NORTHFIELD (AP) - Teams from two colleges in Minnesota and one university in North Dakota are building drones in preparation for an international robotics competition.

Reports say that teams from Carleton and St. Olaf colleges and North Dakota State University are to compete at the International Aerial Robotics event in Atlanta this July.

The contest challenges competitors to build a drone that can avoid obstacles and make decisions on its own. The drone can't rely on external guidance systems like GPS or remote control, so the projects will use cameras, ultrasonic sensors and radar to know where it is.

During the competition, the drones will have to maneuver inside a large auditorium where it'll need to sense robots moving randomly across the floor.