These plots show the ionospheric scintillation index S4 over the last 24 hours, as measured by IPS Ionospheric Scintillation Monitor (ISM) sites. Each colour corresponds to the signal from an individual GPS satellite. S4 values over ~0.6 indicate strong scintillation which can cause loss of lock on the GPS signal. A scintillation index below 0.3 is unlikely to have any affect on GPS .

For more general information on ionospheric scintillation, please visit the About Ionospheric Scintillation page.

IPS operates a number of ISMs in the Australasian region, close to the southern equatorial anomaly, as well as in the sub-Antarctic region to the south of Australia. Locations of IPS ISMs are indicated on the map below. Ionospheric Scintillation data from these instruments is available through the IPS World Data Centre.