SBAS operation in the Indian sector under simultaneous scintillation on different GNSS links

• Severe equinoctial SBAS scintillation in different GEOs links near the EIA crest.
• GNSS receivers׳ loss of lock follows SBAS scintillations.
• Availability of GNSS satellites is severely reduced hampering navigation solution.
• GPS is more vulnerable to scintillation than GLONASS.
• Scintillations at the respective longitudes follow resurgence of EIA.

Scintillation observations of transionospheric signals from two GEOs (55°E and 140°E) and from the satellite constellations of GPS and GLONASS are carried out simultaneously during the equinoctial months of high solar activity years (2011–2012) from Raja Peary Mohan College (RPMC) center situated near the equatorial ionization anomaly (EIA) crest to study the vulnerability conditions of SBAS operation. Scintillations in excess of ~10 dB are recorded simultaneously in the two GEO links in ~8% of the observing days with an average duration of ~28 min. Under this condition the availability of GPS and GLONASS also falls below the optimum number (4) necessary for navigation solution, rendering the SBAS operation doubtful. GPS is found to be more susceptible to exhibit receivers׳ loss of lock than the GLONASS. The study reveals that two GEO links with pierce point longitude separation of ~10° are not suitable for maintaining faithful SBAS opeartion around the EIA crest. Occurrence of GEO scintillations is found to be associated with the strength and duration of the emerging post-sunset EIA structure.