Correction For Refraction And Earth Curvature - Sokkia CX-101 Service Manual

38. EXPLANATION

38.2 Correction for refraction and earth curvature

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(α)
Vertical distance Z = BC(α)
D = L{cosα - (2θ - γ) sinα}
Z = L{sinα + (θ - γ) cosα}
θ = L
cosα/2R
•
g = K Lcosα/2R : Atmospheric refraction correcting item
•
K = 0.142 or 0.2
R = 6371km
a
L

Changing "K (Coefficient of refraction)" value : "33.1 Configuration -
Config Mode-"
302
: Earth curvature correcting item
: Coefficient of refraction
: Radius of earth
: Altitude angle
: Slope distance
Radius of earth
R=6371km