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Ultra-wideband
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 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 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 imaging systems with ... [...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] |
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] |
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] |
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] |
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] |
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] |
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] |
Real-time Location System
Real-time locating systems (RTLS), also known as real-time tracking systems, are used to automatically identify and track the location of objects or people in real time, usually within a building or other contained area. Wireless RTLS tags are attached to objects or worn by people, and in most RTLS, fixed reference points receive wireless signals from tags to determine their location. Examples of real-time locating systems include tracking automobiles through an assembly line, locating pallets of merchandise in a warehouse, or finding medical equipment in a hospital. The physical layer of RTLS technology is often radio frequency (RF) communication. Some systems use optical (usually infrared) or acoustic (usually ultrasound) technology with, or in place of, RF. RTLS tags and fixed reference points can be transmitters, receivers, or both, resulting in numerous possible technology combinations. RTLS are a form of local positioning system and do not usually refer to GPS or to mobi ... [...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] |
IEEE 802
IEEE 802 is a family of Institute of Electrical and Electronics Engineers (IEEE) standards for local area networks (LAN), personal area network (PAN), and metropolitan area networks (MAN). The IEEE 802 LAN/MAN Standards Committee (LMSC) maintains these standards. The IEEE 802 family of standards has had twenty-four members, numbered 802.1 through 802.24, with a working group of the LMSC devoted to each. However, not all of these working groups are currently active. The IEEE 802 standards are restricted to computer networks carrying variable-size packets, unlike cell relay networks, for example, in which data is transmitted in short, uniformly sized units called cells. Isochronous signal networks, in which data is transmitted as a steady stream of octets, or groups of octets, at regular time intervals, are also outside the scope of the IEEE 802 standards. The number 802 has no significance: it was simply the next number in the sequence that the IEEE used for standards projects. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiaomi MIX 4
The Xiaomi MIX 4 is an Android smartphone launched on 10 August 2021 by Chinese company Xiaomi. As of 2021, it is the latest successor to the Xiaomi Mi MIX product line and follows its immediate predecessor the Xiaomi Mi MIX 3 which launched in 2018. The MIX 4 is the first device from Xiaomi to offer an under-display selfie camera, following the Axon 20 5G and Axon 30 from ZTE; Oppo also previewed the technology a week before the MIX 4's release. Design Front panel made from Corning Gorilla Glass Victus. The back is made up of ceramic. The camera unit design is similar to Xiaomi Mi 11 Ultra. On the bottom side there is a USB-C port, speaker, microphone and dual SIM tray. On the top side, there is an additional microphone, IR blaster and second speaker. On the right side, there is a volume rocker and power button. Xiaomi MIX 4 is available in 3 colors: Ceramic Black, Ceramic White and Ceramic Gray. Hardware Chipset The MIX 4 is the first phone to use the Qualcomm Sn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Personal Area Network
A personal area network (PAN) is a computer network for interconnecting electronic devices within an individual person's workspace. A PAN provides data transmission among devices such as computers, smartphones, tablets and personal digital assistants. PANs can be used for communication among the personal devices themselves, or for connecting to a higher level network and the Internet where one master device takes up the role as gateway. A PAN may be wireless or carried over wired interfaces such as USB. A wireless personal area network (WPAN) is a PAN carried over a low-powered, short-distance wireless network technology such as IrDA, Wireless USB, Bluetooth or ZigBee. The reach of a WPAN varies from a few centimeters to a few meters. WPANs specifically tailored for low-power operation of the sensors are sometimes also called low-power personal area network (LPPAN) to better distinguish them from low-power wide-area network (LPWAN). Wired Wired personal area networks provide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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