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Ultrawideband
Ultra-wideband (UWB, ultra wideband, ultra-wide band and ultraband) is a radio technology that can use a very low energy level for short-range, high-bandwidth communications over a large portion of the radio spectrum. UWB has traditional applications in non-cooperative Imaging radar, radar imaging. Most recent applications target sensor data collection, precise locating, and tracking. UWB support started to appear in high-end smartphones 2019. Characteristics Ultra-wideband is a technology for transmitting information across a wide bandwidth (>500 Hertz, MHz). This allows for the transmission of a large amount of signal energy without interfering with conventional narrowband and carrier wave transmission in the same frequency band. Regulatory limits in many countries allow for this efficient use of radio bandwidth, and enable high-data-rate personal area network (PAN) wireless connectivity, longer-range low-data-rate applications, and the transparent co-existence of radar and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RailSAR
The railSAR, also known as the ultra-wideband Foliage Penetration Synthetic Aperture Radar (UWB FOPEN SAR), is a rail-guided, low-frequency impulse radar system that can detect and discern target objects hidden behind foliage. It was designed and developed by the U.S. Army Research Laboratory (ARL) in the early 1990s in order to demonstrate the capabilities of an airborne SAR for foliage and ground penetration. However, since conducting accurate, repeatable measurements on an airborne platform was both challenging and expensive, the railSAR was built on the rooftop of a four-story building within the Army Research Laboratory compound along a 104-meter laser-leveled track. At the time, the railSAR fell into the highest category of UWB radar systems, operating across a 950 MHz-wide band from 40 MHz to 1 GHz on a pulse strength of 2.5 megawatts. It provided fully polarimetric, high resolution radar data and possessed 185% bandwidth compared to other radar systems that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SAFIRE Radar
The Spectrally Agile Frequency-Incrementing Reconfigurable (SAFIRE) radar is a vehicle-mounted, forward-looking ground-penetrating radar (FLGPR) system designed to detect buried or hidden explosive hazards. It was developed by the U.S. Army Research Laboratory (ARL) in 2016 as part of a long generation of ultra-wideband (UWB) and synthetic aperture radar (SAR) systems created to combat buried landmines and IEDs. Past iterations include the railSAR, the boomSAR, and the SIRE radar. Development The SAFIRE radar was initially conceived as a response to the increasing congestion of the radio frequency (RF) spectrum due to the recent growth of wireless technology. As part of an effort to improve upon the existing SIRE radar system, the U.S. Army Research Laboratory designed the SAFIRE radar as a UWB radar that could match or exceed the performance of the SIRE radar while operating in congested RF environments. Instead of impulse UWB, it was fitted with a stepped-frequency design ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SIRE Radar
The Synchronous Impulse Reconstruction (SIRE) radar is a multiple-input, multiple-output (MIMO) radar system designed to detect landmines and improvised explosive devices (IEDs). It consists of a low frequency, impulse-based ultra-wideband (UWB) radar that uses 16 receivers with 2 transmitters at the ends of the 2 meter-wide receive array that send alternating, orthogonal waveforms into the ground and return signals reflected from targets in a given area. The SIRE radar system comes mounted on top of a vehicle and receives signals that form images that uncover up to 33 meters in the direction that the transmitters are facing. It is able to collect and process data as part of an affordable and lightweight package due to slow (40 MHz) yet inexpensive analog-to-digital (A/D) converters that sample the wide bandwidth of radar signals. It uses a GPS and Augmented Reality (AR) technology in conjunction with camera to create a live video stream with a more comprehensive visual dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthogonal Frequency-division Multiplexing
In telecommunications, orthogonal frequency-division multiplexing (OFDM) is a type of digital transmission and a method of encoding digital data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital communication, used in applications such as digital television and audio broadcasting, DSL internet access, wireless networks, power line networks, and 4G/ 5G mobile communications. OFDM is a frequency-division multiplexing (FDM) scheme that was introduced by Robert W. Chang of Bell Labs in 1966. In OFDM, multiple closely spaced orthogonal subcarrier signals with overlapping spectra are transmitted to carry data in parallel.webe.org - 2GHz BAS Relocation Tech-Fair, COFDM Technology Basics 2007-03-02 Demodula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C-UWB
C-UWB is an acronym for continuous pulse ultra-wideband (UWB) technology. C-UWB derives its bandwidth by virtue of the short time duration of the individual pulses. Information can be imparted (modulated) on UWB signals (pulses) by encoding the polarity of the pulse, the amplitude of the pulse, or by using orthogonal pulse shape modulation. Polarity modulation is analogous to BPSK in conventional RF technology. In orthogonal wave shape modulation, two orthogonal UWB pulse shapes are employed. These are further polarity modulated in a fashion analogous to QPSK Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency reference signal (the carrier wave). The modulation is accomplished by varying the sine and cosine inputs at a ... in conventional radio technology. Preferably, the modulating data bits are scrambled or "whitened" to randomize the occurrences of ones and zeros. The pulses are sent contiguously ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Technology
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by another antenna connected to a radio receiver. Radio is very widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing, and other applications. In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking, and satellite communication, among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter. In radar, used to locate and track objects like aircraft, ships, spacecraft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AirTags
AirTag is a tracking device developed by Apple. AirTag is designed to act as a key finder, which helps people find personal objects (e.g. keys, bags, apparel, small electronic devices, vehicles). To locate lost items, AirTags use Apple's crowdsourced Find My network, estimated in early 2021 to consist of approximately one billion devices worldwide that detect and anonymously report emitted Bluetooth signals. AirTags are compatible with any iPhone, iPad, or iPod Touch device capable of running iOS/iPadOS 14.5 or later. Using the built-in U1 chip on iPhone 11 or later (excluding iPhone SE 2nd generation and iPhone SE 3rd generation), users can more precisely locate items using UWB (ultra-wideband) technology. AirTag was announced on April 20, 2021, made available for pre-order on April 23, and released on April 30. History The product was rumored to be under development in April 2019. In February 2020, it was reported that Asahi Kasei was prepared to supply Apple with tens of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matched Filter
In signal processing, a matched filter is obtained by correlating a known delayed signal, or ''template'', with an unknown signal to detect the presence of the template in the unknown signal. This is equivalent to convolving the unknown signal with a conjugated time-reversed version of the template. The matched filter is the optimal linear filter for maximizing the signal-to-noise ratio (SNR) in the presence of additive stochastic noise. Matched filters are commonly used in radar, in which a known signal is sent out, and the reflected signal is examined for common elements of the out-going signal. Pulse compression is an example of matched filtering. It is so called because the impulse response is matched to input pulse signals. Two-dimensional matched filters are commonly used in image processing, e.g., to improve the SNR of X-ray observations. Matched filtering is a demodulation technique with LTI (linear time invariant) filters to maximize SNR. It was originally also known a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BoomSAR
The boomSAR is a mobile ultra-wideband synthetic aperture radar (UWB SAR) system designed by the U.S. Army Research Laboratory (ARL) in the mid-1990s to detect buried landmines and IEDs. Mounted atop a 45-meter telescoping boom on a stable moving vehicle, the boomSAR transmits low frequency (50 to 1100 MHz) short-pulse UWB signals over the side of the vehicle to scope out a 300-meter range area starting 50 meters from the base of the boom. It travels at an approximate rate of 1 km/hour and requires a relatively flat road that is wide enough to accommodate its 18 ft-wide base. Characteristics The boomSAR is a fully polarimetric system that transmits and receives low-frequency waveforms with over 1 gigahertz of usable bandwidth, covering a spectrum from approximately 40 MHz to 1 GHz. Its testbed radar subsystems consist of the antennae, the transmitter, the analog-to-digital (A/D) converter, the processor/data storage system, the timing and control assembly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Army Research Laboratory
The U.S. Army Combat Capabilities Development Command Army Research Laboratory (DEVCOM ARL) is the U.S. Army's foundational research laboratory. ARL is headquartered at the Adelphi Laboratory Center (ALC) in Adelphi, Maryland. Its largest single site is at Aberdeen Proving Ground, Maryland. Other major ARL locations include Research Triangle Park, North Carolina, White Sands Missile Range, New Mexico, Graces Quarters, Maryland, and NASA's Glenn Research Center, Ohio and Langley Research Center, Virginia. ARL also has regional sites in Playa Vista, California (ARL West), Chicago (ARL Central), Austin, TX (ARL South), and Boston (ARL Northeast). DEVCOM ARL has three directorates: *Army Research Office, located in Research Triangle Park *Army Research Directorate *Research Business Directorate History Before the forming of the ARL, the United States Army had research facilities dating back to 1820 when the laboratory at Watertown Arsenal, Massachusetts, studied pyrotechnic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synthetic-aperture Radar
Synthetic-aperture radar (SAR) is a form of radar that is used to create two-dimensional images or three-dimensional reconstructions of objects, such as landscapes. SAR uses the motion of the radar antenna over a target region to provide finer spatial resolution than conventional stationary beam-scanning radars. SAR is typically mounted on a moving platform, such as an aircraft or spacecraft, and has its origins in an advanced form of side looking airborne radar (SLAR). The distance the SAR device travels over a target during the period when the target scene is illuminated creates the large ''synthetic'' antenna aperture (the ''size'' of the antenna). Typically, the larger the aperture, the higher the image resolution will be, regardless of whether the aperture is physical (a large antenna) or synthetic (a moving antenna) – this allows SAR to create high-resolution images with comparatively small physical antennas. For a fixed antenna size and orientation, objects which are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signaling Of The New York City Subway
Most trains on the New York City Subway are manually operated. , the system currently uses Automatic Block Signaling, with fixed wayside signals and automatic train stops. Many portions of the signaling system were installed between the 1930s and 1960s. Because of the age of the subway system, many replacement parts are unavailable from signaling suppliers and must be custom built for the New York City Transit Authority, which operates the subway. Additionally, some subway lines have reached their train capacity limits and cannot operate extra trains in the current system. There have been two different schemes of signaling in the system. The current scheme is used on all A Division and B Division lines, originally built to the Brooklyn–Manhattan Transit Corporation (BMT) and Independent Subway System (IND)'s specifications. An older system was previously used on all of the A Division, but with the conversion of the IRT Dyre Avenue Line signals to the B Division scheme in Sept ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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