Leica TS13 User Manual page 75

Air humidity
Air humidity
correction
Index n
Formulas
Technical Data
The atmospheric correction includes:
Adjustments for air pressure
•
• Air temperature
Relative humidity
•
For highest precision distance measurements, the atmospheric correction
should be determined with an accuracy of 1 ppm. The following parameters
must be redetermined:
Air temperature to 1 °C
•
Air pressure to 3 mbar
•
• Relative humidity to 20 %
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 the IAG Resolutions (1999), and
is valid for:
Air pressure p:
Air temperature t:
Relative air humidity h:
Formula for visible red laser
0.29535 · p
ΔD
= 286.338 -
1
002419_002
DD Atmospheric correction [ppm]
1
p Air pressure [mbar]
t Air temperature [°C]
h Relative humidity [%]
a
1
273.15
x (7.5 * t/(237.3 + t)) + 0.7857
100%
80%
60%
40%
pp Air humidity correction
20%
m [mm/km]
% Relative humidity [%]
°C
C° Air temperature [°C]
Index n
1.0002863
1013.25 mbar
12 °C
60 %
-4
4.126 · 10 · h
x
-
· 10
Carrier wave [nm]
658
75