Radar is a detection system that uses radio waves to determine the range, angle, or velocity of objects. It can be used to detect aircraft, spacecraft, guided missiles, motor vehicles, weather formations, terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna and a receiver and processor to determine properties of the object. Radio waves from the transmitter reflect off the object and return to the receiver, giving information about the object's location and speed. Radar was developed secretly for military use by several nations in the period before and during World War II. A key development was the cavity magnetron in the United Kingdom, which allowed the creation of small systems with sub-meter resolution; the term RADAR was coined in 1940 by the United States Navy as an acronym for RAdio Detection And Ranging. The term radar has since entered English and other languages as a common noun, losing all capitalization.
The following derivation was suggested during RAF RADAR courses in 1954/5: at Yatesbury Training Camp: Radio Azimuth Direction And Ranging. The modern uses of radar are diverse, including air and terrestrial traffic control, radar astronomy, air-defense systems, antimissile systems, marine radars to locate landmarks and other ships, aircraft anticollision systems, ocean surveillance systems, outer space surveillance and rendezvous systems, meteorological precipitation monitoring and flight control systems, guided missile target locating systems, ground-penetrating radar for geological observations. High tech radar systems are associated with digital signal processing, machine learning and are capable of extracting useful information from high noise levels. Radar is a key technology that the self-driving systems are designed to use, along with sonar and other sensors. Other systems similar to radar make use of other parts of the electromagnetic spectrum. One example is LIDAR. With the emergence of driverless vehicles, radar is expected to assist the automated platform to monitor its environment, thus preventing unwanted incidents.
As early as 1886, German physicist Heinrich Hertz showed that radio waves could be reflected from solid objects. In 1895, Alexander Popov, a physics instructor at the Imperial Russian Navy school in Kronstadt, developed an apparatus using a coherer tube for detecting distant lightning strikes; the next year, he added a spark-gap transmitter. In 1897, while testing this equipment for communicating between two ships in the Baltic Sea, he took note of an interference beat caused by the passage of a third vessel. In his report, Popov wrote that this phenomenon might be used for detecting objects, but he did nothing more with this observation; the German inventor Christian Hülsmeyer was the first to use radio waves to detect "the presence of distant metallic objects". In 1904, he demonstrated the feasibility of detecting a ship in dense fog, but not its distance from the transmitter, he obtained a patent for his detection device in April 1904 and a patent for a related amendment for estimating the distance to the ship.
He obtained a British patent on September 23, 1904 for a full radar system, that he called a telemobiloscope. It operated on a 50 cm wavelength and the pulsed radar signal was created via a spark-gap, his system used the classic antenna setup of horn antenna with parabolic reflector and was presented to German military officials in practical tests in Cologne and Rotterdam harbour but was rejected. In 1915, Robert Watson-Watt used radio technology to provide advance warning to airmen and during the 1920s went on to lead the U. K. research establishment to make many advances using radio techniques, including the probing of the ionosphere and the detection of lightning at long distances. Through his lightning experiments, Watson-Watt became an expert on the use of radio direction finding before turning his inquiry to shortwave transmission. Requiring a suitable receiver for such studies, he told the "new boy" Arnold Frederic Wilkins to conduct an extensive review of available shortwave units. Wilkins would select a General Post Office model after noting its manual's description of a "fading" effect when aircraft flew overhead.
Across the Atlantic in 1922, after placing a transmitter and receiver on opposite sides of the Potomac River, U. S. Navy researchers A. Hoyt Taylor and Leo C. Young discovered that ships passing through the beam path caused the received signal to fade in and out. Taylor submitted a report, suggesting that this phenomenon might be used to detect the presence of ships in low visibility, but the Navy did not continue the work. Eight years Lawrence A. Hyland at the Naval Research Laboratory observed similar fading effects from passing aircraft. Before the Second World War, researchers in the United Kingdom, Germany, Japan, the Netherlands, the Soviet Union, the United States, independently and in great secrecy, developed technologies that led to the modern version of radar. Australia, New Zealand, South Africa followed prewar Great Britain's radar development, Hungary generated its radar technology during the war. In France in 1934, following systematic studies on the split-anode magnetron, the research branch of the Compagnie Générale de Télégraphie Sans Fil headed by
Brentwood Ursuline Convent High School is an 11–18 girls, Roman Catholic, secondary school and sixth form with academy status in Brentwood, England. It is a Ursuline school, it is located in the Roman Catholic Diocese of Brentwood. The school first opened in 1900 as a Catholic girls' school; until the 1918 Education Act, there were two schools, St Mary's for ladies and St Philomena's for tradesmen's daughters. These schools merged, it was a direct grant grammar school for girls, with the Brentwood School being a similar school for boys. It became a comprehensive in 1979. In September 1999 the school became a specialist Arts College, it converted to academy status in 2012. Marie José of Belgium, Princess of Belgium.
Rothbury is a town and civil parish in Northumberland, England, on the River Coquet, 13.5 miles northwest of Morpeth and 26 miles of Newcastle upon Tyne. At the 2001 Census, it had a population of 2,107. Rothbury emerged as an important town because of its situation at a crossroads over a ford on the River Coquet. Turnpike roads leading to Newcastle-upon-Tyne, Alnwick and Morpeth allowed for an influx of families and the enlargement of the settlement in the Middle Ages. Rothbury was chartered as a market town in 1291, became a centre for dealing in cattle and wool for the surrounding villages in the Early Modern Period. Today, the town is used as a staging point for recreational walking. Points of interest around Rothbury include the Victorian mansion Cragside, the Simonside Hills and Northumberland National Park; the area around Rothbury was populated during the prehistoric period, as evidenced by finds dating from the Mesolithic period and although all the known finds are from beyond the outer edges of the modern town.
Sites include a cairnfield, standing stone and cup-marked rock on Debdon Moor to the north of the town, a well-preserved circular cairn some 26 feet in diameter, a late Neolithic or Bronze Age standing stone, an extensive hillfort, covering an area 165 by 125 metres and associated cairnfield to the west of the town. No evidence of the Roman period has been found because the town was a considerable distance north beyond Hadrian's Wall. Fragments from an Anglo-Saxon cross dating from the 9th century, are the only surviving relics pre-dating the Norman conquest, they were discovered in 1849, when part of the church was demolished, in 1856. They are now in the University of Newcastle Museum; the first documentary mention of Rothbury, according to a local history, was in around the year 1100, as Routhebiria, or "Routha's town". The village was retained as a Crown possession after the conquest, but in 1201 King John signed the Rothbury Town Charter and visited Rothbury four years when the rights and privileges of the manor of Rothbury were given to Robert Fitz Roger, the baron of Warkworth.
Edward I visited the town in 1291, when Fitz Roger obtained a charter to authorise the holding of a market every Thursday, a three-day annual fair near St Matthew's Day, celebrated on 21 September. Rothbury was not significant at the time, with records from 1310 showing that it consisted of a house, a garden, a bakehouse and a watermill, all of which were leased to tenants; when the line of Fitz Roger died out, the village reverted to being a crown possession, but in 1334 Edward III gave it to Henry de Percy, given the castle and baronry of Warkworth six years earlier. Despite the Scottish border wars, the village rose in prosperity during the 14th century, had become the village with the highest parochial value in Northumberland by 1535. Feuds still dominated local affairs, resulting in some parishioners failing to attend church because of them in the 16th century, at other times, gathering in armed groups in separate parts of the building. Rothbury became a important village in Coquetdale, being a crossroads situated on a ford of the River Coquet, with turnpike roads leading to Newcastle upon Tyne, Alnwick and Morpeth.
After it was chartered as a market town in 1291, it became a centre for dealing in cattle and wool for the surrounding villages. A market cross was erected in 1722, but demolished in 1827. In the 1760s, according to Bishop Pococke, the village had a small craft industry, including hatters. At that time, the village's vicarage and living was in the gift of the Bishop of Carlisle, worth £500 per year. Rothbury has had a bloody history. In the 15th and 16th centuries the Coquet Valley was a pillaging ground for bands of Reivers who attacked and burned the town with terrifying frequency. Near the town's All Saints' Parish Church stands the doorway and site of the 17th-century Three Half Moons Inn, where the Jacobite rebel James Radclyffe, 3rd Earl of Derwentwater stayed with his followers in 1715 prior to marching into a heavy defeat at the Battle of Preston in 1715. Hill farming has been a mainstay of the local economy for many generations. Names such as Armstrong and Robson remain well represented in the farming community.
Their forebears, members of the reiver'clans', were in constant conflict with their Scots counterpart. The many fortified farms, known as bastle houses, are reminders of troubled times which lasted until the unification of the kingdoms of England and Scotland in 1603. There are two stories of the theologian Gilpin at Rothbury's Church; the first is. Realizing that they might break into fighting, Gilpin stood between them asking them to reconcile, they agreed as long. Another story is that Gilpin ask the sexton about it, he told him. Gilpin thus took the glove and put it in his pocket and carried on with his sermon, no-one challenged him. Rothbury is the site of Cragside, a Victorian country house built for the industrialist Sir William Armstrong Lord Armstrong of Cragside; the house was built as a "shooting box" between 1862 and 1865 extended as a "fairy palace" between 1869 and 1900. The house and its estate are open to the public; the Rothbury Electoral Division is in the parliamentary constituency of Berwick-upon-Tweed.
At the 2011 census it had a population of 5,316. Rothbury's Anglican parish church building – All Saints' Church – dates from ci