Technical description of session EOP solution gsfint22 15-NOV-2007 1. Purpose of solution: Determination of UT1 from short, 1.0 -- 1.5 hours, NEOS Intensive VLBI sessions. 2. Analysis center: GSF (NASA Goddard Space Flight Center). 3. Short narrative description of solution: Solution gsfint22 is for the estimation of UT1 from the 1-hour NEOS Intensive experiments. Each session consists of ~12-30 observations on one baseline: NRAO20/WETTZELL before 2000.07.02 and KOKEE/WETTZELL after. The TSUKUB32-WETTZELL intensives are now included in the intensive series. Each session was processed independently. The solution includes all Intensive sessions from 1991.10.01 through 2007.11.09, a total of 3878 sessions. 4. Estimated parameters: -- UT1 angle. -- Atmosphere path delay offset at each station. -- Coefficients of the second order polynomials of clock function. 5. Celestial reference frame: a. A priori source positions: /500/solutions/2007d/2007d_aposteriori.src. This catalog was created in the gsf2007d solution. b. Source positions adjusted in solution: No 6 - Terrestrial reference frame: a. A priori station positions: /500/solutions/2007d/2007d_aposteriori.sit. This catalog was created in the gsf2007d solution. b. A priori station velocities: /500/solutions/2007d/2007d_aposteriori.src. This catalog was created in the gsf2007d solution. c. Reference epoch: 1997.0. d. Station positions/velocities adjusted in solution: No. j. Relativity scale: The terrestrial reference frame is defined using the following metric tensor: G_oo = -(1 - (2W/c^2 + W^2/c^4) + 2L_g ) G_oa = -4W^a/c^3 G_ab = \delta_ab (1 + 2W/c^2 - 2L_g) ) Specifically the old formula 29 in IERS Conventions 1992, page 127-136 was used, although it is known to have a deficiency. THIS METRIC TENSOR DOES NOT CONFORM TO IAU 2000 RESOLUTIONS! k. Permanent tide correction: Yes. "Yes" means that both the permanent and the periodic tides have been modeled, so that the output station position is for after the removal of both the permanent and the periodic tidal effect. The model used includes tide displacements for zero frequency with Love numbers h2(freq=0) = 0.6078, l2(freq=0) = 0.0847 7. Earth orientation: a. A priori precession model: IAU200A Precession-Nutation, IERS 2003 [4] implementation. b. A priori nutation model: IAU2000A Precession-Nutation, IERS 2003 [4] implementation. c. A priori short-period tidal variations in X, Y, UT1 were computed using the hf1102a model, presented in Appendix A. d. EOP estimation: UT1 (without any constraints). e. A priori UT1 and polar motion usno_finals.data http://gemini.gsfc.nasa.gov/solve_save/usno_finals.erp obtained by adding small linear shift and drift to the left columns of original finals.data file generated by USNO, ftp://maia.usno.navy.mil/ser7/finals.data in such a manner that there is no shift or secular drift with respect to the gsf2007d.eops series over the period 2000.1 -- present. 8. A priori geophysical models: a. Troposphere: NMF dry mapping function; Saastamoinen zenith delay calculated using logged pressure, temperature; a priori mean gradients from VLBI data or DAO weather model. b. Solid Earth tide: IERS Conventions 2003 [4], chapter 7, p. 9, steps 1 and 2, including tides of the 2-nd and 3-rd order. c. Ocean loading: 3D ocean loading displacements computed by SPOTL software. The model of displacements caused by ocean loading contains 18 constituents. The following ocean tide models were used: Harmonic Frequency rad/sec Model k2-a 1.324501D+00 1.458530140651D-04 GOT00 admittance k2 3.506941D+00 1.458423171028D-04 GOT00 s2 6.283185D+00 1.454441043329D-04 GOT00 s2-a 4.312500D-02 1.452450074576D-04 GOT00 admittance m2 2.169437D+00 1.405189027044D-04 GOT00 m2-a 1.210284D+00 1.405082057420D-04 GOT00 admittance n2 6.097067D+00 1.378796996516D-04 GOT00 k1-a 1.141827D+00 7.293185551375D-05 GOT00 admittance k1 3.324267D+00 7.292115855138D-05 GOT00 k1-b 2.365113D+00 7.291046158901D-05 GOT00 admittance p1 2.958919D+00 7.252294578148D-05 GOT00 p1-a 3.002044D+00 7.232384890619D-05 GOT00 admittance o1 5.128356D+00 6.759774415297D-05 GOT00 o1-a 1.027610D+00 6.758704719061D-05 GOT00 admittance q1 2.772800D+00 6.495854110023D-05 GOT00 q1-a 4.955240D+00 6.494784413786D-05 GOT00 admittance mtm-a 4.652212D+00 7.973314413516D-06 NAO99.l admittance mtm 5.514660D-01 7.962617451151D-06 NAO99.l mf-a 2.296657D+00 5.334111360775D-06 NAO99.l admittance mf 4.479096D+00 5.323414398410D-06 NAO99.l msf 9.721550D-01 4.925201628510D-06 NAO99.l mm 5.497148D+00 2.639203052741D-06 NAO99.l msm 4.899785D+00 2.285998575769D-06 NAO99.l ssa 3.653480D-01 3.982127698995D-07 NAO99.l paw 5.012885D+00 1.991063797295D-07 equilibrium sa 3.098467D+00 1.990968752920D-07 NAO99.l pcw 2.003605D+00 1.671771314171D-07 equilibrium 18.6 4.100746D+00 1.069696236521D-08 equilibrium d. Pole tide: Mean pole coordinates used for computation of pole tide deformation were set to the IERS 2003 Conventions [4] recommended values (Chapter 7, p. 15). e. Mean site gradients were computed from the GSFC Data Assimilation Office (DAO) model for met data from 1990-95. The atmospheric gradient delay is modeled as: tau = m_grad(el) * [GN*cos(az)+GE*sin(az)], where el and az are the elevation and azimuth of the observation and the gradient mapping function is m_grad. The gradient vector has East and North components GE and GN. Refer to [1], [2]. 9. Data type: Group delays. 10. Data editing: Manual, elevation cutoff 5 degrees. 11. Data weighting. Weights are defined as follows: 1/sqrt ( f**2 + a**2 ) where "f" is formal uncertainty of the ionosphere free linear combination of group delays at X- and S-band obtained by fringe fitting on the base of achieved signal to noise ratio. Session-dependent parameter "a" was computed for each session by an iterative procedure such that the ratio of the sum of squares of weighted residuals to the estimate of their mathematical expectation is about unity. 12. Standard errors reported: All errors derived from least-squares estimation propagated from the data weights and the constraints applied to the troposphere, clock and EOP parameters. 13 Software: CALC 10.0, SOLVE revision date 2006.12.08. References: 1. MacMillan, D.S. and C. Ma, "Atmospheric gradients from very long baseline interferometry observations", Geophys. Res. Lett., 22, 1041-1044, 1995. 2. MacMillan, D.S. and C. Ma, "Atmospheric gradients and the VLBI terrestrial and celestial reference frames", Geophys. Res. Lett., 24, 453-456, 1997. 3. Petrov, L. and J.-P. Boy, "Study of the atmospheric pressure loading signal in VLBI observations", J. Geophys. Res., 10.1029/2003JB002500, vol. 109, No. B03405, 2004. 4. McCarthy, D.D., Petit, G., IERS Technical Note 32, IERS Conventions (2003), 2003. ---------------------------------------------------------------------------- Appendix A. ~~~~~~~~~~~ Coefficients of expansion of short-period variations in polar motion and UT1 (hf1102a model). UT1 tidal terms (microseconds) l l' F D Om GST | Cos | Sin | +pi | | | ----------------------------------------- 2 0 2 0 2 -1 -.13 -1.24 0 0 2 2 2 -1 .19 -.82 1 0 2 0 1 -1 -.50 -.92 1 0 2 0 2 -1 -2.64 -4.90 -1 0 2 2 2 -1 -1.10 -.77 0 0 2 0 1 -1 -2.51 -3.34 0 0 2 0 2 -1 -13.31 -17.72 -1 0 2 0 2 -1 .34 .63 1 0 0 0 0 -1 .48 .77 0 1 2 -2 2 -1 -.21 -.43 0 0 2 -2 2 -1 -3.20 -5.32 0 1 0 0 0 -1 .50 1.89 0 0 0 0 -1 -1 -.19 -.33 0 0 0 0 0 -1 9.83 16.45 0 0 0 0 1 -1 1.33 2.23 0 -1 0 0 0 -1 -.17 .41 0 0 -2 2 -2 -1 .08 -.04 -1 0 0 0 0 -1 .13 1.25 0 0 -2 0 -2 -1 .68 .33 0 0 -2 0 -1 -1 .44 .21 -1 0 -2 0 -2 -1 .18 .75 -1 0 -2 0 -1 -1 .12 .48 2 0 2 0 2 -2 -.30 .61 0 0 2 2 2 -2 -.83 .47 1 0 2 0 2 -2 -1.94 3.13 -1 0 2 2 2 -2 -.19 .67 0 0 2 0 1 -2 .37 -.57 0 0 2 0 2 -2 -9.88 15.37 -1 0 2 0 2 -2 .12 -.34 0 1 2 -2 2 -2 -.06 .17 0 0 2 -2 2 -2 -1.25 7.73 0 1 0 0 0 -2 .24 .27 0 0 0 0 0 -2 .28 2.48 0 0 0 0 1 -2 .08 .74 0 0 3 0 3 -3 .24 .03 0 0 0 4 1 -1 .26 .10 1 0 4 -2 2 -1 .43 -.52 0 0 0 1 0 -1 -.29 -.23 3 -1 2 0 2 -2 .14 .00 1 1 2 0 1 -2 -.26 -.40 0 0 0 -2 2 -2 .23 .09 ----------------------------------------- ----------------------------------------- Polar motion tidal terms (microarcseconds) l l' F D Om GST | Cos | Sin | +pi | | | ----------------------------------------- -2 0 -2 0 -2 1 -6.90 5.52 0 0 -2 -2 -2 1 -8.63 3.00 -1 0 -2 0 -1 1 -5.58 1.48 -1 0 -2 0 -2 1 -29.56 7.83 1 0 -2 -2 -2 1 -7.86 3.64 0 0 -2 0 -1 1 -25.03 8.53 0 0 -2 0 -2 1 -132.70 45.21 1 0 -2 0 -2 1 2.59 .60 -1 0 0 0 0 1 3.26 -8.76 0 -1 -2 2 -2 1 1.25 9.68 0 0 -2 2 -2 1 -49.40 19.23 0 -1 0 0 0 1 25.06 6.71 0 0 0 0 1 1 -3.09 1.76 0 0 0 0 0 1 156.21 -88.75 0 0 0 0 -1 1 21.18 -12.04 0 1 0 0 0 1 4.99 .50 0 0 2 -2 2 1 3.25 2.62 1 0 0 0 0 1 .51 -4.99 0 0 2 0 2 1 5.93 -10.38 0 0 2 0 1 1 3.80 -6.65 1 0 2 0 2 1 .46 .59 1 0 2 0 1 1 .30 .37 -2 0 -2 0 -2 2 4.13 -.28 0 0 -2 -2 -2 2 -1.37 .40 -1 0 -2 0 -2 2 10.48 -12.69 1 0 -2 -2 -2 2 4.33 1.81 0 0 -2 0 -1 2 -1.06 2.12 0 0 -2 0 -2 2 28.34 -56.83 1 0 -2 0 -2 2 1.92 .54 0 -1 -2 2 -2 2 5.42 -4.28 0 0 -2 2 -2 2 -.48 -20.16 0 -1 0 0 0 2 2.61 1.85 0 0 0 0 0 2 -.83 -18.26 0 0 0 0 -1 2 -.25 -5.44 0 0 -3 0 -3 3 1.92 -1.16 0 0 0 -4 -1 1 5.23 -1.47 -1 0 -4 2 -2 1 -1.28 -3.62 0 0 0 -1 0 1 2.33 -2.61 -3 1 -2 0 -2 2 -.88 -1.13 -1 -1 -2 0 -1 2 .24 .00 0 0 0 2 -2 2 .05 -1.31 2 0 2 0 2 -2 2.33 7.19 0 0 2 2 2 -2 2.87 7.66 1 0 2 0 2 -2 .59 43.62 -1 0 2 2 2 -2 -3.07 8.30 0 0 2 0 1 -2 .50 -9.59 0 0 2 0 2 -2 -13.37 257.07 -1 0 2 0 2 -2 1.83 -7.67 0 1 2 -2 2 -2 -7.08 .33 0 0 2 -2 2 -2 -72.53 106.95 0 1 0 0 0 -2 .34 -4.29 0 0 0 0 0 -2 -18.74 12.64 0 0 0 0 1 -2 -5.59 3.77 0 0 3 0 3 -3 -.56 -1.57 3 -1 2 0 2 -2 -.98 4.60 1 1 2 0 1 -2 -.62 4.28 0 0 0 -2 2 -2 -.83 2.72 -----------------------------------------