GALLIUM ARSENIDE (GaAs) - A compound used in integrated circuits (ICs). [10:12] NOTE: GaAs provides a speed of electron mobility about five times that of silicon, and lower power dissipation at the same speed than silicon of the same feature size. Potential GaAs advantages include increased radiation hardness and operation at higher temperatures than can be achieved with silicon. Additionally, the band structure of GaAs allows light-emitting devices to be made, not previously possible with silicon (Recently, etched silicon has also been made to emit light by applying a voltage or a "pumping" light).
GARDIAN - An acronym for General ARea Defense Integrated ANti-missile. GARDIAN is a LASER system that utilized a high energy CHEMICAL LASER to protect military assets against low flying tactical threats such as cruise missiles and UNMANNED AERIAL VEHICLEs (UAVs). GARDIAN generates a laser beam which is focused on a moving target creating immense heat at a single spot, effectively burning a hole in the target. The laser can engage within a few seconds and locks on until the target is destroyed. [10:2557] See also DIRECTED ENERGY WEAPON (DEW).
GARNISHING - In surveillance, natural or artificial material applied to an object to achieve or assist CAMOUFLAGE. []
GARRET SCANNER - An electronic device used to scan rooms for concealed weapons. It includes a "reduced sensitivity" mode for scanning near floors containing reinforcement bars (rebars). []
GAS LASER - A LASER in which a gas is used as a light-emitting source. The electrons in the gas molecules are excited by x-rays plus electrical discharges (called electrical/gas lasers), or by chemical reactions (called CHEMICAL LASERs). The choice of gas determines the color of the output light. [10:2559] See also CRYSTAL LASER, DIODE LASER, DYE LASER.
GATE - (1) An interval of time during which some portion of a circuit or display is allowed to be operative. (2) The circuit which provides gating. [3]
GATE DECEPTION - A SELF SCREENING ECM technique that returns a large jamming or on-frequency noise signal back to a victim automatic tracking radar. The jamming signal is much stronger than, and thus masks in the (velocity, range, or angle) gate, the true signal returned by the radar cross section of the jamming platform. The jamming signal is then gradually increased or decreased relative to the true return signal, causing the radar's gate to move away from the true signal. After a specified time or signal-magnitude, the jamming signal is turned off, causing the radar to lose its track and go into a search mode to reacquire the target. This process then repeats itself. [8]
GATEWAY - A device that forwards information from one network to another. [10:2619] Also called a ROUTER or switch.
GATING - (1) The process of selecting those portions of a signal that exist during one or more selected time intervals. (2) (Radar) The application of enabling or inhibiting pulses during part of a cycle of equipment operation. [3]
GATOR MINE - A component of the Navy's CBU-78/N and the Air Force's CBU-89/B air-launched cluster bombs. Each Navy bomb contains 15 antipersonnel and 45 antitank Gator mines; each Air Force bomb contains 22 antipersonnel and 72 anti-tank Gator mines. Gator mines can also be deployed from vehicles and helicopters using the VOLCANO multiple delivery mine system. [10:2735]
GENERIC WEAPON - A weapon that is useful against any target. []
GENETIC ALGORITHM (GA) - A computer algorithm based on the mechanisms of biological natural selection, using populations of objects which can reproduce based on the biological concepts of survival of the fittest and mutation. [10:51]
GENETIC ANTENNA - An antenna designed through use of GENETIC ALGORITHMs to best meet the antenna specifications. It is particularly useful in situations where existing designs are not adequate. [10:2602] See also FRACTAL ANTENNA.
GENETIC DATA MINING - The automatic extraction of prediction and classification rules from databases using advanced GENETIC ALGORITHMS. [10:2767]
GENOMICS - (1) The study of genes and their function. [] (2) A new technology combining biotechnology, genetic engineering, and microelectronics. []
GEOPOSITIONING - The placement, by radio control, of a satellite from one GEOSYNCHRONOUS position to another. []
GEOSTATIONARY SATELLITE - A satellite that has a circular orbit, lies in the plane of the earth's equator, and moves about the earth's polar axis in the same direction and with the same period as the earth's rotation. Thus, the satellite remains above a fixed point on the earth's equator. [10:14] See also GEOSYNCHRONOUS SATELLITE.
GEOSYNCHRONOUS SATELLITE - A satellite that orbits the earth such that it remains stationary with respect to a given point on the earth because its orbit has the same period of revolution as the earth. That is to say that a radial line originating at the center of the earth and passing through the point of interest on the surface of the earth will also pass through the satellite. [10:2620*] See also GEOSTATIONARY SATELLITE, MOLNIYA ORBIT.
GIANT MAGNETORESISTANCE (GMR) - An application of MAGNETOELECTRONICS. In a GMR material, consisting of a stack of alternating layers of magnetic and nonmagnetic atoms, a small magnetic field can produce a large change in electrical resistance, thus allowing great increases in hard drive densities. [10:2782]
GLARE LASER - A NONLETHAL WEAPON intended to cause temporary loss of sight to the targeted individual (TI). [10:2730]
GLINT -- The inherent random component of error in measurement of position or Doppler frequency of a complex target due to interference of the reflections from different elements of the target. [3]
GLINT ENHANCE JAMMING -- A jamming technique which features a jamming signal transmitted alternately from different antennas, switching from one antenna to the other either sequentially or randomly. []
GLOBAL AREA STRIKE SYSTEM (GLASS) - A system incorporating a HIGH-ENERGY LASER (HEL) system, a KINETIC ENERGY WEAPON (KEW) system, and a transatmospheric vehicle (TAV). The HEL system consists of ground-based lasers and space-based mirrors which direct energy to the intended target. The KEW system consists of terminally-guided projectiles, and the TAV is a flexible platform capable of supporting maintenance and replenishment of the space assets, and can be used for rapid deployment of special operations forces (SOF). [USAF 2025 Study]
GLOBAL INFORMATION MANAGEMENT SYSTEM (GIMS) - A network of intelligent information gathering, processing, analysis, and advisory nodes. GIMS collects, stores, analyzes, fuses, and manages information from ground, air, and space sensors and all-source intelligence. Sensors used include acoustic, optical, radio frequency (RF), olfactory, etc. It employs neural processing to provide information tailored to the user's personal requirements. [USAF 2025 Study]
GLOBAL NAVIGATION SATELLITE SYSTEM (GLONASS) - A Russian small lightweight jammer designed to jam the Global Positioning System (GPS) []
GLOBAL POSITIONING SYSTEM (GPS) - A constellation of 21 operating satellites and three in-orbit spares (1995). Each satellite continuously emits a pair of signals by which the system's precision and accuracy are achieved. GPS receivers employed by various users can provide positioning accuracy to within centimeters. [10:2573] NOTE: The determining of position of a GPS receiver requires the simultaneous measurement of the distances to four orbiting satellites. The measurement of raw range from a single satellite places the receiver on the surface of a sphere centered on the satellite with a radius equal to the measured range. A simultaneous measurement of the range to a second satellite creates a second sphere that intersects the first and creates a sector upon which the receiver may be found. A third measurement produces the intersection of three spheres with only two points common to all three. One of these points will be in space, the other at the receiver's terrestrial position. In theory, these three measurements should be sufficient to produce an unambiguous positional fix. In practice, however, the inaccuracy of the user's inexpensive clock must be accommodated by a range measurement to a fourth satellite. At this point there are four unknowns -- the user's longitude, latitude and altitude measured from the center of the earth, as well as the bias required to bring the user's clock error into synchronicity with system time and four independent range equations. Solving the system of equations yields user position data to an accuracy of at least 15 meters and time to within 100 NANOSECONDs. [10:2599] There are at least two levels of precision associated with GPS -- Coarse/Acquisition (C/A) code, which involves ionospheric and geoid correction algorithms, and encrypted Precision (P) code, presumably for ballistic missile and other military usage.
GLOBAL SURVEILLANCE, RECONNAISSANCE, AND TARGETING SYSTEM (GSRT) - A space-based all-sensor collection, processing, and dissemination system which provides a real-time information database. This database is used to create a VIRTUAL REALITY (VR) image of the area of interest, thus providing all levels of command SITUATIONAL AWARENESS (SA), technical and intelligence information, and command & control (C2). [USAF 2025 Study]
GOVERNMENT OSI PROFILE (GOSIP) - A subset of OPEN SYSTEM INTERCONNECTION (OSI) standards specific to U.S. Government procurements, designed to maximize interoperability in areas where plain OSI standards are ambiguous or allow too many options. [10:2736]
GRACEFUL DEGRADATION - A system design feature to prevent catastrophic failure by allowing the system to operate at a predictably decreasing capability in the presence of increasing subsystem failure. []
GRASER - Gamma X-ray laser. [] NOTE: Grasers are small-size devices having potential for use as directed energy weapons.
GRAY - A term used to indicate countries other than the U.S. or the Soviet Union; e.g., gray forces, gray equipment. [] Contrast with BLUE, RED FORCES.
GRAYBODY - A temperature radiator whose spectral emissivity is less than unity and the same at all wavelengths. [3] NOTE: Graybody radiation can emanate from an infrared-generating missile in flight: from the leading edges, exhaust smoke, and the engine enclosure.
GRAYBODY RADIATOR - A flare designed to emit over a wide spectrum. [10:65]
GRAY-HAT HACKER - A HACKER whose aim is to publicly expose security flaws in software, and who generally posts the results on the Internet. [] Contrast with CRACKER. See also BLACK-HAT HACKER.
GRID - A VACUUM TUBE element used to control the electrical current flowing through the tube by varying its voltage with respect to that of the CATHODE. []
GRIDLOCK - (1) The process of removing navigational and radar biases by calibrating to a common force reference point. This is accomplished by all units of the force simultaneously recording the position of a commonly-held target that has a specified relative position from the force center (or other reference point) at the same instant. [] (2) The computer process used to compare an individual ship's track data with remotely originated track data, and to determine the correction necessary to bring the tracks into alignment. [10:84]
GROUND-BASED ELECTRO-OPTICAL DEEP SPACE SURVEILLANCE SYSTEM (GEODSS) - A system of three telescope sensors linked to video cameras, which feed their space pictures into a nearby computer for display on a monitor and recording on magnetic tape. []
GROUND CLUTTER - CLUTTER resulting from the ground or objects on the ground. [3] See also RADAR CLUTTER, WAVE CLUTTER.
GROUND EFFECT - A condition which occurs when a helicopter hovers near (within 1/2 rotor diameter) of the ground, and is due to the interference of the surface with the airflow pattern of the rotor system. When a helicopter is hovering In Ground Effect (IGE), blade efficiency increases, and less power is required than a hover Out of Ground Effect (OGE). [10:2776] NOTE: Maximum ground effect is achieved when hovering over smooth paved surfaces.
GROUND-EMPLACED MINE SCATTERING SYSTEM (GEMSS) - A mine dispenser designed to be towed by a vehicle. It flips one mine out of a tube every two seconds, and is capable of thus scattering up to eight hundred antipersonnel mines and/or antitank mines per load. The mines are similar to those used by the ADAM system. [10:2735]
GROUND HOMING ON PSEUDO-TARGET - An ECM technique consisting of pointing the ECM antenna in a direction other from that of the victim radar in order to create off-angle noise strobing or false targets. [8*]
GROUNDING - The BONDING of an equipment case, frame or chassis, to an object or vehicle structure to ensure a common [electrical] potential. [1] See also EARTHING.
GROUND PENETRATING RADAR (GPR) - A radar which produces ultrawide-band impulses that penetrate ground substrata and produce signal reflections from more dense deposits contained therein. [10:2681] Also called GPEN RADAR. NOTE: GPRs have been used to detect deposits of gold ore lying two-to-three feet deep within the tunnel wall of a working gold mine. This technology has also been used for detection of subterranean tunnels and fortifications as well as buried antipersonnel and antivehicle mines. In this latter role, however, GPR does not perform well in dry soil and produces false positives from rocks and tree roots. [10:2674] A hand-held GPR system that integrates the ground penetrating radar with a pulsed induction metal detector to produce a unit that can be used by a combat engineer or infantryman to reliably detect buried mines, including heavy anti-tank mines and small plastic anti-personnel mines. [10:2702]
GROUND WAVE - A radio wave that is propagated over the earth and is ordinarily affected by presence of the ground and troposphere. [3] Contrast with SKY WAVE.
GUARD BAND - A frequency band between two channels which gives a margin of safety against mutual interference. [3]
GUARD GATING - An ECCM technique wherein the velocity- and/or range-gate of a tracking radar is protected from GATE DECEPTION, CHAFF, and other forms of ECM by the use of additional gates. [8]
GUARDRAIL/COMMON SENSOR (GR/CS) - An airborne SIGINT collection/location system that integrates the Improved GuardRail V (IGR V), the Communication High Accuracy Airborne Location System (CHAALS) and the Advanced QUICKLOOK (AQL) into the same platform aircraft. The system consists nominally of twelve aircraft which perform operational missions in flights of three. [10:2811] NOTE: The GR/CS can employ five operation modes, selectable by the mission commander: Direct Tether - each aircraft talks to its own tracking operator via a datalink; Extended Tether - The aircraft talks to both the ground station and to the other two aircraft in the flight of three; Untethered - The aircraft records data while aloft for later downloading; Repeater Operations - Extended data-collection capability with downlink to a ground vehicle, which in turn retransmits the data to a satellite for global redirection when a downlink is available; and Direct Air-to-Satellite Relay -- All three aircraft transmit directly to a satellite, which in turn relays to an Integrated Processing Facility (IPF) ground station that does not have to be in the operational area.
GUIDED MUNITION - A "one-on-one" munition: A specific munition engages a specific taget, which is advantageous during close combat situations. An operator is required in the loop to select the target and often assist in the guidance. The munition may be either COMMAND-TO-LINE-OF-SIGHT (CLOS), or possess HOMING GUIDANCE. [12] Contrast with BRILLIANT MUNITION. See also SMART MUNITION.
GULL - In electronic warfare, a floating radar reflector used to simulate a surface target at sea for deceptive purposes. []
GYROCHIP - An angular rate sensor designed to be a reliable replacement for iron gyros. It is a single piece of piezoelectric quartz shaped like a double-ended tuning fork. It uses the Coriolis effect in determining angular rate. The unit operates on 600 milliwatts if DC power and has no motors or bearings and is essentially solid-state. The gyrochip is used in applications that include helicopter yaw control, infrared line of sight stabilization, missile flight control and guidance, parachute instrumentation and periscope stabilization. [10:2524]
GYROTRON - A high power microwave generating device suitable for use as a DIRECTED ENERGY WEAPON in the MILLIMETER WAVE band. [10:16] See also BEAM-PLASMA DEVICE, FREE- ELECTRON LASER; VIRTUAL-CATHODE OSCILLATOR.
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