Non-Subscriber Extract
Integrated defence: DAS evolves to warn aircraft of emergent threats
By Martin Streetly
13 March 2008
In a world where advances in military technology are often taken for granted, it is easy to forget that a truly integrated - rather than federated - defensive aids suite (DAS) for an air vehicle is a relatively new phenomenon that is continuing to push the boundaries of possibility.
An integrated DAS is defined as a self-contained capability that incorporates both warning and countering (active and/or passive as appropriate) functions; is managed by its own control system; is capable of self-execution of a full cycle of actions (from detection to response); and is integrated into its host weapon system in such a way as to complement other onboard functionalities without disrupting them or being disrupted by them.
The key difference between these types of DAS and federated systems, which are frequently mistaken for integrated applications, is their functionality. A federated DAS uses discrete elements that work together but are not capable of an automatic and sequenced response.
In terms of the DAS themselves, a hierarchical sampling would start with 'high-end' systems - such as those developed for the F-22 and F-35 combat aircraft - moving on to 'high to mid-level' systems such as the United States' AN/ALQ-178(V), AN/ALQ-211(V) and Falcon Edge systems; the French Spectre and Integrated Countermeasures Suite (ICMS) applications; the Israeli Advanced Self-Protection Suite (ASPS); the multinational EuroDASS system; and the Swedish EWS39 suite.
Then there are the 'application-dedicated systems', such as the US Guardian and Jeteye systems; the Danish Apache Modular Aircraft Survivability Equipment (AMASE) and Chinook Aircraft Survivability Equipment (CHASE); the French SPS-H/-TA suites; the Turkish Aselsan electronic warfare (EW) self-protection system (ASES); and the UK's Helicopter Integrated DAS (HIDAS).
Both the F-22 and F-35 blend EW and threat-warning capabilities into a complete weapon system, with the whole being tailored to functionality within a low-observable airframe. The F-22 fighter's radar, radar warning, identification and communications capabilities are managed as a single system, with a fused and relevant data display for the pilot. The platform's AN/ALR-94 'EW suite' provides active countermeasures and missile-launch detection, as well as radio frequency (RF) threat detection and integration with the AN/ALE-52 countermeasures dispensing system (CMDS). The F-22's RF emissions are rigorously managed to meet the tactical situation. System control is managed via a dual common integrated processor installation.
The F-35's AN/AAQ-37 Electro-Optical Distributed Aperture System (EODAS, which forms part of the aircraft's overall EO sensor system) provides missile warning, with other EW functions being handled by electronic support and 'digital EW' subsystems that form part of the platform's unified avionics functionality. Both aircraft are equipped with Active Electronically Scanned Array (AESA) radar systems that can be configured to provide active EW and communications outputs, as well as their various air-to-air and air-to-surface operating modes.
The BAE Systems AN/ALQ-178(V) is an integrated radar warning and active countermeasures suite for more traditional tactical fighter aircraft such as the F-16. The equipment comprises a radar warning receiver (RWR), an active jamming chain and a control architecture that comprises a programmable central computer and independent microprocessors to manage RWR, display, jamming and CMDS functionality. The ALQ-178(V) has been progressively upgraded; the latest iterations incorporating elements such as an agile channel RWR; Digital RF Memory (DRFM) technology; agile jamming channels; distributed high-speed/capacity processors; and precision direction-finding. ALQ-178(V) has been installed aboard Israeli (in a [V]1 configuration) and Turkish ([V]3 and [V]5+) F-16s. The (V)5+ variant is also known as Self-Protection EW System (SPEWS) II. Here, the iteration is known to incorporate a DRFM.
The ITT Electronic Systems AN/ALQ-211(V) Suite of Integrated RF Countermeasures (SIRFC) system is a modular, scalable architecture that can incorporate both passive and active RF subsystems, as well as providing precision radar warning; threat geolocation; advanced situational awareness; RF jamming; and EW suite control capabilities (including laser/missile warners and chemical sensors) as required. Other features include in-flight reprogrammability; the use of MIL-STD-1553B and other high-speed buses to facilitate integration with the host platform's avionics fit; and the use of Standard Electronic Module Type E (SEM-E) packaging, standard PowerPC processors and application specific/monolithic microwave integrated circuitry.
Image: An AMASE DAS pod installed on a Dutch AH-64 attack helicopter (Jane's/Patrick Allen)