NAD 83(2011) epoch 2010.00

Welcome to the LSU C4G RTN Web Portal Application!

In 2007 the LSU Center for GeoInformatics (C4G) launched a Real-Time Network (RTN) utilizing special software that taps into the power of the Louisiana Spatial Reference Center’s Continuously Operating Reference Station (CORS) infrastructure offering subscribers a statewide Real Time Kinematic (RTK) Virtual Reference Station (VRS) service, or simply RTN. By using C4G’s RTN services, subscribers can save time and make better use of GNSS equipment with the benefit of being automatically tied into the NSRS and Louisiana’s Vertical Geodetic Control throughout the entire State while receiving Real-Time Network GPS/GNSS positions within the 3D error space of a golf ball.

As with all Global Navigation Satellite System-based positioning, C4Gnet RTN is related to orthometric datums like NAVD88 by way of a geoid model or through a local network adjustment; the latter is accomplished by including and holding fixed several NGS benchmarks with valid coordinates.

C4Gnet RTN data are based on the NGS reference frame coordinates which are currently in IGS08 epoch 2005.00 and NAD 83(2011) Position (Epoch 2010.00) adjustment.

C4GNet ties rovers in Louisiana into the National Spatial Reference System (NSRS) by constraining its RTN to the coordinates published by NGS for each of their National CORS. This creates a dynamic connection for GNSS rovers to the vertical control standard in Louisiana as outlined by the State Legislator in 2006 with LA Revised Statute Act 194, Section 1. R.S. 50:173.1.

C4G in it's role as the Louisiana Spatial Reference Center provides raw CORS data to NGS which they publish to the public from 31 of C4G's GULFNet CORS sites in Louisiana. C4G also offers Free FTP Access to all of our GULFNet CORS data which includes the 31 CORS we provide to NGS and the rest of the CORS sites in the GULFNet CORS network.

C4G also offers Free Access to our GNSS Online Post Processing application. GNSS Online Post Processing is an OPUS-like online post processing service on the C4GNet.XYZ portal site that allows you to upload raw static GNSS observation data and receive absolute positioning calculations based on over 120 reference stations in the GULFNet CORS network. If you want to use this free service, Register Here and contact C4G to activate your free account.

Access to the C4G’s RTN services are available through the C4G’s Web Store by a variety of subscription options. All RTN users must complete the registration process and electronically acknowledge compliance with the end-user Terms of Service agreement.

C4G currently offers Real-Time Network service products under the name of C4Gnet in three different markets; surveying, agriculture and GIS/Mapping.

The LSU College of Engineering has a clear understanding with C4G’s constituents and partners, as well as a definitive commitment to continued success and expansion of the Center for GeoInformatics.


Technical inquiries should be directed to:

Randy Osborne
225-578-4609 or 225-328-8976

System and training inquiries should be directed to:

Clifford J. Mugnier
Chief of Geodesy