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Digital Antenna Array
Digital antenna array (DAA) is a smart antenna with multi channels digital beamforming, usually by using fast Fourier transform (FFT). The development and practical realization of digital antenna arrays theory started in 1962 under the guidance of Vladimir Varyukhin (USSR). History The history of the DAA was started to emerge as a theory of multichannel analysis in the 1920s.Slyusar V. I. Origins of the Digital Antenna Array Theory.// International Conference on Antenna Theory and Techniques, 24–27 May 2017, Kyiv, Ukraine. – Pp. 199 - 20/ref> In the 1940s this theory evolved to the theory of three-channel antenna analyzers. The implementation of effective signal processing in radars by the end of the 1950s predetermined the use of electronic computers in this field. In 1957, Ben S. Meltont and Leslie F. Bailey published article regarding using algebraic operations for signal processing with the help of electronic circuits or analog computer. Three years after in 1960 th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estimation Of Signal Parameters Via Rotational Invariance Techniques
Estimation of signal parameters via rotational invariant techniques (ESPRIT), is a technique to determine the parameters of a mixture of sinusoids in background noise. This technique was first proposed for frequency estimation. However, with the introduction of phased-array systems in everyday technology, it is also used for angle of arrival estimations. One-dimensional ESPRIT At instance t , the M (complex-valued) output signals (measurements) y_m /math>, m = 1, \ldots, M , of the system are related to the K (complex-valued) input signals x_k , k = 1, \ldots, K , asy_m = \sum_^K a_ x_k + n_m where n_m denotes the noise added by the system. The one-dimensional form of ESPRIT can be applied if the weights have the form a_ = e^ , whose phases are integer multiples of some radial frequency \omega_k . This frequency only depends on the index of the system's input, i.e. k . The goal of ESPRIT is to estimate \omega_k 's, given the outputs y_m and the number of input signals, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MUSIC (algorithm)
MUSIC (multiple sIgnal classification) is an algorithm used for frequency estimation and radio direction finding.Schmidt, R.O,Multiple Emitter Location and Signal Parameter Estimation" IEEE Trans. Antennas Propagation, Vol. AP-34 (March 1986), pp. 276–280. History In many practical signal processing problems, the objective is to estimate from measurements a set of constant parameters upon which the received signals depend. There have been several approaches to such problems including the so-called maximum likelihood (ML) method of Capon (1969) and Burg's maximum entropy (ME) method. Although often successful and widely used, these methods have certain fundamental limitations (especially bias and sensitivity in parameter estimates), largely because they use an incorrect model (e.g., AR rather than special ARMA) of the measurements. Pisarenko (1973) was one of the first to exploit the structure of the data model, doing so in the context of estimation of parameters of c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periodogram
In signal processing, a periodogram is an estimate of the spectral density of a signal. The term was coined by Arthur Schuster in 1898. Today, the periodogram is a component of more sophisticated methods (see spectral estimation). It is the most common tool for examining the amplitude vs frequency characteristics of FIR filters and window functions. FFT spectrum analyzers are also implemented as a time-sequence of periodograms. Definition There are at least two different definitions in use today. One of them involves time-averaging, and one does not. Time-averaging is also the purview of other articles ( Bartlett's method and Welch's method). This article is not about time-averaging. The definition of interest here is that the power spectral density of a continuous function, , is the Fourier transform of its auto-correlation function (see Cross-correlation theorem, Spectral density, and Wiener–Khinchin theorem): \mathcal\ = X(f)\cdot X^*(f) = \left, X(f) \^2. Computa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Ultrasound
Medical ultrasound includes Medical diagnosis, diagnostic techniques (mainly medical imaging, imaging) using ultrasound, as well as therapeutic ultrasound, therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics (e.g., distances and velocities) or to generate an informative audible sound. The usage of ultrasound to produce visual images for medicine is called medical ultrasonography or simply sonography, or echography. The practice of examining pregnant women using ultrasound is called obstetric ultrasonography, and was an early development of clinical ultrasonography. The machine used is called an ultrasound machine, a sonograph or an echograph. The visual image formed using this technique is called an ultrasonogram, a sonogram or an echogram. Ultrasound is composed of sound waves with frequency, frequencies greater than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonar
Sonar (sound navigation and ranging or sonic navigation and ranging) 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. "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. Acoustic location in air was used before the introduction of radar. Sonar may also be used for robot navigation, 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 e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MIMO
In radio, multiple-input and multiple-output (MIMO) () is a method for multiplying the capacity of a radio link using multiple transmission and receiving antennas to exploit multipath propagation. MIMO has become an essential element of wireless communication standards including IEEE 802.11n (Wi-Fi 4), IEEE 802.11ac (Wi-Fi 5), HSPA+ (3G), WiMAX, and Long Term Evolution (LTE). More recently, MIMO has been applied to power-line communication for three-wire installations as part of the ITU G.hn standard and of the HomePlug AV2 specification. At one time, in wireless the term "MIMO" referred to the use of multiple antennas at the transmitter and the receiver. In modern usage, "MIMO" specifically refers to a class of techniques for sending and receiving more than one data signal simultaneously over the same radio channel by exploiting the difference in signal propagation between different antennas (e.g. due to multipath propagation). Additionally, modern MIMO usage often refer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AMDR
The AN/SPY-6 is an active electronically scanned array (AESA) 3D radar system developed and built by RTX corporation, formerly Raytheon, and in service with the United States Navy (USN). It provides integrated air and missile defense for Flight III s. Variants are under development for retrofitting Flight IIA ''Arleigh Burke''s and for installation aboard s, s, s ( LHA-8 and future), and s. The first delivery of the AN/SPY-6 to the USN took place on 20 July 2020. In accordance with the Joint Electronics Type Designation System (JETDS), the "''AN/SPY-6''" designation represents the 6th design of an Army-Navy electronic device for surface ship surveillance radar system. The JETDS system also now is used to name all Department of Defense electronic systems. Development In October 2013, "Raytheon Company (RTN) asawarded an almost $386m cost-plus-incentive-fee contract for the Engineering and Manufacturing Development (EMD) phase design, development, integration, test, and deliver ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DSEI
Defence and Security Equipment International (DSEI, formerly stylized DSEi) is a biennial defence and security trade exhibition which serves as a forum between governments, national armed forces, industry, and academics, held at ExCeL London. DSEI 2019 comprised approximately 1,700 exhibitors from 58 countries, and DSEI 2025 is scheduled for 9–12 September 2025. DSEI's history In 1999, the UK's Labour Government privatised the joint British Army and Royal Navy Exhibitions which had taken place since 1976. Exhibition company, Spearhead, launched DSEI (then known as Defence and Systems Equipment International) and the first event took place at Chertsey, Surrey. In 2001, the exhibition moved to its current location at the ExCeL exhibition centre in London Docklands. DSEI rebranded in 2009 to Defence and Security Equipment International. Current ownership In April 2008, Clarion Events acquired DSEI. Controversy In 2007 two exhibitors were expelled by the then organisers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
THAAD
Terminal High Altitude Area Defense (THAAD), formerly Theater High Altitude Area Defense, is an American anti-ballistic missile defense system designed to intercept and destroy short-, medium-, and intermediate-range ballistic missiles in their terminal phase (descent or reentry). The THAAD interceptor carries no warhead, instead relying on its kinetic energy of impact to destroy the incoming missile. THAAD was developed after the experience of Iraq's Scud missile attacks during the Gulf War in 1991. Originally a United States Army program, THAAD has come under the umbrella of the Missile Defense Agency. The Navy has a similar program, the sea-based Aegis Ballistic Missile Defense System, which also has a land component ("Aegis Ashore"). THAAD was originally scheduled for deployment in 2012, but initial deployment took place in May 2008. THAAD has been deployed in the United Arab Emirates (UAE), Israel, Romania, and South Korea. On 17 January 2022, THAAD made its first op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TPY-2
The AN/TPY-2 Surveillance Transportable Radar, also called the Forward Based X-Band Transportable (FBX-T) is a long-range, very high-altitude active digital antenna array X band surveillance radar designed to add a tier to existing missile and air defence systems. It has a range of up to , depending on target/mode. Made by Raytheon, it is the primary radar for the Terminal High Altitude Area Defense (THAAD) missile system, but also cues the AN/MPQ-53 radar of the MIM-104 Patriot system. Patriot PAC-3 is a lower-altitude missile and air defense system than THAAD. In accordance with the Joint Electronics Type Designation System (JETDS), the "''AN/TPY-2''" designation represents the second design of an Army-Navy electronic device for ground transportable surveillance radar system. The JETDS system also now is used to name all Department of Defense electronic systems. The AN/TPY-2 is a missile-defense radar that can detect, classify, track and intercept ballistic missiles. It has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voronezh Radar
Voronezh radars () are the current generation of Russian early-warning radar, providing long distance monitoring of airspace against ballistic missile attack and aircraft monitoring. The first radar, in Lekhtusi near St Petersburg, became operational in 2009. There is a plan to replace older radars with the Voronezh by 2020. Their common name follows the pattern of Soviet radars in being named after a river, the Voronezh. The previous generation of radar was known as the Daryal (after Darial Gorge), Volga (after Volga River) and Daugava ( Daugava River) and the generation before the Dnepr ( Dnieper River), and Dnestr ( Dniester River). The Voronezh radars are described as highly prefabricated meaning that they have a set up time of months rather than years and need fewer personnel than previous generations. They are also modular so that a radar can be brought into (partial) operation whilst being incomplete. Russia has used the launch of these new radars to raise its c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
