WASHINGTON — The Defense Advanced Research Projects Agency is gearing up for a major exercise in which it plans to demonstrate a single user controlling a swarm of about 200 unmanned systems in an urban environment. The November capstone event at Fort Campbell, Kentucky, is part of DARPA ’s OFFensive Swarm-Enabled Tactics (OFFSET) program, which envisions smaller units able to mass up to 250 small aerial and ground unmanned systems in urban areas. One of the major integrators on the effort,