Leica iCON robot 60 User Manual page 62

Air humidity
Air humidity correc-
tion
Index n
Formulas
Reduction to mean
sea level D
2
iCON robot 60/iCON builder 60, Technical Data
The air humidity influences the distance measurement if the climate is extremely hot
and damp.
For high precision measurements, the relative humidity must be measured and
entered along with the air pressure and the temperature.
ppm
+5
+4
+3
+2
+1
+0
-20 -10 0 10 20 30 40 50
TS_104
Type
combined EDM
The index n is calculated from the formula of Barrel and Sears, and is valid for:
Air pressure p:
Air temperature t:
Relative air humidity h:
Formula for visible red laser
0.29525 · p
ΔD
= 286.34 - -
1
TS_105
D
Atmospheric correction [ppm]
1
p Air pressure [mbar]
t Air temperature [°C]
h Relative humidity [%]

1
273.15
x (7.5 * t/(237.3 + t)) + 0.7857
If the basic value of 60 % relative humidity as used by the EDM is retained, the
maximum possible error in the calculated atmospheric correction is 2 ppm, 2 mm/km.
The values for D
are always negative and are derived from the following formula:
2
H
ΔD 6
= -
· 10
2
R
TS_106
100%
80%
60%
40%
20%
ppm Air humidity correction [mm/km]
%
°C
C° Air temperature [°C]
Index n
1.0002863
1013.25 mbar
12 °C
60 %
-4
4.126 · 10 · h
x
· 10
D
Reduction to mean sea level [ppm]
2
H Height of EDM above sea level [m]
6
R 6.378 * 10
Relative humidity [%]
carrier wave [nm]
658
m
62