vertical refraction

The purpose of the study is to attempt to determine the deviation of vertical lines using trigonometric levelling and Global Navigation Satellite System (GNNS) measurements. For the last decades with the emergence of high-precision electronic theodolites and tacheometers, trigonometric levelling becomes a competitor of the geometric levelling of the II and III accuracy classes. This is primarily the definition of exceedances at distances up to 1–2 km for topographic surveying and the study of geodynamic processes in zones of the man-made load.

Aim. To investigate the possibilities of applying non-simultaneous reciprocal trigonometrical levelling over water surfaces while partially taking into account vertical refraction. Methodology. Experimental investigations of vertical refraction over water surfaces during day time on a plain and hilly terrains in summer. Non-simultaneous reciprocal observations were made over different water surfaces with the use of an automated electronic tachymeter.

Aims. The investigations of the transmission of elevations over water surfaces remain topical, so the first aim is to develop the technique of increasing the accuracy of the trigonometric instead of geometrical one. The second aim is to investigate the methods of trigonometric which can be used for the transmission of elevations over water surfaces with the use of modern devices. Methodology. Simultaneous and non-simultaneous reciprocal observations over different water surfaces have been carried out.

A method of measuring of vertical refraction by observed representation of reading scale, which is on the mirror reflector, has been suggested. This method permits direct determination and inserting correction as refraction as result of geometrical leveling.

Research results of leveling refraction in night period are presented. Method of computing value of images fluctuation by means of CCD is given along with more precise formulas for accounting of refraction in night period.

In article described experimental researches of a vertical refraction on results of trigonometrically levelly above water lake surface of Beregany town discover laws of action of a refraction above lake. Methods of exception of influence of this factor are offered.

The new way of measuring of vertical refraction with application of refraction devices is considered in the article. It helps to simplify methods and means of immediate determinations of vertical refraction and to raise the accuracy its measuring.