TY JOUR TI Field Testing of Algorithm for Refraction Coefficient Determining from Gradient Geodetic Measurements for Unilateral Trigonometric Levelling KW trigonometric levelling KW refraction coefficient KW gradient geodetic measurements KW atmospheric stratification JO Izvestia Vuzov. Geodesy and Aerophotosurveying AU Valov, G.E. AU Vshivkova, O.V. PY 2025 IS 69 PB MIIGAiK