Welcome to the LSU Center for GeoInformatics (C4G)
Home of the Louisiana Spatial Reference Center (LSRC) and the 
GULFNet Continuously Operating Reference Station (CORS) Network

Access to the LSU/C4G/LSRC Free GULFNet CORS data
Data can be retrieved via anonymous ftp from CORS.lsu.edu on port: 8021
or by pointing your browser to ftp://cors.lsu.edu:8021/ GULFNet CORS stations are owned and operated by C4G. The data collected by all GULFNet CORS is distributed to the public free of charge. All LSRC CORS GNSS data files collected from GULFNet CORS stations are made available to NGS & the public in Trimble’s proprietary data-file formats (R00/T00/T01/T02) or (.DAT or .TGD). All GULFNet CORS files found in this data archive are logged in formats by native to Trimble GPS/GNSS receivers from "Record Type 27" (RT27) files. The data include observation, meteorological, navigation/ephemeris for the stations. Most data are available within 1 hour from when they were recorded at each remote CORS site.
Louisiana NGS CORS
======================== NGS redistributes some of the GULFNet CORS data to the public free of charge through its partnership with the LSRC at LSU's Center for GeoInformatics. NGS publishes it's subset of the GULFNet CORS data through their CORS website found at the following links. https://geodesy.noaa.gov/CORS/ http://alt.ngs.noaa.gov/CORS NOAA's National Geodetic Survey (NGS) operates the Continuously Operating Reference Station (CORS) network that consists of group of Global Navigation Satellite System (GNSS) reference stations which provide code range and carrier phase data to users in support of postprocessing applications. The stations are owned and operated by federal, state, local agencies, private companies, and university groups, and NGS redistributes their data to the public free of charge. The GNSS data collected at these stations are made available to the public by NGS in Receiver INdependent EXchange (RINEX) format. The data include observation, meteorological, navigation/ephemeris, station logs and NGS coordinate files for the stations. Most data are available within 1 hour from when they were recorded at the remote site, and a few sites have a delay of 24 hours. ACCESS TO DATA ================= Data can be retrieved via anonymous ftp from geodesy.noaa.gov or alt.ngs.noaa.gov or ftp://geodesy.noaa.gov/cors or ftp://alt.ngs.noaa.gov/cors Alternatively a customized data request service is available at: http://geodesy.noaa.gov/UFCORS FILE RETENTION POLICY ====================== RINEX observation, meteorological, navigation and TEQC summary files: Hourly files are only kept for 2 days Daily files are kept permanently However after 30 days the 24hr (daily) RINEX observation files that are gzipped ({ssss}{ddd}0.{yy}o.gz) are decimated to a 30 second sampling rate equivalent to the {ssss}{ddd}0.{yy}d.Z site specific GPS navigation files are only kept for sites that NGS submits to the IGS network Meteorological files are available only for sites with independent meteorological sensors After six-months to one year the second copy of the RINEX observation files that are gzipped is removed i.e. file name {ssss}{ddd}0.{yy}o.gz All orbit files are kept permanently Coord files are updated as needed Logs files are updated as needed Plot files are updated daily NGS CONTACT INFORMATION ================================== If you have questions about this file or about CORS in general please check http://www.ngs.noaa.gov/CORS/ http://alt.ngs.noaa.gov/CORS or email ngs.cors @ noaa.gov


    The Center for GeoInformatics (C4G) in the Department of Civil and Environmental Engineering (CEE) recently received new geodetic instruments to model the Earth’s gravity field. A Scintrex CG-5 Relative Gravity Meter, Leica T60 Total Station, and Trimble R10 GPS Rover Kit were acquired as part of an enhancement grant sponsored by the Louisiana Board of Regents. Drs. George Voyiadjis (PI) and Joshua Kent (Co-PI) led the one-year project, which ended in June, 2017. The instruments are acquired to address the needs of three objectives: First, to develop a novel, high-resolution gravity model of sea level (i.e., geoid); second, to augment knowledge of existing subsidence rates and the driving mechanisms; and finally, promote advanced geodetic research at the University.

Here, as in many river deltas around the world, land surfaces are sinking due to subsidence. On average, southern Louisiana experiences ~10 millimeters per year of subsidence.   Understanding the mechanisms that drive subsidence is essential for mitigating risk and promoting sustainability.  The CG-5 relative gravity meter supports these goals by measuring the relative differences in the Earth’s gravity across southern Louisiana.  Surveys using the total station and R10 rover kit are currently underway to geodetically correlate the CG-5 data with absolute gravity readings collected in the early 2000s by the National Geospatial-Intelligence Agency and the National Geodetic Survey. The updated gravimetric surveys conducted by C4G researchers and staff will deliver much needed insight into the variety of geophysical processes driving the spatially and temporally heterogeneous rates of subsidence measured across the state. 

In addition to the subsidence research, this enhancement grant will directly and indirectly benefit Louisiana’s geodetic stakeholder and consumer communities. For nearly a decade, the C4G has provided tools, services, and other geodetic resources dedicated to precise positioning throughout the state and across the region.  Central to these resources is the C4GNet real-time reference network.  The network includes more than 50 continuously operating GPS reference stations (CORS) installed across Louisiana.  Over the next five years, the C4G plans to geodetically correlate the gravity measurements with antenna heights at each station.   Extended surveys will include CORS in neighboring states.  When completed, the data will contribute to the creation of a novel, high-resolution geoid model that will allow the geodetic community to accurately and precisely measure elevations above sea level.

The instruments acquired by this grant represent an investment into the geodetic research capacity at the C4G and CEE.   In addition to the above goals and objectives, these resources have already been selected for use by investigators in two external funding proposals, both of which will rely on the precision of these instruments to deliver meaningful geodetic solutions.  These instruments not only promote research activities, they have galvanized national and international collaborations with partners across the US Gulf Coast and western Europe.  More information about these instruments and geodetic models is available at the C4G website www.c4g.lsu.edu or gravity.c4g.lsu.edu.

C4G CORS used in C4Gnet and GULFNet Real Time Networks have been valued at over 33 Million dollars a year according to a new government report released June 15th, 2009. The report titled "Socio-Economic Benefits Study: Scoping the Value of CORS and GRAV-D" was prepared for the National Geodetic Survey by Irving Leveson. It shows billions in estimated benefits from NOAA Positioning Products and Services:

• National Spatial Reference System (NSRS): $2.4 billion per year
• CORS: $758 million per year. (C4G has 27 of the 1324 National CORS)
• C4Gnet and GULFNet have 66 CORS with a yearly valuation of $500K each.
• GRAV-D (Once completed): $4.8 billion over 15 years, including $2.2 billion in avoidance costs from improved floodplain management.

Download the entire report!

Bill Henning, NGSThe LSU Center for GeoInformatics hosted a training session on Best Methods to Achieve Accurate, Repeatable Orthometric Heights Using Real Time GNSS Networks. The event was held at the Orleans Parish Levee District Offices in New Orleans, Louisiana on August 15th 2012. The event was attended by over 60 individuals including surveyors, engineers, local, state and federal government officials. 

Some of the topics covered were:

  • Vertical Geodetic Control in Southern Louisiana
  • Providing the National Spatial Reference System in dynamic regions
  • Intro to GNSS
  • Guidelines for Establishing GPS-derived Ellipsoid Heights
  • Guidelines for Establishing GPS-derived
  • Orthometric Heights
  • Improvements to the Geoid Model
  • Real-time Kinematic Surveying and Best Practices
  • Introduction to Real-time Networks

The South Louisiana Flood Protection Authority District - East has made these trainings a Requirement for Professionals Working for the Levee District. Surveyors and Engineers that attended also received 8 Continuing Education Credits. The training provided professional Land Surveyors the requisite training to properly use an RTN system such as GULFNet or C4Gnet to provide current correct elevations. The main speaker was Bill Henning of NGS, one of the premier experts in the GNSS applications field. Registration, food and refreshments were handled by LSPS District 1 and plans are currently in the works to host additional events of this type in Baton Rouge and Shreveport in the near future.

If you are interested in attending one of these training events please sign up for the C4G mailing list or follow C4G in social media on Twitter, Facebook or the C4Gnet RSS feed. You can also find Podcasts, PDF's and Videos of past events on the C4G website or the C4G YouTube channel.


GNSS Market Research and Analysis GPS/GNSS Networks and Services The Global Market for GNSS Augmentation Infrastructure and Services 2009-2013 March 2009 Abstract ©Position One Consulting Pty Ltd 2009 All rights reserved Authors Robert Lorimer & Eric Gakstatter

Global Navigation Satellite Systems (GNSS) include the United States GPS (the most commonly used today), Russia's Glonass, the EU's Galileo, China's Compass, the Indian Regional Navigation Satellite System (IRNSS) and Japan's Quasi-Zenith Satellite System (QZSS).

The signals from all these GNSS are subject to a myriad of errors and may not always tell the truth. Whereas this is not a problem for casual users or those who can tolerate such errors, there are many applications where integrity and accuracy must be improved.