Intelligence, surveillance and reconnaissance

Intelligence, surveillance and reconnaissance (ISR) is both a management activity for three related disciplines, but also three ways to look at information collection. In practice,
 * intelligence is a combination of information collection and analysis that builds a medium-to-long term understanding of a subject. It often creates reference material
 * surveillance is a relatively passive activity of collection coupled with comparison to norms, to detect an out-of-the-ordinary event
 * reconnaissance is an active attempt to investigate a place or situation, if only to find negative information (i.e., where the enemy is not)

As a management activity, the U.S. Joint Chiefs of Staff defines it as An activity that synchronizes and integrates the planning and operation of sensors, assets, and processing, exploitation, and dissemination systems in direct support of current and future operations. This is an integrated intelligence and operations function.

It is common to speak of ISR communications, which tend to have high bandwidths because they transmit complex images. In like manner, ISR aircraft, unmanned aerial vehicles, and sometimes ground vehicles, carry sensors into range of the subject of interest.

ISR is often combined with "C3I", or "command, control, communications and intelligence". The reason for combining may be that the joint communications stream is of special sensitivity. Alternatively, a flying command post may include additional collection systems on which commanders can take immediate action.