Welcome to the Home of LSU C4G
LSU’s College of Engineering created the Center for GeoInformatics (C4G) to build new research and services in Geodesy and GeoInformatics.
C4G's Primary website address is http://C4G.LSU.EDU and we try to tie all of our systems, publications, information and resources together on this website C4G.LSU.EDU, however not all of C4G's web based systems are actually part of this primary website. While we use links to our other systems, some things are more important and time sensitive and require active notifications that a passive website may have a problem keeping up with. Therefore we post to other delivery methods that actively push and manage those that wish to receive these communications. With the following information we will clarify how we post time sensitive information and alerts distributed by C4G and the automated systems we use.
C4G's Web Store is a software transaction system that is not connected to any of our other websites or databases so any account you setup or data you put into the Web Store remains in the web store and payment data is only passed through a secure connection to LSU's bank by way of a payment gateway. Any emails you receive from the Web Store are coming from our servers on the LSU campus in the C4G server lab. Note that receiving an order confirmation from the Web Store is not an indicator that the automated RTN system messages should be getting through to you as the automated RTN messages come from different servers located outside of the LSU Domain.
The infrastructure software we use to run C4Gnet has an automated notification system that sends out account information and renewal notices by email, 30 days and 10 days in advance of an account expiration and again on the day of an account expiration. We don’t actively monitor the status of accounts so these automated messages will be your only warning of an upcoming account expiration or when an account actually expires. When an account expires, the system automatically shuts off the subscription. We have had many clients miss these automated notices so please take some time to login, check and confirm that the email account associated with your primary RTN account is going to the correct address so that you will receive these notices and avoid any interruption of your C4G services. Another possible cause for these automated email notices not being delivered successfully is junk mail or spam filtering. Check junk mail and spam filters for emails from "*@*.lsu.edu" and if possible, create an exclusion for email from any "lsu.edu" address as all future account info will be coming from these addresses.
C4G has an RTN Portal website that is directly connected to the advanced positioning software we use to run the Real-Time Network and other GPS/GNSS tools associated with the services we provide. The features of this portal change based on your user status of being logged in or logged out. Logged out users will find links to a Sensor Map that is dynamicaly connected to the RTN to get the status of CORS stations in Real-Time and links to our User Guide and Best Practice videos and podcasts. Logged in users will find additional links to tools to help in mission planing and management of their account passwords, active subscription details, session history and contact information. If you are a subcriber to the Reference Data Shop, you will find the web based data order system here and we will be introducing new tools in the near future that will be available in this web portal as well.
This document is where you will find the details on all the services and tools we offer to our clients. Things like mount points and the web protal tools are covered in detail and glossary of terms is included to decode the acronyms associated with the services we provide.
When we have information or learn about something that may impact any of our clients, we post to the C4G Facebook Page which automatically pushes the posts to our C4G Twitter Page. While the Facebook posts are verbose, the Twitter posts are limited to 140 characters but they also include a link to the verbose Facebook post to get more details. Facebook or Twitter is the best method to keep up with issues important to RTN Rovers. For those that are unable to receiver Facebook or Twitter posts, there are many free tools that will monitor Facebook or Twitter and forward these posts to other delivery systems such as email, news feed and many other content systems. One of these tools that we have worked with successfully is called IFTTT. This tool uses Recipes to make simple connections between different products and apps. Recipes run automatically in the background and create powerful connections with one simple statement — if this then that. Use this Recipe to send C4G Facebook posts to an email address.
We post videos to the C4G YouTube page from the events we host on topics such as Height Modernization & Best Practices for using Static and Real-Time Network GPS/GNSS. We also post training videos on topics that our clients might find helpful in using the tools and services we provide.
We use MailChimp to manage our mailing list and send out notices about major events and/or to distribute information such as this to keep our mailing list subscribers informed. Note, we Do Not post RTN User Alerts to the C4G Mailing List. Thanks! — C4G Network Administrator
The use of single and dual frequency satellite radio navigation systems, like the Global Positioning System (GPS), has grown dramatically in the last decade. GPS receivers are now in nearly every cell phone and in many automobiles, trucks, and any equipment that moves and needs precision location measurements. High precision dual frequency GPS systems are used for farming, construction, exploration, surveying, snow removal and many other applications critical to a functional society. Other satellite navigation systems in orbit include the European Galileo system and the Russian GLONASS system.
There are several ways in which space weather impacts GPS function. GPS radio signals travel from the satellite to the receiver on the ground, passing through the Earth’s ionosphere. The charged plasma of the ionosphere bends the path of the GPS radio signal similar to the way a lens bends the path of light. In the absence of space weather, GPS systems compensate for the “average” or “quiet” ionosphere, using a model to calculate its effect on the accuracy of the positioning information. But when the ionosphere is disturbed by a space weather event, the models are no longer accurate and the receivers are unable to calculate an accurate position based on the satellites overhead.
In calm conditions, single frequency GPS systems can provide position information with an accuracy of a meter or less. During a severe space weather storm, these errors can increase to tens of meters or more. Dual frequency GPS systems can provide position information accurate to a few centimeters. In this case the two different GPS signals are used to better characterize the ionosphere and remove its impact on the position calculation. But when the ionosphere becomes highly disturbed, the GPS receiver cannot lock on the satellite signal and position information becomes inaccurate.
Geomagnetic storms create large disturbances in the ionosphere. The currents and energy introduced by a geomagnetic storm enhance the ionosphere and increase the total height-integrated number of ionospheric electrons, or the Total Electron Count (TEC). GPS systems cannot correctly model this dynamic enhancement and errors are introduced into the position calculations. This usually occurs at high latitudes, though major storms can produce large TEC enhancements at mid-latitudes as well.
Near the Earth’s magnetic equator there are current systems and electric fields that create instabilities in the ionosphere. The instabilities are most severe just after sunset. These smaller scale (tens of kilometers) instabilities, or bubbles, cause GPS signals to “scintillate”, much like waves on the surface of a body of water will disrupt and scatter the path of light as it passes through them. Near the equator, dual frequency GPS systems often lose their lock due to “ionospheric scintallation”. Ionospheric scintallations are not associated with any sort of space weather storm, but are simply part of the natural day-night cycle of the equatorial ionosphere.
LSU Center for GeoInformatics(C4G) in partnership with the Space & Earth Geodetic Analysis Laboratory (SEGAL) at the Universidade de Beira Interior (UBI) and Instituto Dom Luis (IDL), Portugal will provides a framework for advancing geodetic analysis and modeling. Combining the skills and experiences from these of capable and motivated partners will lead to new opportunities that were previously inaccessible.
The partners will collaboratively pursue research and support for the precise point positioning of GPS/GNSS data, gravimetric geoid modeling, and the application of emerging geo-informatics technologies and services. C4G and SEGAL will develop new tools for analyzing Global Navigation and Satellite Systems (GNSS) data. Long term collaboration will also advance the development of a new gravimetric geoid model for Louisiana.
“Subsidence is a leading cause, if not the principal driver of wetlands losses in Louisiana,” - C4G researcher Joshua Kent.
Louisiana’s coastal wetlands are lost at nearly one football field every hour.” - U.S. Geological Survey
“Gravimetric surveys conducted by the C4G will ultimately allow us to re-connect with the geoid to calculate better elevations" and “knowing how high we are above sea level.” - C4G geodesist Cliff Mugnier.
“We have applied our in-house developed software in the computation of regional and national geoid projects in North Mozambique, Madeira and more recently in Bhutan.” - Machiel Bos, SEGAL researcher
“This collaboration is a unique opportunity to partner with a very enthusiastic team that combines pure and applied research in several areas of geosciences with enormous societal implications,” - Rui Fernandes, of SEGAL.
“I anticipate significant innovation from our relationship.” - George Z. Voyiadjis, Boyd Professor and Director of C4G
Download the Official Press Release for detailed information HERE
2014 Height Mod Playlist
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Center for GeoInformatics101 LSU Student Union BuildingLSU Box #25413Baton Rouge, LA 70803
Louisiana State UniversityEng. Research & Development Bldg.Room 200, 2nd Floor South Stadium Drive
Cliff 225.578.4578 Randy 225.578.4609 Josh 225.578.5260 Larry 225.578.8925