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LSU’s College of Engineering created the Center for GeoInformatics (C4G) to build new research and services in Geodesy and GeoInformatics.

Click Photo of Josh to watch his presentation on Subsidence in Louisiana - December 2016


Click to see videoJoshua David Kent, husband, father of four and coastal Louisiana geographer, died suddenly on Thursday, July 6, 2017, in Baton Rouge, Louisiana. He was born in New Orleans on April 19, 1970, and is survived by his parents David Roland Kent and Roma Ajubita Kent. His beloved wife Kelly Twiggs Kent and his four daughters, Miranda, Elise, Tessa and Juliet also survive him. Josh graduated from De La Salle High school in New Orleans. He received his Bachelor of Science from Louisiana State University where he also received his Masters degree and attained his Doctorate in geography. He has been published extensively, his research focusing on long-term impact of subsidence and global climate change on the emergency evacuation routes in coastal Louisiana. He also researched the location and impact of oil infiltration in our coastal marshes and bays.

Kent Family Donations 

Published in TheNewOrleansAdvocate.com from July 8 to July 10, 2017

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.

*All of the information and plots on this page are from the Space Weather Prediction Center, which is a division of the National Weather Service & National Oceanic and Atmospheric Administration.

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LSU Remains Committed to the Success and Expansion of C4G

LSU Remains Committed to the Success and Expansion of C4G LSU Remains Committed to the Success and Expansion of C4G
  In 2001, LSU’s College of Engineering created a Center for GeoInformatics (C4G) to build new...

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