[IGSMAIL-7257] SP3-d orbit format

[Steve Hilla@noaa.gov]

Author: Steve Hilla


Dear IGS Colleagues,

At the 2016 IGS Workshop in Sydney a recommendation was made to adopt
SP3-d for orbit products created by the IGS Multi-GNSS Pilot Project 
(MGEX).
The new SP3-d orbit format adds three extensions to the previous SP3-c 
format:
the maximum number of satellites is increased from 85 to 999, there are
now an unlimited number of comment records allowed in the header, and
the maximum length of each comment record has been increased from 60
characters to 80 characters.

The SP3-d format document is now available at:
ftp://igs.org/pub/data/format/sp3d.pdf

Best regards,
Steve Hilla
National Geodetic Survey, NOAA