The two antennas of the EISCAT Svalbard Radar
EISCAT, the European Incoherent Scatter Scientific Association, makes measurements of the lower, middle and upper atmosphere and ionosphere using the incoherent scatter radar technique. It is currently operated by funds from Norway, Sweden, Finland, Japan, China and the UK.
EISCAT has two independent radar systems on the Fenno-Scandinavian mainland, with transmitters near Tromsø and receivers in Kiruna and Sodankylä. These systems are called the VHF and UHF and cover the auroral zone. A third radar system in the polar cap is located in Longyearbyen. It is called the EISCAT Svalbard Radar (ESR). All current sites use steerable dish antennas.
EISCAT has proposed a replacement for their UHF/VHF mainland system. This initiative is called EISCAT_3D (E3D). It consists of one new core site and four receiving sites within 50-250 km from the core. E3D will use phased-array technology, allowing for measurements at unprecedented temporal resolution and in full-3D. E3D has been approved for the European ESFRI (European Strategy Forum on Research Infrastructures) roadmap as a research infrastructure. Work is currently ongoing to obtain funding. A video describing EISCAT_3D is found here.