
ppm
+5
+1
+2
+3
+4
+0
-10
-20
0 10 20 30 40 50
°C
100%
80%
60%
40%
20%
TS_104
ppm Air humidity correction
[mm/km]
%
Relative humidity [%]
°C
Air temperature [°C]
Type
Index n
Carrier wave [nm]
Combined EDM
1.0002863
658
The index n is calculated from the formula of the IAG Resolutions (1999), and
is valid for:
Air pressure p:
1013.25 mbar
Air temperature t:
12 °C
Relative air humidity h:
60%
Formula for visible red laser
· 10
x
4.126 · 10
-4
· h
-
0.29535 · p
Δ
D
1
= 286.338 -
002419_002
D
D
1
Atmospheric correction [ppm]
p
Air pressure [mbar]
t
Air temperature [°C]
h
Relative humidity [%]
a
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
D
2
are always negative and are derived from the following for-
mula:
TS_106
Δ
D
2
= -
H
R
· 10
6
D
D
2
Reduction to mean sea level [ppm]
H
Height of EDM above sea level [m]
R
6.378 * 10
6
m
The magnitude of the projection distortion is in accordance with the projection
system used in a particular country, for which official tables are generally
Air humidity
correction
Index n
Formulas
Reduction to mean
sea level
D
D
2
Projection distortion
D
D
3
66
Technical Data
Содержание iCON iCB50
Страница 1: ...Leica iCON Construction Layout Tool iCT30 User Manual Version 2 0 English ...
Страница 71: ......