Saw this posted on another forum
The Federal Aviation Association (FAA) released an announcement on January 19 stating that the Department of Defense would be conducting a series of GPS tests throughout the next month. It is expected that this testing, which will occur January 20 through February 22, will cause the GPS signal to be unreliable or unavailable for different periods of time in the Southeastern United States. We wanted to share this announcement with you so that you can be prepared for any service anomalies that may occur while your fleet is operating in this region.
Specific testing information:
* Location: Centered at 304906N/0802811W or the location know as 105.25 degrees and 52.1 NM from the SSI VOR.
* Dates and times: GPS testing is scheduled on January 20th through February 11th, 2011 from 0000-0245 UTC daily and February 15th through February 22nd, 2011 from 0000-0245 UTC daily.
* Duration: Several test events will be conducted and will be active for 45 minutes followed by 15 minutes of off time.
The FAA's announcement can be found by following this link:
https://www.faasafety.gov/files/notices/2011/Jan/GPS_Flight_Advisory_CSFTL11-01_Rel.pdf