Research on GNSS compatibility methodology based on CT-SSC
Compatibility Analysis of satellite navigation systems has become a research hotspot in recent years. Spectral separation coefficient (SSC), which is one of the most important quantities in GNSS compatibility, has been widely studied. In fact, it is suitable for impact of interfering on the receiver process steps which use prompt correlator channel, but it doesn't reflect the impact of code tracking processing. A code-tracking-based compatibility methodology is proposed, in which the code tracking spectral sensitivity coefficient (CT-SSC) is derived. Different from traditional compatibility methodology, this method does not only relate to power spectral density of desired signals and interfering signals, but also relates to early minus late spacing width. And through the analysis, it shows that the CT-SSCs can even vary 14dBs within one chip spacing and are larger than SSCs up to 5dBs for specific pairs of desired and interfering signals. Finally, the intra and intersystem interferences in GPS L1 band are simulated by both traditional and code-tracking-based compatibility methodology. It is concluded that the former would underestimate intra and intersystem interference.