Previous Abstract Return to Session F4 Next Abstract

Session F4: Application/Impact of PNT Technologies in the Homeland Critical Infrastructure

Use of Iridium Complementary PNT in National Critical Infrastructure
Charlie Meyer, Iridium
Location: Ballroom C
Date/Time: Monday, Jun. 1, 4:25 p.m.

National critical infrastructure has a vital dependency on GPS/GNSS for position, navigation, and timing (PNT) services. PNT is used to synchronize telecommunications, the power grid, national data centers, the stock markets, financial transactions, and many other national services and operations. PNT is also used to track vital shipments and movements of medicines, gold, persons, train and maritime cargo, etc.
A world in which GNSS is routinely degraded, disrupted, deceived, or denied impacts critical infrastructure owners and operators across multiple sectors and seriously threatens our national stability and defense. These unacceptable risks scenarios must be mitigated by Complementary PNT (CPNT) methods.
Iridium operates a constellation of Low Earth Orbit (LEO) satellites that transmit a UTC traceable CPNT signal called STL (Satellite Time and Location) over a dedicated channel operating in the Iridium band. Like Iridium communication services, the PNT signal and services are fully operational and available world-wide. Reception of the commercial Iridium PNT signal requires an STL receiver with an active STL service subscription.
The Iridium PNT service is monitored via a world-wide network of Ground Monitoring Stations (GMSs), some of which have direct access to UTC traceability from national labs; specifically, UTC(NIST), and UTC(IT), with additional GMSs with direct national labs connections planned in 2026.
The GMSs continuously monitor the accuracy of the satellite clocks and provide high-precision ephemerides and clock measurements referenced to the high precision clock references, which is uploaded to the satellite constellation via cross-linked communication channels.
STL receivers receive, demodulate, and process the messages to create localized UTC traceable time, location, and navigation solutions, with NMEA messages that are highly compatible with GPS.
The Iridium PNT service is being integrated into a growing number of national critical infrastructures. This presentation will explain the Iridium PNT services and performance with examples of some of these adaptations.

Previous Abstract Return to Session F4 Next Abstract