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Search Publications by: Andrew Novick (Fed)

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Displaying 1 - 25 of 44

Evaluating Common-View Time Transfer Using a Low-Cost Dual-Frequency GNSS Receiver

February 15, 2024
Author(s)
Aidan Montare, Andrew Novick, Jeffrey Sherman
Common-view time transfer can be performed using either single (L1) or dual (L1/L2) frequency global navigation satellite system (GNSS) signals. Using dual-frequency receivers for common-view has advantages but has historically been of significantly higher

Environmental Effects and Control Systems for GPS Disciplined Clocks (GPSDC)

May 15, 2023
Author(s)
Andrew Novick, Demetrios Matsakis, John Clark
GPSDCs are sensitive to their environment in many ways, and the susceptibility varies with different GPSDC designs. In the short term, temperature shocks can perturb the frequency of the disciplined local oscillator, causing shifts in the time output

Measurement of Transient Environmental Effects in GPS-Disciplined Clocks

January 23, 2023
Author(s)
Andrew Novick, Michael A. Lombardi, Demetrios Matsakis, John Clark
GPS-disciplined clocks (GPSDCs) are designed to optimize the accuracy and stability of their pulse-per-second (PPS) and frequency outputs by steering an internal oscillator to the timing solution from a GPS receiver based on the received satellite signals

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

January 23, 2023
Author(s)
Peter Johnson, Andrew Novick, Michael A. Lombardi
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 Resilient Architecture for the Realization and Distribution of Coordinated Universal Time to Critical Infrastructure Systems in the United States: Methodologies and Recommendations from the National Institute of Standards and Technology (NIST)

November 3, 2021
Author(s)
Jeffrey Sherman, Ladan Arissian, Roger Brown, Matthew J. Deutch, Elizabeth Donley, Vladislav Gerginov, Judah Levine, Glenn Nelson, Andrew Novick, Bijunath Patla, Tom Parker, Benjamin Stuhl, Jian Yao, William Yates, Michael A. Lombardi, Victor Zhang, Douglas Sutton
The Time and Frequency Division of the National Institute of Standards and Technology (NIST), an agency of the United States Department of Commerce (DOC), was tasked with fulfilling Section 4, Part (i) of the Position, Navigation and Timing (PNT) Executive

Improving packet synchronization in an NTP server

January 29, 2018
Author(s)
Andrew N. Novick, Michael A. Lombardi, Kevin Franzen, John Clark
A computer or dedicated client can use the Network Time Protocol (NTP) to synchronize an internal clock to a server that is synchronized by a 1 pulse-per-second (pps) signal from a national timing laboratory. Measuring an NTP server on a local area network

The effects of the January 2016 UTC offset anomaly on GPS clocks monitored at NIST

January 31, 2017
Author(s)
Jian Yao, Michael A. Lombardi, Andrew N. Novick, Bijunath Patla, Jeffrey A. Sherman, Victor S. Zhang
Errors in the Coordinated Universal Time (UTC) offset parameters broadcast by Global Positioning System (GPS) satellites caused many thousands of GPS clocks to be in error by approximately -13 µs on January 25-26, 2016. The erroneous UTC offset information

Accurate, Traceable, and Verifiable Time Synchronization for World Financial Markets

October 7, 2016
Author(s)
Michael A. Lombardi, Andrew N. Novick, George Neville-Neil, Ben Cooke
This paper describes how the National Institute of Standards and Technology (NIST), through a collaboration with Perseus, is providing accurate, traceable, and verifiable time synchronization to stock exchanges in the United States, Europe, and Asia. The

Practical Limitations of NTP Time Transfer

April 12, 2015
Author(s)
Andrew N. Novick, Michael A. Lombardi
The Network Time Protocol (NTP) is commonly utilized to synchronize computer clocks in packet-switched, wide area networks (WANs) such as the public Internet. The delay asymmetry in WANs, often due to inconsistent routing and/or bandwidth saturation, is

A Low-Cost Time Transfer Receiver for Contributions to Coordinated Universal Time

November 6, 2014
Author(s)
Michael A. Lombardi, Andrew N. Novick, Victor S. Zhang
This paper describes a low-cost time transfer receiver that allows timing laboratories, including national metrology institutes and other designated institutions, to contribute data to the computation of Coordinated Universal Time (UTC). The time transfer

Replicating UTC(NIST) at Remote Sites

November 26, 2012
Author(s)
Michael A. Lombardi, Andrew N. Novick, J. Mauricio Lopez-Romero, Rodrigo Ramos
The National Institute of Standards and Technology (NIST) is deploying disciplined oscillators that are referenced to the UTC(NIST) time scale through common-view observations of Global Positioning System (GPS) satellites. We present measurement results

Real-Time Generation of the SIM Time Scale (SIMT) from International Clock Comparisons

August 13, 2011
Author(s)
Michael A. Lombardi, Jose M. Lopez, Andrew N. Novick, Francisco Jimenez, Nelida Diaz-Munoz, Eduardo de Carlos Lopez, Jean-Simon Boulanger, Raymond Pelletier, Ricardo de Carvalho, Raul Solis, Harold Sanchez, Liz C. Forero, Junior Gordon, Daniel Perez, Eduardo Bances, Leonardo Trigo, Victor Masi, Henry Postigo, Anthony Questelles, Anselm Gittens, Rodrigo Ramos P.
The Sistema Interamericano de Metrologia (SIM) is one of the world’s five major regional metrology organizations (RMOs). The SIM members are the national metrology institutes (NMIs) located in the 34 nations of the Organization of American States (OAS)

The SIM Time Network

March 1, 2011
Author(s)
Michael A. Lombardi, Andrew N. Novick, J. Mauricio Lopez-Romero, Francisco Jimenez, Eduardo de Carlos Lopez, Jean-Simon Boulanger, Raymond Pelletier, Ricardo de Carvalho, Raul Solis, Harold Sanchez, Carlos A. Quevedo, Gregory Pascoe, Daniel Perez, Eduardo Bances, Leonardo Trigo, Victor Masil, Henry Postigo, Anthony Questelles
The Sistema Interamericano de Metrologia (SIM) is a regional metrology organization (RMO) whose members are the national metrology institutes (NMIs) located in the 34 nations of the Organization of American States (OAS). The SIM/OAS region extends

WWVB Radio Controlled Clocks: Recommended Practices for Manufacturers and Consumers (2009 edition)

September 8, 2009
Author(s)
Michael A. Lombardi, Andrew N. Novick, John P. Lowe, Matthew J. Deutch, Glenn K. Nelson, Douglas D. Sutton, William C. Yates, D. W. Hanson
Radio controlled clocks represent a true revolution in timekeeping. Clocks that synchronize to NIST radio station WWVB now number in the millions in the United States, and new sales records are being established every year. As a result, many of us are now

The SIM Time and Frequency Network

December 1, 2008
Author(s)
Michael A. Lombardi, Andrew N. Novick, Jose M. Lopez, Francisco Jimenez, Jean-Simon Boulanger, Raymond Pelletier, Ricardo de Carvalho, Raul Solis, Carlos Donado, Harold Sanchez, Carlos A. Quevedo, Gregory Pascoe, Daniel Perez
The Sistema Interamericano de Metrologia (SIM) consists of national metrology institutes (NMIs) located in the 34 member nations of the Organization of American States (OAS), which extends throughout North, Central, and South America, and the Caribbean

The SIM Network: Improved Time Coordination for North, Central, and South America

April 23, 2008
Author(s)
Jose M. Lopez, Michael A. Lombardi, Andrew Novick, Jean-Simon Boulanger, R. de Carvalho, R. Solis, Francisco Jimenez
The Sistema Interamericano de Metrologia (SIM) consists of national metrology institutes (NMIs) located in the 34 member nations of the Organization of American States (OAS), which extends throughout North, Central, and South America, and the Caribbean

Effects of the Rooftop Environment on GPS Time Transfer

December 5, 2006
Author(s)
Michael A. Lombardi, Andrew N. Novick
We examine the effects of the rooftop environment on GPS time transfer, in particular the effects of multipath reflections from nearby metallic objects. Three different antennas sites were selected on the roof of the NIST laboratories at Boulder, Colorado

Time Coordination Throughout the Americas via the SIM Common-View GPS Network

December 5, 2006
Author(s)
Michael A. Lombardi, Andrew N. Novick, Jose M. Lopez, Jean-Simon Boulanger, Carlos Donado
The Sistema Interamericano de Metrologia (SIM) consists of national metrology institutes (NMIs) located in all 34 member nations of the Organization of American States (OAS), which extends throughout North, Central, and South America, and the Caribbean