IMPC provides TEC measurements from Radio Beacons. In IMPC coherent radio waves at 150 and 400 MHz transmitted by several satellites of LEO-systems are monitored with local Beacon receivers.
There are several satellites of LEO-systems transmitting radion beacon signals such as:
When computing the differential phase of both signals, the relative, i.e. uncalibrated TEC may be derived. While measuring the signal strength, the scintillation index S4, a measure of signal strength fluctuations, is also estimated.
The reception is performed by the receiver ITS30S which has been especially developed for beacon measurements by Northwest Research Associates, Inc.
The following local Beacon receivers deliver data to IMPC: