Judging from the actual situation of anti-UAV defense in military ports of major countries in the world, there are three main UAV threats facing military ports in various countries at present and in the future: 

First, small UAVs take off from the vicinity of port bases to carry out mobile reconnaissance, surveillance and guidance operations on military ports. Their main characteristics are that they sneak from "behind" the port, their actions are covert, and it is difficult to distinguish between friend and foe. 

Second, medium and small UAVs take off from the sea-based platforms of combat opponents to carry out reconnaissance, guidance, harassment and strike operations on military ports and important areas. Their main characteristics are that they are mobilely deployed at sea, take off at any time, act quickly, and are difficult to trace.

Third, large UAVs take off from the land of combat opponents to carry out reconnaissance, surveillance, interference guidance, harassment and strike operations on military ports and naval battlefields. Their main characteristics are long duration, wide range of activities and diverse means of threat.