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Doppler Radar
A Doppler radar is a specialized radar that uses the Doppler effect to produce velocity data about objects at a distance. It does this by bouncing a microwave signal off a desired target and analyzing how the object's motion has altered the frequency of the returned signal. This variation gives direct and highly accurate measurements of the radial component of a target's velocity relative to the radar. Concept Doppler effect The Doppler effect (or Doppler shift), named after Austrian physicist Christian Doppler who proposed it in 1842, is the difference between the observed frequency and the emitted frequency of a wave for an observer moving relative to the source of the waves. It is commonly heard when a vehicle sounding a siren approaches, passes and recedes from an observer. The received frequency is higher (compared to the emitted frequency) during the approach, it is identical at the instant of passing by, and it is lower during the recession. This variation of f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Gun
A radar speed gun (also radar gun and speed trap gun) is a device used to measure the speed of moving objects. It is used in law-enforcement to measure the speed of moving vehicles and is often used in professional spectator sport, for things such as the measurement of bowling speeds in cricket, speed of pitched Baseball (ball), baseballs, and speed of tennis serves. A radar speed gun is a Doppler radar unit that may be hand-held, vehicle-mounted or static. It measures the speed of the objects at which it is pointed by detecting a change in frequency of the returned radar signal caused by the Doppler effect, whereby the frequency of the returned signal is increased in proportion to the object's speed of approach if the object is approaching, and lowered if the object is receding. Such devices are frequently used for speed limit enforcement, although more modern LIDAR speed gun instruments, which use pulsed laser light instead of radar, began to replace radar guns during the firs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pocket Radar
Pocket Radar products are handheld K‐band Doppler speed radar guns developed and manufactured by Santa Rosa, Calif.‐based Pocket Radar, Inc. It was intended for those wishing to measure the speed of everyday objects (such as cars and people). Functionality Pocket Radar utilizes very similar microwave signal emission and detection methods found in the Doppler speed radar guns used by law enforcement agencies. The device measures and weighs . when equipped with two AAA batteries. It operates at the 24.125 GHz K-Band frequency and can measure speeds ranging from {{convert, 7, to, 375, mph, abbr=on with an accuracy of ±1 mph (±1.6 km/h) and can also measure feet/second and meters/second. Pocket Radar, Inc Pocket Radar was developed and manufactured by Pocket Radar, Inc. of Santa Rosa, California. The company’s founders, Chris Stewart, Steve Goody, and Grant Moulton were developers in wireless and communication technology companies Hewlett Packard, Cerent Cor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Starboard
Port and starboard are nautical terms for watercraft and aircraft, referring respectively to the left and right sides of the vessel, when aboard and facing the bow (front). Vessels with bilateral symmetry have left and right halves which are mirror images of each other. One asymmetric feature is where access to a boat, ship, or aircraft is at the side, it is usually only on the port side (hence the name). Side Port and starboard unambiguously refer to the left and right side of the vessel, not the observer. That is, the port side of the vessel always refers to the same portion of the vessel's structure, and does not depend on which way the observer is facing. The port side is the side of the vessel which is to the left of an observer aboard the vessel and , that is, facing forward towards the direction the vehicle is heading when underway, and starboard side is to the right of such an observer. This convention allows orders and information to be given unambiguously, witho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Port (nautical)
Port and starboard are nautical terms for watercraft and aircraft, referring respectively to the left and right sides of the vessel, when aboard and facing the bow (front). Vessels with bilateral symmetry have left and right halves which are mirror images of each other. One asymmetric feature is where access to a boat, ship, or aircraft is at the side, it is usually only on the port side (hence the name). Side Port and starboard unambiguously refer to the left and right side of the vessel, not the observer. That is, the port side of the vessel always refers to the same portion of the vessel's structure, and does not depend on which way the observer is facing. The port side is the side of the vessel which is to the left of an observer aboard the vessel and , that is, facing forward towards the direction the vehicle is heading when underway, and starboard side is to the right of such an observer. This convention allows orders and information to be given unambiguously, without ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yagi Antenna
Yagi may refer to: Places *Yagi, Kyoto, in Japan *Yagi (Kashihara), in Nara Prefecture, Japan *Yagi-nishiguchi Station, in Kashihara, Nara, Japan *Kami-Yagi Station, a JR-West Kabe Line station located in 3-chōme, Yagi, Asaminami-ku, Hiroshima, Hiroshima Prefecture, Japan * Rikutyū-Yagi Station, a railway station on the East Japan Railway Company Hachinohe Line located in Hirono, Iwate Prefecture, Japan *Yamato-Yagi Station, a Kintetsu Corporation railway train station situated in the Nara Prefecture Other uses *Yagi (surname) *Typhoon Yagi (other) * Yagi (''Usagi Yojimbo''), a comic book character *Yagi–Uda antenna A Yagi–Uda antenna or simply Yagi antenna, is a directional antenna consisting of two or more parallel resonant antenna elements in an end-fire array; these elements are most often metal rods acting as half-wave dipoles. Yagi–Ud ..., a directional radio antenna * Yagibushi, a popular Japanese folk song and dance {{disambiguation, ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultra High Frequency
Ultra high frequency (UHF) is the ITU designation for radio frequency, radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter (one decimeter). Radio waves with frequencies above the UHF band fall into the super-high frequency (SHF) or microwave frequency range. Lower frequency signals fall into the VHF (very high frequency) or lower bands. UHF radio waves propagate mainly by Line-of-sight propagation, line of sight; they are blocked by hills and large buildings although the transmission through building walls is strong enough for indoor reception. They are used for UHF television broadcasting, television broadcasting, cell phones, satellite communication including GPS, personal radio services including Wi-Fi and Bluetooth, walkie-talkies, cordless phones, satellite phones, and numerous other applications. The Institute of Electrical and Electronics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of its active battle fleet alone exceeding the next 13 navies combined, including 11 allies or partner nations of the United States as of 2015. It has the highest combined battle fleet tonnage (4,635,628 tonnes as of 2019) and the world's largest aircraft carrier fleet, with eleven in service, two new carriers under construction, and five other carriers planned. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the United States Navy is the third largest of the United States military service branches in terms of personnel. It has 290 deployable combat vessels and more than 2,623 operational aircraft . The United States Navy traces its origins to the Continental Navy, which was established during the American Revo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, ma ... [...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] |
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] |
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] |
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