Engineering Surveying Instruments
Engineering surveying instruments are an essential element of engineering surveying, providing the accuracy and reliability needed to perform surveying tasks accurately. Engineering surveying instruments are used to measure distances and angles, and also to measure properties of terrain such as elevation, gradient, slope and contours. Accurate latitude and longitude can be determined with standard engineering surveying instruments, and some instruments may also be used in remote sensing and automation.
The most important engineering surveying instruments are theodolites, total stations, levels, gps receivers and autocollimators.
Theodolites are used to measure horizontal and vertical angles. They operate on the principle of the pendulum and consist of a rotating telescope which measures horizontal angles. The vertical circle is used in measuring vertical angles. The accuracy of theodolites varies from model to model and is related to the size of the telescope.
Total stations are used to measure distances and angles in much the same way as theodolites, but they are more accurate and are used in conjunction with computer software. This enables them to be used in automated surveyed and mapping applications.
Levels are used to measure height differences and are used to set up the vertical datum on surveys. Levels consist of a telescope mounted on a tripod and are used in conjunction with a bubble level to align the telescope correctly.
GPS receivers are used to measure positions in latitude and longitude. They measure the position of a survey point by measuring the time taken for signals to reach the receiver from a number of satellites.
Autocollimators are used for extremely accurate alignment measurements. They consist of a telescope which is locked in a fixed position and is aligned to a light beam which is reflected off a mirror. Autocollimators can be used to measure angular differences and changes in position with a high level of accuracy.
Engineering surveying instruments are essential for accurate surveying and mapping tasks. Without them, engineers would not be able to accurately and reliably determine the properties of terrain or the positions of survey points.
