Data Format of the Key Stone Project VLBI Analysis Results

Yasuhiro Koyama
Kashima Space Research Center
Communications Research Laboratory
893-1 Hirai, Kashima, Ibaraki 314, Japan

1. Introduction

Observed data of the daily VLBI experiment of the Key Stone Project are analyzed every day automatically. The latest results of the daily analysis are available to the public in various ways. Any researchers interested in the Key Stone Project data can access the results over the Internet. At present, following three methods are available to access the results.
                                Table 1. [exp.inf]

 94/08/29 04:54 -- 94/08/30 05:27   94AUG29XX.out   11-Aug-95 17:09:20
 94/12/20 01:00 -- 94/12/21 01:01   94DEC21XX.out    6-Sep-95 11:14:01
 95/01/17 08:07 -- 95/01/18 06:04   95JAN17XX.out   16-Feb-96 23:17:45
 95/01/19 00:00 -- 95/01/20 00:03   95JAN19XX.out    6-Sep-95 11:14:03
 95/01/31 00:00 -- 95/01/31 04:17   95JAN31XX.out    6-Sep-95 11:14:06
 95/02/01 00:00 -- 95/02/01 04:18   95FEB01XX.out    6-Sep-95 11:14:06
 95/02/02 00:16 -- 95/02/02 04:24   95FEB02XX.out    6-Sep-95 11:14:07
 95/02/03 00:00 -- 95/02/03 04:24   95FEB03XX.out    6-Sep-95 11:14:08
 95/02/06 00:00 -- 95/02/06 04:17   95FEB06XX.out    6-Sep-95 11:14:08
 95/02/07 00:00 -- 95/02/07 04:14   95FEB07XX.out    6-Sep-95 11:14:09
                                      .
                                      .
 96/04/07 15:00 -- 96/04/07 20:13   96APR07XX.out   10-Apr-96 14:45:19
 96/04/08 15:00 -- 96/04/08 20:17   96APR08XX.out   10-Apr-96 15:14:27
 96/04/09 15:00 -- 96/04/09 20:15   96APR09XX.out   11-Apr-96 15:01:04

2. e-mail

Baseline lengths and site position displacements from the arbitrarily determined reference position are formatted in a text file and sent to the e-mail addresses registered beforehand. The displacements are expressed in the east-west, north-south, and vertical up-down directions. Reference positions have been determined by an analysis based on the ITRF93 coordinate system upon an experiment performed on January 19, 1995, when two KSP stations (Kashima and Koganei) and 34m antenna station at Kashima participated in the same VLBI experiment. Although this method is only used internally at present, the e-mail address of a responsible researcher in Japan Meteorological Agency (JMA) will be added to the distribution list. JMA will use this information as one of many data related with the earthquake research around Tokyo.

3. anonymous FTP

Either ASCII data files of Postscript graphics files are accessible in the anonymous FTP area of the data analysis computer. One can access all these files at kouma.nict.go.jp by giving 'anonymous' for the username and e-mail address for the password. Following sections describe the data file format of the ASCII data files accessible by means of anonymous FTP.

3.1 Miscellaneous information about each experiment

Miscellaneous information for each experiment can be obtained in the file {\tt exp.inf}. The time and date of the first and last observations in each experiment, along with the data and time when the latest analysis was done, are given in the file. The other file, {\tt stat.dat}, gives statistical information, such as root-mean-square delay residual in the data analysis, number of data used for the analysis and number of data excluded from the analysis. Information on all baselines is stored in a single file.
                               Table 2. [stat.dat]

Exp Code    Duration (Start-End)               Baseline          RMS delay   # of Obs.
                                                                    (ns)    good(bad)
94AUG29XX   94/08/29 04:54 -- 94/08/30 05:27   KASHIM11-KOGANEI     .060      122(131)
94DEC21XX   94/12/20 01:00 -- 94/12/21 01:01   KOGANEI -KASHIM11    .047      139( 54)
95JAN19XX   95/01/19 00:00 -- 95/01/20 00:03   KASHIM11-KOGANEI     .069      151( 40)
95JAN31XX   95/01/31 00:00 -- 95/01/31 04:17   KASHIM11-KOGANEI     .031       40(  2)
95FEB01XX   95/02/01 00:00 -- 95/02/01 04:18   KASHIM11-KOGANEI     .034       37(  5)
95FEB02XX   95/02/02 00:16 -- 95/02/02 04:24   KASHIM11-KOGANEI     .042       36(  5)
95FEB03XX   95/02/03 00:00 -- 95/02/03 04:24   KASHIM11-KOGANEI     .046       36(  6)
95FEB06XX   95/02/06 00:00 -- 95/02/06 04:17   KASHIM11-KOGANEI     .048       33(  9)
95FEB07XX   95/02/07 00:00 -- 95/02/07 04:14   KASHIM11-KOGANEI     .059       33(  6)
                                     .
                                     .
96APR07XX   96/04/07 15:00 -- 96/04/07 20:13   KASHIM11-KOGANEI     .024       86(  3)
96APR08XX   96/04/08 15:00 -- 96/04/08 20:17   KASHIM11-KOGANEI     .021       32( 58)
96APR09XX   96/04/09 15:00 -- 96/04/09 20:15   KOGANEI -MIURA       .027       89(  4)

3.2 Baseline length data

Estimated baseline lengths from every experiments are stored in the file, {\tt baseline.dat}. All the baselines are stored in a single file. Standard deviation of the estimated baseline lengths are given in the last column.
                           Table 3. [baseline.dat]

             MJD        Baseline          BL Length (mm)    Error (mm)
  94AUG29XX  49593.204  KASHIM11-KOGANEI   109099666.40          7.20
  94DEC21XX  49706.042  KASHIM11-KOGANEI   109099655.70          5.40
  95JAN19XX  49736.000  KASHIM11-KOGANEI   109099660.10          4.00
  95JAN31XX  49748.000  KASHIM11-KOGANEI   109099677.20          8.50
  95FEB01XX  49749.000  KASHIM11-KOGANEI   109099682.50         11.50
  95FEB02XX  49750.011  KASHIM11-KOGANEI   109099676.60         11.60
  95FEB03XX  49751.000  KASHIM11-KOGANEI   109099662.90         12.70
  95FEB06XX  49754.000  KASHIM11-KOGANEI   109099653.60         19.60
  95FEB07XX  49755.000  KASHIM11-KOGANEI   109099681.50         19.50
                            .
                            .
  96APR07XX  50180.625  KASHIM11-KOGANEI   109099659.50          2.90
  96APR08XX  50181.625  KASHIM11-KOGANEI   109099677.70         13.70
  96APR09XX  50182.625  KOGANEI -MIURA      57734581.10          4.30

3.3 Site coordinate data

Site coordinates in either global geocentric rectangular coordinate system (XYZ) or the locally defined coordinate system (ENU) are stored in multiple files. There are two files each for all four stations. In case when the site coordinates were fixed as {\it a-priori} information for reference station, the errors in the data files are denoted as 0.00 mm. Otherwise, the errors are given from the one standard deviation obtained through least-square parameter adjustment estimation. Correlation factors between each coordinate component are also given. Each line represent the results from a single experiment.
                           Table 4. [koganei.xyz]
                           
           MJD            X (mm)     X err    Y (mm)     Y err    Z (mm)     Z err   Cxy     Cxz     Cyz
94AUG29XX  49593.204  -3941937455.20 24.85 3368150904.60 18.28 3702235290.20 21.41  -.8925  -.9177   .8722
94DEC21XX  49706.042  -3941937470.60 17.33 3368150901.40 11.06 3702235300.70 15.56  -.9001  -.9520   .8660
95JAN19XX  49736.000  -3941937480.80  6.28 3368150915.60  5.99 3702235307.90  5.63  -.8243  -.8347   .8064
95JAN31XX  49748.000  -3941937479.40 26.66 3368150937.80 18.29 3702235322.50 26.22  -.8978  -.9659   .8617
95FEB01XX  49749.000  -3941937413.90 34.19 3368150885.60 26.07 3702235245.30 32.69  -.8837  -.9634   .8325
95FEB02XX  49750.011  -3941937526.30 39.74 3368150968.90 25.32 3702235336.60 40.70  -.9345  -.9379   .8661
95FEB03XX  49751.000  -3941937479.30 39.95 3368150914.00 26.94 3702235295.30 40.62  -.9059  -.9666   .8655
95FEB06XX  49754.000  -3941937436.00 61.20 3368150869.00 44.65 3702235264.30 57.06  -.8925  -.9679   .8483
95FEB07XX  49755.000  -3941937466.00 62.33 3368150924.60 40.80 3702235280.60 62.51  -.9124  -.9725   .8755
                                     .
                                     .
96APR07XX  50180.625  -3941937481.10 10.40 3368150910.70  8.19 3702235289.70  8.06  -.9034  -.9389   .8903
96APR08XX  50181.625  -3941937410.10124.12 3368150879.40 86.05 3702235248.70100.38  -.9942  -.9953   .9953
96APR09XX  50182.625  -3941937480.80   .00 3368150916.60   .00 3702235307.90   .00   .0000   .0000   .0000


                            Table 5. [koganei.enu]

           MJD            E (mm)     E err    N (mm)     N err    U (mm)     U err   Cen     Ceu     Cnu
94AUG29XX  49593.204           -7.54  7.30          1.54  6.80        -32.51 36.20   .0410   .3630  -.0800
94DEC21XX  49706.042            4.90  5.20          4.44  4.20        -18.57 24.90   .3570   .6240   .1930
95JAN19XX  49736.000             .73  2.60           .38  2.50          -.58  9.70   .0890  -.1350  -.1930
95JAN31XX  49748.000          -17.06  7.80          4.44  6.90         18.79 40.30   .6020   .5340   .3890
95FEB01XX  49749.000          -19.92 10.40         -9.39  9.20        -94.24 52.20   .6340   .3500   .1860
95FEB02XX  49750.011          -10.24 10.40        -16.72 13.00         72.38 60.00   .4760   .6990   .4310
95FEB03XX  49751.000             .97 11.40         -8.58 11.00         -9.70 61.00   .6430   .5750   .4760
95FEB06XX  49754.000            7.05 18.00          2.52 15.00        -78.26 91.90   .6140   .4330   .1760
95FEB07XX  49755.000          -15.73 17.60        -18.63 16.00        -20.90 94.30   .6800   .6280   .4960
                                      .
                                      .
96APR07XX  50180.625            4.65  2.90        -12.68  2.60        -13.60 15.00   .0530   .2410  -.4370
96APR08XX  50181.625          -17.68 17.10         -2.59  9.20        -97.87180.30  -.6710   .8920  -.6710
96APR09XX  50182.625            -.03   .00           .00   .00          -.05   .00   .0000   .0000   .0000

4. World Wide Web (WWW)

By using one of many browser applications for the World Wide Web, one can view and download all the files accessible by means of anonymous FTP. In addition to the data accessible by the anonymous FTP method, one can display plots of these data graphically and browse detailed output of parameter estimation software VLBEST for each experiment. To achieve these capabilities, HTML (Hyper Text Makeup Language) files are automatically produced according to the available data set. The WWW homepage is accessible at the URL http://kouma.nict.go.jp (for Japanese language homepage, use http://kouma.nict.go.jp/index-J.html instead). Figure 1 shows what the homepage of the Key Stone Project looks like.

Figure 1. Homepage of the Key Stone Project (URL http://kouma.nict.go.jp).

In the detailed output of VLBEST, one can access all the adjusted values estimated in the analysis. Usually, the hydrostatic atmospheric delay in the zenith direction at interval of three hours, clock offsets and their rates (clock parameters) at interval of three hours, site coordinates of all stations except for a reference station are the parameters to be adjusted. Theoretical models used in the analysis are also described in the VLBEST output.

5. In the Future

At present, the SINEX data format is being considered to be adopted to release detailed analysis results to the public. The SINEX format is widely used as a standard by the GPS community, and therefore the format will be preferable to exchange data with other organizations. Under the Key Stone Project, SLR and GPS data will be observed too. These data set will also be analyzed and released along with the VLBI data.




Updated on June 25, 1995. Return to CONTENTS