Airborne Early Warning & Control System (AEW&C)

The Indian Air Force has an officially projected requirement for 15 AWACS aircraft. The current three Israeli PHALCON AWACS will be augmented with six indigenous A330-based AWACS with two additional jets as options, plus plans for two more PHALCON jets, making a total of 13 aircraft. The two Netra, when upgraded with the IAF’s stated improvements, will provide greater cover, though not the 360-degree cover the IAF wants from all fifteen jets in the class.

Airborne Early Warning & Control System (AEW&C), is a force multiplier system of systems for detecting & tracking of enemy/hostile aircraft/ UAVs etc. It also enables operators onboard and on ground to identify, assess the threat and take actions to guide interceptors to those for neutralizing those threats. The system is fully net centric, with complete command and control functions not only providing the available information to ground through its multiple data links but also can receive information from ground, integrate and fuse them onboard to provide the operators onboard a composite picture of environment. As a command center, it enables onboard operators to select, command and guide specific interceptor aircrafts towards enemy threat efficiently and neutralize them.

The significant inventions of the early 20th Century, the aircraft and the radar, led to the clever combination of the two technologies, giving birth to a distinctly identified airborne early warning and control (AEW&C) concept, that eventually rewrote the tactics for air warfare.

The roles that the two dominant AEW&C systems, the E-2C Hawkeye and the E-3 AWACS, played duringthe Gulf War (1991) amply illustrated the power of these systems. During operation ‘Desert Shield’ and ‘Desert Storm,’the AEW&C aircraft helped overcome surveillance deficiencies and conducted successful air operations. These assisted the fighter fleet by providing early threat detection and building up situational awareness that led most of the air-to-air engagements being successful.

The AEW&C system has quickly proved itself to be a dominant force multiplier with its abilities to execute multiple functions – surveillance, early warning, electronic intelligence, communication intelligence, command and control tasks, battle management, etc. all from a single airborne platform. The AEW&C systems effectively impacted the dynamics of air warfare and have irreversibly changed its nature.

Both E-2C Hawkeye and E-3 AWACS aircraft carried mechanically-steered array (MSA) antenna in a rotating dome to scan the sky. In the early 1990s, a more versatile breed of AEW&C systems with electronically steered array (ESA) radar started making their appearance progressively. The ESA is mounted in a fixed position on the aircraftstructure and the beam is steered by individually controlling electronically the phase of the radio waves transmitted and received by each of the multiple radiating elements in the antenna. Additionally, in the case of ESA, a low RF power generated in a single place is amplified at multiple places close to each of the radiating elements, thereby the array becomes active as against being passive.

Israel and Russia jointly developed the first AEW&Csystem for India, christened IL-76 AWACS India, with true 360°-azimuth coverage radar built into the Russian Beriev IL-76 aircraft platform. This system is built around an AESA L-band radar. India's IL-76 AWACS uses a conventional circular radome mounted on top of its fuselage. The radome is however, fixed and not rotating. The ELTA radar, with a set of three phased-arrays fed from a single set of T/R modules housed in a triangular configuration inside the radome, will operate in L-band and scan 360° in the azimuth.

Under the DRDO's Airborne Surveillance Platform (ASP) programme, a modified Avro was fitted with a rotodome (a rotating disc which carries the radar antenna) on its fuselage. The 24-ft diameter rotodome contained a radar developed by DRDO and HAL in the late 1980s under Project Guardian. The Project Airavat HS-748 Avro aircraft crashed in the dense forest of north Tamil Nadu on 11 January 1999, killing eight people. The crash, which came when the radome separated from the support pylons and sliced off the top half of fin and rudder, also caused a severe setback to one of India's most ambitious defence research projects.

The Defence Research and Development Organisation (DRDO) next launched an indigenous AEW&C program focussed on specific operational requirements of Indian Air Force. The Centre for Airborne Systems (CABS) of the DRDO was tasked with the development of the system and the Centre pursued the program with participation of multiple work centers from within DRDO as well as Indian industries in the public and private sectors.

The first fully modified Aircraft for indigenously developed Indian Airborne Warning and Control System (AEW&C) aircraft, the EMB-145I took to the skies on 6 December 2011. The primary sensor for the AEW&C is the indigenous AESA S-band radar with adequate detection range against targets of the fighter class of aircraft. Two radiating planar arrays assembled back-to-back and mounted on top of the fuselage in an active antenna array unit (AAAU) provide 240° coverage like Erieye. The AAAU is configured to compactly house 10 x 2 antenna array panels, 160 transmit receive 10 x 2 antenna array panels, 160 transmit receive multi-modules (TRMMs) dividers, beam forming units, beam control units, power supply units and related electronic devices including cables and connectors. This was achieved through an innovative and iterative process to arrive at the AAAU with minimal dimensions and optimum mass properties.

Starting with the Aero India air show in 2015 and at successive events in 2017 and 2019, a scale model of an Airbus A330 with a rotodome was displayed by the DRDO, indicating its preference for the European airframe. In December 2020 it was announced that the project to build the AEW&C system on existing aircraft from the Air India fleet may also mean that India may not buy the six Airbus 330 transport aircraft planned to be acquired earlier The six AEW&C block two planes would be highly capable than their predecessor NETRA plane and provide 360-degree coverage deep inside the enemy territory during missions. The government is expected to clear the project soon," government sources told ANI.