[IGSMAIL-5078]: updated P1-C1 bias values

[Jim Ray (NGS 301-713-2850 x112)]

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IGS Electronic Mail      04 Jan 09:55:33 PST 2005      Message Number 5078
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Author: Jim Ray

Updated values for the <P1-C1> satellite biases are now available and
recommended for use by all IGS Analysis Centers and users of IGS clock
products beginning at the start of GPS week 1306 (16 Jan 2005):

      average <P1-C1> biases (ns) in PRN order (from PRN01 thru PNR40):

 h 2005 01 16
      data bias / -0.028d0, -0.061d0,  0.077d0,  1.334d0, -0.929d0,
     +             0.664d0, -0.912d0, -0.335d0,  0.529d0, -1.567d0,
     +             0.535d0, -9.999d9,  1.541d0,  0.335d0, -1.057d0,
     +            -0.419d0, -0.906d0,  0.098d0, -2.269d0, -1.105d0,
     +            -0.346d0,  0.579d0, -0.221d0,  0.152d0,  0.735d0,
     +             1.247d0, -0.018d0, -0.205d0,  0.842d0,  2.017d0,
     +            -0.307d0, -9.999d9, -9.999d9, -9.999d9, -9.999d9,
     +            -9.999d9, -9.999d9, -9.999d9, -9.999d9, -9.999d9  /

As with the previous set of biases (IGS Mail #4987, 04 Aug 2004), these
are based on the monthly average estimates by the CODE Analysis Center
for December 2004 (for background see IGS Mails #2827, 9 May 2000, and
#3212, 23 Feb 2001, by Stefan Schaer).

Please note that since the last update the constellation has changed
with the launch of a new IIR-13 satellite (SVN61/PRN02) on 06 Nov 2004.
Besides the new bias for PRN02, which is close to zero, the only
other having a bias change greater than 0.2 ns is PRN07 (+0.32 ns),
which has historically been unstable.

The launch of IIR-14, the first in the IIR-M series, is tentatively set
for May.

A new version of the program cc2noncc (Vers 4.8, 04 Jan 2005) and the
file of historic bias values (p1c1bias.hist) will be sent to the IGS
Central Bureau where they will be posted at
<ftp://igscb.jpl.nasa.gov/igscb/software/cc2noncc/>.
A RINEX header comment was also corrected for the C1-only case to
indicate conversion to P1 instead of P2.

--Jim Ray