Three-Dimensional Refractivity Model for Atmospheric Mitigation in Distance and Vertical Angle Measurements

Area of Science:

• Geodesy and Geomatics
• Atmospheric Physics
• Surveying Technology

Background:

• Atmospheric refraction significantly degrades the accuracy of electro-optic geodetic instruments.
• Standard methods struggle to fully compensate for atmospheric effects on distance and angle measurements.

Purpose of the Study:

• To introduce and validate a novel 3D-Refraction Model (3D-RM) for mitigating atmospheric refraction errors.
• To enhance the precision of open-air distance and vertical angle measurements.

Main Methods:

• The 3D-RM integrates in situ meteorological data, digital terrain model (DTM) information, and ERA5 sensible heat flux data.
• It utilizes the Turbulence Transfer Model (TTM) to estimate vertical refractivity gradients at multiple height levels.
• The model was validated using total station observations during two field campaigns.

Main Results:

• Applying the 3D-RM for distance correction demonstrated improved accuracy compared to standard methods relying solely on station meteorological data.
• A variant (3D-RM2) showed that accurate corrections are achievable even without on-site meteorological sensors, enhancing model flexibility.
• The model provides cost-effective and implementable corrections for atmospheric refraction.

Conclusions:

• The 3D-RM offers a significant advancement in correcting atmospheric refraction for geodetic measurements.
• Its flexibility and cost-effectiveness make it a viable alternative to existing, more complex methodologies.
• The model enhances the reliability of geodetic surveying in open-air environments.