A height finder is a ground-based aircraft altitude measuring device. Early height finders were optical range finder devices combined with simple mechanical computers, while later systems migrated to radar devices. The unique vertical oscillating motion of height finder radars led to them also being known as nodding radar. Devices combining both optics and radar were deployed by the U.S. Military. [1]
In World War II, a height finder was an optical rangefinder used to determine the altitude of an aircraft (actually the slant range from the emplacement which was combined with the angle of sight, in a mechanical computer, to produce altitude), used to direct anti-aircraft guns. [2] [3] Examples of American [3] and Japanese [4] versions exist. In the Soviet Union it was usually combined with optical rangefinders. [5] [6]
A height finder radar is a type of 2-dimensional radar that measures altitude of a target.
The operator slews the antenna toward a desired bearing, identifies a target echo at a desired range on the range height indicator display, then bisects the target with a cursor that is scaled to indicate the approximate altitude of the target. [7] Such systems often complement 2-dimensional radars which find distance and direction (search radar); thus using two 2-dimensional systems to obtain a 3-dimensional aerial picture.[ citation needed ] Height finding radars of the 1960s and 70s were distinguished by their antenna being tall, but narrow. As beam shape is a function of antenna shape, the height finder beam was flat and wide horizontally (i.e., not very good at determining bearing to the target), but very thin vertically, allowing accurate measurement of elevation angle, thus altitude.
Modern 3D radar sets find both azimuth and elevation, making separate height finder radars largely obsolete.
A fire-control system (FCS) is a number of components working together, usually a gun data computer, a director and radar, which is designed to assist a ranged weapon system to target, track, and hit a target. It performs the same task as a human gunner firing a weapon, but attempts to do so faster and more accurately.
Secondary surveillance radar (SSR) is a radar system used in air traffic control (ATC), that unlike primary radar systems that measure the bearing and distance of targets using the detected reflections of radio signals, relies on targets equipped with a radar transponder, that reply to each interrogation signal by transmitting encoded data such as an identity code, the aircraft's altitude and further information depending on its chosen mode. SSR is based on the military identification friend or foe (IFF) technology originally developed during World War II, therefore the two systems are still compatible. Monopulse secondary surveillance radar (MSSR), Mode S, TCAS and ADS-B are similar modern methods of secondary surveillance.
Gun laying is the process of aiming an artillery piece or turret, such as a gun, howitzer, or mortar, on land, in air, or at sea, against surface or aerial targets. It may be laying for direct fire, where the gun is aimed similarly to a rifle, or indirect fire, where firing data is calculated and applied to the sights. The term includes automated aiming using, for example, radar-derived target data and computer-controlled guns.
A wind profiler is a type of weather observing equipment that uses radar or sound waves (SODAR) to detect the wind speed and direction at various elevations above the ground. Readings are made at each kilometer above sea level, up to the extent of the troposphere. Above this level there is inadequate water vapor present to produce a radar "bounce." The data synthesized from wind direction and speed is very useful to meteorological forecasting and timely reporting for flight planning. A twelve-hour history of data is available through NOAA websites.
In naval gunnery, when long-range guns became available, an enemy ship would move some distance after the shells were fired. It became necessary to figure out where the enemy ship, the target, was going to be when the shells arrived. The process of keeping track of where the ship was likely to be was called rangekeeping, because the distance to the target—the range—was a very important factor in aiming the guns accurately. As time passed, train, the direction to the target, also became part of rangekeeping, but tradition kept the term alive.
A radar display is an electronic device to present radar data to the operator. The radar system transmits pulses or continuous waves of electromagnetic radiation, a small portion of which backscatter off targets and return to the radar system. The receiver converts all received electromagnetic radiation into a continuous electronic analog signal of varying voltage that can be converted then to a screen display.
The Iowa-class battleships are the most heavily armed gunships the United States Navy has ever put to sea, due to the continual development of their onboard weaponry. The first Iowa-class ship was laid down in June 1940; in their World War II configuration, each of the Iowa-class battleships had a main battery of 16-inch (406 mm) guns that could hit targets nearly 20 statute miles (32 km) away with a variety of artillery shells designed for anti-ship or bombardment work. The secondary battery of 5-inch (127 mm) guns could hit targets nearly 9 statute miles (14 km) away with solid projectiles or proximity fuzed shells, and was effective in an anti-aircraft role as well. Each of the four battleships carried a wide array of 20 mm and 40 mm anti-aircraft guns for defense against enemy aircraft.
Wave radar is a type of radar for measuring wind waves. Several instruments based on a variety of different concepts and techniques are available, and these are all often called. This article, gives a brief description of the most common ground-based radar remote sensing techniques.
Ship gun fire-control systems (GFCS) are analogue fire-control systems that were used aboard naval warships prior to modern electronic computerized systems, to control targeting of guns against surface ships, aircraft, and shore targets, with either optical or radar sighting. Most US ships that are destroyers or larger employed gun fire-control systems for 5-inch (127 mm) and larger guns, up to battleships, such as Iowa class.
Irbis-E is a Russian multi-mode, hybrid passive electronically scanned array radar system developed by Tikhomirov NIIP for the Sukhoi Su-35 multi-purpose fighter aircraft. NIIP developed the Irbis-E radar from the N011M Bars radar system used on Sukhoi Su-30MKI aircraft.
Gyro rate unit refers to a fire-control computer developed by the Royal Navy of the United Kingdom in 1937, and which was used extensively on British warships in World War II. In the 1930s the Royal Navy began to investigate the possibility of combining gyroscopes with optical sights to directly and accurately measure target aircraft speed and direction and began development of the GRU in 1937. A gyroscope was attached, via mechanical linkage, to an optical monocular sight to form the gyro rate unit or GRU.
The Wasserman radar was an early-warning radar built by Germany during World War II. The radar was a development of FuMG 80 Freya and was operated during World War II for long range detection. It was developed under the direction of Theodor Schultes, beginning in 1942. Wasserman was based on largely unchanged Freya electronics, but used an entirely new antenna array in order to improve range, height-finding and bearing precision.
Radar envelope is a critical Measure of Performance (MOP) identified in the Test and Evaluation Master Plan (TEMP). This is the volume of space where a radar system is required to reliably detect an object with a specific size and speed. This is one of the requirements that must be evaluated as part of the acceptance testing process.
Radar, Gun Laying, Mark I, or GL Mk. I for short, was an early radar system developed by the British Army to provide range information to associated anti-aircraft artillery. There were two upgrades to the same basic system, GL/EF and GL Mk. II, both of which added the ability to accurately determine bearing and elevation.
The Type 277 was a surface search and secondary aircraft early warning radar used by the Royal Navy and allies during World War II and the post-war era. It was a major update of the earlier Type 271 radar, offering much more power, better signal processing, new displays, and new antennas with greatly improved performance and much simpler mounting requirements. It allowed a radar with performance formerly found only on cruisers and battleships to be fitted even to the smallest corvettes. It began to replace the 271 in 1943 and was widespread by the end of the year.
The depression range finder (DRF) was a fire control device used to observe the target's range and bearing to calculate firing solutions when gun laying in coastal artillery. It was the main component of a vertical base rangefinding system. It was necessitated by the introduction of rifled artillery from the mid-19th century onwards, which had much greater ranges than the old smoothbore weapons and were consequently more difficult to aim accurately. The DRF was invented by Captain H.S.S. Watkin of the Royal Artillery in the 1870s and was adopted in 1881. It could provide both range and bearing information on a target. The device's inventor also developed a family of similar devices, among them the position finder, which used two telescopes as a horizontal base rangefinding system, around the same time; some of these were called electric position finders. Some position finders retained a depression range finding capability; some of these were called depression position finders. Watkin's family of devices were deployed in position finding cells, a type of fire control tower, often in configurations that allowed both horizontal base and vertical base rangefinding. Watkin's system included automatic electrical updating of range and bearing dials near the guns as the position finders were manipulated, and a system of remotely firing the guns electrically from the position finding cell. The improved system was trialled in 1885 and widely deployed in the 1890s. Functionally equivalent devices were developed for the United States Army Coast Artillery Corps and its predecessors, called depression position finders or azimuth instruments depending on function, adopted in 1896 and deployed widely beginning in the early 1900s as the Endicott program of modern coastal defences was built. These devices were also used by both countries to control submarine (underwater) minefields.
The AMES Type 82, also widely known by its rainbow codename Orange Yeoman, was an S-band 3D radar built by Marconi and used by the Royal Air Force (RAF), initially for tactical control and later for air traffic control (ATC).
Martello is a family of phased array radar systems developed by Marconi Electronic Systems in the 1970s and introduced operationally in the early 1980s. They provided long-range early warning capabilities but also had the accuracy needed for interception plotting and "putting on" of other weapons systems like surface-to-air missiles. The name comes from the Martello towers that provided defence in earlier years.
The cheese antenna, also known as a pillbox antenna, is a type of microwave-frequency parabolic antenna used in certain types of radar. The antenna consists of a cylindrical parabolic reflector consisting of sheet metal with a parabolic curve in one dimension and flat in the other, with metal plates covering the open sides, and a feed antenna, almost always some sort of feed horn, in front, pointing back toward the reflector. When the antenna is wide along its flat axis it is called a pillbox antenna and when narrow a cheese antenna. The name comes from the resulting antenna looking like a segment that has been cut from a wheel of cheese.
AN/SPS-8 is a two-dimensional radar manufactured by General Electric. It was used by the US Navy as a height finding radar after World War II, and was equipped aboard naval ships during the Cold War. Variants include AN/SPS-8A, AN-SPS/8B, AN/SPS-8C and AN/SPS-8D After modernization, it was redesignated as AN/SPS-30.
