Among the newest computer-driven technologies available to assist surveying engineers in their work of developing and processing spatial data are (1) total station instruments, including robotic systems; (2) the global positioning systems (GPS); (3) digital photogrammetry and light detection ranging (LIDAR); (4) satellite remote sensing; and (5) geographic information system (GIS). These new systems are enabling surveying engineers to provide new and better types of information at lower cost and in fraction of time previously required.

4. Total Station

5. A total station is an optical instrument used in modern surveying and archaeology as well as by police, crime scene investigators, private accident reconstructionists and insurance companies to take measurements of scenes. It is a combination of an electronic theodolite (transit), an electronic distance meter (EDM) and software running on an external computer known as a data collector.

6. Total Station Instruments:- Beginning in about 1980, an EDM component, which also had been improved to enable automatic readout, was combined with an electronic theodolite to create a single instrument called the total station . The functions of the distance and angle measuring components were controlled by an interfaced computer. Modern total station instruments can now make slope distance measurements, autometically display the results, and also store the data in the computer memory.

7. They can also measure angles both in horizontal planes and vertical planes, and again the results can be automatically displayed and stored. The on-board computer can use these measured data in real time to resolve horizontal and vertical distances, to calculate the positions and elevations of points, or to set points for construction projects. Total station instruments are probably the most commonly used and important instruments in modern surveying today, having practically replaced all transits, theodolites, and stand alone EDM instruments.

8. With a total station one may determine angles and distances from the instrument to points to be surveyed. With the aid of trigonometry and triangulation , the angles and distances may be used to calculate the coordinates of actual positions (X, Y, and Z or northing, easting and elevation ) of surveyed points, or the position of the instrument from known points, in absolute terms. The data may be downloaded from the theodolite to an external computer and application software will generate a map of the surveyed area.

9. Components of a Total Station EDM Electronic theodolite On-Board Micro-processor Data Collector (built in or separate unit) Data Storage (internal or memory card) Prisms

10. Micro-processor Averages multiple angle measurements Averages multiple distance measurements Computes horizontal and vertical distances Corrections for temp, pressure and humidity Computes inverses, polars, resections Computes X, Y and Z coordinates P A B “RESECTION”

11. Specifications Range Reflectorless –> 3 – 70 meters Single Prism -> 1 – 2000 m Triple Prism -> 1 – 2200 m Accuracy Angles –> 1 - 5” Distance –> 3mm + 2ppm (prism) -> 4mm + 3ppm (reflectorless) Data Storage 2000 – 4000 points

12. Field to Finish Operation Control/operation (robotic) Measurement and basic comps Final Comps, checks and outputs Transfer remotely (radio/cell phone) Memory card USB and Compact Flash Automatic target recognition

13. Some total stations also have a GPS interface which combines these two technologies to make use of the advantages of both (GPS - line of sight not required between measured points; Traditional Total Station - high precision measurement especially in the vertical axis compared with GPS) and reduce the consequences of each technology's disadvantages (GPS - poor accuracy in the vertical axis and lower accuracy without long occupation periods; Total Station - requires line of sight observations and must be set up over a known point or within line of sight of 2 or more known points).

14. 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 best quality total stations are capable of measuring angles down to 0.5 arc-second. Inexpensive "construction grade" total stations can generally measure angles to 5 or 10 arc-seconds.

15. Measurement of distance is accomplished with a modulated microwave or infrared carrier signal, generated by a small solid-state emitter within the instrument's optical path, and bounced off of the object to be measured. The modulation pattern in the returning signal is read and interpreted by the onboard computer in the total station. The distance is determined by emitting and receiving multiple frequencies, and determining the integer number of wavelengths to the target for each frequency . Most total stations use a purpose-built glass Porro prism as the reflector for the EDM signal, and can measure distances out to a few kilometers, but some instruments are "reflectorless", and can measure distances to any object that is reasonably light in color, out to a few hundred meters. The typical Total Station EDM can measure distances accurate to about 3 millimeters or 1/1000th of a foot.

16. Some modern total stations are ' robotic ' allowing the operator to control the instrument from a distance via remote control. This eliminates the need for an assistant staff member to hold the reflector prism over the point to be measured. The operator holds the reflector him/herself and controls the total station instrument from the observed point. Robotic total station instruments can automatically and repeatedly measure distances and angles to a moving reflector and store the values in memory without need of an operator. With its built-in computer it can also calculate instantaneous positions and rely them by radio to users. This has many potential applications, including real-time tracking and positioning for hydrographic surveys, dredging operations, and of particular interest, “stakeless” construction.

17. Application

18. Vehicular Accident Reconstruction applications Total stations are used by police, crime scene investigators, private accident reconstructionists and insurance companies to take measurements of scenes. Once they take accurate measurements with a total station they can use software to recreate the accident in a 3D animation .

19. Mining applications Total stations are the primary survey instrument used in many mining applications. Underground mining As the development drifts in an underground mine are driven, a total station will be used to record the absolute location of the tunnel walls ( stope ), ceilings (backs), and floors. This data can then be loaded into a CAD program, and compared to the designed layout of the tunnel. At regular intervals, the survey party will install stations. These are small steel plugs that are drilled into the walls or the back. The plugs are installed in pairs. 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. When the survey crew wants to set up the total station in a drift, they use a set of plugs to locate the total station.

20. Continuing Evolution of Measurement Technologies Leica Smartstation Topcon Imaging TS Merging TS and GPS Merging TS and Lidar Terrestrial Photogrammetry? High Resolution Satellite Imagery GoogleEarth Broadcast of Real-Time Corrections

21. Thank You