Comparison between GPS and Galileo satellite availability in the presence of CW interference

GNSS receivers have been shown to be most vulnerable to CW interference.It affects the acquisition process of the signal and can also pass through thetracking loop filters to affect the received satellite signal quality. Carrier tonoise density ratio (C/No) is an indicator of received signal quality to thereceiver. Lower C/No means lower quality of the received signal. Galileosatellites will be soon in place operating together with GPS satellites.Considering the designer¿s intention of maintaining interoperability betweendifferent satellite navigation systems, it is reasonable to seek a quantifiedcomparison between the different systems in terms of vulnerability to CWinterference. In this paper, considering the signal structures, thecharacterization of the effect of CW interference on the C/No for GPS andGalileo is investigated and compared. It is shown that for the availableGalileo signal (GIOVE-A BOC(1, 1) in the E1/L1 band), the worst spectralline happens far from the L1 frequency. A frequency was selected which ismidway between the GPS and Galileo worst spectral lines, and for the samepower of RFI, GPS is shown to be more vulnerable to interference. Also theprobability of availability of one GPS satellite is compared with that of oneGalileo satellite in terms of interference power and frequency