An autoregressive adaptive Kalman filter carrier tracking approach for mitigating ionospheric scintillation effects in GNSS receivers

Abstract Ionospheric scintillation causes a serious threat to the accuracy, integrity, and reliability of Global Navigation Satellite System (GNSS) receivers, leading to significant amplitude fading, and rapid phase fluctuations. The GNSS receivers with traditional carrier-tracking loops may sometimes fail to retain signal integrity during high scintillation scenarios, leading to degraded positioning performance or even loss of lock and can seriously affect the dynamic systems and safety of life-critical applications. We present an Autoregressive Adaptive Kalman Filter (AR-KF) based tracking approach to enhance the robustness of the GNSS receivers under scintillation conditions. The adaptive KF algorithm in the proposed framework dynamically adjusts the time-varying characteristics of the parameters in its tracking loop by leveraging insights gained from a sophisticated and high rate software defined radio-frequency (RF) system collocated by a specialized ionospheric monitoring GNSS receiver whereas the succeeding AR algorithm plays a crucial role by intelligently predicting and refining the carrier phase estimates, thereby mitigating the distortions and enhancing the GNSS tracking loop resiliences. The efficacy of the proposed filtering algorithm is evaluated using real-time GNSS signals affected by weak, moderate, and strong scintillation conditions. Experimental results demonstrate that the combined approach in this work can ensure relatively robust navigation and timing performance by effectively tracking even in severe scintillation conditions. The analysis revealed minimal intervention of the algorithm during weak scintillation but intelligently improving the performance in moderate, and strong scintillation scenarios. The findings from this study suggest the effectiveness of integrating adaptive KF and AR architecture through advanced signal processing methodologies into GNSS receivers, offering a consistent solution for navigational applications during strong scintillation conditions.