Nizhny Novgorod Research Institute of Radio Engineering

The Nizhny Novgorod Research Institute of Radio Engineering (NNIIRT) is a Russian electronics company specializing in the development and manufacture of radar equipment. Founded in 1947, it is based in the city of Nizhny Novgorod.

Beginning in 1975, NNIIRT developed the first '3D' VHF radar capable of measuring height, range, and azimuth to a target. This effort produced the 55Zh6 'Nebo' VHF surveillance radar, which passed acceptance trials in 1982.

In the post-Cold War era, NNIIRT developed the 55Zh6 Nebo U 'Tall Rack' radar, which has been integrated with the SA-21 anti-aircraft weapons system. This system is deployed around Moscow.

In 2013, NNIIRT announced the further development of the 55Zh6UME Nebo-UME, which combines VHF and L band radars on a single assembly.