The survey corrections are calculated using the following formulas.
Curvature and Refraction Formula
The following formula calculates the vertical angle (in radians):
where:
- OVA: Old vertical angle (in radians)
- VA: Vertical angle (in radians)
- SD: Slope distance
- R: Spheroid radius (if a coordinate system zone is set, this value is obtained from the zone)
- k: Coefficient of refraction
Atmospheric Conditions Formula
The following formula determines the slope distance:
where:
- OSD: Old slope distance
- SD: Slope distance
- C: Constant for the EDM carrier (for example, Sokkia Lietz 0.86)
- P: Atmospheric pressure in mm Hg
- RI: Group refractive index for EDM carrier (for example, Sokkia Lietz 287.96)
- T: Dry air temperature in degrees Celsius
Sea Level Formula
The following formula calculates the horizontal distance at sea level:
where:
- OHD: Old horizontal distance
- HD: Horizontal distance
- SE: Station elevation
- R: Spheroid radius (if a coordinate system zone is set, this value is obtained from the zone)
Collimation Formulas
The following formulas determine the collimation:
Horizontal collimation:
- For FACE 1: Horizontal Angle = Measured Horizontal Angle + Horizontal Collimation Error
- For FACE 2: Horizontal Angle = Measured Horizontal Angle - Horizontal Collimation Error
Vertical collimation (all vertical angles are converted to zenith):
- For FACE 1: Vertical Angle = Measured Vertical Angle + Vertical Collimation Error
- For FACE 2: Vertical Angle = Measured Vertical Angle - Vertical Collimation Error