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Abstract
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 the
tracking loop filters to affect the received satellite signal quality. Carrier to
noise density ratio (C/No) is an indicator of received signal quality to the
receiver. Lower C/No means lower quality of the received signal. Galileo
satellites will be soon in place operating together with GPS satellites.
Considering the designer¿s intention of maintaining interoperability between
different satellite navigation systems, it is reasonable to seek a quantified
comparison between the different systems in terms of vulnerability to CW
interference. In this paper, considering the signal structures, the
characterization of the effect of CW interference on the C/No for GPS and
Galileo is investigated and compared. It is shown that for the available
Galileo signal (GIOVE-A BOC(1, 1) in the E1/L1 band), the worst spectral
line happens far from the L1 frequency. A frequency was selected which is
midway between the GPS and Galileo worst spectral lines, and for the same
power of RFI, GPS is shown to be more vulnerable to interference. Also the
probability of availability of one GPS satellite is compared with that of one
Galileo satellite in terms of interference power and frequency.