IGS Clock Working Group Charter
Chair: Michael Coleman
Website: IGS Clocks Working Group Website
Knowledge Base: IGS Clocks Working Group Knowledge Base
The “IGS/BIPM Pilot Project to Study Accurate Time and Frequency Comparisons using GPS Phase and Code Measurements” was created jointly by the International GPS Service (IGS) and the Bureau International des Poids et Mesures (BIPM) in 1998. The main goal was to investigate and develop operational strategies to exploit geodetic GPS methods for improved global availability of accurate time/frequency comparisons.
Generally, activities fell into four areas: deployment of geodetic receivers at more timing laboratories and improved installations for timing applications; extending the IGS clock products to include tracking receivers as well as satellite clocks; developing methods to accurately calibrate the internal instrumental delays in GPS tracking equipment; and promoting comparisons of geodetic clock estimates with those of independent techniques.
Given that the development goals of the IGS/BIPM Pilot Project were generally completed by 2002, it has been succeeded by this IGS Clock Products Working Group (CPWG), effective 1 January 2003. In this way, the time/frequency transfer activities of the IGS are assimilated into the regular operations of the organization. It is recognized, however, that the corresponding activity within the BIPM and the international timing community may continue for a longer period in the deployment, development, and evaluation stage. Despite this difference, continued close cooperation and interaction between the IGS and BIPM are essential and mutually beneficial. The appointment of BIPM representatives to the IGS Governing Board and to the CPWG acknowledge this importance.
Goals and Responsibilities
The Working Group is responsible for coordinating all aspects of time and frequency transfer operations within the IGS and for cooperative activities with the BIPM, timing laboratories, and other external timing organizations. The central objective is to maintain and improve the suite of IGS clock and related products, ensuring the highest quality is continuously available to the user community. The Working Group establishes appropriate conventions and standards to perform its timing functions, in close collaboration with the IGS Analysis Centers and Analysis Coordinator.
It is expected that IGS clock products will conform to internationally recognized standards to the fullest extent possible, including close alignment to the UTC/TAI time scale maintained by the BIPM. Station operators should be promptly informed of any diagnostic results that may be discerned from the clock analysis results.
In addition to the main clock products, the Working Group should provide users with all ancillary data and services needed for their full utilization. The CPWG should maintain a comprehensive, public website and should prepare all appropriate reports and other publications.
Clock Products Coordinator
The Working Group is chaired by the IGS Clock Products (CP) Coordinator, who is designated by the IGS Governing Board. The CP Coordinator is responsible for the day-to-day functions of the CPWG. The most important operational requirement is to ensure that all designated clock products are routinely generated and available to the user community, consistent with the standards and specifications established by the CPWG.
The CP Coordinator represents the IGS to external organizations in all timing matters and is a non-voting member of the IGS Governing Board.
Working Group Membership
Each IGS Analysis Center producing clock products will have a representative on the CPWG. In addition, up to six at-large members may be chosen to represent other timing interests. An IGS Central Bureau representative, the IGS Analysis Coordinator, and a representative from the BIPM Time Section are ex officio members of the CPWG.
Terms of Service
The membership of the CPWG will be reviewed and updated every four years. At that same time, the committment of the CP Coordinator to continue will be either reconfirmed or a successor will be solicited. The status of the CPWG should be reviewed by the IGS Governing Board at least every two years.
[Charter last updated December 2002]
Clock Products Working Group Members
Michael Coleman (NRL)
Gerard Petit (BIPM), Chair
Rolf Dach (AIUB)
M. Ge (GFZ)
Jake Griffiths (NGS)
Jan Kouba (NRCan)
G. Gendt (GFZ) Lahaye (NRCan)
M. Heflin (JPL)
Pascale Defraigne (ROB)
Patrizia Tavella (IEN)
Ken Senior (NRL)
Jim Ray (IGS Coord)
I. Romero (ESA/ESOC)
J. Rhode (NGS)
Kristine Larson (CU)
Larry Young (JPL)
William Bertiger (JPL)
Associate Analysis Centers involved with the Clock Products WG include all IGS ACs producing Clocks: CODE, NRCan, ESOC, GFZ, JPL, MIT, USNO
[Membership roster last updated 2013]