[IGSMAIL-4672]: proposed new GPS message format

[Jim Ray]

******************************************************************************
IGS Electronic Mail      31 Oct 00:08:43 PST 2003      Message Number 4672
******************************************************************************

Author: Jim Ray

GPS users should be aware that a preliminary proposed format
has recently been issued for public comment for the "Improved
Clock and Ephemeris" (ICE) parameters that will be broadcast
in the new L5 navigation message.  A draft version (30 Sep 2003)
of IS-GPS-705 for the L5 user segment interface (without the
new ICE parameters) is also open for review and comments.  The
ICE proposal is in document PPIRN-705-001 dated 23 Oct 2003,
which would be incorporated into IS-GPS-705 when finalized.

These documents and comment forms are available at JPO's Public
Interface Control Working Group (ICWG) website at:
  http://gps.losangeles.af.mil/engineering/icwg/
Comments should be submitted by 12 Dec 2003.

Note that the ICE format proposal is intended to overcome the
present limitations of the ICD-GPS-200 nav message to allow
the possibility for much more accurate broadcast information
in the future.  So the long-term impact on GPS users could be
significant.  The adopted L5 message format will be added to
the L2C specifications in a future update of ICD-GPS-200.  In
preparation for that, an ICD-GPS-200/705 Public ICWG meeting
is planned for November 2003.