Ground Tracking Station (GTS) Products

The file naming conventions used in the section use a single letter to designate each GTS: 'p' for Pushchino, 'd' for Goldstone, 't' for Tidbinbilla, 'm' for Madrid, and 'g' for Green Bank.

What: VLBI data from the satellite will be recorded on VLBI tapes at the GTSs. Tapes will be dismounted from the recorder when the tapes have reached their capacity or after n days have elapsed since the tape was mounted, whichever comes first. Currently, for VLBA tapes n = 3, and for S2 tapes n = 8. These tapes must arrive at the designated correlator within 2 weeks of the last observation on the tape.

How: Tape labelling and shipping schemes are available by e-mail from vlbatape@nrao.edu for VLBA tapes and are given in "S2 SVHS Tape Handling Overview for VSOP" for S2 tapes. Shipping addresses for correlators are given in Mission Element Points-of-Contact.

When: Tapes must arrive at the correlator no later than 2 weeks after the last support period included on the tape. GBTS will ship tapes within 72 hours of the time data were last written to tape.

What: Ku-band telemetry headers will be used by the GOCG to monitor the health and safety of the spacecraft and by RSOG to produce necessary log and calibration files. Telemetry headers are provided in 10 or 15 minute blocks in near real-time, and for the complete pass after the pass has finished.

How: The GBTS will make telemetry headers available in 15 minute blocks. The 15 minute blocks will have names based on the start time of each block, in the format YYMMDDHHMM.ktg, where the YYMMDD is the date of the data in the file and the HHMM is the time of the first data in the file, but in even 15 minute boundaries (e.g. data taken on 97 March 15 from 0h22m01s to 0h30m00s UTC will be placed in a file named '9703150015.ktg').
DOTS will create 10 minute telemetry header files.
The file format will be given in "RadioAstron Science Header Data Format".

When: For the GBTS, each telemetry header block will be available 2 minutes after the end of that 15 minute block (e.g. 9703150015.ktg will be available at 97 March 15 at 00h32m00s).
DOTS will place files on its FTP site within 30 minutes of the start of each 10 minute telemetry header file.

Where: For DSN GTSs: the 10 minute THFs are available from pub/RadioAstron/raoper/data/srt/dsn/kutlm2, on the DOTS FTP site.
For the GBTS: the files are available in the GBTS FTP site in directory /ovlbi/out/kutlm2.
For the Pushchino GTS: from /RadioAstron/RAoper/data/srt/push/kutlm on the RSOG FTP site.
See Mission Element FTP Sites for details of these sites.

How: Files are made available by the GTSs. File names are of the form YYMMDDHHMM.ktX[.v], where the time refers to the start time defined by the BGN2LK command in the SRS file, and the X is the single letter code for the GTS.
For the GBTS and the DOTS, the telemetry headers will be recorded in a single file for the entire tracking pass. If there are data dropouts during the pass, there will be gaps in the THF records. If the two-way link begins on 97 March 15 at 0h22m01s UTC, all telemetry data will be placed in the file named '9703150022.ktg'.
After the file for the whole pass has been placed on the FTP site, all shorter intermediate files will be deleted for the GBTS, but will be maintained for the DOTS.
The file format will be given in "RadioAstron Science Header Data Format".

When: The telemetry headers from the Pushchino GTS will be made available to the RSOG less than one hour after reception at the GTS.
For the GBTS, the entire telemetry header data for a tracking pass will be made available no later than 24 hours after the pass ends.
DOTS will make the complete THF available within 30 minutes of the end of the pass.

Where: For DSN GTSs: The full tracking pass THFs will be placed in pub/RadioAstron/raoper/data/srt/dsn/kutlm on the DOTS FTP site.
For the GBTS: The files will be available in the GBTS FTP site in directory /ovlbi/out.
For Pushchino the full THFs will be placed in the GOCG FTP site in the directory /vlbi/spectr/ra/kutlm.
See Mission Element FTP Sites for details of these sites.

What: A time correction (or 'delta-t') file will be constructed from the phase residual file for each tracking pass. These files will be made available on a per-pass basis. This data product is used for correcting the time-tags for the VLBI tape data.

How: The file format is given in "Time Corrections File Interface". File names are of the form YYMMDDHHMM.kcX[.v], where the time refers to the time at the start of the file, and the X is the single letter code for the GTS.

When: File will be made available to the RSOG and the correlators within 7 days of the tracking pass.

Where: For DSN GTSs: The full TCFs will be placed in pub/RadioAstron/raoper/data/srt/dsn/delta_t on the DOTS FTP site.
For the Pushchino GTS: in /RadioAstron/RAoper/data/srt/push/delta_t on the RSOG FTP site.
For the GBTS: The files will be available in the GBTS FTP site in directory /ovlbi/out.

What: The Time Components File contains information on certain corrections used in the detailed production of each TCF; for example, the troposphere delay variation, ionospheric delay variation, and the station clock variation relative to UTC. At present, only the GBTS and the DOTS will produce this file.

How: The file format is described in "Time Components File for Space VLBI". File names are of the form YYMMDDHHMM.tcX[.v], where the time refers to the time at the start of the file, and the X is the single letter code for the GTS.

When: File will be made available within 7 days of the tracking pass to the RSOG and the correlators.

Where: For DSN GTSs: The files will be placed in pub/RadioAstron/raoper/data/srt/dsn/delta_t on the DOTS FTP site.
For the Pushchino GTS: from /RadioAstron/RAoper/data/srt/push/delta_t on the RSOG FTP site.
For the GBTS: The files will be available in the GBTS FTP site in directory /ovlbi/out.

What: One DPL is produced per pass per recorder. Each DPL line contains a time stamp and an entry. The various components of the DPL are described in turn in the following sub-sections.

How: The DPL format is described in "Data processing log format (tracking stations to VSOG)". Data Processing Logs are named YYMMDDHHMM-R.kTX[.v] where T is `l' for VLBA logs and `s' for S2 logs, R is the recorder number defined in the SRS file and the X is the single letter code for the GTS.

When: File will be made available to the RSOG within 4 days of the tracking pass.

Where: For DSN GTSs: The files will be placed in pub/RadioAstron/RadioAstronoper/data/srt/dsn/dplog on the DOTS FTP site.
For the GBTS the files will be available on the GBTS FTP site in the directory /ovlbi/out.
The Pushchino GTS log will be placed in RadioAstron/raoper/data/srt/push/corrlog.

What: The DPL will include a 'partial' correlator input log file for each tracking pass. The GTS will supply only GTS-specific information in the log entries, hence the term 'partial'; the RSOG will supply spacecraft-specific information to create the 'merged' correlator input log to be supplied to correlators - see Merged Correlator Input Log

How: See documents "Alternative log input to the VLBA correlator for space VLBI observations", and "SVLBI Space Radio Telescope Log Input to the Canadian (S2) Correlator".

What: Phase calibration tones will be extracted and placed as time-tagged entries in the DPL.

How: See "RadioAstron phase calibration format for SVLBI tracking stations", and "Supplementary record types in the correlator input logs created by the NRAO OVLBI Earth station at Green Bank".

What: The DPL will include flag entries, covering the parameters which relate to the GTS performance. The RSOG will add flags related to spacecraft performance and generate a final flag table for use by the PI. The file may be passed to the PI via the correlator output or may reside on one of the RSOG computer sites for retrieval by the PI.

How: See "Flag dictionary for space radio telescope log files".

What: Auxiliary information that is not needed by the correlator but has been requested by the RSOG is called a station performance log. This file contains information about GTS performance and may be constructed from a number of internal-GTS data products.

How: The file format is given in "(Spacecraft/Station) Performance Log Interface". File names are of the form YYMMDDHHMM.kpX[.v], where YYMMDD is the date of the BGN2LK entry in the SRS file for that pass.

Where: Files will be available via the GBTS FTP site in directory /ovlbi/out; on the DOTS FTP site /pub/RadioAstron/raoper/data/srt/dsn/perflog; and on the RSOG FTP site in /RadioAstron/RAoper/data/srt/push/perflog.

What: DSN GTS monitor data will be made available by the JPL/DOTS for each pass. The monitor data contains information relating to DSN GTS antenna, boresight, transmitter, tracking and receiver, telemetry, pre-pass and post-pass tests, and subsystem performance.

How: File format is described in JPL/DSN internal document "820-13 MON-5-17". Filenames are of the form YYMMDDHHMM.kmX . Both binary and ('gzip'-ped, .gz) ASCII versions of the MDF will be made available.

When: A complete file will be made available post-pass from the JPL/DOTS archive within 24 hours after the support period.

Where: Files will be available via on the DOTS FTP site /pub/RadioAstron/raoper/data/srt/dsn/mondata.

What: Status reports will be generated by each GTS on a regular basis, nominally once a week, and submitted to the RSOG. The RSOG will have the responsibility of reviewing the reports and making recommendations to ensure the optimal performance of each mission element. These status reports from the mission elements will allow the RSOG to optimize the scheduling and execution of SVLBI experiments.

How: Reports are named YYMMDD.stX, where YYMMDD is the first start date covering the period of the report. Normally the interval reported in a single file is the 1 week period matching the interval scheduled in the latest SRS file. An example report, showing the preferred format is as follows:

When: Files are available 1 day after the last day of the interval reported. Usually files for the previous week are generated on the following Monday.

Where: Files will be available from the GBTS FTP site in directory /ovlbi/out, from the DOTS FTP site in /pub/RadioAstron/raoper/status/gts/, and from the RSOG FTP site in subdirectory /RadioAstron/RAoper/status/gts.