The Global Positioning System (GPS) is a U.S. space-based global navigation satellite system. It provides reliable positioning, navigation, and timing services to worldwide users on a continuous basis in all weather, day and night, anywhere on or near the Earth which has an unobstructed view of four or more GPS satellites. GPS is made up of three segments: Space, Control and User.
MISTRAM (MISsile TRAjectory Measurement) was a high-resolution tracking system used by the United States Air Force to provide highly detailed trajectory analysis of rocket launches. A "classic" ranging system used since the 1960s uses radar to time a radio signal's travel to a target (in this case, the rocket) and back. This technique is accurate to approximately 1%.
An Inertial Navigation System (INS) is a navigation aid that uses a computer, motion sensors and rotation sensors to continuously calculate via dead reckoning the position, orientation, and velocity (direction and speed of movement) of a moving object without the need for external references. It is used on vehicles such as ships, aircraft, submarines, guided missiles, and spacecraft.
A wire-guided missile is a missile that is guided by signals sent to it via thin wires connected to both the missile and its guidance mechanism, which is located somewhere near the launch site. As the missile flies, the wires are reeled out behind it. This guidance system is most commonly used in anti-tank missiles, where its ability to be used in areas of limited line-of-sight make it useful, while the range limit imposed by the length of the wire is not a serious concern.
SACLOS (short for Semi-Automatic Command to Line of Sight) is a second-generation method of missile guidance. In SACLOS, the operator has to continually point a sighting device at the target while the missile is in flight. Electronics in the sighting device and/or the missile then guide it to the target. There are two common ways SACLOS can work:
MCLOS (short for Manual Command to Line of Sight) is a first-generation method for guiding guided missiles. With an MCLOS missile, the operator must track the missile and the target simultaneously and guide the missile to the target. Typically the missile is steered with a joystick, and its path is observed through a periscope-type telescopic sight.
Semi-active radar homing, or SARH, is a common type of missile guidance system, perhaps the most common type for longer range air-to-air and surface-to-air missile systems. The name refers to the fact that the missile itself is only a passive detector of a radar signal – provided by an external (“offboard”) source — as it reflects off the target. NATO brevity code for a semi-active radar homing missile launch is Fox One.
Missile guidance refers to a variety of methods of guiding a missile or a guided bomb to its intended target. The missile's target accuracy is a critical factor for its effectiveness. Guidance systems improve missile accuracy by improving its "Single Shot Kill Probability" (SSKP). These guidance technologies can generally be divided up into a number of categories, with the broadest categories being "active," "passive" and "preset" guidance.
A laser designator is a laser light source which is used to designate a target. Laser designators provide targeting for laser guided bombs, missiles, or precision artillery munitions, such as the Paveway series of bombs, Lockheed-Martin's Hellfire, or the Copperhead round, respectively. When a target is marked by a designator, the beam is invisible and does not shine continuously. Instead, a series of coded pulses of laser-light are fired.
Beam-riding, also known as beam guidance, is a technique of directing a missile to its target by means of radar or a laser beam. It is one of the simplest forms of guidance using radar or lasers. The main use of this kind of system is to destroy airplanes or tanks. First, an aiming station (possibly mounted in a vehicle) in the launching area directs a narrow radar or laser beam at the enemy aircraft or tank.
Fire-and-forget is a third-generation method of missile guidance. The military use the term for a type of missile which does not require further guidance after launch such as illumination of the target or wire guidance (TOW), and can hit its target without the launcher being in line-of-sight of the target.
Command guidance is a type of missile guidance in which a ground station or aircraft relay signals to a guided missile via radio (or possibly through a wire connecting the missile to the launcher) and tell the missile where to steer in order to intercept its target. Additionally, it is possible to send a command to the missile to detonate, even if the missile itself has a fuze or fuzes.
Active radar homing is a missile guidance method in which a guided missile contains a radar transceiver and the electronics necessary for it to find and track its target autonomously. NATO brevity code for an active radar homing missile launch is Fox Three.
Infrared homing refers to a passive missile guidance system which uses the emission from a target of electromagnetic radiation in the infrared part of the spectrum to track and follow it. Missiles which use infrared seeking are often referred to as "heat-seekers", since infrared (IR) is just below the visible spectrum of light in frequency and is radiated strongly by hot bodies.
An all-aspect missile is one which is able to track a target no matter which way the target faces relative to the missile. In other words, an all-aspect missile can be launched against a target in a tail-chase engagement, in a head-on engagement, in a side-on engagement, from above, from below, etc.
Laser guidance is a technique of guiding a missile or other projectile or vehicle to a target by means of a laser beam. Some laser guided systems utilise beam riding guidance, but most operate more similarly to semi-active radar homing (SARH). This technique is sometimes called SALH, for Semi-Active Laser Homing.
A staring array, staring-plane array, focal-plane array (FPA) or focal-plane is an image sensing device consisting of an array (typically rectangular) of light-sensing pixels at the focal plane of a lens. FPAs are used most commonly for imaging purposes (e.g. taking pictures or video imagery), but can also be used for non-imaging purposes such as spectrometry, LIDAR, and wave-front sensing.
Proportional navigation (PN) (Pro-Nav) is a guidance law used in some form or another by most homing air target missiles. It is based on the fact that two vehicles are on a collision course when their direct Line-of-Sight does not change direction. PN dictates that the missile velocity vector should rotate at a rate proportional to the rotation rate of the line of sight (Line-Of-Sight rate or LOS-rate), and in the same direction.
TERPROM (Terrain Profile Matching) is a military navigation Ground Proximity Warning System (GPWS, employed on aircraft and missiles, which uses stored digital elevation data combined with navigation system and radar altimeter inputs to compute the location of the aircraft or missile above the surface of the earth. It is also used as a warning system to prevent aircraft from flying too close to the ground.
Terrain Contour Matching, or TERCOM, is a navigation system used primarily by cruise missiles. It uses a pre-recorded contour map of the terrain that is compared to measurements made during flight by an on-board radar altimeter. A TERCOM system considerably increases the accuracy of a missile compared to inertial navigation systems (INS). The increased accuracy allows a TERCOM-equipped missile to fly closer to obstacles and generally lower altitudes, making it harder to detect by ground radar.
The Advanced Inertial Reference Sphere, or AIRS, is a highly accurate inertial guidance system designed for use in the LGM-118A Peacekeeper ICBM which was intended for precision nuclear strike against Soviet missile silos.
The D-17B is a computer used in missile guidance systems, specifically the Minuteman I NS-1OQ missile guidance system, which contains a D-17B computer, the associated stable platform, and power supplies. The D-17B weighs approximately 62 pounds (28 kg), contains 1,521 transistors, 6,282 diodes, 1,116 capacitors, and 504 resistors. These components are mounted on double copper-clad, engraved, gold-plated, glass fiber laminate circuit boards.
The D-37C is the computer component of the all-inertial NS-17 Missile Guidance Set (MGS) for accurately navigating to its target thousands of miles away. The NS-17 MGS was used in the Minuteman II (LGM-30F) ICBM. The MGS, originally designed and produced by the Autonetics Division of North American Aviation, could store multiple preprogrammed targets in its internal memory.
The UDOP (UHF Doppler) multistatic radar and multiradar system (MSRS) utilizes Doppler radar for missile tracking and trajectory measurement. A target is illuminated at 450 MHz. Five receiving stations, located along the baselines with the lengths from 25 to 75 miles, receive signals from the target's transponder at 900 MHz. These five stations yield slant-range rate. To computed the range or position, an initial position is required from some other tracking system.