Measurement and signature intelligence in the context of "Human intelligence (intelligence gathering)"

The National Reconnaissance Office (NRO) is a member of the United States Intelligence Community and an agency of the United States Department of Defense which designs, builds, launches, and operates the reconnaissance satellites of the U.S. federal government. It provides satellite intelligence to several government agencies, particularly signals intelligence (SIGINT) to the National Security Agency (NSA), imagery intelligence (IMINT) to the National Geospatial-Intelligence Agency (NGA), and measurement and signature intelligence (MASINT) to the Defense Intelligence Agency (DIA). The NRO announced in 2023 that it plans within the following decade to quadruple the number of satellites it operates and increase the number of signals and images it delivers by a factor of ten.

NRO is considered, along with the Central Intelligence Agency (CIA), NSA, DIA, and NGA, to be one of the "big five" U.S. intelligence agencies. The NRO is headquartered in Chantilly, Virginia, 2 miles (3.2 km) south of Washington Dulles International Airport.

A reconnaissance aircraft (colloquially, a spy plane) is a military aircraft designed or adapted to perform aerial reconnaissance with roles including collection of imagery intelligence (including using photography), signals intelligence, as well as measurement and signature intelligence. Modern technology has also enabled some aircraft and UAVs to carry out real-time surveillance in addition to general intelligence gathering.

Before the development of devices such as radar, military forces relied on reconnaissance aircraft for visual observation and scouting of enemy movement. An example is the PBY Catalina maritime patrol flying boat used by the Allies in World War II: a flight of U.S. Navy Catalinas spotted part of the Japanese fleet approaching Midway Island, beginning the Battle of Midway.

Strategic intelligence (STRATINT) pertains to the collection, processing, analysis, and dissemination of intelligence that is required for forming policy and military plans at the national and international level. Much of the information needed for strategic reflections comes from Open Source Intelligence. Other sources include traditional HUMINT (especially in recent years), Signals intelligence including ELINT, MASINT which overlaps with SIGINT/ELINT to some degree, and 'National technical means of verification' (e.g. spysats). The father of intelligence analysis and of the strategic intelligence concept was Sherman Kent, in his seminal work Strategic Intelligence for American World Policy, first published in 1949. For Kent, strategic intelligence is ”the knowledge upon which our nation's foreign relations, in war and peace, must rest".

Strategic intelligence pertains to the following system of abilities that, according to Michael Maccoby, characterize some of the most successful leaders in business, government and military.: