Leica Geosystems TPS1100 Professional Series - User Manual - Manual (Page 152)

152
TPS1100 - User Manual 2.2.1en Technical specifications
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Atmospheric correction ∆∆∆∆∆ D
1
The distance displayed is correct only
if the scale correction in ppm (mm/
km) which has been entered
corresponds to the atmospheric
conditions prevailing at the time of
the measurement.
The atmospheric correction includes
adjustments for air pressure, air
temperature and relative humidity.
If, 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 millibars; relative humidity
to 20%.
It is usually sufficient to take the
atmospheric correction from the dia-
gram and to enter this value with the
keyboard.
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.
The index n for the infrared EDM
(carrier wave 780nm) = 1.0002830.
For the visible red laser (carrier wave
670nm), n = 1.0002859.
The index n is calculated from the
formula of Barrel and Sears, and is
valid for air pressure p = 1013.25
mbar, for air temperature t = 12°C
and for relative air humidity h = 60%.
Formula for infrared EDM:
Air-humidity correction in mm/km
(ppm), air temperature in °C, relative
humidity in %
∆ D
1
= 283.04 - 0.29195 · p
(1 + α · t)
4.126 · 10 -4 · h
(1 + α · t)
· 10 x
∆ D
1
= 285.92 - 0.29492 · p
(1 + α · t)
4.126 · 10 -4 · h
(1 + α · t)
· 10 x
Formula for visible red laser:
ppm
+5
+4
+3
+2
+1
+0
100%
80%
60%
40%
20%
-20 -10 0 10 20 30 40 50 °C