From cma@bootes.gsfc.nasa.gov Fri Sep 10 18:42 EDT 1999 Received: from bootes.gsfc.nasa.gov by leo.gsfc.nasa.gov; Fri, 10 Sep 1999 18:41:59 -0400 Return-Path: Received: by bootes.gsfc.nasa.gov; Fri, 10 Sep 1999 18:41:58 -0400 From: Chopo Ma Subject: tech description for 1122 TRF To: kdb@bootes.gsfc.nasa.gov Date: Fri, 10 Sep 1999 18:41:57 EDT Cc: cma@bootes.gsfc.nasa.gov, dsm@bootes.gsfc.nasa.gov X-Mailer: Elm [revision: 212.2] Status: RO ******************************************************************** Technical description of solution GSFC1122 1. Purpose of solution: TRF/CRF for session EOP 2. Analysis center: GSFC 3. Short narrative description of solution: GSFC1122 estimates station position and velocty parameters to define TRF/CRF for computing EOP time series. Source positions are also estimated. The TRF is attached to ITRF97 by no-net-rotation and no-net translation conditions for position and to NUVEL1-A NNR by similar conditions from velocity. The CRF is attached to the ICRF by a no-net-rotation condition using the ICRF defining sources. Sources with <5 good observations or <2 sessions and <25 good observations were excluded. A priori mean gradients were derived from VLBI data for 34 stations observed at least 40 times as of mid 1998 and from the DAO weather model for the other stations. 4. Estimated parameters: a. celestial frame: right ascension, declination b. terrestrial frame: X, Y, Z, Xdot, Ydot, Zdot c. Earth orientation: x, y, UT1-TAI, UT1dot, dpsi, deps d. zenith troposphere: continuous piecewise linear, 20 min interval rate constraint generally 50 ps/hr NMF wet partial derivative e. troposphere gradient: 6hr east and north piecewise continuous at nonmobile stations offset constraint 0.5 mm, rate 2.0 mm/day f. station clocks: quadratic + continuous piecewise linear with 1 hr interval rate constraint generally 5 E-14 g. baseline clocks: set in initial analysis - usually used h. other: global antenna axis offsets for nonmobile stations 5. Celestial reference frame: a. a priori source positions: ICRF b. source positions adjusted in solution: yes If yes, c. definition of orientation: no-net-rotation tie to the ICRF using only the ICRF defining sources d. source position estimation: all global 6 - Terrestrial reference frame: a. a priori station positions: ITRF97 b. a priori station velocities: NUVEL1-A NNR c. reference epoch: 1997.0 d. station positions/velocities adjusted in solution: yes If yes, e. definition of origin, orientation, and their time evolution: no-net-translation and no-net-rotation of position for: GILCREEK WETTZELL LA-VLBA NRAO20 NYALES20 KOKEE MK-VLBA HARTRAO FORTLEZA HOBART26 KASHIMA DSS45 no-net-translation and no-net-rotation of velocity for: WESTFORD RICHMOND WETTZELL HOBART26 DSS45 f. station parameter estimation: X, Y, Z, Xdot, Ydot, Zdot globally for all stations, some with constraints g. stations with constraints: A priori rate errors of 0, 3, and 3 mm/yr for U, E, and N respectively but because the following stations generally have only one occupation, their velocities follow NUVEL1-A NNR. AUSTINTX AZORES BERMUDA BLOOMIND BREST CARNUSTY CARROLGA CHLBOLTN DAITO GRASSE HOFN HOHENFRG HOHNBERG KARLBURG KIRSBERG LEONRDOK METSHOVI MILESMON MIYAZAKI MIZNAO10 MIZUSGSI OCOTILLO SAGARA SEST SINTOTU TITIJIMA TOULOUSE USSURISK USUDA64 VICTORIA VLA MCD_7850 FTD_7900 The velocities of the following pairs of stations are constrained to be the same. DSS65 ROBLED32 SESHAN25 SHANGHAI DSS45 TIDBIN64 FORT_ORD FORTORDS MOJAVE12 MOJ_7288 OVRO_130 OVR_7853 ONSALA60 MV2ONSLA NRAO_140 NRAO85_1 KAUAI HALEAKAL YELLOWKN YLOW7296 GORF7102 GGAO7108 WETTZELL TIGOWTZL RICHMOND MIAMI20 TSUKUBA TSUKUB32 h. stations with discontinuous positions and date of discontinuity: YAKATAGA 871201 SOURDOGH 871201 WHTHORSE 871201 FORTORDS 891001 PRESIDIO 891001 NRAO85 3 901201 MOJAVE12 920627 DSS15 920627 MEDICINA 960601 EFLSBERG 961001 DSS65 970415 TSUKUB32 990401 i. stations with nonlinear velocities: HRAS 085 - 2 month piecewise linear, continuous position j. relativity scale: e.g., LE : local Earth in agreement with TCG (IUGG Resolution) 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. 7. Earth orientation: a. a priori precession model: IAU(1976) b. a priori nutation model: KSV c. a priori short-period tidal variations in x, y, UT1: 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 ----------------------------------------- d. EOP estimation: x, y, UT1, UT1dot, deps, dpsi each day with a priori error of 45 mas for pole and 3 ms for UT1 to allow estimation for one-baseline sessions; deps amd dpsi are relative to standard IAU precession and nutation models. 8. A priori geophysical models: a. troposphere: NMF dry mapping function; Sastamoinen zenith delay calculated using logged pressure, temperature; a priori mean gradients from VLBI data or DAO weather model b. solid Earth tide: IERS Conventions c. ocean loading: IERS Conventions d. atmosphere loading: using site pressure admittances estimated from VLBI data or computed from convolution of loading Green's function with NMC weather model data 9. Data type: delays 10. Data editing: 7 deg elevation cutoff 11. Data weighting: reweighting by station for each session such that the additional RSSed noise makes the chi-square unity in a single session solution 12. Standard errors reported: all errors derived from least-squares estimation propagated from a priori data uncertainties from fringing, ionosphere calibration error and noise RSSed for each station for each session and taking into account the constraints applied to troposphere, clock and EOP parameters 13 Software: CALC 8.2, SOLVE 5.0129 14. Other information: EOP estimated at midpoint of session SHANGHAI, USSURISK, and DAITO data lack ionosphere calibration Sources with <5 good observations or <2 sessions and <25 good observations excluded