Two weeks ago, we told you that the Secret Service was going to fly drones around Washington, DC — the start of some mysterious "exercises" on which it provided few details. Today the Associated Press is reporting that the agency has been flying drones in the dead of night in an effort to study how they can be tracked, jammed, and knocked out of the sky.

The surge in activity stems from a recent crash on the White House lawn. That drone was reportedly flown by an off-duty US intelligence employee, who no doubt is getting mercilessly teased in the break room.

The Secret Service is looking into ways to detect a signal, for example a video stream being sent from the drone back to the pilot, and use that to follow its flight path. The agency also wants to experiment with jamming the radio and Wi-Fi signals used to control the drone.

The current exercises were meant to help the Secret Service understand what impact this kind of signal interference could have on local internet and phone networks and what role surrounding trees, buildings, and monuments could have on its aerial defense systems.

The major limitation of jamming just the signals used for the pilot's control is that many commercial drones can be programmed to autonomously fly a route using GPS waypoints. Breaking that system would be more complex, although not impossible. Working with Homeland Security, researchers from the University of Texas have successfully hijacked the GPS of a commercial drone.