Subject: [IGSMAIL-1057] Wk808-812 IGS Final Orb.
From: AC Coordinator
Date: Thu, 7 Sep 1995 6:01:37 PDT

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IGS Electronic Mail      Thu Sep  7  6:01:37 PDT 1995      Message Number 1057
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Author: AC Coordinator
Subject: Wk808-812 IGS Final Orb.

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IGS Final orbits/clocks completed and put onto CDDIS (Weeks 808 - 812)
                                                     (Jul 02 - Aug 05, 1995)
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    The IGS Rapid Orbits for this period were recomputed using up to date
    orbits and the final EOP values of Bulletin B, published by IERS. ( Daily
    values, page 2 of Bull. B ) The EOP were corrected for the difference
    between the IERS pole series  and ITRF as published in the IERS 1993 Annual
    Report (p. II-19, Table II-3), so both the IGS orbits and the associated
    ERP files are consistent with ITRF93 (current epoch).

    We have downloaded all the submitted ephemeris and ERP files from CDDIS
    before the final orbit/clock combination to ensure that the sets are
    complete and up to date. In the final combination we have largely followed
    the actions taken during the Rapid orbit generation and since there were
    very few orbit resubmissions, both the IGS Rapid and Final orbits are
    virtually the same except for the orientation difference (IGS mean pole and
    Bull.B). Orbit evaluation are also nearly the same, since we used centre
    specific ERP in the long arc evaluations. For more information see the
    corresponding summary files on CDDIS.

    The clock solution alignment and centre clock weight assignment are based
    on non-SA broadcast satellite corrections only (PRN12, 15, 28). This should
    result in an objective clock weighting, provided that the non-SA satellites
    are representative of centre clock solution quality. Starting with the GPS
    week 756 the new IGS erp format (see IGSMAIL# 662) is used by all Analysis
    Centres and for the IGS erp files. ERP rates, whenever given, are also
    utilized in both orbit combination and the long arc evaluation.

PRODUCTS GENERATED:

The resulting final IGS ephemeris and clocks are in daily files in the SP3
format. The sat. orb. accuracy codes displayed in the headers are based on
weighted RMS for each satellite. Note that each file contains all the submitted
satellites. If a satellite or centre had to be excluded from the combination it
is noted in the summary file along with the reason for doing so.

The IGS FINAL ORBIT files generated and uploaded into CDDIS @ NASA/GSFC are:

IGS08080-6.SP3   IGS GPS orbit/clock files for days 0-6, week 0808
IGS08090-6.SP3   IGS GPS orbit/clock files for days 0-6, week 0809
IGS08100-6.SP3   IGS GPS orbit/clock files for days 0-6, week 0810
IGS08110-6.SP3   IGS GPS orbit/clock files for days 0-6, week 0811
IGS08120-6.SP3   IGS GPS orbit/clock files for days 0-6, week 0812

IGS08087.ERP    EOP associated with the above orbits (Bull. B aligned to ITRF)
IGS08097.ERP    EOP associated with the above orbits (Bull. B aligned to ITRF)
IGS08107.ERP    EOP associated with the above orbits (Bull. B aligned to ITRF)
IGS08117.ERP    EOP associated with the above orbits (Bull. B aligned to ITRF)
IGS08127.ERP    EOP associated with the above orbits (Bull. B aligned to ITRF)

IGS08087.SUM    Complete summary/statistics report
IGS08097.SUM    Complete summary/statistics report
IGS08107.SUM    Complete summary/statistics report
IGS08117.SUM    Complete summary/statistics report
IGS08127.SUM    Complete summary/statistics report

The old Rapid Orbit files have been renamed (on CDDIS) to:
(Note this is temporary, based on discussions with ACs and GB and may be
changed)

IGR08080-6.SP3   Rapid service orbits/clocks for days 0-6, week 0808
IGR08090-6.SP3   Rapid service orbits/clocks for days 0-6, week 0809
IGR08100-6.SP3   Rapid service orbits/clocks for days 0-6, week 0810
IGR08110-6.SP3   Rapid service orbits/clocks for days 0-6, week 0811
IGR08120-6.SP3   Rapid service orbits/clocks for days 0-6, week 0812

IGR08087.ERP     IGS Mean EOP associated with the above orbits 
IGR08097.ERP     IGS Mean EOP associated with the above orbits
IGR08107.ERP     IGS Mean EOP associated with the above orbits
IGR08117.ERP     IGS Mean EOP associated with the above orbits
IGR08127.ERP     IGS Mean EOP associated with the above orbits

IGR08087.SUM     Rapid service complete summary/statistic report 
IGR08097.SUM     Rapid service complete summary/statistic report 
IGR08107.SUM     Rapid service complete summary/statistic report 
IGR08117.SUM     Rapid service complete summary/statistic report 
IGR08127.SUM     Rapid service complete summary/statistic report 

 *****************************************************************************

REMARKS/CORRECTIONS:
            ************* NOTE: ***************************
Since Wk 808 the IGS Rapid combinations are performed directly in ITRF frame, 
without any EOP alignments. The associated erp files (IGR0WWW7.erp) contain
weighted averages of all submitted erp solutions given at 12h UT each day
(using the orbit weights), augmented with the current IERS Bull.A UT1-UTC.
Consequently, since Wk 808, the IGR erp contain 7 daily EOP values at 12h UT,
unlike the Final orbit erp (and the Rapid orbit erp prior Wk 808) which
contain 9 daily IERS EOP values at 0h UT to facilitate accurate interpolation 
during the whole week period.
            ***********************************************

The following table shows the average statistics of the Final Orbit/clock 
combination for the current period (Wks 0808-0812).

Start: 95 Jul 02 / wk808
End:   95 Aug 05 / wk812

     STA  DX    DY    DZ     RX     RY     RZ   SCL  RMS  WRMS LaRMS  RMSc  Days
    ----------------------------------------------------------------------------
cod  60  0.00  0.03  0.00  -0.40  -0.12  -0.05  0.0    8    7    9   297.5   35
         0.01  0.01  0.01   0.19   0.17   0.16  0.1
emr  28  0.01 -0.01  0.01   0.01   0.04   0.23  0.0    9    9   14     0.9   35
         0.01  0.01  0.01   0.25   0.21   0.15  0.1
esa  47  0.01 -0.01 -0.02   0.28   0.20  -0.10 -0.1 1259   14   16    30.4   35
         0.01  0.01  0.01   0.25   0.22   0.30  0.1
gfz  46 -0.03 -0.02  0.00  -0.13   0.20  -0.26 -0.2  118  120   15    10.6   35
         0.01  0.01  0.01   0.20   0.14   0.16  0.1
jpl  34  0.01  0.04  0.02  -0.47   0.15   0.13  0.1    9    9    9     0.8   35
         0.01  0.01  0.01   0.29   0.22   0.12  0.1
ngs  40  0.00 -0.03 -0.03  -0.26   0.29  -0.18  0.4   21   21   21  7464.9   35
         0.01  0.02  0.02   0.44   0.32   0.41  0.4
sio  36  0.00 -0.06 -0.02   0.06  -0.21   0.00  0.1   18   17   20     0.0   35
         0.01  0.01  0.06   0.44   0.30   0.24  0.2

     Units: m   - DX, DY, DZ, RMS, WRMS, LaRMS (Long arc orbit RMS)
            mas - RX,RY,RZ
            ppb - SCL
            ns  - RMSc (sv clock)

The following table shows the average statistics of the Final Orbit/clock 
combination for the current year since Jan 1/95. (Wks 0782-0812).

Start: 95 Jan 01 / wk782
End:   95 Aug 05 / wk812

     STA  DX    DY    DZ     RX     RY     RZ   SCL  RMS  WRMS LaRMS  RMSc  Days
    ----------------------------------------------------------------------------
cod  54  0.00  0.01  0.00  -0.45   0.02   0.07  0.0   10    9   12  4827.3  217
         0.01  0.01  0.01   0.24   0.30   0.21  0.1
emr  26  0.01 -0.02  0.00  -0.15  -0.06   0.11 -0.1   11   10   15     1.0  217
         0.01  0.01  0.01   0.37   0.32   0.20  0.2
esa  36  0.00 -0.01 -0.02   0.25   0.20  -0.02  0.0  506   15   19    24.9  217
         0.01  0.01  0.01   0.44   0.41   0.36  0.2
gfz  42 -0.04 -0.01  0.00  -0.25   0.17  -0.23 -0.3   49   49   16    14.3  217
         0.01  0.01  0.01   0.20   0.25   0.18  0.1
jpl  33  0.01  0.05  0.01  -0.53   0.07   0.11  0.1   10   10   10     1.0  217
         0.01  0.01  0.01   0.25   0.29   0.16  0.1
ngs  36  0.01 -0.03 -0.02  -0.35   0.34  -0.04  0.6   21   20   22  8212.3  217
         0.02  0.02  0.02   0.40   0.39   0.39  0.3
sio  34  0.01 -0.06  0.03   0.21  -0.23  -0.45  0.1   23   20   23     0.0  217
         0.02  0.03  0.08   0.59   0.64   2.20  0.3

     Units: m   - DX, DY, DZ, RMS, WRMS, LaRMS (Long arc orbit RMS)
            mas - RX,RY,RZ
            ppb - SCL
            ns  - RMSc (sv clock)

[Mailed From: Jan Kouba <[email-masked]>]