Carrier frequency disturbance distributions on GPS during equatorial ionospheric scintillation

Abstract

In the equatorial region, deep amplitude fading in global positioning system (GPS) signals frequently occurs during the strong ionospheric scintillation, it can lead to the loss of lock in GPS carrier tracking loops, and result in increased positioning error and even navigation interruption. The relationships between amplitude scintillation indices and detrended carrier frequency are investigated, based on GPS L1 C/A signals during the last peak of the solar cycle at the low latitude site of São José dos Campos, Brazil (23.2S, 45.9W) from 2013 to 2015. Corresponding mathematic model of the probability distribution function is built for the first time to provide statistical analysis on the above relationships. The results show that the standard carrier frequencies reveal an almost linear relation with the amplitude scintillation indices. Moreover, the frequency widths of de-Trended frequency are proportional to levels of amplitude scintillation when the value of the peak probability is lower than the corresponding boundary. A conclusion can be drawn that different levels of amplitude scintillation will influence the fluctuation of the carrier frequency. The analysis will provide useful guidance to set the receiver's bandwidth with respect to the different scintillation levels and design the advanced tracking algorithms to improve the robustness and precision of the GPS receiver.