The
Nizhny Novgorod Research Institute of Radio Engineering (Russian acronym: NNIIRT) has since 1948 developed a number of radars. These were mainly radars in the VHF-band, and many of which featured developments in technology that represented "first offs" in the Soviet Union. Innovations include the first Soviet air surveillance radar with a circular scan: the
P-8 Volga (NATO: KNIFE REST A) in 1950, the first
3D radar: the 5N69 Salute (NATO: BIG BACK) in 1975, and in 1982 the first VHF-band 3D-radar: the 55Zh6 Nebo (NATO: TALL RACK). Other innovations were radars with frequency hopping; the
P-10 Volga A (NATO: KNIFE REST B) in 1953, radars with transmitter signal coherency and special features like moving target indicator (MTI); the
P-12 Yenisei (NATO: SPOON REST) in 1955 as well as the P-70 Lena-M with chirp signal modulation in 1968 or the widely used
P-18 Terek (NATO: SPOON REST D) in 1970. == NIIDAR ==