Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by:

Displaying 26 - 43 of 43

Time and Frequency Transfer Activities at NIST

December 1, 2008

Author(s)

Victor S. Zhang, Michael A. Lombardi

The National Institute of Standards and Technology (NIST) maintains one of the world s most accurate and stable time scales, and also developed and maintains the primary frequency standard for the United States. Various techniques are used to compare the

Long Baseline Comparisons of the Brazilian National Time Scale to UTC(NIST) Using Near Real-Time and Post Processed Solutions

November 27, 2007

Author(s)

Michael A. Lombardi, Victor S. Zhang, Ricardo de Carvalho

We present the results of C/A code common-view GPS comparisons between the UTC(NIST) time scale, located at the National Institute of Standards and Technology (NIST) in Boulder, Colorado, and the Brazilian national time scale, UTC(ONRJ), located at the

Long-term Stability of Remote Clock Comparisons with IGS Clock Products

November 27, 2007

Author(s)

Victor S. Zhang, Thomas E. Parker, Marc A. Weiss

The International GNSS Service (IGS) clock products contain clock information of the local reference for the IGS tracking receivers with respect to the IGS time. The clock information is obtained from GPS carrier-phase measurements. Many timing

Estimate the Receiver Delay for Ionosphere-Free code (P3) GPS Time Transfer

January 1, 2007

Author(s)

Victor S. Zhang

Estimating the Receiver Delay for Ionosphere-Free Code (P3) GPS Time Transfer

December 5, 2006

Author(s)

Victor S. Zhang

The ionosphere-free code (P3) GPS time transfer uses the dual-frequency measurements from GPS geodetic receivers to minimize the errors in the ionospheric delay correction. The P3 GPS time transfer requires the knowledge of the receiver delays on both the

Characterizing the Performance of GPS Disciplined Oscillators with Respect to UTC(NIST)

August 29, 2005

Author(s)

Michael A. Lombardi, Andrew N. Novick, Victor S. Zhang

Global Positioning System Disciplined Oscillators (GPSDOs) are now the primary standard of time and frequency at many laboratories and calibration facilities. They are generally treated as self-calibrating standards, and their users generally assume that

Sources of Instabilities in Two-Way Time Transfer

August 29, 2005

Author(s)

Thomas E. Parker, Victor S. Zhang

Two-Way Satellite Time and Frequency Transfer (TWSTFT) has become an important component in the international system for comparing time and frequency over long distances. In order to make further improvements in the stability of TWSTFT a more complete