Topcon DS Series - Page 138

22. CHANGING THE SETTINGS
131
 Collimation correction
The instrument has a collimation correction function that automatically corrects horizontal angle
errors caused by horizontal axis and leveling axis errors. Normally set this item to "Yes".
 V mode (vertical angle display method)
 Sea level correction
The instrument calculates horizontal distance using slope distance values. As this horizontal
distance does not take height above sea level into consideration, performing spherical correction
is recommended when measuring at high altitudes. Spherical distance is calculated as follows.
Where: R = radius of the spheroid (6372.000m)
H
a
= averaged elevation of the instrument point and target point
d
1
= horizontal distance
 Dist.reso. (Distance resolution)
Select distance resolution of fine measurement. Distance resolution of rapid and tracking
measurement will shift with this setting.
Zenith Horiz
Horiz 90°
Spherical distance
RHa–
R
------------------
d
1
×=