Loss of Lock Characteristics of Global Positioning System Signals Under Ionospheric Scintillations at Guntur, India

Ionospheric scintillation has been considered as one of the major threats to space-based navigation and communication system as well as satellite monitoring and tracking applications. The scintillations in the ionospheric layer of the upper atmosphere refers to plasma irregularities, resulting in signal fading or even loss of lock that may take a significant amount of time to establish lock to the satellites. Hence, it is one of the important aspects to understand the characteristics of ionospheric scintillations for developing a realistic modeling and forecasting system. In the present work, the amplitude scintillation index (S4 index) and the phase scintillation index (σφ index) are used to examine scintillations using the data recorded at a low latitude station, i.e., KL University (Geographic 16.37°N, 80.37°E), Guntur, India. The GPS L1 signal is observed to lose lock for two days on October 8 and 18, 2022. Over the course of two days, the scintillation values, and their effect on the high-rate C/No data are tracked. Some of the satellite signals that were disrupted during the loss of lock time are detected, and the scintillation consequences of those satellites are examined. Lock failure and increased scintillation levels are seen on both days after local sunset, manifesting irregularities over the low latitude Indian region.