Topcon GM-100 Series User Manual

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41. EXPLANATIONS
The instrument measures distance, taking into account correction for refraction and earth curvature.
Distance Calculation Formula
Distance Calculation Formula; with correction for refraction and earth curvature taken into account. Follow the
Formula below for converting horizontal and vertical distances.
Horizontal distance D = AC( )
Vertical distance Z = BC( )
D = L{cos - (2 - ) sin }
Z = L{sin + ( - ) cos }
= L • cos /2R : Earth curvature correcting item
g = K • Lcos /2R : Atmospheric refraction correcting item
K = 0.142 or 0.2 : Coefficient of refraction (Ref.index)
R = 6371km : Radius of earth
a : Altitude angle
L : Slope distance
Changing "K (Coefficient of refraction)" value : "33.1 Observation Conditions - Angle/Tilt"
41.2 Correction for Refraction and Earth Curvature

Topcon GM-100 Series Specifications

General

Brand	Topcon
Model	GM-100 Series
Category	Measuring Instruments
Language	English