Pulkovo EOP and Reference Systems Analysis Center (PERSAC)

PUL VLBI Analysis Center at Pulkovo Observatory

• General Information
• Products
• PUL VLBI Analysis Center
• GNSS station PULK
• Pulkovo Observatory
• Related links
• Contact

General Information

Pulkovo EOP and Reference Systems Analysis Center (PERSAC) is located at the Pulkovo Observatory. Main PERSAC activities include:

• Processing of VLBI, GPS, and optical observations aimed at analysis of the Earth rotation, station displacement, and celestial reference system.
• Operating a permanent GNSS station PULK.
• Investigation of low-frequency variations in Earth rotation (polar motion, length of day, celestial pole motion).

Products

• Mean Pole coordinates (with prediction).

• Celestial Pole Offset (CPO) and Free Core Nutation (FCN). Four daily updated CPO and FCN series (models) are provided.

  File fcn1.dat contains the ZM1 FCN model with variable amplitude and phase. This model is provided for the period from 1984.0 to (current date minus 1.5 yr) to obtain geophysically meaningful data without significant edge effect. The IVS combined EOP series is used for computation.

  File fcn2.dat contains the ZM2 CPO model computed by smoothing the IVS combined EOP series with forward and backward prediction covering the period from 1976 to (last IVS EOP epoch plus 2 yr).

  File fcn3.dat contains the ZM3 FCN model with variable amplitude and phase computes by the methods described in the paper 2 given below. This model is provided for the period from 1986.8 to (current date minus 215 days) to obtain geophysically meaningful data without significant edge effect.

  File fcn4.dat contains the ZM4 CPO model, which is the ZM3 model with addition of the bias term.

  Files fcn2n.dat, fcn2n.dat, and fcn2n.dat contains the ZM2N, ZM3N, and ZM4N CPO models, respectively, computed similarly to ZM2, ZM3, and ZM4 models using the NEOS EOP series instead of IVS series with forward prediction covering the period from 1985 to (last NEOS EOP epoch plus 2 yr).

  The CPO models are aimed primarily at users who need the maximum accuracy of the CRF<->TRF transformation without bothering about theoretical background and geophysical meaning. The CPO models can also be used for improvement of the precession and low-frequency nutation conventional model. The FCN models are aimed primarily at users who are interested in geophysical interpretation of the observations.

  If you use these CPO and/or FCN series in your work, please cite the following papers.
  Malkin Z.M. (2007) Empiric Models of the Earth's Free Core Nutation. Solar System Research, Vol. 41, No. 6, 492-497. DOI: 10.1134/S0038094607060044
  Malkin Z. (2013) Free core nutation and geomagnetic jerks. J. of Geodynamics, Vol. 72, 53-58. DOI: 10.1016/j.jog.2013.06.001

• VLBI Intensives UT1 series in the IERS format.

Related links

• International Astronomical Union (IAU)
• International Association of Geodesy (IAG)
• International Earth Rotation and Reference Systems Service (IERS)
• International VLBI Service for Geodesy and Astrometry (IVS)
• International GNSS Service (IGS)
• International Laser Ranging Service (ILRS)
• International DORIS Service (IDS)

All the author's materials and results presented at this webpage are distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution, and reproduction in any medium or format, as long as you give appropriate credit to the original author and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Contact:   Zinovy Malkin, malkin@gaoran.ru