Weather Radar Calibration Method Based on UAV-Suspended Metal Sphere

Area of Science:

• Meteorology and Atmospheric Science
• Remote Sensing Technology
• Geospatial Engineering

Background:

• Accurate weather radar calibration is essential for high-quality severe convective weather monitoring.
• Existing calibration methods can be labor-intensive and may not provide real-time positional data.
• The need for efficient and precise calibration techniques is critical for advancing meteorological observations.

Purpose of the Study:

• To develop and validate a UAV-based metal sphere calibration method for weather radar.
• To establish a complete calibration process with accuracy evaluation metrics.
• To improve the efficiency and precision of radar calibration for severe weather applications.

Main Methods:

• Utilizing a UAV platform with a high-precision RTK system and laser range camera for real-time metal sphere positioning.
• Implementing a UAV-suspended metal sphere technique for quantitative calibration of radar reflectivity (Z) and differential reflectivity (ZDR).
• Developing a "coarse adjustment + fine adjustment + staring" sphere-finding technique using RHI, PPI, and FIX scanning modes for accurate target acquisition.

Main Results:

• The combined RTK and laser camera system significantly improved radar target acquisition efficiency.
• UAV-suspended metal sphere calibration achieved accuracies of within 0.5 dB for Z and 0.2 dB for ZDR.
• The established sphere-finding technique successfully centered the metal sphere in the radar bin, minimizing errors.

Conclusions:

• The UAV-based metal sphere calibration method provides an efficient and accurate approach for weather radar calibration.
• This technique enhances the reliability of observational data for severe convective weather monitoring.
• The developed method supports periodic quantitative calibration and qualitative inspection of critical radar parameters.