GNSS and Timing: the Need for a Global PNT Infrastructure

Dr. ing. Marco Lisi

(marco.lisi@ieee.org)

International Workshop on "GNSS technologies advances in a multiconstellation framework“ SOGEI, Roma, 21-22 January 2016

What then is time?

“What then is time? If no one ask me, I know. If someone ask me to explain, I know not.” Saint Augustine of Ippo Confessions, Book XI, Chapter XIV

Summary

• Global Navigation Satellite Systems, such as GPS, GLONASS, Galileo and Beidou, constitute a worldwide utility, tightly interconnected with all other critical infrastructures, from electric power distribution systems to air traffic management systems, from railways to water and oil piping networks;

• Timing is the most strategic and essential of the services offered by GNSS’s, and the one most affecting all critical infrastructures of our society;

• The sectors most relying on GNSS’s for timing are communications (e.g. Internet, cellular networks and satellite networks), energy, financial services and transportation systems;

• The promise for a worldwide, reliable, continuous, resilient and precise timing reference is likely to lie in a worldwide, totally integrated PNT system of systems.

Where are we and where are we going? “When” are we?

Stonehenge: a prehistoric solar “clock”

Obelisks in ancient Egipt

Sundials in ancient Rome

Water and sand hourglasses

The Antikitera astronomic calculator (150–100 B.C.)

Medieval clocks (1/2)

Medieval clocks (2/2)

Cristoforo Colombo, a genius in navigation

Compass, speed log, hourglass, observation of the stars and sun, knowledge of currents and winds, and a meticulous care in the compilation of the logbook were for many centuries the basis of the "estimated navigation" ("dead reckoning"). A brilliant user of this technique, as it is clear from reading the chronicles of his journeys, was Cristoforo Colombo.

Galileo and the isochronism of the pendulum

Galileo Galilei

Christiaan Huygens and the pendulum clock

Navigation & Timing: John Harrison and the chronometer

1 second per day

Clocks accuracy evolution

The European GNSS: Galileo

Galileo FOC Satellites (OHB)

Galileo On-board Atomic Clock (Selex ES)

"Passive Hydrogen Maser" (PHM): 1 second every 3 milion years!

GNSS: a Constellation of Ultra Stable Clocks in the Sky

GNSS’s as a worldwide UTC reference

UTC: UNIVERSAL TIME COORDINATED

Penetration of GNSS Devices

Multi-constellation GNSS Timing Receivers

5G: the next wave in mobile communications

5G infrastructure architecture

5G, Internet of Things and Timing

GNSS Timing: the GPS view

GNSS Timing and Critical Infrastructures

The role of the European GNSS Agency

Galileo Time Service Provider (GTSP)

Galileo Timing Services

The European approach to a Resilient PNT Infrastructure

Miniaturized Atomic Clocks

Worldwide System of Systems Timing Infrastructure

Conclusion

• Our society has become essentially dependent on the world Positioning, Navigation and Timing infrastructure, today mainly based on GNSS’s;

• Many critical infrastructures would literally collapse in case of a total, worldwide GNSS failure, mainly because of their dependency on an exact timing reference;

• The European GNSS Agency (a.k.a. GSA) will play a vital role in making the European GNSS Galileo more resilient, service-oriented and interoperable with GPS;

• The development of non-GNSS solutions and of autonomous platforms and technologies will lead to a worldwide, totally integrated PNT system of systems, able to resolve to a large extent all present limitations and vulnerabilities.

Time is our only truly non-renewable resource