Leveraging GNSS Accuracy With a Barometer

The global navigation satellite system (GNSS) suffers from vertical accuracy degradation due to satellite geometry and environmental factors. This article proposes a novel barometric velocity correction (BVC) that integrates GNSS and barometric data to improve altitude accuracy. Unlike conventional approaches that treat the barometer as an altitude reference, the proposed BVC uses barometric data as odometric data to estimate vertical velocity, which is integrated into an extended Kalman filter (EKF) framework. Through theoretical analysis, including Kalman gain and uncertainty propagation analysis, we validate the effectiveness and advantages of the BVC. We evaluated the proposed method using comprehensive experiments with synthetic and real-world data. Experiments with synthetic data show that the BVC method significantly improves altitude accuracy, reducing vertical errors by up to 27.6% compared to conventional methods. The proposed BVC method proves particularly effective in handling barometric bias and varying GNSS conditions. Real-world experiments further validate the system’s effectiveness, particularly in handling frequent altitude transitions and achieving reliable loop closure where conventional methods exhibit instabilities. This work provides a practical and straightforward sensor integration approach for precise altitude estimation in urban settings with potential applications across various 3-D positioning systems.