KEYBOARD AND DISPLAY
A total station is activated through its control panel, which consists of a keyboard and multiple line LCD. A number of instruments have two control panels, one on each face, which makes them easier to use.
In addition to controlling the total station, the keyboard is often used to code data generated by the instrument - this code will be used to identify the object being measured.
On some total stations it is possible to detach the keyboard and interchange them with other total stations and with GPS receivers.This is called integrated surveying .
The microprocessor built into the total station is a small computer and its main function is controlling the measurement of angles and distances. The LCD screen guides the operator while taking these measurements.
The built in computer can be used for the operator to carry out calibration checks on the instrument.
The software applications available on many total stations include the following:
Slope corrections and reduced levels
Horizontal circle orientation
Resection (or free stationing)
Missing line measurement
Remote elevation measurement
Although all manufacturers quote ranges of several kilometres to a single prism.
For those construction projects where long distances are required to be measured, GPS methods are used in preference to total stations. There is no standard difference at which the change from one to the other occurs, as this will depend on a number of factors, including the accuracy required and the site topography.
Rapid measurement reduces the measurement time to a prism to between 0.5 and 1's for both phase shift and pulsed systems, but the accuracy for both may degrade slightly.
Tracking measurements are taken extensively when setting out or for machine control, since readings are updated very quickly and vary in response to movements of the prism which is usually pole-mounted.In this mode, the distance measurement is repeated automatically at intervals of less than 0.5s.
For reflector less measurements taken with a phase shift system, the range that can be obtained is about 100m, with a similar accuracy to that obtained when using a prism or foil.