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ELINT stands for ELectronic Signals INTelligence, and refers to intelligence-gathering by use of electronic sensors.

ELINT primarily focuses on non-communications signals intelligence. Signal identification is performed by analyzing the collected parameters of a specific signal, and either matching it to known criteria, or recording it as a possible new emitter. ELINT data is usually highly classified information, and is protected as such.

The data gathered is typically pertinent to a rival's defence network, especially the electronic parts such as radars, surface-to-air missile systems, aircraft, etc. It can be performed from ground stations near the opponent's territory, ships off their coast, aircraft near or in their airspace, or by satellite.

The primary goal of ELINT is to acquire data which would be valuable in the event of a conflict. Knowing where each surface-to-air missile and anti-aircraft artillery system is and its type means that air raids can be plotted to avoid the most heavily defended areas and to fly on a flight profile which will give the aircraft the best chance of evading ground fire and fighter patrols. It also allows for the jamming or spoofing of the enemy's defence network (see electronic warfare).

ELINT can also acquire data about where the ships, command and control centers, surface-to-air missile systems and other assets of the enemy are so they can be struck in the event of a war. Good electronic intelligence can be very important to stealth operations; stealth aircraft are not totally undetectable and need to know which areas to avoid. Similarly, conventional aircraft need to know where fixed or semi-mobile air defence systems are so that they can shut them down or fly around them. ELINT is an important component of the sensor grid for Network-centric warfare.

Combining other sources of information and ELINT allows traffic analysis to be performed on electronic emissions which contain human encoded messages. The method of analysis differs from SIGINT in that any human encoded message which is in the electronic transmission is not analysed during ELINT. What is of interest is the type of electronic transmission and its location. For example during the Battle of the Atlantic in World War II, Ultra SIGINT was not always available because Bletchley Park was not always able to read the U-Boat Enigma traffic. But "Huff-Duff" (High Frequency Direction Finder) was still able to find where the U-Boats were by analysis of radio transmissions and the positions through triangulation from the direction located by two or more Huff-Duff systems. The Admiralty was able to use this information to plot courses which took convoys away from high concentrations of U-Boats.

• HUMINT: Human intelligence
• COMINT: Communications intelligence
• SIGINT: Signals intelligence
• IMINT: Imagery intelligence