Signals intelligence (SIGINT) is the act and field of intelligence-gathering by interception of signals, whether communications between people or from electronic signals not directly used in communication. Signals intelligence is a subset of intelligence collection management. As classified and sensitive information is usually encrypted, signals intelligence may necessarily involve cryptanalysis. Traffic analysis—the study of who is signaling to whom and in what quantity—is also used to integrate information, and it may complement cryptanalysis.
Electromagnetic warfare or electronic warfare (EW) is warfare involving the use of the electromagnetic spectrum or directed energy to control the spectrum, attack an enemy, or impede enemy operations. The purpose of electromagnetic warfare is to deny the opponent the advantage of—and ensure friendly unimpeded access to—the EM spectrum. Electromagnetic warfare can be applied from air, sea, land, or space by crewed and uncrewed systems, and can target communication, radar, or other military and civilian assets.
The Joint Tactical Information Distribution System (JTIDS) is an L band Distributed Time Division Multiple Access (DTDMA) network radio system used by the United States Department of Defense and their allies to support data communications needs, principally in the air and missile defense community. It produces a spread spectrum signal using Frequency-shift keying (FSK) and Phase-shift keying (PSK) to spread the radiated power over a wider spectrum (range of frequencies) than normal radio transmissions. This reduces susceptibility to noise, jamming, and interception. In JTIDS Time Division Multiple Access (TDMA) (similar to cell phone technology), each time interval (e.g., 1 second) is divided into time slots (e.g. 128 per second). Together, all 1536 time slots in a 12-second interval are called a "frame". Each time slot is "bursted" (transmitted) at several different carrier frequencies sequentially. Within each slot, the phase angle of the transmission burst is varied to provide PSK. Each type of data to be transmitted is assigned a slot or block of slots (channel) to manage information exchanges among user participation groups. In traditional TDMA, the slot frequencies remain fixed from second to second (frame to frame). In JTIDS TDMA, the slot frequencies and/or slot assignments for each channel do not remain fixed from frame to frame but are varied in a pseudo-random manner. The slot assignments, frequencies, and information are all encrypted to provide computer-to-computer connectivity in support of every type of military platform to include Air Force fighters and Navy submarines.
Tropospheric scatter, also known as troposcatter, is a method of communicating with microwave radio signals over considerable distances – often up to 500 kilometres (310 mi) and further depending on frequency of operation, equipment type, terrain, and climate factors. This method of propagation uses the tropospheric scatter phenomenon, where radio waves at UHF and SHF frequencies are randomly scattered as they pass through the upper layers of the troposphere. Radio signals are transmitted in a narrow beam aimed just above the horizon in the direction of the receiver station. As the signals pass through the troposphere, some of the energy is scattered back toward the Earth, allowing the receiver station to pick up the signal.
Courier 1B, is the world's first active repeater communications satellite, Courier 1B was successfully launched on October 4, 1960 at 17:45:00 GMT from Cape Canaveral, Florida. The first Courier satellite in Project Courier, Courier 1A, was lost 2.5 minutes after lift-off on August 18, 1960.
A secret broadcast is, simply put, a broadcast that is not for the consumption of the general public. The invention of the wireless was initially greeted as a boon by armies and navies. Units could now be coordinated by nearly instant communications. An adversary could glean valuable and sometimes decisive intelligence from intercepted radio signals:
A signaller, signalman, colloquially referred to as a radioman or signaleer in the armed forces is a specialist soldier, sailor or airman responsible for military communications. Signallers, a.k.a. Combat Signallers or signalmen or women, are commonly employed as radio or telephone operators, relaying messages for field commanders at the front line, through a chain of command which includes field headquarters. Messages are transmitted and received via a communications infrastructure comprising fixed and mobile installations.
The United States Army Signal Corps (USASC) is a branch of the United States Army that creates and manages communications and information systems for the command and control of combined arms forces. It was established in 1860, the brainchild of Major Albert J. Myer, and had an important role in the American Civil War. Over its history, it had the initial responsibility for portfolios and new technologies that were eventually transferred to other U.S. government entities. Such responsibilities included military intelligence, weather forecasting, and aviation.
Military communications or military signals involve all aspects of communications, or conveyance of information, by armed forces. Examples from Jane's Military Communications include text, audio, facsimile, tactical ground-based communications, naval signalling, terrestrial microwave, tropospheric scatter, satellite communications systems and equipment, surveillance and signal analysis, security, direction finding and jamming. The most urgent purposes are to communicate information to commanders and orders from them.
The Royal Australian Corps of Signals (RASigs) is one of the 'arms' of the Australian Army. It is responsible for installing, maintaining, and operating all types of telecommunications equipment and information systems. The motto of the Signals Corps is Certa Cito and is translated as 'Swift and Sure', signifying the aim of the signal service – that communication be carried out with maximum speed and certainty. Like their British counterparts, the Royal Australian Corps of Signals' flag and hat badge feature Mercury, the winged messenger of the gods, affectionately referred to by members of the corps as "Jimmy".
The Signal Corps in the American Civil War comprised two organizations: the U.S. Army Signal Corps, which began with the appointment of Major Albert J. Myer as its first signal officer just before the war and remains an entity to this day, and the Confederate States Army Signal Corps, a much smaller group of officers and men, using similar organizations and techniques as their Union opponents. Both accomplished tactical and strategic communications for the warring armies, including electromagnetic telegraphy and aerial telegraphy. Although both services had an implicit mission of battlefield observation, intelligence gathering, and artillery fire direction from their elevated signal stations, the Confederate Signal Corps also included an explicit espionage function.
The Battlefield Airborne Communications Node (BACN) is a United States Air Force (USAF) airborne communications relay and gateway system carried by the unmanned EQ-4B and the manned Bombardier E-11A aircraft. BACN enables real-time information flow across the battlespace between similar and dissimilar tactical data link and voice systems through relay, bridging, and data translation in line-of-sight and beyond-line-of-sight situations. Its ability to translate between dissimilar communications systems allows them to interoperate without modification.
Signals intelligence operational platforms are employed by nations to collect signals intelligence, which is intelligence-gathering by interception of signals, whether between people or between machines, or mixtures of the two. As sensitive information is often encrypted, signals intelligence often involves the use of cryptanalysis. However, traffic analysis—the study of who is signalling whom and in what quantity—can often produce valuable information, even when the messages themselves cannot be decrypted.
Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves. They are received by another antenna connected to a radio receiver. In addition to communication, radio is used for radar, radio navigation, remote control, remote sensing, and other applications.
The Communications-Electronics Command (CECOM) is a Life Cycle Management Command (LCMC) of the United States Army based at Aberdeen Proving Ground, Maryland, United States. It is one of four such commands under the Army Materiel Command (AMC), and is the Army's provider and maintainer of Command, Control, Communications, Computers, Cyber, Intelligence, Surveillance and Reconnaissance (C5ISR) capabilities.
PM WIN-T is a component of Program Executive Office Command, Control and Communications-Tactical in the United States Army. PM WIN-T has been absorbed into PM Tactical Networks as Product Manager for Mission Networks.
The Russian Signal Troops , also known as the Signal Communications Troops, is a Combat Arm of the Russian Ground Forces, responsible for military communications.
16-line message format, or Basic Message Format, is the standard military radiogram format for the manner in which a paper message form is transcribed through voice, Morse code, or TTY transmission formats. The overall structure of the message has three parts: HEADING, TEXT, and ENDING. This heading is further divided into procedure, preamble, address, and prefix. Each format line contains pre-defined content. An actual message may have fewer than 16 actual lines, or far more than 16, because some lines are skipped in some delivery methods, and a long message may have a TEXT portion that is longer than 16 lines by itself.
The German Radio Intelligence Operation were signals intelligence operations that were undertaken by German Axis forces in Europe during World War II. In keeping with German signals practice since 1942, the term "communication intelligence" had been used when intercept units were assigned to observe both enemy "radio and wire" communication. When the observation of only enemy "radio" communication was undertaken, the term was "radio intelligence". The term "intercept service" was also used up until 1942.
The Iris Digital Communications System, also known as the Tactical Command, Control, and Communications System (TCCCS), is a tactical communication system used by the Canadian Army. It was a pioneering system that integrated voice and data communications via the Internet Protocol and ST-II protocol. Elements of the Iris system, together with the High-capacity data radio, later formed the foundation of the British Army's Bowman communications system.
