On Nov 1, 2:47*pm, HIPAR wrote:

Regarding *WDGPS, *I really don't understand who actually controls
access to the system. *If NASA operates the core system, what kind of
agreement does the US government have with Deere allowing them
exclusive commercial marketing rights under the Starfire trademark?
NASA/JPL doesn't say much about that.

--- *CHAS

JPL alludes to commercial opportunities on their site, but don't give
specifics of licensing, fees, etc. Clicking on the "Customer Portal"
tab yields a certificate error message.

http://www.gdgps.net/system-desc/network.html

"The core of the GDGPS network is the NASA Global GPS Network (GGN), a
JPL-owned and operated network of roughly 70 geodetic-quality, dual
frequency receivers, distributed globally. Additional real-time sites
are contributed by a variety of U.S. and international partner
organizations. The result is the world's largest real-time GPS
tracking network, with more than 100 global sites (as of October
2006). All these sites stream their GPS measurements at 1 Hz to the
GDGPS Operation Centers (GOCs), where it is processed and analyzed in
real-time.

.. . . The GDGPS system is proud to count 4 national timing
laboratories among it contributing network partners. In particular,
the United States Naval Observatory (USNO) contributes two monitoring
sites driven by its Master Clock, allowing the GDGPS System to provide
its global users the most accurate real-time realization of USNO UTC.

.. . . We continue to expand our network, and welcome contributions
from interested organizations. We offer our network partners a variety
of benefits, including real-time positioning, timing, and
environmental monitoring, as well as data archiving and data
distribution through the NASA CDDIS facility."

http://www.gdgps.net/applications/index.html

"The GDGPS System produces differential corrections to the GPS
broadcast ephemeris with unparelleled accuracy and seamless global
validity. Various GDGPS technology components and data products are
being used by nearly all of the providers of premium global
differential corrections. The underlying software and algorithms are
being used by the FAA's Wide Area Augmentation System (WAAS), and its
Japanese counterpart, MSAS. "

http://www.gdgps.net/system-desc/references.html

Kevin Dixon, "StarFi A Global SBAS for Sub-Decimeter Precise Point
Positioning," ION GNSS 2006, Fort Worth, TX, September 2006,
http://www.gdgps.net/system-desc/papers/starfire.pdf

"The central processing hubs are based upon a version of the Real Time
GIPSY (RTG) suite, originally developed by the Jet Propulsion
Laboratory for precise real time orbit and clock determination of
GNSS. This has been refined to optimize positioning accuracy of NavCom
developed GNSS hardware.

.. . . The StarFire correction stream consists of the RTG generated
GNSS precise orbit and clock values differenced with respect to the
GNSS broadcast ephemeris.

, , , The RTG code is the latest state of the art implementation from
NASA's Jet Propulsion Laboratory."

More on RTG:

http://gipsy.jpl.nasa.gov/igdg/system/od/index.html

Some older publications imply that JPL and NavCom (or John Deere --
think they were spun off once, then brought back) may have had a joint
venture at one time.

The world map in this 2004 paper shows roughly equal number of JPL and
NavCom reference stations (NavCom in green, the John Deere color):

http://www.gmat.unsw.edu.au/wang/jgp...2/v3n12p19.pdf

This 2001 NavCom press release (reprinted in GPS World) describes a
joint ventu

http://www.navcomtech.com/News/PressReleases.cfm?id=8