The ionosphere is the ionized part of the upper atmosphere of Earth, from about 48 km (30 mi) to 965 km (600 mi) above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on Earth. It also affects GPS signals that travel through this layer.
Radar is a radiolocation system that uses radio waves to determine the distance (ranging), angle (azimuth), and radial velocity of objects relative to the site. It is used to detect and track aircraft, ships, spacecraft, guided missiles, and motor vehicles, and map weather formations, and terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna and a receiver and processor to determine properties of the objects. Radio waves from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds.
The High-frequency Active Auroral Research Program (HAARP) is a University of Alaska Fairbanks program which researches the ionosphere - the highest, ionized part of Earth's atmosphere.
The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the conventional boundary between the UHF and SHF bands at 3.0 GHz. The S band is used by airport surveillance radar for air traffic control, weather radar, surface ship radar, and some communications satellites, especially those satellites used by NASA to communicate with the Space Shuttle and the International Space Station. The 10 cm radar short-band ranges roughly from 1.55 to 5.2 GHz. The S band also contains the 2.4–2.483 GHz ISM band, widely used for low power unlicensed microwave devices such as cordless phones, wireless headphones (Bluetooth), wireless networking (WiFi), garage door openers, keyless vehicle locks, baby monitors as well as for medical diathermy machines and microwave ovens. India's regional satellite navigation network (IRNSS) broadcasts on 2.483778 to 2.500278 GHz.
The 2-meter amateur radio band is a portion of the VHF radio spectrum that comprises frequencies stretching from 144 MHz to 148 MHz in International Telecommunication Union region (ITU) Regions 2 and 3 and from 144 MHz to 146 MHz in ITU Region 1 . The license privileges of amateur radio operators include the use of frequencies within this band for telecommunication, usually conducted locally with a line-of-sight range of about 100 miles (160 km).
The Poker Flat Research Range (PFRR) is a launch facility and rocket range for sounding rockets in the U.S. state of Alaska, located on a 5,132-acre (20.77 km2) site at Chatanika, about 30 miles (50 km) northeast of Fairbanks and 1.5 degrees south of the Arctic Circle. More than 1,700 launches have been conducted at the range to study the Earth's atmosphere and the interaction between the atmosphere and the space environment. Areas studied at PFRR include the aurora, plasma physics, the ozone layer, solar proton events, Earth's magnetic field, and ultraviolet radiation. Rockets launched at PFRR have attained an apogee of 930 miles (1,500 km).
Low-frequency radar is radar which uses frequencies lower than 1 GHz such as L-band, UHF, VHF, and HF, as opposed to the usual radar bands, which range from 2 GHz to 40 GHz.The radar cross section of any target depends on the frequency transmitted by the radar. Below 900 MHz the target radar cross section increases exponentially, however the increased radar cross section means that there is also much more radar return from undesirable sources, such as cloud cover and rain. It is because of this that radars traditionally use much higher frequencies, with an exception being the radars operated in the 3-30 MHz band which are used as over-the-horizon radar stations because signals in that range are able to reflect off the ionosphere.
A radar altimeter (RA), also called a radio altimeter (RALT), electronic altimeter, reflection altimeter, or low-range radio altimeter (LRRA), measures altitude above the terrain presently beneath an aircraft or spacecraft by timing how long it takes a beam of radio waves to travel to ground, reflect, and return to the craft. This type of altimeter provides the distance between the antenna and the ground directly below it, in contrast to a barometric altimeter which provides the distance above a defined vertical datum, usually mean sea level.
The Super Dual Auroral Radar Network (SuperDARN) is an international scientific radar network consisting of 35 high frequency (HF) radars located in both the Northern and Southern Hemispheres. SuperDARN radars are primarily used to map high-latitude plasma convection in the F region of the ionosphere, but the radars are also used to study a wider range of geospace phenomena including field aligned currents, magnetic reconnection, geomagnetic storms and substorms, magnetospheric MHD waves, mesospheric winds via meteor ionization trails, and interhemispheric plasma convection asymmetries. The SuperDARN collaboration is composed of radars operated by JHU/APL, Virginia Tech, Dartmouth College, the Geophysical Institute at the University of Alaska Fairbanks, the Institute of Space and Atmospheric Studies at the University of Saskatchewan, the University of Leicester, Lancaster University, La Trobe University, the Solar-Terrestrial Environment Laboratory at Nagoya University, and the Institute for Space Astrophysics and Planetology.
An early-warning radar is any radar system used primarily for the long-range detection of its targets, i.e., allowing defences to be alerted as early as possible before the intruder reaches its target, giving the air defences the maximum time in which to operate. This contrasts with systems used primarily for tracking or gun laying, which tend to offer shorter ranges but offer much higher accuracy.
The Geophysical Institute of the University of Alaska Fairbanks conducts research into space physics and aeronomy; atmospheric sciences; snow, ice, and permafrost; seismology; volcanology; and tectonics and sedimentation. It was founded in 1946 by an act of the United States Congress.
Canadian Geospace Monitoring (CGSM) is a Canadian space science program that was initiated in 2005. CGSM is funded primarily by the Canadian Space Agency, and consists of networks of imagers, meridian scanning photometers, riometers, magnetometers, digital ionosondes, and High Frequency SuperDARN radars. The overarching objective of CGSM is to provide synoptic observations of the spatio-temporal evolution of the ionospheric thermodynamics and electrodynamics at auroral and polar latitudes over a large region of Canada.
An ionospheric heater, or an ionospheric HF pump facility, is a powerful radio wave transmitter with an array of antennas which is used for research of plasma turbulence, the ionosphere and upper atmosphere. These transmitters operate in the high frequency (HF) range (3-30 MHz) at which radio waves are reflected from the ionosphere back to the ground. With such facilities a range of plasma turbulence phenomena can be excited in a semi-controlled fashion from the ground, during conditions when the ionosphere is naturally quiet and not perturbed by for example aurora. This stimulus-response type of research complements passive observations of naturally excited phenomena to learn about the ionosphere and upper atmosphere.
SANAE IV is a current South African Antarctic research base located in Vesleskarvet, Queen Maud Land. The base is part of the South African National Antarctic Program (SANAP) and is operated by the South African National Antarctic Expedition.
Terence James Elkins is an Australian-born American physicist. In 1960, he participated in an expedition from Mawson Station which conducted the first geological surveys of the Napier Mountains in Antarctica. The highest of this group of mountains, Mount Elkins, was subsequently named after him. In 1979, he received the Harold Brown Award, the Air Force's highest honour for research and development, for research he conducted that contributed to the development of the AN/FPS-118 over-the-horizon backscatter (OTH-B) air defence radar system. This system, consisting of six one-megawatt transmitters and their associated horizontal linear phased array antennas, is currently the largest radar system in the world.
The Unwin Radar is a scientific radar array at Awarua, near Invercargill, New Zealand 46.51°S 168.38°E.
The Millstone Hill Steerable Antenna, or MISA, is a fully steerable dish antenna, 46 metres (151 ft) in diameter, designed by the Stanford Research Institute (SRI) in 1959. It is currently located at MIT Haystack Observatory in Westford, Massachusetts.
Arrival Heights are clifflike heights which extend in a north-east–south-west direction along the west side of Hut Point Peninsula, just north of Hut Point in Ross Island, Antarctica. They were discovered and named by the British National Antarctic Expedition, 1901–04, under Robert Falcon Scott. The name suggests the expedition's arrival at its winter headquarters at nearby Hut Point.
The AN/FPS-14 was a medium-range search Radar used by the United States Air Force Air Defense Command.
IFF Mark II was the first operational identification friend or foe system. It was developed by the Royal Air Force just before the start of World War II. After a short run of prototype Mark Is, used experimentally in 1939, the Mark II began widespread deployment at the end of the Battle of Britain in late 1940. It remained in use until 1943, when it began to be replaced by the standardised IFF Mark III, which was used by all Allied aircraft until long after the war ended.
