Subject: [IGSMAIL-1082] Wk 0813-816 IGS Final Orb
From: AC Coordinator
Date: Thu, 5 Oct 1995 9:52:56 PDT

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IGS Electronic Mail      Thu Oct  5  9:52:56 PDT 1995      Message Number 1082
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Author: AC Coordinator
Subject: Wk 0813-816 IGS Final Orb

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IGS Final orbits/clocks completed and put onto CDDIS (Weeks 813 - 816)
                                                     (Aug 06 - Sep 02, 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:

IGS08130-6.SP3   IGS GPS orbit/clock files for days 0-6, week 0813
IGS08140-6.SP3   IGS GPS orbit/clock files for days 0-6, week 0814
IGS08150-6.SP3   IGS GPS orbit/clock files for days 0-6, week 0815
IGS08160-6.SP3   IGS GPS orbit/clock files for days 0-6, week 0816

IGS08137.ERP    EOP associated with the above orbits (Bull. B aligned to ITRF)
IGS08147.ERP    EOP associated with the above orbits (Bull. B aligned to ITRF)
IGS08157.ERP    EOP associated with the above orbits (Bull. B aligned to ITRF)
IGS08167.ERP    EOP associated with the above orbits (Bull. B aligned to ITRF)

IGS08137.SUM    Complete summary/statistics report
IGS08147.SUM    Complete summary/statistics report
IGS08157.SUM    Complete summary/statistics report
IGS08167.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)

IGR08130-6.SP3   Rapid service orbits/clocks for days 0-6, week 0813
IGR08140-6.SP3   Rapid service orbits/clocks for days 0-6, week 0814
IGR08150-6.SP3   Rapid service orbits/clocks for days 0-6, week 0815
IGR08160-6.SP3   Rapid service orbits/clocks for days 0-6, week 0816

IGR08137.ERP     IGS Mean EOP associated with the above orbits 
IGR08147.ERP     IGS Mean EOP associated with the above orbits
IGR08157.ERP     IGS Mean EOP associated with the above orbits
IGR08167.ERP     IGS Mean EOP associated with the above orbits

IGR08137.SUM     Rapid service complete summary/statistic report 
IGR08147.SUM     Rapid service complete summary/statistic report 
IGR08157.SUM     Rapid service complete summary/statistic report 
IGR08167.SUM     Rapid service complete summary/statistic report 

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

REMARKS/CORRECTIONS:
            ************* NOTE: ***************************
Since Wk 803 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 803, the IGR erp contains 7 daily EOP values at 12h UT,
unlike the Final orbit erp (and the Rapid orbit erp prior Wk 803) which
contain 9 daily IERS EOP values at 0h UT to facilitate accurate interpolation 
for the whole week period.
            ***********************************************

The following table shows the average statistics of the Final Orbit/clock 
combination for the current period (Wks 0813-0812).

Start: 95 Aug 06 / wk813
End:   95 Sep 02 / wk816

     STA  DX    DY    DZ     RX     RY     RZ   SCL  RMS  WRMS LaRMS  RMSc  Days
    ----------------------------------------------------------------------------
cod  61  0.00  0.03 -0.02  -0.45  -0.23   0.00  0.1    8    7    8    76.9   28
         0.01  0.01  0.01   0.18   0.25   0.17  0.1
emr  28  0.01 -0.02  0.00  -0.07  -0.08   0.23 -0.1    8    8   13     0.9   28
         0.01  0.01  0.01   0.23   0.32   0.13  0.1
esa  49  0.00 -0.01 -0.03   0.37  -0.04  -0.20  0.1   15   14   14    32.8   28
         0.01  0.01  0.01   0.17   0.31   0.28  0.1
gfz  47 -0.03 -0.01  0.00  -0.20   0.07  -0.17 -0.2    9    9   13     6.5   28
         0.01  0.00  0.01   0.16   0.21   0.18  0.1
jpl  34  0.01  0.04  0.00  -0.44   0.03   0.10  0.2    8    8    8     0.8   28
         0.01  0.01  0.01   0.19   0.28   0.09  0.1
ngs  41  0.01 -0.01  0.00  -0.31  -0.13  -0.22 -0.1   12   11   15  2192.2   28
         0.01  0.01  0.01   0.30   0.41   0.24  0.1
sio  33  0.00 -0.05  0.03  -0.26  -0.25   0.62  0.014181 9521   14     0.0   28
         0.01  0.01  0.03   0.20   0.29   1.45  0.1

     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 (Wks 0782-0816).

Start: 95 Jan 01 / wk782
End:   95 Sep 02 / wk816

     STA  DX    DY    DZ     RX     RY     RZ   SCL  RMS  WRMS LaRMS  RMSc  Days
    ----------------------------------------------------------------------------
cod  55  0.00  0.01  0.00  -0.45  -0.01   0.06  0.0   10    9   12  4542.0  245
         0.01  0.02  0.01   0.23   0.30   0.21  0.1
emr  26  0.01 -0.02  0.00  -0.14  -0.06   0.13 -0.1   10   10   15     1.0  245
         0.01  0.01  0.01   0.36   0.32   0.19  0.2
esa  37  0.00 -0.01 -0.02   0.27   0.17  -0.04  0.1  476   15   19    25.9  245
         0.01  0.01  0.01   0.42   0.41   0.35  0.2
gfz  43 -0.03 -0.01  0.00  -0.24   0.16  -0.22 -0.3   46   46   15    13.7  245
         0.01  0.01  0.01   0.19   0.25   0.18  0.1
jpl  33  0.01  0.05  0.01  -0.52   0.07   0.11  0.1   10   10   10     0.9  245
         0.01  0.01  0.01   0.25   0.29   0.15  0.1
ngs  37  0.01 -0.03 -0.01  -0.35   0.29  -0.06  0.5   20   20   21  7764.3  245
         0.02  0.02  0.02   0.39   0.42   0.38  0.4
sio  34  0.01 -0.06  0.03   0.16  -0.23  -0.33  0.1 4794 3219   22     0.0  245
         0.02  0.03  0.07   0.58   0.61   2.15  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]>]