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Guidance, navigation and control (abbreviated GNC, GN&C, or G&C) is a branch of engineering dealing with the design of systems to control the movement of vehicles, especially, automobiles, ships, aircraft, and spacecraft. In many cases these functions can be performed by trained humans. However, because of the speed of, for example, a rocket's dynamics, human reaction time is too slow to control this movement. Therefore, systems—now almost exclusively digital electronic—are used for such control. Even in cases where humans can perform these functions, it is often the case that GNC systems provide benefits such as alleviating operator work load, smoothing turbulence, fuel savings, etc. In addition, sophisticated applications of GNC enable automatic or remote control.
Guidance, navigation, and control systems consist of 3 essential parts: navigation which tracks current location, guidance which leverages navigation data and target information to direct flight control "where to go", and control which accepts guidance commands to affect change in aerodynamic and/or engine controls.
GNC systems are found in essentially all autonomous or semi-autonomous systems. These include:
Related examples are:
A missile is an airborne ranged weapon capable of self-propelled flight aided usually by a propellant, jet engine or rocket motor. Historically, 'missile' referred to any projectile that is thrown, shot or propelled towards a target; this usage is still recognized today with any unguided jet- or rocket-propelled weapons generally described as rocket artillery. Airborne explosive devices without propulsion are referred to as shells if fired by an artillery piece and bombs if dropped by an aircraft.
The attitude indicator (AI), formerly known as the gyro horizon or artificial horizon, is a flight instrument that informs the pilot of the aircraft orientation relative to Earth's horizon, and gives an immediate indication of the smallest orientation change. The miniature aircraft and horizon bar mimic the relationship of the aircraft relative to the actual horizon. It is a primary instrument for flight in instrument meteorological conditions.
A guidance system is a virtual or physical device, or a group of devices implementing a controlling the movement of a ship, aircraft, missile, rocket, satellite, or any other moving object. Guidance is the process of calculating the changes in position, velocity, altitude, and/or rotation rates of a moving object required to follow a certain trajectory and/or altitude profile based on information about the object's state of motion.
Semi-active radar homing (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. Semi-active missile systems use bistatic continuous-wave radar.
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 Probability of Guidance (Pg).
Draper Laboratory is an American non-profit research and development organization, headquartered in Cambridge, Massachusetts; its official name is The Charles Stark Draper Laboratory, Inc. The laboratory specializes in the design, development, and deployment of advanced technology solutions to problems in national security, space exploration, health care and energy.
The Apollo primary guidance, navigation, and control system was a self-contained inertial guidance system that allowed Apollo spacecraft to carry out their missions when communications with Earth were interrupted, either as expected, when the spacecraft were behind the Moon, or in case of a communications failure. The Apollo command module (CM) and lunar module (LM), were each equipped with a version of PGNCS. PGNCS, and specifically its computer, were also the command center for all system inputs from the LM, including the alignment optical telescope, the radar system, the manual translation and rotation device inputs by the astronauts as well as other inputs from the LM systems.
Command guidance is a type of missile guidance in which a ground station or aircraft relay signals to a guided missile via radio control or through a wire connecting the missile to the launcher and tell the missile where to steer to intercept its target. This control may also command the missile to detonate, even if the missile has a fuze.
This is an alphabetical list of articles pertaining specifically to aerospace engineering. For a broad overview of engineering, see List of engineering topics. For biographies, see List of engineers.
A star tracker is an optical device that measures the positions of stars using photocells or a camera. As the positions of many stars have been measured by astronomers to a high degree of accuracy, a star tracker on a satellite or spacecraft may be used to determine the orientation of the spacecraft with respect to the stars. In order to do this, the star tracker must obtain an image of the stars, measure their apparent position in the reference frame of the spacecraft, and identify the stars so their position can be compared with their known absolute position from a star catalog. A star tracker may include a processor to identify stars by comparing the pattern of observed stars with the known pattern of stars in the sky.
Flight controllers are personnel who aid space flight by working in such Mission Control Centers as NASA's Mission Control Center or ESA's European Space Operations Centre. Flight controllers work at computer consoles and use telemetry to monitor various technical aspects of a space mission in real-time. Each controller is an expert in a specific area and constantly communicates with additional experts in the "back room". The flight director, who leads the flight controllers, monitors the activities of a team of flight controllers, and has overall responsibility for success and safety.
A navigation system is a computing system that aids in navigation. Navigation systems may be entirely on board the vehicle or vessel that the system is controlling or located elsewhere, making use of radio or other signal transmission to control the vehicle or vessel. In some cases, a combination of these methods is used.
The Tamam Division of the Systems Missiles and Space Group of the Israel Aerospace Industries (IAI) is a manufacturing plant in the development and production of high performance Inertial and Electro-Optic (EO) products and systems and maritime drones.
A precision-guided munition is a guided munition intended to precisely hit a specific target, to minimize collateral damage and increase lethality against intended targets. During the First Gulf War guided munitions accounted for only 9% of weapons fired, but accounted for 75% of all successful hits. Despite guided weapons generally being used on more difficult targets, they were still 35 times more likely to destroy their targets per weapon dropped.
TriDAR, or Triangulation and LIDAR Automated Rendezvous and Docking, is a relative navigation vision system developed by Neptec Design Group and funded by the Canadian Space Agency and NASA. It provides guidance information that can be used to guide an unmanned vehicle during rendezvous and docking operations in space. TriDAR does not rely on any reference markers positioned on the target spacecraft. Instead, TriDAR relies on a laser based 3D sensor and a thermal imager. TriDAR's proprietary software uses the geometric information contained in successive 3D images to match against the known shape of the target object and calculate its position and orientation.
An inertial navigation system is a navigation device that uses motion sensors (accelerometers), rotation sensors (gyroscopes) and a computer to continuously calculate by dead reckoning the position, the orientation, and the velocity of a moving object without the need for external references. Often the inertial sensors are supplemented by a barometric altimeter and sometimes by magnetic sensors (magnetometers) and/or speed measuring devices. INSs are used on mobile robots and on vehicles such as ships, aircraft, submarines, guided missiles, and spacecraft. Older INS systems generally used an inertial platform as their mounting point to the vehicle and the terms are sometimes considered synonymous.
Spacecraft attitude control is the process of controlling the orientation of a spacecraft with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc.
An inertial measurement unit (IMU) is an electronic device that measures and reports a body's specific force, angular rate, and sometimes the orientation of the body, using a combination of accelerometers, gyroscopes, and sometimes magnetometers. When the magnetometer is included, IMUs are referred to as IMMUs.
In the field of weaponry, terminal guidance refers to any guidance system that is primarily or solely active during the "terminal phase", just before the weapon impacts its target. The term is generally used in reference to missile guidance systems, and specifically to missiles that use more than one guidance system through the missile's flight.
A synthetic air data system (SADS) is an alternative air data system that can produce synthetic air data quantities without directly measuring the air data. It uses other information such as GPS, wind information, the aircraft's attitude, and aerodynamic properties to estimate or infer the air data quantities. Though air data includes altitude, airspeed, pressures, air temperature, Mach number, and flow angles, existing known SADS primarily focuses on estimating airspeed, Angle of Attack, and Angle of sideslip. SADS is used to monitor the primary air data system if there is an anomaly due to sensor faults or system faults. It can also be potentially used as a backup to provide air data estimates for any aerial vehicle.