[IGSMAIL-5260]: final update for P1-C1 bias values & cc2noncc

Wed Nov 23 08:16:03 PST 2005

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IGS Electronic Mail      23 Nov 08:16:42 PST 2005      Message Number 5260
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Author: Jim Ray

It is recommended that users update their <P1-C1> satellite biases, if
they have not done so recently.  Below are the set of biases determined by
Stefan Schaer (AIUB) as a byproduct of his ionosphere monitoring.  These
values are the 30-day averages of the daily estimates ending on 19 Nov 2005.
Note that since the last announced update (IGS Mail #5078, 04 Jan 2005) the
GPS constellation has changed with the launch of the new IIR-M1 satellite
(SVN53/PRN17) on 26 Sep 2005 and the decommissioning of SVN31/PRN31 on
25 Oct 2005.  Besides the new bias for PRN17, the only other having a bias
change greater than 0.3 ns is PRN23 (+0.35ns).

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

 h 2005 10 03
      data bias / -0.233d0, -0.033d0, -0.163d0,  1.234d0, -0.944d0,
     +             0.444d0, -1.132d0, -0.416d0,  0.366d0, -1.651d0,
     +             0.591d0, -9.999d9,  1.529d0,  0.108d0, -1.326d0,
     +            -0.525d0,  1.391d0, -0.012d0, -2.026d0, -1.228d0,
     +            -0.392d0,  0.532d0,  0.130d0, -0.069d0,  0.575d0,
     +             1.083d0, -0.189d0, -0.232d0,  0.643d0,  2.016d0,
     +            -0.073d0, -9.999d9, -9.999d9, -9.999d9, -9.999d9,
     +            -9.999d9, -9.999d9, -9.999d9, -9.999d9, -9.999d9  /

The launch of IIR-M2 (SVN55/PRN15) is tentatively set for early 2006.

A new version of the program cc2noncc (Vers 5.0, 23 Nov 2005) and the
file of historic bias values (p1c1bias.hist) will be posted at the IGS
Clock Products website <https://goby.nrl.navy.mil/IGStime/index.php>.
With this version, the users is now REQUIRED to supply an external file of
bias values (p1c1bias.hist); there are no active bias values used in the
source code.  Also, this utility does NOT account for the inter-modulation
biases that are expected with any new GPS signals, such as the L2C signal
beginning with SVN53/PRN17.

NOTE THAT THIS IS THE FINAL UPDATE OF THE BIASES AND SOURCE CODE THAT
I PLAN TO MAKE.  Hereafter, users are responsible for all maintenance
functions.  I recommend Stefan's website at
<http://www.aiub.unibe.ch/ionosphere.html> for the <P1-C1> biases.

--Jim Ray