VieVS User Workshop 14 – 16 September, 2011 Vienna VIE_MOD Lucia Plank

VieVS User Workshop PART I:theory PART II:program/workflow PART III:usage

VieVS User Workshop computed delay τ adjustment (lsm) observed delay from NGS-card file, corrected for ionosphere I. THEORY computed delay Vie_mod o-c

I. THEORY VieVS User Workshop Geocentric Celestial Reference System ITRS BCRS International Terrestrial Reference System GCRS Lorentz-transformation BCRS retarded baseline corr. Barycentric Celestial Reference System source Lorentz-transformation gravitational retardation

VieVS User Workshop 2011 adjustment (lsm) observed delay from NGS-card file, corrected for ionosphere I. THEORY computed delay Vie_mod o-c models + EOP (oceanic & gravitational high frequency terms, nutation corrections) + solid Earth tides + troposphere delay (VMF / GMF / NMF) + ocean loading (FES2004 / EOT08a / GOT00 / AG06) + thermal antenna deformation + axis offset + atmosphere loading 5 partial derivatives

VieVS User Workshop II. WORKFLOW 0. INPUT FILES (scan, parameter, antenna, sources) 1.EARTH ORIENTATION read EOP | Interpolation | Add high frequency models | Ephemerides | Transformation matrix TRS-CRS | Source vector 2.STATION COORDINATES loop over scans loop over stations Station corrections (SET | ocean loading | atmosphere loading | pole tide | station velocity) | tropospheric parameters end stations 3.COMPUTED DELAY loop over baselines calculation of the time delay following the consensus model (incl. relativistic & gravitative corr.) | troposphere | axis offset | thermdef. 4.PARTIAL DERIVATIVES wrt. EOP | wrt. source coordinates | wrt. station coordinates | wrt. Love and Shida numbers end baselines 5.STORE RESULTS end scans 6.SAVE (scan, parameter, antenna, sources) 0. INPUT FILES (scan, parameter, antenna, sources) 1.EARTH ORIENTATION read EOP | Interpolation | Add high frequency models | Ephemerides | Transformation matrix TRS-CRS | Source vector 2.STATION COORDINATES loop over scans loop over stations Station corrections (SET | ocean loading | atmosphere loading | pole tide | station velocity) | tropospheric parameters end stations 3.COMPUTED DELAY loop over baselines calculation of the time delay following the consensus model (incl. relativistic & gravitative corr.) | troposphere | axis offset | thermdef. 4.PARTIAL DERIVATIVES wrt. EOP | wrt. source coordinates | wrt. station coordinates | wrt. Love and Shida numbers end baselines 5.STORE RESULTS end scans 6.SAVE (scan, parameter, antenna, sources)

VieVS User Workshop III. USAGE

8 TRF: stored at:../TRF/VTRF2008.mat station coordinates (TRS) reference epoch station velocities Other: - self-created TRF -../TRF/*.txt - specified format TRF: stored at:../TRF/VTRF2008.mat station coordinates (TRS) reference epoch station velocities Other: - self-created TRF -../TRF/*.txt - specified format

9 III. USAGE CRF: stored at:../CRF/ICRF2.mat right ascension ra declination de ++ (structure index, …) Other: - self-created CRF - not finished yet CRF: stored at:../CRF/ICRF2.mat right ascension ra declination de ++ (structure index, …) Other: - self-created CRF - not finished yet

10 III. USAGE Ephemerides: stored at:../EPHEM/jpl_421.mat Earth, Sun, Moon, Planets remembered for 2nd run (jpl_421_05SEP12XA_N004) not critical for “normal” VLBI Ephemerides: stored at:../EPHEM/jpl_421.mat Earth, Sun, Moon, Planets remembered for 2nd run (jpl_421_05SEP12XA_N004) not critical for “normal” VLBI

11 III. USAGE Earth Orientation Parameters: c04 08 (daily) series from the IERS webpage;../EOP/C04_08_1962_now.txt; updates might be necessary; predefined EOP:../EOP/*.txt; watch format dX, dY: include/exclude from c04 table; mainly contains FCN high frequency EOP ocean tides: interpf; table 8.2 (xp,yp) & 8.3 (ut) diurnal & semi-diurnal libration: table 5.1a (xp,yp) & 5.1b (ut) DON‘T CHANGE ANYTHING, THEN YOU‘RE CONSISTENT WITH THE IERS CONVENTIONS ! Earth Orientation Parameters: c04 08 (daily) series from the IERS webpage;../EOP/C04_08_1962_now.txt; updates might be necessary; predefined EOP:../EOP/*.txt; watch format dX, dY: include/exclude from c04 table; mainly contains FCN high frequency EOP ocean tides: interpf; table 8.2 (xp,yp) & 8.3 (ut) diurnal & semi-diurnal libration: table 5.1a (xp,yp) & 5.1b (ut) DON‘T CHANGE ANYTHING, THEN YOU‘RE CONSISTENT WITH THE IERS CONVENTIONS !

12 III. USAGE Interpolation of EOP: lagrange: window of 4 data points - tidal UT variations: removed before interpolation, re-added linear: interpolation between the midnight before and after observation time. For a session from 18:00 to 18:00 this means, that there are 2 a priori lines and a break at midnight. Interpolation of EOP: lagrange: window of 4 data points - tidal UT variations: removed before interpolation, re-added linear: interpolation between the midnight before and after observation time. For a session from 18:00 to 18:00 this means, that there are 2 a priori lines and a break at midnight.

13 III. USAGE Precession/Nutation Model:

14 III. USAGE Station corrections: hear more from Hana Thermdef: [A. Nothnagel, J. of Geodesy, 2008] Station corrections: hear more from Hana Thermdef: [A. Nothnagel, J. of Geodesy, 2008]

15 III. USAGE Pressure and temperature: Met data from NGS-file GPT as backup External.trp files Pressure and temperature: Met data from NGS-file GPT as backup External.trp files

16 III. USAGE A priori troposphere gradients:

17 III. USAGE Mapping function: for atmospheric corrections on the delay VM1:../VM1/yyyy_VM1.mat regular update! GMF: applied when no VM1 available Mapping function: for atmospheric corrections on the delay VM1:../VM1/yyyy_VM1.mat regular update! GMF: applied when no VM1 available

18 III. USAGE Quality code limit: Accept observations < or = limit Good quality observations have quality code 0 Quality code limit: Accept observations < or = limit Good quality observations have quality code 0

19 III. USAGE External ionosphere correction:

20 III. USAGE Cut-off Elevation angle: all observations below this local elevation [°, degrees] are skipped Cut-off Elevation angle: all observations below this local elevation [°, degrees] are skipped

21 III. USAGE Outliers: use/dont‘t use outlier file (chosen in init_qu) Outliers: use/dont‘t use outlier file (chosen in init_qu)

22 III. USAGE PUSH