GNSS vulnerabilities

Abstract

Ionospheric effect, multipath, and interference are the three important error sources for satellite-based positioning. Ionospheric content interferes with GNSS signals, inducing errors for users calculating their position from such signals. Besides, since GNSS was designed to operate in ideal line-of-sight conditions, observables are highly influenced by the signals arriving to the receiver along multiple propagation paths in locations with high possibility of reflection or refraction of the signal, such as urban scenarios. Finally, due to their very low power at the Earth surface, GNSS signals are vulnerable to RF interference, which can severely degrade the receiver performance. The chapter will assess the effects of these impairments and will present the strategies to detect and correct them.