Common Signal Intelligence (SIGINT) Definitions

Which may be helpful when using this site and the linked information provided.

AFSS (USAFSS): Air Force Security Service (now Air Intelligence Agency). Air Force Cryptologic and SIGINT operating element.

ASA (USASA): Army Security Agency (United States Army Security Agency). 1945 - 1976. (successor USAINSCOM since 1977) US Army Cryptologic/SIGINT operating element.

Bearing/Shot: See LOB.

COMINT: Communications Intelligence. Technical (such as Traffic Analysis) and intelligence information derived from foreign communications by other than the intended recipients.

DF/RDF/HFDF/ARDF: Direction Finding/Radio Direction Finding/High Frequency (Radio) Direction Finding/Airborne Radio Direction Finding.

DIA: Defense Intelligence Agency (US Department of Defense).

DUFFY: In ASA a Radio Direction Finding Operator. Origins may be with the British from World War II when R/DF was often referred to as "Huff-Duff".

ELINT: Electronic Intelligence.

Fix/Plot: Determining the location of a radio emitter by triangulation and evaluation of LOB (on appropriate maps/charts) received from several radio direction finding sties.

GCHQ: Government Communications Headquarters. United Kingdom organization with similar responsibilities as the NSA.

HUMINT: Human Intelligence. CIA and DIA in the US have primary responsibility.

INSCOM (USINSCOM): Intelligence & Security Command (United States Army Intelligence & Security Command). Replacement organization of the ASA. Formed 1977 using ASA elements and other intelligence elements of the US Army.

LOB: Line of Bearing. Azimuth bearing from a direction finding site to a distant target radio signal emitter. (Example: 048 degrees from True North)

MOS: Military Occupational Specialty -- Army

NSA (NSA/CSS): National Security Agency (US Department of Defense-DOD). NSA/CSS - National Security Agency/Central Sercurity Service (siginifying NSA operational control of much of the SCAs SIGINT operations.)

NSG/NSGA: Naval Security Group/Naval Security Group Activity. US Navy Cryptologic operating element/unit. 1935 - 2005

RFP/AIT: Radio Fingerprinting/Advanced Identification Techniques. The technique of identifying specific radio emitters by their unique signal characteristics. Very similar in concept to fingerprinting individuals. From NSA:

(U) Radio Fingerprinting (RFP) - identify and classify the unique characteristics of individual radio transmitters by the study of oscillograms of their signals. Also called transmitter identification.

From a friend: "Radio Fingerprinting was the analysis of frequency & amplitude modulations to determine similarities and distinctions. The signals were captured with a hi-speed camera using = paper-based film and developed via a special processing machine. There were analysts specially trained to do the analysis. There was also a trick on being the operator as a primary goal was to capture a majority of "dahs" vice "dits". You also had to be aware of just when the target was about to stop transmitting or else you just might push the "record" button and waste 20 ft of film!"

RRC/G/FS: Radio Research. Cover designation for Army Security Agency units during the Vietnam conflict. Such as: 509th Radio Research Group (509th RRG); 330th RRC (330th ASA Company); 303rd RRBN (303rd Army Security Agency Battalion); 8th RRFS (8th ASA Field Station).

SCA: Service Cryptologic Agency(Activity). Army Security Agency, Naval Security Groups, Air Force Security Service.

SIT/AIT: Special Identification Techniques/Advanced Identification Techniques. ASA/INSCOM usage. Within the Army, consisted of the disciplines of Radio Direction Finding, Radio Fingerprinting (RFP) later referred to as Wave Form Analysis. Discipline included the collection of the data, plotting or analyzing and reporting results to requesting section/department and/or supported command and national authority levels.

SIGINT: Signals Intelligence. NSA/CSS: "SIGINT is a category of intelligence that includes transmissions associated with communications, radars, and weapons systems used by our adversaries. It complements other forms of intelligence that are the responsibility of other U.S. agencies in the Intelligence Community. For example, Human Intelligence (HUMINT) is primarily the responsibility of the Central Intelligence Agency and Defense Intelligence Agency, and Imagery Intelligence (IMINT) belongs to the National Geospatial-Intelligence Agency. Together, all of these different - yet complementary - disciplines give our Nation's leaders a greater understanding of the intentions of our enemies."