Modern investigation and monitoring technology can be divided into three types according to investigation activities.

Analysis: There are many classification methods of modern reconnaissance technology, which are usually divided into the following four categories:

1. The investigation tasks, nature, scope, information use and the functions caused are different: strategic reconnaissance, campaign reconnaissance and tactical reconnaissance;

2. The vehicles of reconnaissance equipment and their differences in use: ground (water surface), underwater, air and space reconnaissance systems;

3. According to different technical principles of remote sensing equipment: optical (visible light, multi-spectrum, infrared, microwave), electronic, acoustic reconnaissance, etc.

4. Different ways of reconnaissance activities: armed reconnaissance and surveillance, spy reconnaissance and surveillance, and technical reconnaissance and surveillance;