The Army will conduct overnight GPS jamming testing across a huge swath of central Texas for most of February. Although such interference testing is relatively common, particularly in the Southwest, the scope and potential impact of this one is unusual. The agency says that between 11 p.m. and 5 a.m. local time for two weeks (Feb. 5-12, Feb. 15-22) and on Feb.2, from 3 a.m. to 5 a.m. Feb.13 and 14, and from 2:01 a.m. and 5 a.m. from Feb. 23-27, a 600-mile diameter circle of airspace (at 25,000 feet) will have GPS disruptions affecting WAAS, GBAS, and ADS-B. The circle is centered on Fort Hood, which is about 60 miles north of Austin. The test area covers Dallas, Houston, San Antonio, and Oklahoma City and may result in “unreliable or unavailable GPS signals.”
The agency says NOTAMs will be issued 24 hours before the tests but they are subject to change with little or no notice. Pilots who notice issues with their GPS-reliant avionics are encouraged to report anomalies in accordance with the AIM paragraphs 1-1-13 and 5-3-3. The testing won’t just affect aviation. At the surface, it has the potential to screw up cars, phones, tablets, watches, and anything else that uses GPS in a circle more than 190 miles across. Apparently not all devices will be affected. Here’s the FAA advisory:
As I understand it, a lot of ground-based systems rely heavily upon the timing signals from GPS satellites. At its core a GPS satellite is just an atomic clock. Cell phone towers use this hyper-accurate timing signal to synchronize calls and data within and between towers. Financial institutions use this timing to synchronize buy and sell orders. Power companies use it to synchronize power line frequency between substations. This last part is interesting because Texas (by design) has pretty much cut itself off from the rest of the U.S. power grid in order to avoid federal oversight. I believe this also means it can’t rely upon the national grid for backup.
I’d be curious to see if any of the above systems are affected in a noticeable way by this outage.
Good thing they picked a remote area to test in.
Can you spell VOR?
How about using Kwajalein instead?
If they want to test and exercise operations in a GPS denied environment just turn off the GPS systems in the vehicles and aircraft.
Utterly irresponsible.