Short Answer:

A total station works by combining angle measurement and distance measurement in one instrument. It uses a telescope to sight a target, an electronic system to measure horizontal and vertical angles, and a laser or infrared beam to measure the distance to a target prism. Then, the total station calculates the coordinates of the target point using this data.

All the collected information is displayed on a screen and saved in the instrument’s memory. The user can later transfer this data to a computer or use it directly for plotting, mapping, or construction layout.

Detailed Explanation:

How a total station works

A total station is a smart and advanced surveying tool that combines a theodolite (for measuring angles), an electronic distance measuring device (EDM), and a computer unit. These components work together to give accurate positions of points on the ground. The total station collects field data digitally and makes surveying fast, accurate, and convenient.

Step-by-step working of a total station:

1. Setting up the instrument
   The total station is fixed on a tripod and leveled properly using the built-in spirit level or electronic level. It is centered exactly over a ground survey point using a plumb bob or optical plummet.
2. Orientation of the instrument
   Before starting measurement, the total station is oriented. This can be done by aiming at a known reference point to establish direction or bearing, especially in large surveys.
3. Sighting the target
   The surveyor uses the telescope to sight a prism, which is placed on a staff or held over the point to be measured. The crosshairs inside the telescope help align the view accurately with the prism.
4. Measuring angles
   The instrument uses internal electronic sensors to measure:

• Horizontal angles: The angle between the direction of the reference point and the target.
• Vertical angles: The angle between the line of sight and the horizontal level.

These angles are measured digitally and shown on the display.

5. Measuring distance
   The total station sends an infrared or laser beam from the instrument to the prism. The beam reflects back to the total station. The instrument measures the time it takes for the beam to travel to the prism and return. This time is used to calculate the slope distance between the total station and the prism.

Some modern total stations can also work without a prism using reflectorless mode, where the beam reflects off any solid object.

6. Coordinate calculation
   Once the angles and distances are known, the total station’s computer automatically calculates the coordinates (X, Y, Z) of the target point using trigonometric formulas. These coordinates are displayed on the screen and stored in memory.
7. Data storage and transfer
   All measured data is stored in the internal memory or an SD card. It can be transferred to a computer through USB, Bluetooth, or data cables. This allows surveyors to use software for plotting, mapping, and analysis.
8. Additional features
   Many total stations have extra functions such as:

• Stakeout: Helps mark the ground points according to design coordinates.
• Area and volume calculation: Useful in construction and earthwork.
• Remote elevation measurement: Used when the base is not accessible.
• Robotic control: Allows single-person operation by automatically following the prism.

Conclusion

A total station works by sighting a target, measuring angles and distances electronically, and using this information to calculate exact coordinates. It makes surveying much faster and more accurate than traditional tools, and its digital system reduces errors and simplifies data handling.