Analysis of GPS/EGNOS Positioning Quality Using Different Ionospheric Models in UAV Navigation

Area of Science:

• Geomatics Engineering
• Satellite Navigation Systems
• Geophysics

Background:

• Unmanned Aerial Vehicles (UAVs) increasingly rely on Global Navigation Satellite Systems (GNSS) for geoinformation acquisition.
• The European Geostationary Navigation Overlay Service (EGNOS) enhances GNSS positioning, particularly for aviation.
• Accurate positioning is crucial for UAV applications, necessitating robust navigation algorithms.

Purpose of the Study:

• To evaluate the positioning quality of a modified Global Positioning System (GPS)/EGNOS algorithm.
• To compare the performance of different ionospheric models (EGNOS, Klobuchar for GPS/BeiDou, NeQuick for Galileo) in GNSS positioning.
• To assess the impact of phase-smoothing of code observations on positioning accuracy.

Main Methods:

• Modified GPS/EGNOS algorithm development.
• Implementation and comparison of EGNOS, Klobuchar (GPS/BeiDou), and NeQuick (Galileo) ionospheric models.
• Analysis of positioning accuracy with and without ionospheric corrections.
• Evaluation of phase-smoothing technique on code observations.

Main Results:

• The original EGNOS ionospheric model yielded superior accuracy and better horizontal-vertical correlation compared to other tested models.
• Removing ionospheric corrections negatively impacted positioning quality.
• Phase-smoothing of code observations resulted in maximum horizontal errors of ~1.3m and vertical errors of ~2.2m.

Conclusions:

• The EGNOS ionospheric model is effective for enhancing GPS/EGNOS positioning accuracy.
• Phase-smoothing is a valuable technique for improving GNSS positioning precision.
• Results are specific to the study area in north-eastern Poland.