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Displaying 26 - 50 of 86

Long-Term Uncertainty in Time Transfer Using GPS and TWTFT Techniques

April 13, 2015
Author(s)
Victor S. Zhang, Thomas E. Parker, Jian Yao
The techniques of GPS time and frequency transfer (code based and carrier phase) and two-way satellite time and frequency transfer (TWSTFT) are widely used in remote clock comparison and in the computation of International Atomic Time (TAI). Many timing

Measured Ionosphere Delay Correction for Code-Based GPS Time Transfer

December 4, 2014
Author(s)
Victor S. Zhang, Zhiqi Li
Nowadays, more and more dual-frequency, multichannel receivers are used in GPS time and frequency transfer applications. Instead of using the modeled ionosphere delay correction or using the IGS ionospheric map, we can obtain the ionosphere delay

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

A Study of the Diurnal in the Transatlantic TWSTFT Difference

September 7, 2013
Author(s)
Victor S. Zhang, Thomas E. Parker
The daily variation (diurnal) in the two-way satellite time and frequency transfer (TWSTFT) difference is one of the most significant instabilities of the TWSTFT technique. The diurnal comes from the daily delay change of the TWSTFT signal paths. In recent

Enabling accurate differential calibration of modern GPS receivers

November 26, 2012
Author(s)
Stefania Romisch, Victor S. Zhang, Thomas E. Parker, Steven R. Jefferts
The difference between the local time reference and a GNSS receiver's internal time base is an essential contributor to the calibration of that receiver when used as a timing device. In the past, in the absence of a PPS output signal provided by the

Measurement of the velocity of the neutrino with MINOS

November 26, 2012
Author(s)
Stefania Romisch, P Adamson, Neil Ashby, G. Barr, M. Bishal, A. Blake, G. J. Bock, D. Bogert, Russell Bumgarner, S. V. Cao, S. Childress, M. Christensen, J. Coelho, L. Corwin, D. Cronin-Hennessy, J. K. de Jong, N. E. Devenish, M. V. Diwan, C. O. Escobar, J. J. Evans, E. Falk, G. J. Feldman, C. Flores, Blair Fonville, M. V. Frohne, H. R. Gallager, A. Gavrilenko, R. A. Gomes, P. Gouffon, N. Graf, R. Gran, K. Grzelak, A. Habig, J. Hartnell, R. Hatcher, Jonathan Hirschauer, A. Holin, J. Hylen, G M. Irwin, Z. isvan, C. James, Steven R. Jefferts, D. Jensen, T. Kafka, S. M. Kasahara, G. Koizumi, M. Kordosky, A. Kreymer, K. Lang, J. Ling, P. J. Litchfield, P. Lucas, W. A. Mann, M. L. Marshak, M. Mathis, Demetrios Matsakis, N. Mayer, Angela Mckinley, M. M. Medeiros, R. Mehdiyev, J. R. Meier, B. Mercurio, M. D. Messier, W. H. Miller, S. R. Mishra, S. Moed Sher, C. D. Moore, L. Mualem, J. A. Musser, J. K. Nelson, H. Newman, R. J. Nichol, J. A. Nowak, J. C. O'Conner, W. P. Oliver, M. Orchanian, R. B. Pahlka, J. Paley, Thomas E. Parker, R. B. Patterson, G. Pawloski, S. PhanBudd, R. K. Plunkett, N. Poonthattatil, Ed Powers, X. Qiu, A. Radovic, B. Rebel, C. Rosenfeld, H. A. Rubin, M. C. Sanchez, J. Schneps, P Schireiner, A. Schreckenberger, R. Sharma, A, Sousa, N. Tagg, R, L. Talaga, J. Thomas, M. A. Thomson, X. Tian, S. C. Tognini, R. Toner, D. Torretta, G. Tzanakos, J. Urheim, P. Vahel, A. Webber, R. C. Webb, C. White, L. H. Whitehead, L. Whitehead, K. P. Wilson, S. G. Wojcicki, J. Wright, Victor S. Zhang, R. Zwaska
The MINOS experiment uses a beam of predominantly muon-type neutrinos generated using protons from the Main Injector at Fermilab in Batavia, IL and travelling 735 km through the Earth to a disused iron mine in Soudan, MN. The 10 us-long beam pulse contains

Recent Calibrations of UTC(NIST) and UTC(USNO)

November 26, 2012
Author(s)
Victor S. Zhang, Thomas E. Parker, Russell Bumgarner, Jonathan Hirschauer, Angela Mckinley, Stephen Mitchell, Ed Powers, Jim Skinner, Demetrios Matsakis
The National Institute of Standards and Technology (NIST) and the United States Naval Observatory (USNO) use GPS common-view, carrier-phase time transfer and Two Way Satellite Time and Frequency Transfer (TWSTFT, also known as TWSTT) techniques in our time

Synchronization between remote sites for the MINOS experiment

November 26, 2012
Author(s)
Stefania Romisch, Steven R. Jefferts, Victor S. Zhang, Thomas E. Parker, Neil Ashby, P Adamson, G. Barr, A. Habig, J Meier, C. James, R. Nicol, R. Plunkett, C. Rosenfeld, Russell Bumgarner, M. Christensen, Jonathan Hirschauer, Blair Fonville, Demetrios Matsakis, Ed Powers, J. Wright, Angela Mckinley
In the context of time-of-flight measurements, the timing at the departure and arrival locations is obviously critical to the outcome of the experiment. In the case of neutrino time-of-flight experiments, the locations are many hundreds of kilometers apart

Coordinating GPS Calibrations Among NIST, NRL, USNO, PTB, and OP

July 31, 2011
Author(s)
Marc A. Weiss, Victor S. Zhang, J White, K Senior, Demetrios Matsakis, S. Mitchell, P Uhrich, D Valat, W Lewandowski, G. Petit, Andreas Bauch, T. Feldman, A. Proia
Reviewing calibration results over the history since early 1980’s among several labs shows very mixed results. The best stabilities of receivers, as given by calibrations, are of the order of a few ns or better over a year, though many results are quite a

Distributing UTC(NIST) to Industrial Time and Frequency Users

November 18, 2009
Author(s)
Michael A. Lombardi, Victor S. Zhang
The National Institute of Standards and Technology (NIST) maintains one of the world s most accurate and stable time scales, UTC(NIST), as well as the NIST-F1 cesium fountain, the primary frequency standard for the United States. These standards are

Two-Way Satellite Time and Frequency Transfer Using 1 MChip/S codes

November 16, 2009
Author(s)
Victor S. Zhang, Thomas E. Parker, Demetrios Matsakis, Joseph Achkar, Daniele Rovera, Dirk Piester, Andreas Bauch, Luca Lorini
The Ku-band transatlantic and Europe to Europe two-way satellite time and frequency transfer (TWSTFT) operations used the 2.5 MChip/s pseudo-random codes with 3.5 MHz bandwidth until the end of July, 2009. The cost of TWSTFT operation is associated with