13-1
13 CORRECTION FOR REFRACTION AND EARTH CURVATURE
13
CORRECTION FOR REFRACTION AND EARTH
CURVATURE
The instrument measures distance, taking into account correction for refraction and earth curvature.
13.1 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
) or BE(
β
)
Vertical distance Z =BC(
α
) or EA(
β
)
D = L{cos
α
–(2
θ
–
γ
) sin
α
}
Z = L{sin
α
+(
θ
–
γ
) cos
α
}
θ
= L
•
cos
α
/2R........... Earth curvature
correcting item
γ
=K
•
Lcos
α
/2R.......
Atmospheric
refraction
correcting item
K =0.14 or 0.2.......... Coefficient of
refraction
R =6372km.............. Radius of earth
α
( or
β
)................... Altitude angle
L .............................. Slope distance
●
The conversion formula for horizontal and vertical distances is as follows when correction for
refraction and earth curvature is not applied.
D=L
•
cos
α
Z=L
•
sin
α
Note:
The coefficient of the instrument has been set at 0.14 before shipment (K=0.14).
if the "K" value is to be changed, refer to 16 “SELECTING MODE”.
Summary of Contents for GPT-3000 Series
Page 1: ...GPT 3000 SERIES GPT 3002 GPT 3003 GPT 3005 GPT 3007 PULSE TOTAL STATION INSTRUCTION MANUAL...
Page 2: ......
Page 137: ...12 4 12 SETTING ATMOSPHERIC CORRECTION...
Page 138: ...12 5 12 SETTING ATMOSPHERIC CORRECTION...
Page 179: ......