DRDO AEW&CS

The Airborne Early Warning and Control System (AEWACS) is a project of India's Defence Research & Development Organization to develop an AWACS system for the Indian Air Force.

Program history
In 2003, the Indian Air Force (IAF) and Defence Research and Development Organisation (DRDO) carried out a joint study of the system-level requirements and feasibility of development for an Airborne Early Warning and Control (AEWAC) system. The government then approved the project for the development of the AEWAC system by DRDO. Primary responsibility for the project was with DRDO's Bangalore-based Centre for Airborne Systems (CABS), which led the design, system integration and testing of the system. LRDE was responsible for the design of the radar array. Defence Electronics Application Laboratory, based in Dehradun, was responsible for the Data Link and Communication Systems for AEW&CS.

The DRDO AEWACS program aims to deliver three radar-equipped surveillance aircraft to the Indian Air Force. The aircraft platform selected was the Embraer ERJ 145. Three ERJ 145 were procured from Embraer at a cost of US $ 300 Million, including the contracted modifications to the airframe. The project goal was to deploy these AEW&C aircraft by 2013. India's sole previous effort to develop an AEWAC system was the Airborne Surveillance Platform, but the program, codenamed Airavat, was ended after the only testbed crashed. The AEW&C project aimed to supplement the larger and more capable EL/W-2090 AWACS acquired by the IAF from Israel. Three EL/W-2090 systems have been ordered, with follow-on orders of 3 more expected in 2010. Apart from providing the IAF with a cheaper and hence, more flexible AEW&C platform as a backup to its more capable EL/W-2090 class systems, the DRDO AEW&C project aimed to develop the domestic ability to design and operationalize airborne surveillance platforms.

The delivery of six additional systems ordered in October 2010 is to begin from 2015. In June 2010, it was reported that the Indian Air Force is said to be looking at acquiring up to 20 additional systems, in addition to the existing systems on order.

Partners
The responsibility between various DRDO laboratories is split as follows:
 * 1) LRDE and DEAL - Primary radar, and IFF
 * 2) DEAL - Communication Systems and Data Link
 * 3) DARE - Self Protection suite, EW & CSM
 * 4) DLRL - Self Protection suite (counter measures)
 * 5) CABS - Overall Program Management, Integration & development of the data handling system, displays, mission computers et al.

Various Indian private sector firms are involved in the program. National Aerospace Laboratories contributed to the aerodynamic studies of the antenna array, and flight modelling of the entire AEWACS platform.

Design
Two radiating planar arrays assembled back-to-back and mounted on top of the fuselage in an active antenna array unit (AAAU) will 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 has been achieved through an innovative and iterative process to arrive at the AAAU with minimal dimensions and optimum mass properties. A unique feature of the indigenous TRMM designis that eight trans-receive modules are combined compactly to form a single TRMM, thus facilitating high density installation of 160 of them in the AAAU to power the surveillance radar.

Additionally, the aircraft has other mission capabilities like, Identification friend or foe (IFF), electronic and communication support measures, C-band line-of-sight and Ku-band SATCOM datalinks, etc., similar to those on the AWACS and CAEW systems. The important modes of operation of the primary 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 will be 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. Inter-operability with AWACS, other AEW&C aircraft, fighters and ground-exploitation stations is ensured using the datalinks with voice and data channels. The aircraft cabin houses five operator work stations to adequately meet requirements of the operational mission tasks.

An air-to-air refuelling, system enables extended operations at times of need. The endurance of the platform aircraft is about nine hours with one air-to-air refuelling.

Capabilities
The AEWACS aircraft will have an AESA primary radar with IFF. The system will also have ESM (Electronic Support Measures) and CSM (Communications Support Measures) ability. Datalinks to network the AEWACS with fighters, and ground based control systems will also be provided, as will be the SATCOM (Satellite Communication System). The aircraft will also have a comprehensive self-defence suite. The avionics suite will be linked via a datahandling system, controlled by Mission computers.

DRDO's public overview of the AEWACS aircraft stated:


 * The Radar will have an extended range mode against fighter aircraft, and will consist of two back to back AESA arrays, with an additional dedicated IFF array.
 * The ESM system will be able to track sources with a directional accuracy of 2 deg. RMS and a frequency accuracy of 1 MHz.
 * The ESM system will have complete 360 degree coverage in azimuth and have a database of up to 3000 emitters against which threats will be scanned.
 * Communication Support Measure system will analyse and record intercepted communications both inflight and post flight.
 * Self Protection Suite will have a passive Missile Approach Warning System, a Radar Warning Receiver and countermeasures dispensers. The SPS will be integrated with the ESM & CSM suite.
 * The aircraft will support Inflight refuelling.
 * The aircraft will have SATCOM, and datalinks to pass on ESM, CSM and radar data to ground stations and datalinks to pass on target information to fighters. More than 40 other aircraft will be datalinked together by the AEW&C aircraft.

Status
The first round of modifications to the first EMB-145 fuselage for India’s early warning aircraft were made in March 2011 in preparation for integration with the Indian-designed antenna.

In June 2010, it was reported that the Active Array Antenna Unit (AAAU), developed by DRDO’s Center for Airborne Systems (CABS), was to be integrated into the modified EMB-145 aircraft. First test flight of the system was expected in early 2011.

The first modified fuselage platform was handed over to DRDO by Embraer in February 2011. Ground and flight tests of the aircraft were to be followed by installation of radar and other equipment. The first fully modified EMB-145i Aircraft with the antenna and its electronic payload made its maiden flight on December 6, 2011 at Embraer  facilities  at Sao Jose dos Campos in Brazil with about 1000 Mission System Components  provided by CABS, DRDO. These included the critical item – AESA (Active Electronic Scanning Antenna) Radar Antenna developed by DRDO and certified from  ANAC, International FAR Certification Agency. at Sao Jose dos Campos in Brazil. Some of the sensitive advanced systems were replaced with dummy equipment of equivalent size and weight. These were to be integrated later in India following flight certification. A two-year certification period is expected. DRDO is expected to receive the next two aircraft platforms to start integration by mid-2012.

Maiden flight of the second fully modified aircraft for the indigenously developed Indian Airborne Early Warning and Control System (AEW&C) was held at 1930 IST on 4 April 2012 at the San Jose dos Campos in Brazil. The necessary Mission systems & components including the dummy AAAU (Active Antena Array Unit) are successfully fitted onboard Embraer EMB 145I aircraft.

Embraer Defense and Security, on August 16, 2012 delivered the first EMB 145 Airborne Early Warning and Control (AEW&C) class of aircraft to the Government of India, in a ceremony held at Embraer’s headquarters in São José dos Campos, Brazil. The delivery follows successful completion of ground and flight tests of the aircraft which met operational targets established by both Embraer and Centre for Airborne Systems (CABS) of Defence Research & Development Organisation (DRDO). Later on the aircraft will be delivered to the Indian Air Force after integration of missions systems of DRDO by CABS in India.

First Delivery
The first fully modified aircraft for India's indigenous Airborne Early Warning and Control System landed on Indian soil at CABS (Centre for Airborne Systems, Bangalore, a DRDO laboratory) at 22:10 hours at HAL airport, Wednesday night at 22 August 2012. The acceptance of the aircraft was completed over a period of 15 days at Embraer Facilities in Brazil, by a team from CABS,  its work centres, CEMILAC, DGAQA & IAF.

The aircraft ferried with several mission system external components of DRDO including the (AESA radar) Active Electronically scanned Array Antenna with passive electronics fitted on the aircraft. The arrival of this aircraft marks the beginning of another phase of journey leading to the next major milestone of integration of the DRDO developed mission system, which will be followed by development flight trials in India beginning of 2013. It may be noted that this is the first aircraft delivered by M/s Embraer for which the contract was signed in 2008. The next aircraft is expected to arrive in December 2012.

Future programs
DRDO and Bangalore-based Centre for Air Borne Systems (CABS)are to launch a new project `AWACS-India'. Initially, two AWACS aircraft will be developed, with four more to follow at a later stage. Clearances are underway for the new project to be launched.