ACTIVE ELECTRONICALLY SCANNED ARRAY

APAR AESA

An 'Active Electronically Scanned Array' (AESA), also known as 'active phased array radar' is a type of radar whose transmitter and receiver functions are composed of numerous small transmit/receive (T/R) modules. AESA radars feature short to instantaneous (millisecond) scanning rates and have a desirable low probability of intercept.
As solid state devices, AESA radars have vastly simpler mechanical designs. They require no complex hydraulics for antenna movement nor hinge appendages that are prone to failure. The AESA radar occupies less space than typical radar, because of its lesser infrastructure requirements and of course its absent range of motion. The distributed transmit function also eliminates the most common single-point failure mode seen in a conventional radar. With these improvements, maintenance crews are far less severely taxed, and the radar is much more reliable.
Main advantages over mechanically scanned arrays are extremely fast scanning rate, much higher range, tremendous number of targets being tracked and engaged (multiple agile beams), low probability of intercept, ability to function as a radio/jammer, simultaneous air and ground modes, Synthetic Aperture Radar.
Mechanical steering may be added to AESA radars for increased radar field of view; The movement performance of the antenna would not need to be nearly as great as that of a traditional radar, as the radar sweep is not integral to the contact update rate.

Contents
Features
The Difference Between AESA and PESA
List of AESA radars
Airborne systems
Ground and sea-based systems
See also
External links

Features


AESA radars have:

★ High ECM resistance:


★ The extremely fast scan of the radar makes it difficult for an ECM device to find the correct azimuth and elevation in which the radar's main lobe is currently directed.


★ High gain associated with AESA radars gives them high ERP, which makes it difficult for an active ECM device, using noise jamming techniques, to successfully jam such a radar.

★ The extremely fast scan of the emitter gives it LPI features.

★ Less suspectibility to voltage failures, due to the relatively very low voltage in which each and every single radiating element operates; This is combined with graceful degradation.

The Difference Between AESA and PESA


In a passive electronically scanned array (PESA), the microwave feed network in the back of the antenna is powered by a single radio frequency (RF) source (magnetron, klystron, TWT, etc.), sending its waves into phase shift modules (usually digitally-controlled), which, in turn, feed the numerous emitting elements.
An AESA, instead, has an individual RF source for each of its many transmit/receive elements, making them "active".
This provides for a graceful degradation, so that many T/R modules may fail and the radar would not stop functioning.
AESA radars replace the traditional radar RF sources (magnetron/klystron/TWT), which usually require extremely high operating voltage and power, with multiple solid state RF sources operating at low voltage (40 to 60 volts). Solid state electronics use silicon or gallium arsenide based power amplifier technology and benefit to some extent from mass production techniques developed for consumer electronics. US based manufacturers of the AESA radars used in the F22 and Super Hornet include Northrop Grumman [1] and Raytheon [2]. and These companies also design, develop and manufacture the transmit/receive modules which comprise the 'building blocks' of an AESA radar. The requisite electronics technology was developed in-house via Department of Defense research programs such as MIMIC Program [3] [4].

List of AESA radars


Airborne systems


Northrop Grumman/Raytheon AN/APG-77, for the F-22 Raptor

Northrop Grumman AN/APG-80, for the F-16E/F Block 60 Fighting Falcon

Northrop Grumman AN/APG-81, for the F-35 Joint Strike Fighter

Northrop Grumman Multi-role AESA, for the Boeing Wedgetail (AEW&C)

Northrop Grumman APY-9, for the E-2D Advanced Hawkeye

Raytheon AN/APG-63(V)2 and AN/APG-63(V)3, for the F-15C Eagle

Raytheon AN/APG-79, for the F/A-18E/F Super Hornet

Raytheon AN/APQ-181 (AESA upgrade currently in development), for the B-2 Spirit bomber

AMSAR, from the European GTDAR consortium, for Eurofighter and Rafale fighters

SELEX Seaspray 7000E, for helicopters

Elta EL/M-2075 radar for the IAI Phalcon AEW&C system

Mitsubishi Electric Corporation AESA for the Mitsubishi F-2 fighter

Ericsson Erieye AEW&C and NORA AESA for JAS 39 Gripen

Phazotron NIIR Zhuk-AE, for MiG-35

Tikhomirov NIIP Epaulet-A

Elta EL/M-2083 aerostat-mounted air search radar

Elta EL/M-2052, for fighters
Ground and sea-based systems


APAR multi-function radar, primary sensor of Dutch De Zeven Provinciën and German Sachsen class frigates

Elta EL/M-2080 ''Green Pine'' ground-based early warning AESA radar

AN/SPY-3 multi-function radar for U.S. DD(X), CG(X) and CVN-21 next-generation surface vessels

Raytheon U.S. National Missile Defense X-Band Radar (XBR)

SAMPSON multi-function radar for UK. Type 45 destroyers

MEADS's fire control radar

THAAD system fire control radar

See also



Radar

Phased array

Transmitter

Receiver

Passive electronically scanned array

External links



Active Electronically Steered Arrays – A Maturing Technology

FLUG REVUE December 1998: Modern fighter radar technology

Phased Arrays and Radars – Past, Present and Future

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