The U.S. National Institute of Standards and Technology (NIST) determined that Satellite Time and Location (STL) is a reliable timing source. Highly consistent with Coordinated Universal Time (UTC) and based on a signal that is independent from Global Positioning System (GPS) and other Global Navigation Satellite Systems (GNSS), STL service delivers consistent performance deep indoors beyond the reach of GNSS signals.

The agency has been working to develop non-GNSS sources of UTC and categorized STL as one of these. A recent project compared both a GPS-disciplined clock (GPSDC) and a Satelles EVK-2 evaluation unit with a comparable quartz oscillator to UTC(NIST), the national time scale in the U.S., for a 50-day period. The GPS device received its signal from an outdoor antenna while the Satelles device was connected to an antenna in a deep indoor environment the GNSS signals could not reach.

Time deviation calculations estimated the signals’ stability of each device as they relate to the UTC(NIST) time scale. The difference between the measurements of the two systems was small enough for NIST to conclude that STL stability is comparable to GNSS and can deliver the signal indoors, which GPS cannot. Averaging one day’s results, GPS instability was less than two nanoseconds, while the STL instability was slightly higher at less than three nanoseconds.

Source: NIST

STL uses satellites in low Earth orbit to deliver a positioning, navigation and timing (PNT) service to back up GPS and other GNSS. The NIST study confirmed that PNT-reliant applications provide accurate, reliable timing without GNSS.

Visit www.satelles.com for more information about STL.