M. Kaufman, S. Pasynok e - mail: mark@vniiftri.ru, pasynok@vniiftri.ru
Russian State Time, Frequency and Earth Rotation Service (RTE) is permanently functioning system of Russian facilities and organizations incorporated into the common scientific, technical and metrological activity, which includes continuous reproduction, keeping and dissemination of the national time scale and also determination of Earth s orientation parameters (EOP). The Main Metrological Center (MMC) of the Service is located in National Research Institute for Physical and Radio-technical Measurements (VNIIFTRI).
Points of the observations Russian VLBI network KVASAR KVO Russian GPS/GLONASS receivers net (RAS, ROSSTANDARD, ROSREESTR & others) Russian SLR station Russian Centers of data processing and analysis (IAA RAS, IAC GLONASS,VIIFTRI) forms the it s own raws of EOP for VLBI, GNSS and SLR Rapid combination solutions in MMC RTE
VNIIFTRI processed VLBI observation from 2004 but now we have to renew our VLBI processing software. Why we choose the VieVS? 1. It s multisystem software (LINUX,UNIX,Windows) 2. It has easy readable code which one can comparatively easy to understand and add supplements themselves when it is needed. VNIIFTRI uses VieVS since 2010
But for Rapid Service (when data are processed at night when people sleep) there are some desirable additional features for automatic work of the VieVS software, in particular: - collect of data of observations; - start of program; - find the outliers and problem station; - creation and saving detailed text and graphical protocols of automatic processing; - create EOP files in IERS and our internal. We developed the Matlab function EOP_START.m for these purposes.
NGS (IVS) EOP(IERS) ATM(Vienna TU) Collect of new data Detect of session type (24-h or Intensive 1-h) Setting of processing parameters VieVS Block s ITERATIONS: VIE_INIT VIE_MOD VIE_LSM Correctin ng EOP in IVS Format GOOD Analysis of outliers PROBLEMS FTP for users Graphical and text protocols for following handling analysis
MAIN PROCESSING PARAMETERS Unknowns Pole coordinates Universal Time Nutation ti Tropospheric zenith wet delay Tropospheric gradients x,y UT1 dx,dydy ZWD NGR,EGR Sessions 1h 24h Power of clock polynoms PWL 1 3
1. SEARCH OF OUTLIERS The outlier is detected t d when the O-C > 5*σ0. We use not RMS as σ0, but interquartile range (IQR). The such data IQR is a robust estimate of the spread of the data, since changes in the upper and lower 25% of the data do not affect it. If there are outliers in the data, then the IQR is more representative than the RMS as an estimate of the spread of the body of the data. 2. DETECT OF BAD STATIONS The station is interpreted as BAD when the number of non-outlier outlier observations is less then 10% of mean number of observations per station. The information about bad observations and stations is saved in the OUTLIERS and OPT files of VieVS structure.
RESULTS The results of each session processing are interpolated to the mean epoch of session and are converted in one string according to IVS format for EOP data. The string contains: MJD; EOP (x, y, UT1, dx, dy); EOPs uncertainties; wrms residual dl delay of thesession inps; correlation coefficients : k(x, y); k(x, UT1); k(y, UT1); k(dx/dy); number of observables; 6 character of IVS session code; span of the observation (in hours); rates of EOPs and their uncertainties; sequence of two character IVS station identifiers. The string is inserted in the longtime series files in chronological order (it replace the previous version string for these session if it is founded there).
The experimental evaluations are daily provided since of 2011. The results are saved in files named as rte2011a.eopi; rte2011a.eoxyeoxy and are accessable on ftp address: ftp.vniiftri.ru/out_data/vlbi_rte/