Intensive Test Campaign for SBAS Service Extension in Equatorial Regions

An innovative carrier tracking loop technique is here proposed to be embraced in GNSS receivers operating in equatorial or polar regions, where ionosphere scintillation can affect integrity and continuity of raw measurements from GNSS signals, with main target of expansions of current Satellite Based Augmented Systems (SBAS) coverage. Taking benefit from previous TASI developments in the frame of scintillation effects mitigation, the carrier tracking loop scheme based on a “light” Kalman filter implementation is here enhanced by an adaptive configuration enabled to rescale the process noise covariance matrix as function of the real-time experimented and measured scintillation activity, through S4 and sigma-phi parameters. On top of this, an improved smart loss-of-lock indicator has been introduced in order to further limit data gaps in case of ionosphere-induced deep amplitude fading, acting in parallel with other receiver-side barriers to mitigate integrity risks. These implemented features and the attained promising results during the test campaign, as presented in this work, likely improve the robustness against the scintillation threat, improve the continuity of signals tracking measurements and enable the possibility of extending SBAS services coverage in Equatorial Regions.