Signal Intelligence (SIGINT)

Signal intelligence is based on sources of information from electromagnetic interceptions (radars and communications) coming from different sensors (space (satellite), air platforms (manned or unmanned aircrafts) and ground based platforms).
By extension, signal intelligence refers to all the processing activities of this type of information (collection, evaluation, analysis, dissemination).
Signal intelligence is part of the wider family of Intelligence Operations and includes ELINT (Electronic Intelligence) and COMINT (Communication Intelligence).
Signal Intelligence must not be confused with other technical intelligence (image intelligence, acoustic intelligence), from human intelligence and from open source intelligence (Figure 1).
The US NSA defines SIGINT as “the intelligence derived from electronic signals and systems used by foreign targets, such as communications systems, radars, and weapons systems. SIGINT provides a vital window for our nation into foreign adversaries’ capabilities, actions, and intentions.”

Task of SIGINT is to detect, analyze and compare with a previously built Data Base the EM environment for understanding the enemy organization, plans and changes.

Figure 1: Allocation of SIGINT in the Intelligence Operations

In order to achieve the RF spectrum monitoring, the SIGINT mission needs to be accurately prepared.
A-priori information’s are made available to the SIGINT Mission for comparison with new detected emissions in real time (RT) or near-real time (NRT) for tactical purposes.
Data acquired and stored during a SIGINT mission are off-line analyzed for SIGINT Data Base update purposes.
The SIGINT Data Base creates strategic information; a selected part of the SIGINT Data Base is used at tactical level to create the a-priori data for the Electronic Order of Battlefield (EOB).
EOB represents the best and quick knowledge of the Battlefield in terms of Electro-Magnetic spectrum (EMS) and its evolution along the time.
EOB includes Detection, Identification, Classification, Localization, Analysis and Collection of all the possible Enemy emissions, divided in:
• Communication Order of Battle (COB)
• Radar Order of Battle (ROB)

The main steps of a SIGINT Mission are:
• Mission Preparation: all the information supporting the mission are identified and made available.
• Mission Execution: acquisition and storage of data and first level of analysis execution (RT or NRT)
• Post Mission: preparation of the mission de-briefing, analysis of the mission and first level of report generation
• Data Analysis: detailed analysis of the data captured along the mission
• Dissemination: sharing of new information with relevant organizational entities
• Database Update: new data are inserted in the Data base and are available for the coming missions

Figure 2: main steps of a SIGINT Mission