This is the official 2018 season kickoff for Sitrep, a (mostly) regular Ars video series. We'll be presenting quick updates every few weeks on the latest tech-focused developments in defense and national security and how those developments affect the world at large.

For much of February—and in some places, well into March—the US military will be jamming signals from the Global Positioning System as part of training exercises over vast swaths of the Western United States, as well as in smaller areas surrounding major military facilities across the US.

A major source of the GPS jamming will be Red Flag 18-1, the first phase of the air war games staged every year from Nellis Air Force Base in Nevada, with events ranging as far north as the Seattle air traffic control area. Electronic warfare aircraft, including the Navy's EA-18 Growler and the Air Force's EC-130 Compass Call, will play a role in shutting down the satellite navigation system for everything within as large as a 450 nautical mile radius.

The jamming will be restricted for the most part to periods between 11pm and 2am Eastern Time. This is when commercial air traffic is at its least dense, so the impact on air travel should be negligible. But the exact times may vary. And jamming tests for other exercises during the same period—including some at or off the coast of Navy nuclear sub bases at Bangor in Washington and Kings Bay, Georgia—may have an impact on commercial shipping and fishing vessels.

Red Flag 18-1 includes participants from all four service branches of the Department of Defense, as well as units of the British Royal Air Force and the Royal Australian Air Force." [This] primarily is a strike package focused training venue," said Colonel Michael Mathes, commander of the 414th Combat Training Squadron at Nellis. But while strike packages—practice bombing missions and stand-off missile attacks—are the end product, the exercise also includes a "cyber" component, in which the adversary team will attempt to disrupt operations through everything from phishing emails to electronic warfare.

That's where the GPS jamming comes in. The US and allied military forces lean heavily on GPS navigation, especially in the air—even some weapons systems depend on GPS for guidance. But because of the relative low power of GPS signals from satellites—as we've pointed out on a number of occasions—GPS is particularly prone to jamming or spoofing.

North Korea has become particularly adept at using GPS jamming to disrupt life (and military operations) in South Korea—even affecting air traffic flying into Seoul on several occasions and causing South Korean fishing fleets to return to port out of fear of drifting into North Korean waters.

The GPS jamming during Red Flag and other exercises this winter are intended to prepare pilots and air crews for operations under those sorts of hostile electromagnetic conditions. The Army will conduct its own GPS jamming exercises as well at Fort Bragg in North Carolina, Fort Polk in Louisiana, and at the National Training Center at Fort Irwin, California, during the same timeframe.

Listing image by US Air Force