GPS and ionospheric scintillations

TLDR

Ionospheric scintillations, caused by ionization density irregularities, produce rapid phase and amplitude variations that can interrupt or degrade GPS signals, especially near the magnetic equator during solar maximum. The article aims to review GPS and ionospheric scintillations for space weather scientists and GPS engineers. The review examines how scintillations affect GPS receiver operation, including signal fading, ranging errors, and dilution of precision.

Abstract

Ionospheric scintillations are one of the earliest known effects of space weather. Caused by ionization density irregularities, scintillating signals change phase unexpectedly and vary rapidly in amplitude. GPS signals are vulnerable to ionospheric irregularities and scintillate with amplitude variations exceeding 20 dB. GPS is a weak signal system and scintillations can interrupt or degrade GPS receiver operation. For individual signals, interruption is caused by fading of the in‐phase and quadrature signals, making the determination of phase by a tracking loop impossible. Degradation occurs when phase scintillations introduce ranging errors or when loss of tracking and failure to acquire signals increases the dilution of precision. GPS scintillations occur most often near the magnetic equator during solar maximum, but they can occur anywhere on Earth during any phase of the solar cycle. In this article we review the subject of GPS and ionospheric scintillations for scientists interested in space weather and engineers interested in the impact of scintillations on GPS receiver design and use.