Abstract
Ionospheric scintillation is one of the most challenging sources of errors in global navigation satellite systems (GNSS). It is an effect of space weather that introduces rapid amplitude and phase fluctuations to transionospheric signals and, as a result, it severely degrades the tracking performance of receivers, particularly carrier tracking. It can occur anywhere on the earth during intense solar activity, but the problem aggravates in equatorial and high-latitude regions, thus posing serious concerns to the widespread deployment of GNSS in those areas. One of the most promising approaches to address this problem is the use of Kalman filter-based techniques at the carrier tracking level, incorporating some a priori knowledge about the statistics of the scintillation to be dealt with. These techniques aim at dissociating the carrier phase dynamics of interest from phase scintillation by modeling the latter through some correlated Gaussian function, such as the case of autoregressive processes. However, besides the fact that the optimality of these techniques is still to be reached, their applicability for dealing with scintillation in real-world environments also remains to be confirmed. We carry out an extensive analysis and experimentation campaign on the suitability of these techniques by processing real data captures of scintillation at low and high latitudes. We first evaluate how well phase scintillation can be modeled through an autoregressive process. Then, we propose a novel adaptive, low-complexity autoregressive Kalman filter intended to facilitate the implementation of the approach in practice. Last, we provide an analysis of the operational region of the proposed technique and the limits at which a performance gain over conventional tracking architectures is obtained. The results validate the excellence of the proposed approach for GNSS carrier tracking under scintillation conditions.
Highlights
It is well known that global navigation satellite systems (GNSS) have become the key technology for positioning and navigation purposes using satellite ranging signals
Since we are interested in phase measurements, we focus on the phase-lock loop (PLL)-type discriminators, the well-known four-quadrant arctangent (ATAN2) discriminator as it duplicates the dynamic range of the Costas PLL and is robust to phase variations
The adaptive hard-limited (AHL) implementation is thought to deal with the nonlinear amplitude fades introduced by scintillation, whereby the Kalman filter (KF)-AR is affected by abnormal measurements that may compromise the linearity of the phase discriminator, degrading its performance and even driving the technique to lose lock
Summary
It is well known that global navigation satellite systems (GNSS) have become the key technology for positioning and navigation purposes using satellite ranging signals. Their maturity, widespread deployment and accuracy in open-sky environments are leading to a growing demand for extending GNSS beyond the limits of its original designs. The ionosphere is the upper earth’s atmosphere ionized by solar radiation, and it has a significant influence on transionospheric radio wave propagation. Ionospheric scintillation is a known effect of space weather whereby ionospheric
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
