[IGSMAIL-4937]: updated P1-C1 bias values

[Jim Ray]

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IGS Electronic Mail      10 May 01:38:08 PDT 2004      Message Number 4937
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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 1271 (16 May 2004):

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

 h 2004 05 16
      data bias / -0.076d0, -9.999d9,  0.014d0,  1.473d0, -0.872d0,
     +             0.565d0, -0.809d0, -0.563d0,  0.327d0, -1.579d0,
     +             0.609d0, -9.999d9,  1.600d0,  0.311d0, -1.040d0,
     +            -0.460d0, -0.915d0,  0.014d0, -2.410d0, -1.084d0,
     +            -0.298d0,  0.652d0, -9.999d9,  0.258d0,  0.552d0,
     +             1.247d0, -0.020d0, -0.162d0,  0.949d0,  2.082d0,
     +            -0.366d0, -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 #4825, 04 Feb 2004), these
are based on the monthly average estimates by the CODE Analysis Center
for April 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 decommissioning of the old PRN23 on 13 Feb 2004, the end of
life of PRN02 on 23 Feb 2004 (though not officially decommissioned
yet), and the new IIR-11 satellite (PRN19) launched on 20 Mar 2004.
Besides the bias changes for PRN02, PRN19, and PRN23, the only other
having a bias change greater than 0.2 ns is PRN22, which became
operational in late Dec 2003.

In addition, the following receivers have been added to the class
reporting C/A (C1) instead of P1, as well as P2: "LEICA SR520 ",
"LEICA SR530 ", "NOV MILLEN-RT2", "NOV MILLEN-STD", "NOV MILLEN-STDW".
Refer to IGS Mail #4924 from Stefan Schaer concerning the Novatel
receivers.

Since satellite IIR-12 is due to be launched on 05 June, the next
bias update will probably be needed in July.

A new version of the program (cc2noncc Vers 4.6, 10 May 2004) 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/>.

--Jim Ray