Reference

Glossary

CRPA(Controlled Reception Pattern Antenna)
An antenna that spatially filters out interference.
eLoran(enhanced Long-Range Navigation)
A terrestrial, high-power, GNSS-independent PNT system; a leading resilience alternative.
GNSS(Global Navigation Satellite System)
The generic term for all satellite constellations (GPS, Galileo, GLONASS, BeiDou). GPS is one GNSS.
GPS(Global Positioning System)
The United States satellite navigation system; the most widely used GNSS. One of several GNSS constellations.
Grandmaster clock
The device distributing precise time across a network, usually disciplined by GNSS.
Holdover
How long a clock stays accurate after losing its reference signal.
Jamming
Drowning genuine satellite signals in radio noise so receivers cannot use them.
PNT(Positioning, Navigation and Timing)
The three services derived from satellite signals, underpinning far more of modern infrastructure than navigation alone.
PTP / NTP(Precision Time Protocol / Network Time Protocol)
How time moves through networks. PTP for microsecond-class needs, NTP for general use.
RTS 25
The MiFID II technical standard on clock synchronisation for trading venues and firms.
Spoofing
Broadcasting counterfeit satellite signals so receivers report false position or time without error.
Traceable time
Time provably linked, through an unbroken documented chain, to UTC. The regulatory standard.
UTC(Coordinated Universal Time)
The global reference timescale.