Medium to long-range air defence: the evolution of radars

31 March 2021

The evolution of radars is closely related to changing threats. Today's enemies often do not operate under a single flag, and their threat lies in the existence of systems that vary greatly in their conception and technical complexity. Technological evolution has made possible a high degree of innovation in the design of radar systems. In particular, an increase in the level of component digitalisation has optimised the use of the power and time – primary resources available in radar – increasing the energy radiated to where it is needed most and reducing the time taken to detect and identify potential threats. Thanks to the use of Active Electronically Scanned Arrays (AESAs) in antennas containing large numbers of transmitter-receiver units, it is possible to direct instantaneously the radar beam towards the origins of a possible threat, monitoring several points simultaneously and varying the observation time.

The ability to direct the radars and continuously observe the potential threat, makes them exponentially more effective than their predecessors, which were limited to antennas that perpetually rotated 360° with a constant emission of power in all directions. AESAs cut power wastage through their ability to direct the energy beam onto the target with higher frequency; therefore, guaranteeing greater continuity and tracking accuracy on the monitored area and therefore an improved reaction capacity.

The modularity of AESAs also allows for more rapid development of versions based on the same type of system architecture but with different physical configurations more suited to the users’ logistical needs. Examples include mobility, ease of transport and reliability, therefore minimising deployment costs and reducing fuel consumption and generator size.

Another characteristic of modern radar systems is their ability to operate in a network, and be integrated with other components. This allows them to be managed simultaneously by multiple users, providing a different functionality for each user offering greater flexibility and cost reduction.

Within an integrated defence system, AESA sensors such as those of the KRONOS family -obtain information about the origin of possible threats and can use this to increase detection capacity by increasing the energy radiated in that direction.

An example of this is the integration of long-range radars (with a range of 400-500 km) such as the Leonardo RAT-31 DL - or its mobile version the RAT-31 DL/M– with an Early Warning function that can considerably increase the nominal range of a KRONOS GRAND.

Leonardo has invested significant resources in AESAs from the very beginning. One of the key steps the company took in this direction was its investment in its own foundry for the development of gallium nitride MMICs (Monolithic Microwave Integrated Circuits) used to produce radiant modules for AESA systems. Having this technology in-house now means that Leonardo is independent of third-party suppliers and able to constantly innovate.

The KRONOS family of multifunctional AESA radars was born from this technology, simultaneously and automatically performing surveillance, tracking and missile guidance functions against multiple threats.

The KRONOS family (available in the different frequency bands, L, C, and X) is available for both naval and land-based operations. The first one includes the KRONOS NAVAL for short-medium-range applications, the medium/long-range GRAND NAVAL and the long-range/ATBM POWER SHIELD , in rotating configuration; the DUAL BAND, in QUAD or STARFIRE fixed configurations. The equivalent ground-based radars are the LAND, the GRAND MOBILE, the GRAND Mobile HP and the GROUND SHIELDavailable in mobile/transportable/fixed configuration; To date, almost 50 KRONOS radars have been delivered – to the Italian armed forces, as well as worldwide.

KRONOS radars are high performance systems. Their coverage, acquisition, speed and tracking continuity, even against very low altitude targets; means that they can detect even small air and naval targets in the same scan, maintaining a single operating mode. All GRAND models, the POWER SHIELD and the GROUND SHIELD are capable of detecting and tracking ballistic missiles, with the last 2 in particular specifically designed for defence against medium range ballistic missiles (range up to 3000 km). The KRONOS family’s radars can operate in hostile electromagnetic environments, having emission characteristics that are difficult to detect by the opponent's countermeasures systems (ECM), and thus guaranteeing high protection from disruptive activities and deception.

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