Technical description of solution rfc_2022d Purpose of solution: get the best positions of all sources with two or more good observations Short narrative description of solution: 1) Data set: All dual-band X/S Mark-3, Mark-4, Mark-5, S2, K3, K4, K5, VLBA, VERA, LBA observations under geodesy and astrometry programs, and K-band only VLBA sessions. This includes 897 absolute astromery experiments from 59 dedicated astrometric pgrograms and 6779 IVS geodetic VLBI experiments. In total, 8009 VLBI experiments from 1980.04.11 through 2022.06.07, 21,893,876 estimates of group delay were used in solutions. The dataset was split into seven parts: VLBA X/S experiments, VLBA X/C experiments, VLBA X-band experiments, VLBA K-band experiments, VLBA C-band experiments, VERA experiments, and selected astrometric experiment and all other observing sessions. These parts were processed with slightly different procedures for outlier elimination and re-weighting. Positions of sources with declination above -40 deg are almost entirely derived from VLBA data. Non-VLBA data contributed to positions of southern sources and only marginally contributed to positions of sources with declination > -40 deg. All absolte astromery exeriments at the VLBA, LBA, and EVN were reprocessed anew using measured interferometric visibilites that can be found in raw correlator output using advanced fringe fitting software PIMA. PIMA improves detection limit with respect to AIPS processing by sqrt(N_IF), where N_IF is the number of intermediate frequencies (IF) per band, either 4 or 8 in most VLBA experiment, thus improving sensitivity by the factor of 2-3. Reprocessing allowed to detect many sources previously undetected, and increase the number of points for other weak sources. X-band, S-band, C-band, K-band, and dual-band (X/C plus X/S) data were processed separately: outliers eliminated, group delay ambiguities were resolved once again, and additive contributions to apriori weights were re-evaluated. The sequence: group delay ambiguity resolution, outlier elimination, re-weighting, astrometric solutions, apriori position update was repeated several times. For IVS data, outliers were eliminated and reweighting parameters were recomputed. 2) Theoretical path delay was computed using VTD package with the state of the art model: -- including computation of the troposphere slant path delay by integration of a system of non-linear differential equations of radio wave propagation using the field of refractivity index computed from results of the 4D numerical weather model MERRA2. -- including ocean loading, atmospheric pressure loading, atmospheric tides; -- including solid Earth tides according to the Mathews anelastic model MDG97AN -- using empirical harmonic Earth orientation variations model heo_20210317 -- using computation of the ionosphere delay using GPS TEC maps after April 1998 (only for single-band experiments). 3) Parameterization: 3.1) Clock for each station except the one taken as a reference was modeled with a sum of the 2nd degree polynomial over the experiment duration and the B-spline of the first degree with time span of 60 minutes. The clock rate was constrained to zero with reciprocal weights 2.D-14 s/s. Clock breaks and clock rate breaks at some stations were estimated for a limited number of experiments. 3.2) Atmosphere path delay in zenith direction for each station was modeled with the B-spline of the first degree with time span of 20 minutes. The atmosphere path delay rate in zenith direction was constrained to zero with reciprocal weights 40 ps/s. 3.3) The direction of the axis symmetry of the local atmospheric path delay for each station, except those defined in the exception list, was modeled with the B-spline of the first degree with time span of 6 hours. 3.4) The baseline-dependent clocks were estimated for each linear independent triangle for each experiment separately. 3.5) The polar motion and UT1 as well as their rates of change were estimated for each experiment separately. 3.6) Daily offsets to nutation were estimated for each experiment separately. 3.7) Position of stations was modeled with a sum of four components using all available data: a) position at reference epoch, 2000.01.01 b) linear velocity c) Sum of harmonic model at four frequencies: alpha) diurnal beta) semi-diurnal gamma) annual delta) semi-annual d) B-spline for the following stations: AIRA CHICH10 DSS15 DSS65 EFLSBERG FORTORDS GGAO7108 GILCREEK HOBART26 HRAS_085 KASHIM11 KASHIM34 KOGANEI MEDICINA MK-VLBA MIURA MOJAVE12 PIETOWN PRESIDIO SINTOTU3 SOURDOGH TATEYAMA TIGOCONC TSUKIB32 VERAMZSW WHTHORSE YAKATAGA The B-spline model accounts for non-linear motion and discontinuities caused by seismic and post-seismic motion, as well displacement of the antenna reference point caused by rail repairs. 3.8) Coordinates of all sources with 2 or more good observations were estimated using all available data. 3.9) Antenna axis offsets lengths for 66 stations were estimated using all available data. 4) Constraints: 4.1) Net translation and net rotation constraints were imposed on positions of 48 stations in such a manner, that the resulting position of these stations have no net translation and net rotation with respect to the positions in the ITRF2000 catalogues. 4.2) Net translation and net rotation constraints were imposed on velocities of 44 stations in such a manner, that the resulting velocities of these stations have no net translation and net rotation with respect to the velocities in the ITRF2000 catalogues. 4.3) Net rotation constraints were imposed on coordinates of 212 sources in such a manner, that the resulting coordinates of these sources have no net rotation with respect to the coordinates of these sources in the ICRF catalogue marked as "defining". 4.4) Velocities of 38 stations with insufficiently long history were constrained to the apriori values with reciprocal weights 0.1 mm/yr for the vertical component and 3 mm/year for horizontal components. 4.5) Weak constraints with reciprocal weights of 1.D-4 rad were imposed on portions of all sources. Comment: constraints 4.1, 4.2, and 4.3 are necessary for solving for coordinates and their first time derivatives. Coordinates and their time derivatives cannot be determined solely from observations. The observations allows to determine the family of solutions. Since equations of photon propagation are differential equations, the solution of differential equations depends on boundary conditions. The constraints 4.1, 4.2, and 4.3 provide the set of boundary condition that allows to pick up an element from the family of solution determined by observations. 5) Solutions. The main astrometric solutions uses all available data. The a priori uncertainties were re-scale by E = dsqrt ( E_A^2 + E_B(B)^2 + e*M(E1)^2 + e*M(E2)^2 ) where E_A is the a priori uncertainties of the group delay or the ionosphere free combination of group delays computed by the fringe fitting algorithm E_B(B) is the baseline dependent correction to weight computed for each experiment, each baseline separately in such a manner that the ration of the weighted sum of postfit residuals for a given baseline to its mathematical expectation is close to zero. M(e) mapping function, i.e. the ratio of the slanted path delay in neutral atmosphere at given direction to the path delay at zenith direction. Ei elevation angle of a source at the i-th station e scaling coefficient of propagation of remaining errors in atmospheric path delay. Value of 0.02 was used in this solution. The reported errors in the output catalogue were produced from formal uncertainties by applying the reweighting: err = sqrt ( ( a(delta)*unc)**2 + b(delta)**2 ) where unc is formal uncertainty of estimates from the LSQ solutions and a(alpha), b(delta) are elevation dependent parameters of the empirical error model.