VIII Международная студенческая научная конференция Студенческий научный форум - 2016

Leveling is determination of the elevations of the points on the earth’s surface with the reference to a starting point ( “ordinance datum”) or sea level. Leveling is one of the types of the geodetic measurements used to create a geodetic control network ( leveling network) and to make topographic surveying, as well as to plan, construct, and maintain engineering structures, railroads, highways and so on. The results of leveling are used in research concerning the figure of the earth, variations in the levels of the seas and oceans and vertical movements of the earth’s crust.

Almost all of these tasks require high accuracy measurements. It determines the quality of their solutions, and valid data interpretation. The measurement accuracy is ultimately determined by the characteristics of the used devices and the characteristics of the production methods. The specialist must understand the details of the surveying instruments, use them properly and have an idea about the possible sources of the errors and take timely steps to address and mitigate the impact of these errors on the measurement results.It is important to consider the effect of the basic errors in the measurements of the horizontal angles, Zenith distances and elevations and primarily the effects of the atmospheric refraction.

There are several types of refraction: astronomical, satellite and terrestrial. Astronomical refraction is the process when the target is in infinity, with a target the beam passes the entire thickness of the atmosphere. Satellite refraction occurs when the objective is in the near-earth space, the terrestrial refraction at the earth's surface. Refraction of the light make it complicated the precise and accurate measurements and at present, when the accurate and high-precision instruments are available, it practically determines the accuracy of the measurements.

Bibliography:

1. http://geodesist.ru/forum/threads/vysokotochnoe-nivelirovanie.12039/

2. http://privetstudent.com/referaty/geologiya-referaty/1003-vysokotochnoe-i-tochnoe-geometricheskoe-nivelirovanie.html

3. http://textarchive.ru/c-2081493-p11.html

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