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Publications related to Activities of the Working Group (listed by topic area)


SIM Time Network (SIMTN) and SIM Time Scale (SIMT)

  • J. M. Lopez-Romero, N. Diaz-Munoz, E. de Carlos-Lopez, M. A. Lombardi, M. Gertsvolf, and R. de Carvalho, "Improvements in SIM Time Network and SIM Time Scale Performance," Proceedings of the 2014 Simposio de Metrologia, Querétaro, Mexico, 6 p., October 2014.

  • J. M. López-Romero, M. A. Lombardi, N. Díaz-Muñoz, and E. de Carlos-Lopez, "Improved Performance, Remote Realization, and Accessibility of the Inter-American Metrology System (SIM) Time Scale," Proceedings of the 2014 NCSL International Workshop and Symposium, Orlando, Florida, 22 p., July 2014.

  • J. M. López-Romero, M. A. Lombardi, N. Díaz-Muñoz, and E. de Carlos-Lopez, "SIM Time Scale," IEEE Transactions on Instrumentation and Measurement, vol. 62, no. 12, pp. 3343-3350, December 2013.

  • J. M. López-Romero, M. A. Lombardi, N. Díaz-Muñoz, and E. de Carlos-Lopez, "A new algorithm for clock weights for the SIM Time Scale," Proceedings of the 2012 Simposio de Metrologia, Querétaro, Mexico, 6 p., October 2012.

  • J. M. López-Romero, M. A. Lombardi, N. Díaz-Muñoz, and E. de Carlos-Lopez, "International time and frequency comparisions in real time: recent results," IEEE Conference on Precision Electromagnetic Measurements (CPEM) Digest, pp. 694-695, July 2012.

  • J. M. López-Romero, M. A. Lombardi, and N. Díaz-Muñoz, "Automated Clock Comparisions and Time Scale Generation in the SIM Region," MAPAN: The Journal of the Metrology Society of India, vol. 27, no. 1, pp. 49-53, April 2012.

  • J. M. López-Romero, M. A. Lombardi, A. N. Novick, F. Jimenez, N. Díaz-Muñoz, E. de Carlos-Lopez, J. S. Boulanger, R. Pelletier, R. de Carvalho, R. Solis, H. Sanchez, L. C. Hernandez Forero, J. Gordon, D. Perez, E. Bances, L. Trigo, V. Masi, H. Postigo, A. Questelles, A. Gittens, and R. Ramos, "Real-Time Generation of the SIM Time Scale (SIMT) from International Clock Comparisons," Proceedings of the XXXth General Assembly of the International Union of Radio Science (URSI), 4 p., August 2011.

  • M. A. Lombardi, A. N. Novick, J. M. López-Romero, F. Jimenez, E. de Carlos-Lopez, J. S. Boulanger, R. Pelletier, R. de Carvalho, R. Solis, H. Sanchez, C. A. Quevedo, G. Pascoe, D. Perez, E. Bances, L. Trigo, V. Masi, H. Postigo, A. Questelles, and A. Gittens, "The SIM Time Network," NIST Journal of Research, vol. 116, no. 2, pp. 557-572, March-April 2011.

  • J. M. López-Romero, M. A. Lombardi, and N. Díaz-Muñoz, "SIM Time Scales," Proceedings of the 2010 Simposio de Metrologia, Querétaro, Mexico, 8 p., October 2010.

  • J. M. López-Romero and M. A. Lombardi, "The Development of a Unified Time and Frequency Program in the SIM Region," NCSLI Measure: The Journal of Measurement Science, vol. 5, no. 3, pp. 30-36, September 2010.

  • J. M. López-Romero, N. Díaz-Muñoz, and M. A. Lombardi, "Establishment of the SIM Time Scale," INFOSIM: Informative Bulletin of the Interamerican Metrology System - OAS, pp. 39-43, August 2009.

  • M. A. Lombardi, "The SIM Time Network and its Contributions to Metrology in the Americas," Metrologist: NCSLI Worldwide News, pp. 16-21, April 2009.

  • M. A. Lombardi, A. N. Novick, J. M. López-Romero, F. Jimenez, J. S. Boulanger, R. Pelletier, R. de Carvalho, R. Solis, C. Donado, H. Sanchez, C. A. Quevedo, G. Pascoe, and D. Perez, "The SIM Time and Frequency Network," INFOSIM: Informative Bulletin of the Interamerican Metrology System - OAS, pp. 15-25, December 2008.

  • J. M. López-Romero, N. Díaz-Muñoz, and M. A. Lombardi, "Establishment of the SIM Time Scale," Proceedings of the 2008 Simposio de Metrologia, Querétaro, Mexico, 5 p., October 2008.

  • J. M. López-Romero, M. A. Lombardi, A. N. Novick, J. S. Boulanger, R. de Carvalho, R. Solis, and F. Jimenez, 2008, "The SIM Network: Improved Time Coordination for North, Central, and South America," Proceedings of the 22nd European Frequency and Time Forum (EFTF), 9 p., April 2008.

  • M. A. Lombardi, A. N. Novick, J. M. López-Romero, J. S. Boulanger, R. Pelletier, and C. Donado, "Time Coordination Throughout the Americas via the SIM Common-View GPS Network," Proceedings of the 38th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting, pp. 427-437, December 2006.

  • J. M. López-Romero, M. A. Lombardi, A. N. Novick, J. S. Boulanger, R. Pelletier, and C. Donado, "SIM Time and Frequency Comparison Network in Near Real Time," Proceedings of the 2006 Simposio de Metrologia, Querétaro, Mexico, 5 p., October 2006.

  • M. A. Lombardi, A. N. Novick, J. M. López-Romero, J. S. Boulanger, and R. Pelletier, "The Interamerican Metrology System (SIM) Common-View GPS Comparison Network," Proceedings of the Joint 2005 IEEE Frequency Control Symposium and Precise Time and Time Interval (PTTI) Systems and Applications Meeting, pp. 691-698, August 2005.

    Calibrations (Frequency)

  • C. A. Quevedo-Fernandez and L. C. Hernandez-Forero, "Comparador de Fase de Hasta Ocho Señales de Reloj (frecuencia) Simultáneas," National Instruments Case Study 12036, 4 p., 2009.

  • C. A. Quevedo-Fernandez and L. C. Hernandez-Forero, "Automatic Phase Comparison with the Legal Colombian Standard Clock Frequency Signal," National Instruments Case Study 14396, 4 p., 2009.

    Calibrations (Remote)

  • L. Hernández-Huerta, J. M. López-Romero, S. López-López, E. de Carlos-López, and F. Jiménez-Tapia, "Red de Comparación de Relojes Atómicos de Cesio en Telmex," Proceedings of the 2008 Simposio de Metrologia, Querétaro, Mexico, 5 p., October 2008.

  • M. A. Lombardi and A. N. Novick, "Remote Time Calibrations via the NIST Time Measurement and Analysis Service," NCSLI Measure: The Journal of Measurement Science, vol. 1, no. 4, pp. 50-59, December 2006.

    Calibrations (Stopwatches and Timers)

  • H. Diaz and L. Palma, "Medición de la base de tiempo del cronómetro digital por el método de inducción," Proceedings of 2015 SEMETRO Conference, Rio Grande do Sul, Brazil, 4 p., November 2015.

  • O. Fallas-Cordero, I. Castro-Blanco, and H. Sánchez, "Comparación interlaboratorial de cronómetros 2014," Tecnología en Marcha, vol. 28, no. 3, pp. 64-73, July-September 2015.

  • H. Diaz and H. Postigo, "Calibración de cronómetros digitales por el método de inducción con una incertidumbre de medición ≤ 0,1 μs/s," Proceedings of 2013 SEMETRO Conference, Buenos Aires, Argentina, 4 p., September 2013.

  • L. M. Mojica and R. F. Solis, "Error de Tiempo en Cronometros Digitales en Base a Mediciones de Intervalo de Tiempo y Frecuencia," Proceedings of 2011 SEMETRO Conference, Natal, Brazil, 8 p., September 2011.

  • L. M. Mojica and R. F. Solis, "Sistema de Bajo Costo Para Calibracion Automatizada de Cronometros Digitales," Proceedings of 2011 SEMETRO Conference, Natal, Brazil, 4 p., September 2011.

  • R. F. Solis, L. M. Mojica, H. Sanchez, O. G. Fallas, J. M. López-Romero, F. Jiménez, H. Diaz, H. Postigo, D. Perez, W. Adad, V. Masi, A. Ibrahim, M. A. Lombardi, B. Hoger, R. de Carvalho, J. L. M. Kronenberg, G. C. Orozco, T. Reddock, D. Slomovitz, and L. Trigo, "An Interlaboratory Stopwatch Comparision in the SIM Region," NCSLI Measure: The Journal of Measurement Science, vol. 6, no. 3, pp. 56-62, September 2011.

  • J. Jiménez and H. Sánchez, "Calibracion de Cronometros Mediante la Medicion de la Frequencia del Oscilador de Cuarzo," Proceedings of 2009 SEMETRO Conference, João Pessoa, Paraíba, Brazil, 3 p., June 2009.

  • J. Jiménez, "Sistema automatizado de calibración de cronómetros y relojes mediante la medición de la frecuencia de operación del oscilador interno," Instituto Tecnológico de Costa Rica, 147 p., February 2009.

  • J. C. Gust, R. M. Graham, and M. A. Lombardi, "Stopwatch and Timer Calibrations," NIST Special Publication 960-12, 66 p., January 2009.

  • L. Trigo and D. Slomovitz, "Calibración de cronómetros digitales por método de inducción," IEEE Encuentro de Energía, Potencia, Instrumentación y Medidas, Montevideo, Uruguay, pp. 21-23, October 2008.

    Calibrations (Stroboscopes)

  • H. Diaz and L. Palma, "Calibración de estroboscopios utilizando un sistema de medición de frecuencias," Proceedings of the 2016 Simposio de Metrologia, Querétaro, Mexico, 2 p., September 2016.

    Calibrations (Tachometers)

  • L. C. Hernandez and N. Bahamon, "Estimacion de Incertidumbre en La Calibracion de Tacometros Opticos," Revista de Fisica, no. 52, pp. 68-82, June 2016.

  • H. Diaz and L. Palma, "Calibration of optical tachometers using a generator system of light pulses," IEEE Conference on Precision Electromagnetic Measurements (CPEM) Digest, Rio de Janeiro, Brazil, 2 p., August 2014.

    Disciplined Clocks and Oscillators

  • M. A. Lombardi, J. M. López-Romero, and N. Díaz-Muñoz, "Automated Control of National Time Standards via the SIM Time Scale," Proceedings of 2013 SEMETRO Conference, Buenos Aires, Argentina, 4 p., September 2013.

  • M. A. Lombardi, A. N. Novick, J. M. López-Romero, and R. Ramos, "Replicating UTC(NIST) at Remote Sites," Proceedings of the 44th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting, pp. 79-90, December 2012.

  • L. Trigo and D. Slomovitz, "Long Term Experimental Results of a Rubidium Atomic Clock with Drift Compensation," Proceedings of 2011 SEMETRO Conference, Natal, Brazil, 3 p., September 2011.

  • M. A. Lombardi, "A NIST Disciplined Oscillator: Delivering UTC(NIST) to the Calibration Laboratory," NCSLI Measure: The Journal of Measurement Science, vol. 5, no. 4, pp. 46-54, December 2010.

  • M. A. Lombardi and A. P. Dahlen, "A common-view disciplined oscillator," Review of Scientific Instruments, vol. 81, no. 5, p. 055110, May 2010.

    Network Time Protocol (NTP)

  • A. N. Novick and M. A. Lombardi, "A comparison of NTP servers connected to the same reference clock and the same network," Proceedings of the 48th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting, pp. 264-270, January 2017.

  • Raúl Fernando Solís Betancur, "Servicio de Diseminación de Tiempo Por Red en el CENAMEP AIP," Proceedings of the 2016 Simposio de Metrologia, Querétaro, Mexico, 2 p., September 2016.

  • A. N. Novick and M. A. Lombardi, "Practical Limitations of NTP Time Transfer," Proceedings of the Joint 2015 IEEE Frequency Control Symposium and the European Frequency and Time Forum (EFTF), pp. 570-574, April 2015.

  • M. A. Lombardi, J. Levine, J. M. López-Romero, F. Jiménez, J. Bernard, M. Gertsvolf, H. Sanchez, O. G. Fallas, L. C. Hernández Forero, R. J. de Carvalho, M. N. Fittipaldi, R. F. Solis, and F. Espejo, "International Comparisons of Network Time Protocol Servers," Proceedings of the 46th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting, pp. 57-66, December 2014.

  • F. J. Jimenez-Tapia and J. M. López-Romero, "Sincronization de la Hora Oficial con Servidor NTP CRONOS del CENAM," Proceedings of the 2012 Simposio de Metrologia, Querétaro, Mexico, 6 p., October 2012.

    Satellite Time Transfer

  • D. Luna, D. Perez, A. Cifuentes, and D. Gomez, "Three-Cornered Hat Method via GPS Common-View Comparisons," IEEE Transactions on Instrumentation and Measurement, vol. 66, no. X, pp. xx-xx, 2017.

  • J. Yao, M. A. Lombardi, A. N. Novick, B. Patla, J. A. Sherman, and V. Zhang, "The effects of the January 2016 UTC Offset anomaly on GPS-controlled clocks monitored at NIST," Proceedings of the 48th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting, pp. 155-163, January 2017.

  • D. Luna, D. Perez, F. Palacios, and A. Cifuentes, "Análisis de estabilidad en relojes atómicos por medio de la técnica Vista Común GPS," ANALES AFA, vol. 27, no. 2, pp. 73-78, February 2016.

  • M. A. Lombardi, A. N. Novick, and V. S. Zhang, "A Low-Cost Time Transfer Receiver for Contributions to Coordinated Universal Time," NIST Journal of Research, vol. 119, pp. 583-601, November 2014.

  • M. A. Lombardi, V. S. Zhang, and R. de Carvalho, "Long Baseline Comparisons of the Brazilian National Time Scale to UTC(NIST) Using Near Real-Time and Post-Processed Solutions," Proceedings of the 39th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting, pp. 415-426, November 2007.

    Stock Market Synchronization

  • J. Bernard, A. Charbonneau, B. Hoger, H. Pham, and M. Gertsvolf, "NRC Remote Clock - A Secure and Traceable Time Source," Proceedings of the 48th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting, pp. 73-79, January 2017.

  • M. A. Lombardi, A. N. Novick, G. Neville-Neill, and B. Cooke, "Accurate, Traceable, and Verifiable Time Synchronization for World Financial Markets," NIST Journal of Research, vol. 121, pp. 436-463, October 2016.

    Time Scales, Time Transfer, and Time Dissemination (General)

  • Raúl Fernando Solís Betancur, "Desarrollo de un Sistema Para la Gestión de la Información para el Laboratorie Primario de Tiempo y Frecuencia," Proceedings of the 2016 Simposio de Metrologia, Querétaro, Mexico, 2 p., September 2016.

  • J. M. López-Romero and M. A. Lombardi, "Timekeeping in the Americas," Revista Mexicana de Astronomía y Astrofísica (Serie de Conferencias), vol. 46, pp. 1-6, October 2015.

  • R. F. Solis and L. M. Mojica, "Application of SIMT and UTCr timescales for the maintenance of the Universal Time Coordinated in Panama," Proceedings of the 2014 IEEE Central America and Panama Convention (CONCAPAN XXXIV), Panama City, Panama, 5 p., November 2014.

  • R. F. Solis and L. M. Mojica, "Establecimiento y Evolucion de la Metrologia de Tiempo y Frecuencia en Panama," Proceedings of the 2012 Simposio de Metrologia, Querétaro, Mexico, 6 p., October 2012.

  • R. F. Solis, "Desarrollo del Tiempo Universal Coordinado en Panamá," RIDTEC, vol. 8, no. 1, pp. 16-25, July 2012.

  • R. F. Solis and L. M. Mojica, "Realizacion y Mantenimiento de la Hora UTC Panama," INFOSIM: Informative Bulletin of the Interamerican Metrology System - OAS, pp. 1-9, June 2011.

  • M. A. Lombardi and V. Zhang, "Distributing UTC(NIST) to Industrial Time and Frequency Users," Proceedings of the 2009 Encuentro Nacional de Metrologia Electrica (ENME), Querétaro, Mexico, 5 p., November 2009.

  • V. Zhang and M. A. Lombardi, "Time and Frequency Transfer Activities at NIST," Proceedings of the 40th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting, pp. 623-639, November 2008.

  • J. M. López-Romero and N. Díaz-Muñoz, "Progress in the generation of the UTC(CNM) in terms of a virtual clock," Metrologia, vol. 45, pp. S59-S65, December 2008.



    Software for Time and Frequency Data Analysis


  • AMTyF Software (Analisis de Mediciones de Tiempo y Frecuencia), developed by Francisco J. Jimenez Tapia of CENAM with the menus in Spanish. This software is useful for the graphing and analysis of frequency and phase data, and also for stability analysis using the Allan deviation. It runs on Windows XP and earlier versions of Windows, but not yet with Vista. To install the software, extract all of the contents of the ZIP file to a folder on your hard drive, and then run the SETUP.EXE program.