22
The standard atmospheric value of ZTS-320 series Total
Station (i.e. the atmospheric conditions when the correction is
zero)
Atm: 1013 Pa
Temp:20
℃
The calculation of atmospheric correction
△
S= 277.825- 0.29434P/(1+0.003661T) (ppm)
In the formula:
△
S:
correction coefficient (unit: ppm)
P: atmospheric pressure (unit: hPa)
T: temperature (unit:
℃
)
3.6.1 Set up the Atmospheric Correction value (ppm)
directly
You may measure the temperature and pressure to find out
the atmospheric correction (ppm) through the correction formula
or from the atmospheric correction chart. Continuing with the
operations in 3.5, press soft key „Enter‟ to move inserter down to
the „PPM‟ column to enter the value.
3.6.2 Calculate the Atmospheric Correction out with
temperature and pressure sensor
First, measure the temperature and pressure around the
station in advance.
e.g. Temp: +25
℃
atm:1017.5
Press soft key „Enter‟ to move inserter to the „Temp‟
column and type in „25.0‟;
Press soft key „Enter‟ to move inserter to the „Press‟
column and type in „1017.5‟;
Press soft key „Enter‟ to move the inserter to the „prism c‟
column;
(the„PPM‟ column now displays 3)
Press ‟ENT‟ to save the parameter. Our system will display
„Record: ***(name of the point)‟ and exit the dialogue box. The
point is saved now .
3.7 The Correction of the Atmospheric refraction
and the Earth Curvature
When measuring horizontal distance and elevation, our
instrument corrects the atmospheric refraction and the earth
curvature automatically.
The formulas of two corrections about our instrument are
as followed:
Corrected Horizontal Distance :