GPS L1 phase scintillation using wavelet analysis at high latitude

Abstract

Phase scintillation, e.g. as observed from GPS satellites by ground receivers, is generally measured as the standard deviation of the random fluctuations of the phase received over a fixed period of time which is ofteny taken to be 60s. The measured phase scintillation can be an important tool in understanding the ionospheric turbulence producing it, and consequently its effect on GPS positioning. Therefore, it is important to develop reliable ways of quantifying it. A new approach employing a wavelet analysis is implemented in this work to investigate GPS carrier phase fluctuations for different scintillation conditions using GPS data received at high latitudes where the scintillation effect is particularly marked. The phase scintillation obtained using wavelet analysis is also compared with that derived from the standard PSD technique using FFTs. It is concluded that this wavelet approach appears to be a promising method for recording fast variations of phase due to diffraction by ionospheric irregularities. Furthermore, the wavelet analysis, because it can better characterize conditions of non-stationary, can lead to a better understanding of these effects on phase lock loss in GPS receiver PLLs and hence can aid the design of GPS receivers that are more robust to scintillation effects.