Deep Dive on the DASS

The EuroDASS consortium is studying how the Typhoon’s Praetorian DASS could be improved to safeguard the aircraft against emerging threats. This may result in both hardware and software enhancements for the subsystem in the future.

The EuroDASS consortium, responsible for the Praetorian Defensive Aids Subsystem (DASS) equipping the Eurofighter Typhoon has launched a study on the DASS’ modernisation.

The 18-month study will examine future upgrades for the equipment. The EuroDASS consortium includes Leonardo, Elettronica, Indra and Hensoldt. A press release announcing the news stated that the upgrade will be performed to allow Praetorian to remain abreast of emerging threats. The contract award forms part of the Long Term Evolution (LTE) study examining potential improvements for the aircraft writ large. This is to ensure it remains operationally relevant until 2050. The LTE contract, worth $58 million, was awarded by the North Atlantic Treaty Organisation’s Eurofighter and Tornado Management Agency to Eurofighter GmbH during the Paris Air Show this June.

Open sources state that the Praetorian comprises a radar warning receiver and accompanying Electronic Support Measure (ESM) covering a 100 megahertz to 10 gigahertz/GHz waveband. This encompasses most airborne and ground-based/naval surveillance and fire control radars in service today. A laser warning receiver adorns the Praetorian suites outfitting the Royal Air Force and Royal Saudi Air Force Typhoons. Meanwhile all of the Praetorian systems in service, and awaiting construction, include a Ka-band (32GHz to 38GHz) radar-based missile approach warning system and a countermeasures dispenser. Electronic attack is provided by an electronic countermeasure generating 50 watts of output power covering a six gigahertz to twelve gigahertz waveband. Alongside chaff and flare countermeasures, Praetorian can also dispense Leonardo BriteCloud series RF (Radio Frequency) countermeasures. These decoys can transmit across a waveband of 5.25GHz to 17.7GHz. This provides the aircraft with protection against active radar homing air-to-air/Surface-to-Air Missiles (SAMs), particularly those transmitting in wavebands beyond ten gigahertz including Ku-band threats.

According to Phil Liddiard, Leonardo’s vice president of combat air systems, the study will comprise two stages: The first will analyse potential future threats to the aircraft and architectural augmentations which improve its resistance to those threats via the enhancement of Praetorian. It will also focus on removing obsolescence in the DASS. Stage one will be completed by the end of 2019. Stage two will see Typhoon operators “looking at the study’s output and offering some suggestions” regarding Praetorian’s enhancement by the end of 2020. Mr. Liddiard says that the study is likely to concentrate on future software additions for the DASS in particular examining mechanisms by which mission data, such as the threat libraries Praetorian relies on, could be updated more expeditiously. The study may also recommend enhancements to the DASS hardware meaning that this “could be substantially different” from the self-protection hardware used by the aircraft today.

Operationally, one area which could be examining as part of the study is how to protect the aircraft from low-band ground-based air surveillance radars. Russia is making significant investments in low-band radars which, due to the wavelengths they transmit, have the wherewithal to detect aircraft with a low Radar Cross Section (RCS) albeit at the expense of precision. For example, Russia is introducing the NNIIRT 55ZH6M Nebo-M (NATO reporting name Tall Rack) ground-based air surveillance radar into service. This radar is thought to rely on Very High Frequency transmissions in 133MHz to 144MHz and 216MHz to 225MHz wavebands. While the Praetorian’s ESM may be capable of detecting transmissions from such radars, there maybe a growing imperative to also jam such threats. This is because these radars could provide materiel such as Russia’s Almaz-Antey S-400 (SA-21 Growler) high-altitude SAM system with a geographical indication as to where low RCS aircraft are, and where they might be heading. As Mr. Liddiard notes this study represents a “deep dive on the DASS,” and a way of ensuring that the Typhoon family can continue to address emerging threats well into the 2030s.

by Dr. Thomas Withington