Signals Intelligence
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29 April 1998 Thanks to Jeffrey T. Richelson and Ballinger The U.S. Intelligence Community Jeffrey T. Richelson New York, Ballinger, 1989 This excerpt from Second Edition (soft), pp. 167-197 Chapter 8 SIGNALS INTELLIGENCE Signals intelligence (SIGINT) is traditionally considered to be one of the most important and sensitive forms of intelligence. The interception of foreign signals can provide data on a nation's diplomatic, scientific, and economic plans or events as well as the characteristics of radars, spacecraft and weapons systems. SIGINT can be broken down into five components: • communications intelligence (COMINT) • electronics intelligence (ELINT) • radar intelligence (RADINT) • laser intelligence (LASINT) • non-imaging infrared. As its name indicates, COMINT is intelligence obtained by the interception, processing, and analysis of the communications of foreign governments or groups, excluding radio and television broadcasts. The communications may take a variety of forms--voice, Morse code, radio-teletype or facsimile. The communications may be encrypted, or transmitted in the clear. The targets of COMINT operations are varied. The most traditional COMINT target is diplomatic communications--the communications from each nation's capital to its diplomatic establishments around the world. The United States has intercepted and deciphered the diplomatic communications of a variety of nations-- Britain during the 1956 Suez Crisis, Libya's communications to its East Berlin People's Bureau prior to the bombing of a nightclub in West Berlin in 1985, Iraq's communications to its embassy in Japan in the 1970s. The United States also targets the communications between different components of a large number of governments. On some occasions both components are located within the country, on other occasions at least one is located outside national boundaries. Communications that may be targeted include those between government officials, different ministries, a ministry or agency and subordinate units throughout the country and abroad, 1 arms factories, military units during exercises and operations, and police and security forces and their headquarters. More specifically, the United States intercepts communications between the Soviet Ministry of Defense and Military District headquarters, and between Military District headquarters and units in the field; between transmitter stations and Soviet submarines; between the President of Egypt and his subordinates (including the time when Egypt was holding the hijackers of the Achille Lauro); and between military units at all levels in the Philippines. In 1980, U.S. intercepts of Soviet communications generated a fear that the Soviets were about to invade Iran. In 1983 intercepts allowed the United States to piece together the details concerning the sinking of a Soviet submarine in the North Pacific.1 At times, entire sets of targets may be dropped or have their coverage dramatically increased. In the early 1970s the United States dropped COMINT coverage of the Soviet civil defense network (coverage was later resumed). In 1983 it began an all-source intelligence program (that included COMINT) to improve intelligence on the Soviet prison camp system, with the specific intent of issuing a study that would embarrass the Soviets. The intelligence was intended to determine the location of the camps, existing conditions, and the number of political prisoners. Governmental communications do not exhaust the set of COMINT targets. The communications of political parties or guerilla movements may also be targeted. The communications of the African National Congress in South Africa, the El Salvadoran rebels, and the Greek Socialist Party are all likely targets of COMINT activities. In addition, the communications of terrorist groups can also be COMINT targets--both to permit understanding of how the group functions and the personalities of its leaders, and to allow prediction of where and how the groups will strike next. Another major set of COMINT targets are associated with economic activity (of both the legal and illegal variety)--for example, the communications of multinational corporations and narcotics traffickers. In 1970, the predecessor to the Drug Enforcement Administration informed the NSA that it had "a requirement for any and all COMINT information which reflects illicit traffic in narcotics and dangerous drugs." Specific areas of interest included organizations and individuals engaged in such activities, the distribution of narcotics, narcotic cultivation and production centers, efforts to control the traffic in narcotics, and all violations of U.S. Laws concerning narcotics and dangerous drugs.2 Electronic intercept operations are intended to produce electronic intelligence (ELINT) by intercepting the non-communication signals of military and civilian hardware, excluding those signals resulting from atomic detonations. Under NSA project KILTING, all ELINT signals are stored in computerized reference files containing the most up-to-date technical information about the signals. The earliest of ELINT targets were World War II air defense radar systems. The objective was to gather emanations that would allow the identification of the presence and operating characteristics of the radars--information that could be used to circumvent or neutralize the radars (through direct attack or electronic countermeasures) during bombing raids. Information desired included frequencies, signal strengths, pulse lengths and rates, and other specifications. Since that time, intelligence, space tracking, and ballistic missile early-warning radars have joined the list of ELINT targets. In the early 1950s the primary targets were Soviet Bloc (including PRC) radars. Soviet radars remain a prime ELINT target. Monitoring Soviet radars also has an arms control verification aspect, since the 1972 ABM Treaty restricts the use of radars in an "ABM mode." During the Vietnam war, North Vietnamese radars were also major targets. Libyan and Iranian radars are clearly prime targets in the late 1980s. 2 A subcategory of ELINT is Foreign Instrumentation Signals Intelligence (FISINT). Foreign instrumentation signals are electromagnetic emissions associated with the testing and operational deployment of aerospace, surface, and subsurface systems that have military or civilian applications. Such signals include, but are not limited to, signals from telemetry, beaconing, electronic interrogators, tracking-fusing-aiming/command systems, and video data links.3 A subcategory of FISINT is Telemetry Intelligence (TELINT). Telemetry is the set of signals by which a missile, missile stage, or missile warhead sends, back to earth, data about its performance during a test flight. The data relate to structural stress, rocket motor thrust, fuel consumption, guidance system performance, and the physical conditions of the ambient environment. Intercepted telemetry can provide data to estimate the number of warheads carried by a given missile, its payload and throw-weight, the probable size of its warheads, and the accuracy with which the warheads are guided at the point of release from the missile's post-boost vehicles.4 Radar intelligence--the intelligence obtained from the use of non-imaging radar--is similar to ELINT in that no intercepted communications are involved. However, RADINT does not depend on the interception of another object's electronic emanations. It is the radar which emanates electronic signals--radio waves--and the deflection of those signals allows for intelligence to be derived. Information that can be obtained from RADINT includes flight paths, velocity, maneuvering, trajectory, and angle of descent. Two further categories of SIGINT were listed in the proposed National Security Agency charter of 1980--information derived from the collection and processing of (I) non-imaging infrared, and (2) coherent light signals. The former involves sensors that can detect the absence/presence and movement of an object via temperature. The term "coherent light signal" refers to lasers, and hence this category includes the interception of laser communications, as well as the emissions from Soviet laser research and development activities.5 The ease with which signals (whether communications or electronic signals) can be intercepted and understood depends on three factors: the method of transmission, the frequencies employed, and the encipherment system (or lack of) used to conceal the signals meaning form unauthorized personnel. The most secure form of transmission is that sent by cables, either land lines or underwater cables. Communications or other signals transmitted through such cables cannot be snatched out of the air. Interception of cable traffic has involved physically tapping into the cables or using "induction" devices that are placed in the proximity of the cables and maintenance of equipment at the point of access. This might be unobtainable with respect to hardened and protected internal landlines, the type of landline that carries much high-priority, secret command and control communications. Undersea cables are most vulnerable since the messages transmitted by them are then transmitted by microwave relay once the cable reaches land. A tremendous volume of communications is sent via satellite systems. Domestic and international telephone messages, and military and business communications are among those regularly transmitted via satellite using ultra, very, super, and extremely high frequencies (UHF, VHF, SHF