a communication interface configured to communicate with a first unmanned aircraft having a first camera to be used for detecting an obstacle and a second unmanned aircraft having a second camera to be used for detecting an obstacle with higher detection accuracy than the first camera; and

a controller configured to determine, based on position information for first obstacles, a second area in which a density of first obstacles is equal to or greater than a reference value, determine a flight path along which the first unmanned aircraft travels to a destination, detect, in a case that a target point in the second area is present on the flight path, a second obstacle at the target point using the second unmanned aircraft before the first unmanned aircraft begins traveling to the destination, the second obstacle being less visible than the first obstacle and present in the vicinity of the first obstacle, modify the flight path using information regarding the detected second obstacle so that the first unmanned aircraft navigates around the second obstacle, and notify the first unmanned aircraft of the modified flight path to cause the first unmanned aircraft to begin traveling to the destination along the modified flight path.