Leica FlexLine TS10, User Manual

Page: 58 / 64

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 avail-
able. The following formula is valid for cylindrical projections such as that of
Gauss-Krüger:
TS_107
Δ
D
3
=
X
2
2R
2
· 10
6
D D
3
Projection distortion [ppm]
X Easting, distance from projection
zero line with the scale factor 1
[km]
R
6.378 * 10
6
m
In countries where the scale factor is not unity, this formula cannot be directly
applied.
Atmospheric corrections in ppm with temperature [°C], air pressure [mb] and
height [m] at 60% relative humidity.
TS_108
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
11
0 11
5 120
125
130
135
140
50°C 50°C
40°C 40°C
30°C 30°C
20°C 20°C
10°C 10°C
0°C 0°C
-10°C -10°C
-20°C -20°C
550 mb
5000 m 4500
600 650 700 750 800 850 900 950 1000 1050 mb
550 mb 600 650 700 750 800 850 900 950 1000 1050 mb
4000 3500 3000 2500 2000 1500 1000 500 0 m
Reduction to mean
sea level
D
D
2
Projection distortion
D D
3
Atmospheric
corrections °C
58 Technical Data