Measuring the Timing Accuracy of Satellite Time and Location (STL) Receivers

Published

January 23, 2023

Author(s)

Peter Johnson, Andrew Novick, Michael A. Lombardi

Abstract

We present measurements of the timing accuracy and stability of Satellite Time and Location (STL) receivers with respect to UTC(NIST), the coordinated universal time scale (UTC) operated by the National Institute of Standards and Technology (NIST). STL is a mature timing and location service provided by Satelles that utilizes the Iridium constellation of 66 low Earth orbit (LEO) satellites. The service is fully operational and available anywhere in the world and is resilient to regional outages of the Global Positioning System (GPS). We demonstrate that a typical STL receiver with an oven-controlled crystal oscillator (OCXO) can provide a stable output pulse with an average time offset near 10 ns and a maximum time offset of less than 200 ns with respect to UTC(NIST). We also present measurements of an STL receiver with a local rubidium oscillator that demonstrates improved short-term stability and a maximum time offset of less than 75 ns.

Proceedings Title

Proceedings of the 2023 Precise Time and Time Interval (PTTI) Meeting

Conference Dates

January 23-26, 2023

Conference Location

Long Beach, CA, US

Conference Title

2023 Precise Time and Time Interval Meeting

Pub Type

Conferences

Download Paper

Local Download

Keywords

GPS, low-earth orbit satellites (LEO), Satellite Time and Location Service (STL), time transfer

Citation

Johnson, P. , Novick, A. and Lombardi, M. (2023), Measuring the Timing Accuracy of Satellite Time and Location (STL) Receivers, Proceedings of the 2023 Precise Time and Time Interval (PTTI) Meeting, Long Beach, CA, US, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=936181 (Accessed October 8, 2025)