Technical description of solution bkg2014a_dsnx 1. Purpose of solution: 24 hours session solution for IVS time series of baseline lengths and basis solution for combination techniques 2 - Analysis Center: Federal Agency for Cartography and Geodesy (BKG Leipzig) 3. Short narrative description of solution: All available dual-band Mark III/IV/V observations from 1984 on were analysed for this solution. The orientation of CRF is defined by the a priori source positions of ICRF2. ICRF2 defining sources were fixed to their ICRF2 positions. All other sources were estimated for each 24-hours session with a constraint of 10**(-7) rad. The TRF is defined by no-net-translation and rotation constraints for the coordinates of all sites in a VLBI session related to VTRF2008a except for AIRA, CHICHI10, CTVASTJ, DSS13, TSUKUB32, HART15M, KASHIM34, KOGANEI, KUNMING, TIANMA65, TIGOCONC, UCHINOUR, VERAISGK, VERAMZSW, YEBES40M. The values of the official list of VLBI antenna axis offsets antenna-info.txt based on gsfc_itrf2013.axo.txt were used. Use of CALC11 includes the standards of IERS Conventions 2010. Ocean loading model TPXO.7.2 omputed by H. G. Scherneck was applied (blokq.c11.dat). Thermal expansion modelling developed by A. Nothnagel (2008) was used with antenna properties from antenna-info.txt. The values of station eccentricities were taken from the official IVS-table ECCDAT.ecc. The Vienna mapping function (VMF1) is applied for troposphere correction modelling in form of TRP files from GSFC. The atmospheric pressure loading time series provided by the Goddard VLBI group which are available on the Web at http://lacerta.gsfc.nasa.gov/aplo (Petrov & Boy, 2004) are used. 4. Estimated parameters: a. celestial frame: right ascension, declination except for 295 defining sources ICRF2 b. terrestrial frame: X, Y, Z c. Earth orientation: X-pole, Y-pole, UT1-TAI, Xdot, Ydot, UT1dot, X-nutation, Y-nutation d. zenith troposphere: 1h piece-wise linear functions, rate constraint generally 50 ps/hour, e. troposphere gradient: east and north offset, offset constraint 0.5 mm, rate constraint 2.0 mm/day f. station clocks: 1h piece-wise linear functions, rate constraint generally 5.E-14 g. baseline clocks: set in initial analysis - usually used h. other: No 5. Celestial reference frame: a. a priori source positions: ICRF2 b. source positions adjusted in solution: yes, except for 295 defining sources ICRF2 6 - Terrestrial reference frame: a. a priori station positions: VTRF2008a b. a priori station velocities: VTRF2008a c. reference epoch: 2000.0 d. station positions adjusted in solution: yes e. definition of origin, orientation, and their time evolution: no-net-translation and no-net-rotation of position with respect to VTRF2008a for all stations of the VLBI session except for AIRA, CHICHI10, CTVASTJ, DSS13, TSUKUB32, HART15M, KASHIM34, KOGANEI, KUNMING, TIANMA65, TIGOCONC, UCHINOUR, VERAISGK, VERAMZSW, YEBES40M. 7. Earth orientation: a. a priori precession/nutation model: IAU2006/2000 Precession/Nutation b. a priori short-period tidal variations in Xpol, Ypol and UT1 due to short period tidal were applied as recommended in the IERS 2010 Conventions c. a priori UT1 and polar motion: usno_finals.data (http://gemini.gsfc.nasa.gov/solve_save/usno_finals.erp) 8. A priori geophysical models: a. troposphere: Use of TRP files with total a priori atmospheric slant delay from GSFC based on VMF1 b. solid Earth tide: IERS 2010 Conventions c. ocean loading: TPXO.7.2 model d. pole tides: IERS 2010 Conventions e. atmosphere loading: atmospheric pressure loading time series provided by GSFC (available at http://lacerta.gsfc.nasa.gov/aplo/aplo_bds.tar.bz2) f. antenna thermal deformation: IVS antenna thermal deformation model of Nothnagel 2008 g. axis offsets: values of the official list of VLBI antenna axis offsets antenna-info.txt based on gsfc_itrf2013.axo.txt were used h. a priori gradients: values from GSFC Data Assimilation Office (DAO) model, gsfc_dao_gmao_mgr.txt 9. Data type: Group delays 10. Data editing: 5 deg elevation cutoff, editing of outliers during adjustment when necessary. 11. Data weighting: Observations are weighted using std reported in observational files; re-weighting iteration for each session to achieve the chi-square unity. 12. Standard errors reported: Reported formal errors are derived from least-squares estimation propagated from data uncertainties and weighted as discussed in #11. 13. Software: CALC Version: 11.01 SOLVE release 2014.02.21 References: Axel Nothnagel (2008) Short Note: Conventions on thermal expansion modelling of radio telescopes for geodetic and astrometric VLBI; Journal of Geodesy, DOI: 10.1007/s00190-008-0284-z. L. Petrov, J.-P. Boy, Study of the atmospheric pressure loading signal in VLBI observations, Journal of Geophysical Research, 10.1029/2003JB002500, Vol. 109, No. B03405, 2004. Appendix A. ----------- >>> FORMAT DESCRIPTION <<< >>> ################## <<< Sinex output implementation in the VLBI Analysis software system Calc/Solve Leonid Petrov 2008.04.29 Abstract This document describes the way how Calc/Solve writes down a listing of a VLBI solution in Sinex format. Questions and comments about this guide should be sent to: Leonid Petrov ( pet@leo.gsfc.nasa.gov ) Table of contents: 1 ................ Overview 2 ................ Deviations from the SINEX 1.00 standard 2.1 ........... New block SOLUTION/CONSTRAINT_EQUATION_INFO 2.2 ........... New block SOLUTION/CONSTRAINT_EQUATION_MATRIX 2.3 ........... New block SOLUTION/CONSTRAINT_EQUATION_VECTOR 2.4 ........... New block SOLUTION/CONSTRAINT_WEIGHT_MATRIX 2.5 ........... New block SOLUTION/DECOMPOSED_NORMAL_MATRIX BLOCK 2.6 ........... New block SOLUTION/DECOMPOSED_NORMAL_VECTOR BLOCK 2.7 ........... New block NUTATION/DATA 2.8 ........... New block PRECESSION/DATA 2.9 ........... New block SOURCE/ID 3 ................ Deviations from the SINEX 2.10 standard 4 ................ Implementation in Solve 4.1 ........... Syntax of INCLUDE_PARAM and EXCLUDE_PARAM lists 4.2 ........... Examples of INCLUDE_PARAM and EXCLUDE_PARAM lists 4.3 ........... Treatment of station with discontinuous motion 4.4 ........... Restrictions ________________________________________________________________________________ 1 Overview ========== SINEX stands for "Solution INdependent EXchange format". This format was developed by Blewitt et al. (1994) http://www.dgfi.badw-muenchen.de/gps/sinex.html and http://alpha.fesg.tu-muenchen.de/iers/sinex/sinex_v2_appendix1.pdf for facilitating the task of combining several GPS solutions. Original design of Sinex format was made for solving this specific task. However, later this format evolved towards to a common machine-readable form of solution listings for other space geodesy techniques, VLBI and SLR, and attempts were made for overcoming flaws of the original design. This process of evolution is not yet completed, therefore, different software systems implement a little bit different flavors of Sinex format. Listings in Sinex format produced by Solve contain information about stations, sources, estimates of the parameters, their covariance matrix, constraint equation, right-hand side of constraint equations and weight matrix of constraint equations. In addition to these results, a portion of the decomposed normal matrix and normal vector can be included in the listing as well. A user has control which blocks should be included in the listing. The current implementation of the Sinex format does not allow to include in the listing any parameter which was solved for. Only some type of parameters, like station position, EOP, etc can be included. However, a user has total control which parameters among the parameters of the supported type are to be included or not included in the listing. 2 Deviations from the SINEX 1.00 standard ========================================= Solve currently writes listing either in Sinex 2.10 format or in Sinex 2.20 format. Deviations from the Sinex 1.00 standard are as follows: 1) Eight new blocks were added: SOLUTION/CONSTRAINT_EQUATION_INFO SOLUTION/CONSTRAINT_EQUATION_MATRIX SOLUTION/CONSTRAINT_EQUATION_VECTOR SOLUTION/CONSTRAINT_WEIGHT_MATRIX The purpose of these four blocks is to overcome the flaw of original design of Sinex format and provide complete information about all constraints used in the solution. SOLUTION/DECOMPOSED_NORMAL_MATRIX SOLUTION/DECOMPOSED_NORMAL_VECTOR The purpose of these blocks is to provide information about transformed normal equations before applying constraints. NB: one of the three items: covariance matrix, constraint equations and decomposed normal equations is redundant: having two of them one can derive the third one. NUTATION/DATA PRECESSION/DATA The purpose of this section is to provide information about used nutation/precession model and to define parameter "estimates of nutation angles". 2) SOLUTION/STATISTICS block has new items: WEIGHTED SQUARE SUM OF O-C sum { y(T) * w * y } WRMS OF POSTFIT RESIDUALS sum { (A*e - y)(T) * w * (A*e - y) )/Sp ( w ) where y -- the difference between the observed time delay and theoretical; A -- matrix of equations of conditions; e -- vector of the parameter adjustments; w -- weight matrix; Sp -- stands for the mathematical operation of computing trace of a matrix: the sum of diagonal elements. Summing is done over all observations used in parameter estimation. Comment: field WEIGHTED SQUARE SUM OF O-C is not computed in global mode. Meaning of other parameters: NUMBER OF OBSERVATIONS total number of used observables NUMBER OF UNKNOWNS total number of unknowns, including those, which are not shown in the Sinex listing SQUARE SUM OF RESIDUALS (VTPV) sum { (A*e - y)(T) * w * (A*e - y) ) VARIANCE FACTOR sum { (A*e - y)(T) * w * (A*e - y) )}/ ( N - M - Sp( Cov(A) * B(T) * z * B ) ) where Cov(A) -- covariance matrix of the entire solution (NB: Sinex listing may have only a portion of the solution) B -- matrix of equations of constraints; z -- weight matrix of constraints; N -- total number of equations of conditions (observables); M -- total number of unknowns. 3) The blocks which keep element of matrices do not have fields "Second Matrix Element" and "Third Matrix Element". The purpose of this change is to facilitate the process of creation of the listing and to reduce significantly the probability of errors. 4) SOLUTION/MATRIX_APRIORI is not provided. The reason is that Solve does not operate the notion of apriori covariance matrix. And it also uses singular constraints which cannot be reduced to the form of apriori covariance matrix. Since full information about constraints is provided in other blocks, SOLUTION/MATRIX_APRIORI is considered as an obsolete block. 2.1 New block SOLUTION/CONSTRAINT_EQUATION_INFO ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ___________________________________________________________________ |S_O_L_U_T_I_O_N__C_O_N_S_T_R_A_I_T__I_N_F_O__B_L_O_C_K_____________| | | | | |__Field_________|______Description__________________|___Format_____| | | | | | Constraint | Row index for the constraint | 1X,I5 | | Equation Row | equation matrix. It must match | | | Index | the index of the constraint | | | | equation. | | |________________|___________________________________|______________| | | | | | Constraint | Identifier of the constraint | 1X,A8 | | Equation | | | | Identifier | | | |________________|___________________________________|______________| | | | | | Constraint | Index of vector constraint. | 1X,I5 | | Equation | 1 for scalar constraint. | | | Sub-index | | | | | | | |________________|___________________________________|______________| | | | | | Constraint | Description of the constraint | 1X,A40 | | Equation | | | | Description | | | |________________|___________________________________|______________| This block provides description of constraint equations. Matrix of constraint equations has dimension N_cns * N_par, where N_cns -- the number of constraint equations, N_par -- number of estimated parameters. The first field of the CONSTRAINT_EQUATION_INFO keeps the index of the constraint, the second field keeps constraint identifier. Currently, the following constraint identifiers are supported: NNT_POS -- net rotation on station position. This vector constraint defines three equations: 1: sum { Delta_X } = const 2: sum { Delta_Y } = const 3: sum { Delta_Y } = const where Delta_X, Delta_Y, Delta_Z are X, Y and Z component of the adjustment to station position. NNR_POS -- net rotation on station position. This vector constraint defines three equations: 1: sum { Phi_X } = const 2: sum { Phi_Y } = const 3: sum { Phi_Y } = const where Phi_X, Phi_Y and Phi_Z are the components of the vector of a small rotation defined as Phi = ( r x Delta r )/ |r|^2 * R_e here r -- vector of station coordinate; Delta r -- vector of adjustments to station position R_e -- Earth's equatorial radius. Units: dimensionless NNT_VEL -- net rotation on station velocity. This vector constraint defines three equations: 1: sum { Delta_X } = const 2: sum { Delta_Y } = const 3: sum { Delta_Y } = const where Delta_X, Delta_Y, Delta_Z are X, Y and Z component of the adjustment to station position. NNR_VEL -- net rotation on station velocity This vector constraint defines three equations: 1: sum { Phi_X } = const 2: sum { Phi_Y } = const 3: sum { Phi_Y } = const where Phi_X, Phi_Y and Phi_Z are the components of the vector of a small rotation defined as Phi = ( r x Delta v )/ |r|^2 * R_e here r -- vector of station coordinates; Delta r -- vector of adjustments to station velocity; R_e -- Earth's equatorial radius. Units: 1/yr NNR_SRC -- net rotation on source coordinates 1: sum { Phi_X } = const 2: sum { Phi_Y } = const 3: sum { Phi_Y } = const where Phi_X, Phi_Y and Phi_Z are the components of the vector of a small rotation EOP_XPL -- constraint on X pole coordinate EOP_YPL -- constraint on Y pole coordinate EOP_UT1 -- constraint on UT1 angle EOR_XPL -- constraint on X pole rate EOR_YPL -- constraint on Y pole rate EOR_UT1 -- constraint on UT1 rate VEL_U -- constraint on Up topocentric coordinate of station velocity VEL_E -- constraint on East topocentric coordinate of station velocity VEL_N -- constraint on North topocentric coordinate of station velocity VEL_X -- constraint on X coordinate of station velocity VEL_Y -- constraint on Y coordinate of station velocity VEL_Z -- constraint on Z coordinate of station velocity STA_U -- constraint on Up topocentric coordinate of station position STA_E -- constraint on East topocentric coordinate of station position STA_N -- constraint on North topocentric coordinate of station position STA_X -- constraint on X coordinate of station position STA_Y -- constraint on Y coordinate of station position STA_Z -- constraint on Z coordinate of station position BLC_VAL -- constraint on baseline clocks DCL_ORG -- constraint on declination of the set of certain sources GRD_OFF -- constraint on atmosphere path delay gradient offset NUT_OFF -- constraint on offset of nutation in longitude and nutation in obliquity OAT_RAT -- constraint on rate of changes of atmosphere path delay OCL_RAT -- constraint on clock drift RAS_ORG -- constraint on right ascension of the set of certain sources SRC_COO -- constraint on source right ascension and declination STA_ORG -- constraint on position of certain stations STA_TIE -- constraint on differences in position of several sites VEL_DIR -- constraint on horizontal projection of the differences in velocities of two stations VEL_ORG -- constraint on velocities of certain stations VEL_SET -- constraint on linear combination of velocity components VEL_TIE -- constraint on differences in velocities of several sites VEL_VER -- constraint on vertical component of station velocity Constraints on segmented parameters STA_PWC -- constraint on site velocity in the the case when site position is modeled by linear spline GRD_RAT -- constraint on atmosphere path delay gradient rate ATM_RAT -- constraint on atmosphere path delay rate between segments CLO_RAT -- constraint on clock rate between segments UT1_RAT -- constraint on UT1 rate in the case of linear spline EOP parametrization XPL_RAT -- constraint on X pole coordinate in the case of linear spline EOP parametrization YPL_RAT -- constraint on Y pole coordinate in the case of linear spline EOP parametrization Constraint equation sub-index is 1 for scalar constraint, like EOP_XPL and runs over components of vector constraints, like NNT_POS (1,2,3 in this example). 2.2 New block SOLUTION/CONSTRAINT_EQUATION_MATRIX ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This block keep matrix of constraint equations. Equations are organized by rows. Zero elements are omitted. _____________________________________________________________________ |__S_O_L_U_T_I_O_N__C_O_N_S_T_R_A_I_T__E_Q_U_A_T_I_O_N__B_L_O_C_K_____| | | | | |__Field___________|______Description__________________|___Format_____| | | | | | Constraint | Row index for the constraint | 1X,I5 | | equation row | equation matrix. It must match | | | Index | the index of the constraint | | | | equation. | | |__________________|___________________________________|______________| | | | | | Constraint | Column index for the Constraint | 1X,I5 | | equation | Equation. It must match the | | | column index | parameter index in the | | | | SOLUTION/ESTIMATE block for the | | | | same parameter. | | |__________________|___________________________________|______________| | | | | | Constraint | Matrix element at the location | 1X,E21.14 | | matrix element | (row index, column index). | | |__________________|___________________________________|______________| 2.3 New block SOLUTION/CONSTRAINT_EQUATION_VECTOR ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This block keeps the right-hand side of constraint equations. ___________________________________________________________________ |__S_O_L_U_T_I_O_N__C_O_N_S_T_R_A_I_T__V_A_L_U_E__B_L_O_C_K_________| | | | | |__Field_________|______Description__________________|___Format_____| | | | | | Constraint | Row index for the constraint | 1X,I5 | | Equation Row | equation vector. It must match | | | | the index of the constraint | | | | equation. | | |________________|___________________________________|______________| | | | | | Right hand | Value of right hand part of the | | side value | constraint equation. | 1X,E21.15 | |________________|___________________________________|______________| | | | | | Sigma | Reciprocal weight which is | | | | ascribed to this constraint | 1X,E21.15 | | | equation. | | |________________|___________________________________|______________| | | | 48 | |______________| 2.4 New block SOLUTION/CONSTRAINT_WEIGHT_MATRIX ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This block contains the elements of the weight matrix of constraint equations. Zero elements are omitted. ______________________________________________________________________ |_____________C_O_N_S_T_R_A_I_N_T___W_E_I_G_H_T___M_A_T_R_I_X__________| | | |__Field__________________Description_______________________Format_____| | | | | | Row index of the | Row index for the weight | 1X,I5 | | weight matrix | constraint matrix. It matches | | | of constraint | the index of the constraint | | | equations | equation. | | |___________________|___________________________________|______________| | | | | | Column index of | Column index for the weight | 1X,I5 | | the weight matrix | constraint matrix. It matches the | | | of constraint | index of the constraint equation | | | equations | | | |___________________|___________________________________|______________| | | | | | Weight matrix of | Matrix element at the location | 1X,E21.14 | | constraint | (row index, column index). | | | equations element | | | |___________________|___________________________________|______________| 2.5 New block SOLUTION/DECOMPOSED_NORMAL_MATRIX BLOCK ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This block contains decomposed normal equations for the subset of parameters described in the SOLUTION/ESTIMATE block. In the case if the SOLUTION/ESTIMATE block described all parameters adjusted in the solution, decomposed normal matrix is equivalent to the full normal matrix. In the case if the SOLUTION/ESTIMATE block describes only a subset of parameters, then the decomposed normal matrix D_ii is defined as D_ii = N_ii - N_ei(T) * (C_ee + N_ee){-1} * N_ei where N_ii -- the block of normal matrix which corresponds to the equations included in the SOLUTION/ESTIMATE list; N_ee -- the block of normal matrix which corresponds to omitted parameters; N_ei -- the block of normal matrix which corresponds to the product of equations of conditions of the omitted parameters and parameters included in the SOLUTION/ESTIMATE list. C_ee -- the block of normal matrix of constraints which corresponds to omitted parameters; Solve computes D_ii as D_ii = (V_ii){-1} - C_ii where V_ii -- covariance matrix of the parameters mentioned in SOLUTION/ESTIMATE list; C_ii -- the block of normal matrix of constraints which corresponds to the parameters in SOLUTION/ESTIMATE list. It is assumed that C_ei = 0 C_ei -- the block of normal matrix of constraints which corresponds to the product of equations of constraints of the omitted parameters and parameters from the SOLUTION/ESTIMATE list. ___________________________________________________________________ |__S_O_L_U_T_I_O_N__D_E_C_O_M_P_O_S_E_D__N_O_R_M_A_L__M_A_T_R_I_X___| | | | | |__Field_________|______Description__________________|___Format_____| | | | | | Decomposed | Row index for the normal matrix. | 1X,I5 | | normal matrix | It must match the parameter index | | | row index | in the SOLUTION/ESTIMATE block | | | | for the same parameter. | | |________________|___________________________________|______________| | | | | | Decomposed | Column index for the normal matrix| 1X,I5 | | normal matrix | It must match the parameter index | | | column index | in the SOLUTION/ESTIMATE block | | | | for the same parameter. | | |________________|___________________________________|______________| | | | | | Decomposed | Matrix element at the location | 1X,E21.14 | | normal matrix | (row index, column index). | | | element | | | |________________|___________________________________|______________| 2.6 New block SOLUTION/DECOMPOSED_NORMAL_VECTOR BLOCK ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This block contains decomposed right hand parts of normal equations for the subset of parameters described in the SOLUTION/ESTIMATE block. In the case if the SOLUTION/ESTIMATE block describes all parameters adjusted in the solution, the decomposed normal vector is equivalent to the full normal vector. In the case if the SOLUTION/ESTIMATE block describes only a subset of parameters, then the decomposed normal vector d_i is defined as d_i = n_i - N_ei(T) * (C_ee + N_ee){-1} * n_e where n_i -- the block of normal vector which corresponds to the equations listed in the SOLUTION/ESTIMATE; n_e -- the block of the normal vector which corresponds to the omitted parameters; N_ee -- the block of normal matrix which corresponds to omitted parameters; N_ei -- the block of normal matrix which corresponds to the product of equations of conditions of the omitted parameters and parameters from the SOLUTION/ESTIMATE list. C_ee -- the block of normal matrix of constraints which corresponds to omitted parameters; Solve computes d_i as d_i = D_i * e_i where e_i -- vector of the estimates of the parameters from the SOLUTION/ESTIMATE list. ___________________________________________________________________ |__S_O_L_U_T_I_O_N__D_E_C_O_M_P_O_S_E_D__N_O_R_M_A_L__V_E_C_T_O_R___| | | | | |__Field_________|______Description__________________|___Format_____| | | | | | Estimated | Index of the estimated parameter. | 1X,I5 | | Parameter | | | | Index | | | | | | | |________________|___________________________________|______________| | | | | | Element of | Element of the decomposed normal | 1X,E21.14 | | decomposed | ( Row Number , Column Number ). | | | normal vector | ( Row Number , Column Number ). | | |________________|___________________________________|______________| | | | 28 | |______________| 2.7 New block NUTATION/DATA ~~~~~~~~~~~~~~~~~~~~~~~~~~~ This block describes which apriori nutation model is used and what is the reference model to which the nutation angles are referred. ___________________________________________________________________ |_________________N_U_T_A_T_I_O_N___D_A_T_A___L_I_N_E_______________| | | | | |__Field_________|______Description__________________|___Format_____| | | | | | [Nutat. Code] | Code for nutation reference | 1X,A8 | | | NONE | | | | REN2000 | | | | IAU1980 | | | | IERS1996 | | | | IAU2000a | | | | IAU2000b | | |________________|___________________________________|______________| | | | | | [Nut. Usage] | Usage flag: APR or REF | 1X,A3 | | | APR means that the previous | | | | field kept the nutation model | | | | used for apriori. | | | | REF means that the previous | | | | field kept the nutation model | | | | used as a reference. | | | | NONE means that the total | | | | nutation angles are presented | | |________________|___________________________________|______________| | | | | | Comments | | 1X,A66 | |________________|___________________________________|______________| | | | 80 | |______________| 2.8 New block PRECESSION/DATA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This block describes the apriori precession constant which was used. ___________________________________________________________________ |_________________N_U_T_A_T_I_O_N___D_A_T_A___L_I_N_E_______________| | | | | |__Field_________|______Description__________________|___Format_____| | | | | | [Prec. Code] | Code for nutation reference | 1X,A8 | | | NONE | | | | IAU1980 | | | | IAU2000 | | |________________|___________________________________|______________| | | | | | Comments | | 1X,A70 | |________________|___________________________________|______________| | | | 80 | |______________| Nutation angles can be presented either as nutation in obliquity and nutation in longitude in accordance to Newcomb-Andoyer formalism or as nutation X, nutation Y in accordance to Ginot-Capitaine formalism. Contrary to claims of Dr. Capitaine, both approaches are equivalent. 2.9 New block SOURCE/ID ~~~~~~~~~~~~~~~~~~~~~~~ ___________________________________________________________________ |_____________R_A_D_I_O___S_O_U_R_C_E___D_A_T_A___L_I_N_E___________| | | | | |__Field_________|______Description__________________|___Format_____| | | | | | Source Code | Call sign for a source | 1X,A4 | |________________|___________________________________|______________| | | | | | IERS name | IERS name of the radio source | 1X,A8 | |________________|___________________________________|______________| | | | | | ICRF name | ICRF name of the radio source | 1X,A16 | |________________|___________________________________|______________| | | | | | IAU name | IAU J2000.0 name of the radio | 1X,A10 | | | source | | |________________|___________________________________|______________| | | | | | IVS name | IVS name of the radio source | 1X,A8 | |________________|___________________________________|______________| | | | | | Comments | Comments or other names of the | 1X,A29 | | | radio source | | |________________|___________________________________|______________| | | | 80 | |______________| 3 Deviations from the SINEX 2.10 standard ========================================= Sinex listing in 2.20 format has different names for parameters in accordance to an anonymous document circulated in 2008 known as "Proposal 2". 4 Implementation in Solve ========================= Solve normally produces the listing in its own so-called "spool-format". In addition to the spool listing, Solve has a limited ability to generate listings in Sinex format. It can write the listing in Sinex format when it runs in batch mode. Description of the keyword Sinex in the control language can be found in http://gemini.gsfc.nasa.gov/solve_root/help/solve_guide_03.html#section3.13 When a user requests to apply specific constraints, Solve does not modify normal matrix immediately. Procedures of imposing constraints collect all constraint equation coefficients, weights, right hand part equations as well as constraint description in an intermediate data structure. After collecting all information about constraints Solve "applies" constraints by modifying normal matrix and normal matrix. If a Sinex output option is specified, then Solve passes this intermediate data structure to the routine which writes listing down and, thus, this subroutine has access to full information about the constraints. Solve allows a user to specify which items among ESTIMATES, COVARIANCES, CONSTRAINTS, DECOMPOSED_NORMAL_EQUATIONS or all of them are to be included in the listing together with mandatory blocks. Solve allows a user to specify which parameters are to be included in the output. Currently, Solve does not allow to include any parameter in the listing, but only one from the pre-defined list of supported parameter. 4.1 Syntax of INCLUDE_PARAM and EXCLUDE_PARAM lists ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INCLUDE_PARAM and EXCLIDE_PARAM files contain the parameter lists. List consists of one or more lines with Solve intrinsic 20-characters long parameter names. The lines which starts from # are considered as comments. Wild-card symbols * and ? can be included. Solve check the name of each estimated parameter against INCLUDE_PARAM list. If the name matches with at least one line (except comment) then the name is flagged as "included". After that Solve check each parameter against EXCLUDE_PARM list. If it matches with at least one line (except comment) then it is flagged as "excluded". All parameters which are flagged as "included" and are not flagged as "excluded" will be included in the Sinex output. The list of intrinsic parameter names: Parameters which can be put in the listing in Sinex format: ssssssss X COMPONENT X-coordinate of station position at reference epoch ssssssss Y COMPONENT Y-coordinate of station position at reference epoch ssssssss Z COMPONENT Z-coordinate of station position at reference epoch ssssssss X VELOCITY X-coordinate of station velocity ssssssss Y VELOCITY Y-coordinate of station velocity ssssssss Z VELOCITY Z-coordinate of station velocity ssssssss Xyymmdd-COO X-coordinate of station position at epoch yymmdd ssssssss Yyymmdd-COO Y-coordinate of station position at epoch yymmdd ssssssss Zyymmdd-COO Z-coordinate of station position at epoch yymmdd ssssssss Xyymmdd-POS X-coordinate of station position at epoch yymmdd ssssssss Yyymmdd-POS Y-coordinate of station position at epoch yymmdd ssssssss Zyymmdd-POS Z-coordinate of station position at epoch yymmdd ssssssss AXIS OFFSET axis offset of the ssssssss station X WOBBLE 0yymmddhhmm X-coordinate of pole position at epoch yymmddhhmm X WOBBLE 1yymmddhhmm Time derivative of X pole coordinate at yymmddhhmm Y WOBBLE 0yymmddhhmm Y-coordinate of pole position at epoch yymmddhhmm Y WOBBLE 1yymmddhhmm Time derivative of Y pole coordinate at yymmddhhmm UT1-TAI 0yymmddhhmm UT1 angle at epoch yymmddhhmm UT1-TAI 1yymmddhhmm First time derivative of UT1 angle at epoch yymmddhhmm LONGITUDE NUTATION Nutation in longitude OBLIQUITY NUTATION Nutation in obliquity qqqqqqqq RIGHT ASCEN Right ascension at J2000.0 epoch qqqqqqqq DECLINATION Declination at J2000.0 epoch qqqqqqqq RIGHT ASC V Proper motion in right ascension qqqqqqqq DEC VELO Proper motion in declination Other parameters which the current version of Solve cannot put in the listing in Sinex format: ssssssssA0yymmddhhmm Atmosphere path delay at epoch yymmddhhmm ssssssssa0yymmddhhmm Atmosphere path delay at epoch yymmddhhmm ssssssssC0yymmddhhmm Global clock offset at epoch yymmddhhmm ssssssssC1yymmddhhmm Global clock rate at epoch yymmddhhmm ssssssssC2yymmddhhmm Global clock rate drift at epoch yymmddhhmm ssssssss--ssssssss C baseline dependent clocks ssssssssNGyymmddhhmm Atmosphere gradient in north direction ssssssssEGyymmddhhmm Atmosphere gradient in east direction X WOBBLE 2yymmddhhmm Second time derivative of X pole coordinate at yymmddhhmm Y WOBBLE 2yymmddhhmm Second time derivative of Y pole coordinate at yymmddhhmm UT1-TAI 2yymmddhhmm Second time derivative of UT1 angle at epoch yymmddhhmm Gamma Relativistic PPN parameter gamma where "ssssssss" stands for the IVS station name "qqqqqqqq" stands for the IVS source name "yyddmmhhss" stands for time epoch like 980729113459 -- July 29, 1998 11 hours 34 minutes 59 seconds. 4.2 Examples of INCLUDE_PARAM and EXCLUDE_PARAM lists ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1. daily_inc.bsc # # -- Include parameters which will be put in Sinex listing # # The following parameters are to be included in the Sinex listing: # # 1) Station coordinates # 2) pole coordinates # 3) UT1 # 4) rate of change of pole coordinates # 5) rate of change of UT1 # 6) daily nutation angles # ?????????X COMPONENT ?????????Y COMPONENT ?????????Z COMPONENT ?????????X??????-COO ?????????Y??????-COO ?????????Z??????-COO ?????????X??????-POS ?????????Y??????-POS ?????????Z??????-POS X WOBBLE 0* X WOBBLE 1* Y WOBBLE 0* Y WOBBLE 1* UT1-TAI 0* UT1-TAI 1* LONGITUDE NUTATION OBLIQUITY NUTATION 2. daily_exc.bsc # # -- Exclude parameters which will be put in Sinex listing # # Nothing to exclude # 3. daily_esc_notigo.bsc # # -- Exclude parameters which will be put in Sinex listing # # All parameters related to station TIGOCONC are excluded # # (NB: no common constraint equations with other stations can be # imposed if computation of the decomposed normal matrix is required ) # TIGOCONC* 4.3 Treatment of station with discontinuous motion ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ It is an empirical fact that some stations has a quasi-instant motion due to seismic events, rails repair and other reasons of instability of VLBI site positions. It is an analyst who determines the appropriate model for handing such stations. In the case if an analyst trusts to results of the measurements of such a motion by an independent technique, f.e. results of local survey before and after rails repairing, then position of the station is modeled by one parameter, and the motion of the station is described by the set of eccentricity values at the epochs before and after the motion. If an analyst does not trust to independent measurements, or such measurements are unavailable, f.e. in the case of seismic motion, then coordinates of such station are described by a model X = a1*B0(t0,t1) + a2*B0(t1,t2) + ... + b*(t-tref) where B0 -- a basis spline of the 0-th order on the range t0, t1 ( it is 1 at the range [t0, t1], and 0 otherwise ) tref -- reference epoch; t0 -- epoch of the first observations; t1, t2 ... -- epoch of discontinuities. Parameters a1, a2 ... have the same parameter name STAX, STAY, STAZ, but they are distinguished by sub-index 1,2... in the field SBIN (former name SOLN). This field is used in sections SITE/EPOCHS, SITE/APRIORI, SITE/ESTIMATES. If the station did not have discontinuity in the motion than SBIN always has the value 1. The modern approach is to model non-liner site position with B-spline or order 0,1,2,3. Sinex format does not allow to put in the listing estimates of B-spline of order higher than 0. 4.4 Restrictions ~~~~~~~~~~~~~~~~ The current implementation (2002.10.04) cannot write the listing in Sinex format in several cases: 1) Constraint NO_NET_TRANSLATION is not supported. Use NO_NET_TRANSLATION_POSITION instead of that. 2) Suppressions VELOCITIES NO STATIONS NO SOURCES NO PROPER_MOTIONS NO 3) Solve cannot put in the listing site position modeled by linear spline. 4) Currently, Solve can include in Sinex listing global parameters if it runs in global mode and local parameters if it runs in independent mode. It cannot include local parameters if it runs in global mode. This restriction may be lifted in the future. 5) Solve cannot include in the listing in Sinex format second and higher order UT1 and polar motion time derivatives. 6) Solve cannot include user parameters in the listing in Sinex format, but can include user constraints. 7) No common constraints between included and not included parameters can be imposed if computation of decomposed normal matrix is required. Solve will issue a warning if a constraint equation has non-zero elements for the parameters from both groups of included and not included parameters in the case if computation of a decomposed normal matrix is required, and will issue an error message and stop if the decomposed normal matrix is to be included in the sinex listing.