Ionospheric Scintillation Effects on GPS Receivers during Solar Minimum and Maximum

The ionosphere has practical importance in GPS (Global Positioning System) applications because it influences transionospheric radio wave propagation. Among various phenomena in the ionosphere, ionospheric scintillation is characterized by rapid fluctuation and fading of the received signal intensity due to electron density irregularity inside the ionosphere. Deep signal fading caused by scintillation can lead to loss of lock of the carrier tracking loop in GPS receivers. The aircraft navigation system based on GPS and WAAS (Wide Area Augmentation System) uses code and carrier phase data to create the position estimate. If a significant number of carrier tracking channels lose lock simultaneously, the system cannot provide service until reacquiring a sufficient number of channels. Although scintillation is not frequent in the mid-latitude region, it is a potential hazard in terms of availability and continuity of the service in the equatorial region [1].