Performance evaluation of tracking NavIC L5 signals under scintillation conditions

Ionosphere scintillation causes rapid and abrupt fluctuations in the intensity and phase of the signal due to the ionosphere irregularities. It is proved to be detrimental to the effective functioning of navigation systems. The reliability and integrity of GNSS system is dependent on the performance of signal tracking loops of the GNSS receivers which are adversely affected during scintillation. The study presents the analysis of the impact of scintillation on the receiver performance particularly carrier tracking loops which may provide cues of handling scintillation signals and overcome its drastic influence on the receiver functioning. The performance of the carrier tracking loop under scintillation is analysed and evaluated in terms of signal locking ability, correlator power, carrier to noise ratio and tracking error. The methodology involves generating simulated scintillation signals based on statistical model and modulating the real NavIC L5 signals with simulated scintillations to generate scintillated signal to test the performance of the software implemented carrier tracking loop. The study concludes with possible strategies such as adaptable loop bandwidth and extending integration time to subdue scintillation effects on receiver performance.