[Sonar X2 Keygen Torrent
Melvin Amey
Sonar (sound navigation and ranging or sonic navigation and ranging)[2] is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances (ranging), communicate with or detect objects on or under the surface of the water, such as other vessels.[3]
"Sonar" can refer to one of two types of technology: passive sonar means listening for the sound made by vessels; active sonar means emitting pulses of sounds and listening for echoes. Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water.[4] Acoustic location in air was used before the introduction of radar. Sonar may also be used for robot navigation,[5] and sodar (an upward-looking in-air sonar) is used for atmospheric investigations. The term sonar is also used for the equipment used to generate and receive the sound. The acoustic frequencies used in sonar systems vary from very low (infrasonic) to extremely high (ultrasonic). The study of underwater sound is known as underwater acoustics or hydroacoustics.
The first recorded use of the technique was in 1490 by Leonardo da Vinci, who used a tube inserted into the water to detect vessels by ear.[6] It was developed during World War I to counter the growing threat of submarine warfare, with an operational passive sonar system in use by 1918.[3] Modern active sonar systems use an acoustic transducer to generate a sound wave which is reflected from target objects.[3]
Although some animals (dolphins, bats, some shrews, and others) have used sound for communication and object detection for millions of years, use by humans in the water was initially recorded by Leonardo da Vinci in 1490: a tube inserted into the water was said to be used to detect vessels by placing an ear to the tube.[6]
The use of sound to "echo-locate" underwater in the same way as bats use sound for aerial navigation seems to have been prompted by the Titanic disaster of 1912.[8] The world's first patent for an underwater echo-ranging device was filed at the British Patent Office by English meteorologist Lewis Fry Richardson a month after the sinking of Titanic,[9] and a German physicist Alexander Behm obtained a patent for an echo sounder in 1913.[10]
During World War I the need to detect submarines prompted more research into the use of sound. The British made early use of underwater listening devices called hydrophones, while the French physicist Paul Langevin, working with a Russian immigrant electrical engineer Constantin Chilowsky, worked on the development of active sound devices for detecting submarines in 1915. Although piezoelectric and magnetostrictive transducers later superseded the electrostatic transducers they used, this work influenced future designs. Lightweight sound-sensitive plastic film and fibre optics have been used for hydrophones, while Terfenol-D and lead magnesium niobate (PMN) have been developed for projectors.
By 1918, Britain and France had built prototype active systems. The British tested their ASDIC on HMS Antrim in 1920 and started production in 1922. The 6th Destroyer Flotilla had ASDIC-equipped vessels in 1923. An anti-submarine school HMS Osprey and a training flotilla of four vessels were established on Portland in 1924.
By the outbreak of World War II, the Royal Navy had five sets for different surface ship classes, and others for submarines, incorporated into a complete anti-submarine system. The effectiveness of early ASDIC was hampered by the use of the depth charge as an anti-submarine weapon. This required an attacking vessel to pass over a submerged contact before dropping charges over the stern, resulting in a loss of ASDIC contact in the moments leading up to attack. The hunter was effectively firing blind, during which time a submarine commander could take evasive action. This situation was remedied with new tactics and new weapons.
The tactical improvements developed by Frederic John Walker included the creeping attack. Two anti-submarine ships were needed for this (usually sloops or corvettes). The "directing ship" tracked the target submarine on ASDIC from a position about 1500 to 2000 yards behind the submarine. The second ship, with her ASDIC turned off and running at 5 knots, started an attack from a position between the directing ship and the target. This attack was controlled by radio telephone from the directing ship, based on their ASDIC and the range (by rangefinder) and bearing of the attacking ship. As soon as the depth charges had been released, the attacking ship left the immediate area at full speed. The directing ship then entered the target area and also released a pattern of depth charges. The low speed of the approach meant the submarine could not predict when depth charges were going to be released. Any evasive action was detected by the directing ship and steering orders to the attacking ship given accordingly. The low speed of the attack had the advantage that the German acoustic torpedo was not effective against a warship travelling so slowly. A variation of the creeping attack was the "plaster" attack, in which three attacking ships working in a close line abreast were directed over the target by the directing ship.[17]
The new weapons to deal with the ASDIC blind spot were "ahead-throwing weapons", such as Hedgehogs and later Squids, which projected warheads at a target ahead of the attacker and still in ASDIC contact. These allowed a single escort to make better aimed attacks on submarines. Developments during the war resulted in British ASDIC sets that used several different shapes of beam, continuously covering blind spots. Later, acoustic torpedoes were used.
Early in World War II (September 1940), British ASDIC technology was transferred for free to the United States. Research on ASDIC and underwater sound was expanded in the UK and in the US. Many new types of military sound detection were developed. These included sonobuoys, first developed by the British in 1944 under the codename High Tea, dipping/dunking sonar and mine-detection sonar. This work formed the basis for post-war developments related to countering the nuclear submarine.
During the 1930s American engineers developed their own underwater sound-detection technology, and important discoveries were made, such as the existence of thermoclines and their effects on sound waves.[18] Americans began to use the term SONAR for their systems, coined by Frederick Hunt to be the equivalent of RADAR.[19]
In 1917, the US Navy acquired J. Warren Horton's services for the first time. On leave from Bell Labs, he served the government as a technical expert, first at the experimental station at Nahant, Massachusetts, and later at US Naval Headquarters, in London, England. At Nahant he applied the newly developed vacuum tube, then associated with the formative stages of the field of applied science now known as electronics, to the detection of underwater signals. As a result, the carbon button microphone, which had been used in earlier detection equipment, was replaced by the precursor of the modern hydrophone. Also during this period, he experimented with methods for towing detection. This was due to the increased sensitivity of his device. The principles are still used in modern towed sonar systems.
To meet the defense needs of Great Britain, he was sent to England to install in the Irish Sea bottom-mounted hydrophones connected to a shore listening post by submarine cable. While this equipment was being loaded on the cable-laying vessel, World War I ended and Horton returned home.
During World War II, he continued to develop sonar systems that could detect submarines, mines, and torpedoes. He published Fundamentals of Sonar in 1957 as chief research consultant at the US Navy Underwater Sound Laboratory. He held this position until 1959 when he became technical director, a position he held until mandatory retirement in 1963.[20][21]
There was little progress in US sonar from 1915 to 1940. In 1940, US sonars typically consisted of a magnetostrictive transducer and an array of nickel tubes connected to a 1-foot-diameter steel plate attached back-to-back to a Rochelle salt crystal in a spherical housing. This assembly penetrated the ship hull and was manually rotated to the desired angle. The piezoelectric Rochelle salt crystal had better parameters, but the magnetostrictive unit was much more reliable. High losses to US merchant supply shipping early in World War II led to large scale high priority US research in the field, pursuing both improvements in magnetostrictive transducer parameters and Rochelle salt reliability. Ammonium dihydrogen phosphate (ADP), a superior alternative, was found as a replacement for Rochelle salt; the first application was a replacement of the 24 kHz Rochelle-salt transducers. Within nine months, Rochelle salt was obsolete. The ADP manufacturing facility grew from few dozen personnel in early 1940 to several thousands in 1942.
One of the earliest application of ADP crystals were hydrophones for acoustic mines; the crystals were specified for low-frequency cutoff at 5 Hz, withstanding mechanical shock for deployment from aircraft from 3,000 m (10,000 ft), and ability to survive neighbouring mine explosions. One of key features of ADP reliability is its zero aging characteristics; the crystal keeps its parameters even over prolonged storage.
Passive sonar arrays for submarines were developed from ADP crystals. Several crystal assemblies were arranged in a steel tube, vacuum-filled with castor oil, and sealed. The tubes then were mounted in parallel arrays.
The standard US Navy scanning sonar at the end of World War II operated at 18 kHz, using an array of ADP crystals. Desired longer range, however, required use of lower frequencies. The required dimensions were too big for ADP crystals, so in the early 1950s magnetostrictive and barium titanate piezoelectric systems were developed, but these had problems achieving uniform impedance characteristics, and the beam pattern suffered. Barium titanate was then replaced with more stable lead zirconate titanate (PZT), and the frequency was lowered to 5 kHz. The US fleet used this material in the AN/SQS-23 sonar for several decades. The SQS-23 sonar first used magnetostrictive nickel transducers, but these weighed several tons, and nickel was expensive and considered a critical material; piezoelectric transducers were therefore substituted. The sonar was a large array of 432 individual transducers. At first, the transducers were unreliable, showing mechanical and electrical failures and deteriorating soon after installation; they were also produced by several vendors, had different designs, and their characteristics were different enough to impair the array's performance. The policy to allow repair of individual transducers was then sacrificed, and "expendable modular design", sealed non-repairable modules, was chosen instead, eliminating the problem with seals and other extraneous mechanical parts.[22]
795a8134c1