DRDO's "UTTAM" indigenously developed Active Electronically Scanned Array (AESA) Radar installed on Tejas on a Static display at Aero India 2019

Defence Research and Development Organisation (DRDO) has displayed an Active Electronically Scanned Array (AESA) radar meant for the Tejas fighter of which some 100 have been ordered by the Indian Air Force.

The radar is a fully functional prototype developed by DRDO’s Electronics and Radar Establishment (LRDE). The radar, mounted inside a glass nose of the Tejas aircraft was shown to the public for the first time at the Aero India 2019 in Bangalore.

The radar, called ‘Uttam,’ features fully active array and wide band waveform generation. It has Azimuth and Elevation mono-pulse for high accuracy fire control, high resolution tracking of sea and air and ground targets, auxiliary channels for Jammer suppression and multiple target tracking under dense clutter environment.

UTTAM has capabilities like, Identification friend or foe (IFF), electronic and communication support measures, C-band line-of-sight and Ku-band SATCOM data-links, etc., similar to those on the AWACS and Conformal Airborne Early Warning & Control Systems (CAEW) systems. It has been especially designed to track multiple targets suitable for firing missiles at in air-to-air, air-to -ground and air-to-sea modes.

The important modes of operation of the UTTAM radar system are the surface surveillance and the air surveillance. The sensor has the abilities to search, track-while-scan, priority tracking, high performance tracking, etc. In priority tracking, the targets will be placed in full track mode even if these cross the primary surveillance area. In high performance tracking, additional measurements are made to improve the tracking accuracy. Utilising active aperture technology, the radar provides a fast-beam agile system that can operate in several modes concurrently.

UTTAM features an active phased array (APAR) which gives it superior scanning performance over legacy passive phased array radar. Unlike most contemporary radars, Uttam features Quad solid-state transmit/receive module (TRM) i.e. a single plank consists of 4 TRMs. It allows the array to be more densely packed. Each TRM is equipped with low noise power amplifier, built-in test facility, digital phase-gain, and side lobe control elements. The inert model displayed at Aero India 2019 had ~184 QTRMs i.e. 736 TRMs. The array temperature is controlled by a liquid coolant circulation system. The QTRM configuration makes Uttam maintenance friendly. The radar can be scaled up or down depending on antenna size requirement.

Fight tests of the radar, mounted on two Tejas aircraft are expected to begin in a month. Three radars have already completed static and ground tests and certified for flight by the Indian Centre for Military Airworthiness and Certification (CEMILAC). A fourth radar will be mounted on an executive jet for test purposes.

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