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Electronic Guide Light
(EGL)
Automatic corrections
7.9
Use of scale
correction
Atmospheric correc-
tion DD1
Air humidity
Technical Data
Working range:
Position accuracy:
The following automatic corrections are made:
Line of sight error
•
Tilting axis error
•
Earth curvature
•
Circle eccentricity
•
Compensator index error
•
Vertical index error
•
Standing axis tilt
•
Refraction
•
ATR zero point error
•
Scale Correction
By entering a scale correction, reductions proportional to distance can be
taken into account.
Atmospheric correction.
•
Reduction to mean sea level.
•
Projection distortion.
•
The slope distance displayed is correct 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
•
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.
5 m to 150 m (15 ft to 500 ft)
5 cm at 100 m (1.97" at 330 ft)
65
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