Investigating the PLL tuning effects on receiver tracking performance under high and low latitude ionospheric scintillation with an SDR BDS receiver

Amplitude and phase scintillation respectively refer to the rapid and random intensity and phase fluctuations of Radio Frequency (RF) signals caused by ionospheric irregularities. Both amplitude and phase scintillation occur at low latitudes, while phase scintillation is dominant at high latitudes. Scintillation can severely degrade the positioning performance of Global Navigation Satellite System (GNSS). The Phase Locked Loop (PLL) bandwidth and coherent integration time are important to determine the tracking performance of GNSS receivers. This study investigates the PLL tuning effects on the tracking performance by exploiting a software-defined radio (SDR) BeiDou Navigation Satellite System (BDS) B1C and B2a receiver based on simulated scintillation data. The results show that the configuration of bandwidth has a greater impact on the BDS receiver compared with the integration time under scintillation. The tracking errors caused by phase scintillation are suppressed by the increase of loop bandwidth. On the other hand, the tuning of loop bandwidth has little impact on the carrier to noise density ratio (C/N₀) level of PLL. Additionally, a Kalman Filter (KF)-based PLL is implemented in the receiver to mitigate scintillation effects. The study is of great importance for better understanding the effects of scintillation with different latitudes on the tracking loop performance of BDS software receiver. It can also contribute to designing PLL adjustment strategies for different scintillations under high and low latitudes to adapt to scintillation.