The future of radar: the evolution of a technology with a long history

We talk with Alfonso Farina, one of the fathers of modern radar

22 October 2021

The range of applications for radars is huge in every field, and the potential for future developments is immense. Leonardo is committed to keeping alive the history of past achievements, while at the same time looking to the future. This is the background for our conversation with Alfonso Farina, an outstanding contributor to radar development, who has been with Leonardo for nearly 50 years and continues to work on boosting Italy's technological capabilities.

Born in 1948 in a provincial village near Rieti, Alfonso graduated from Rome’s Sapienza University in 1973 and joined the Selenia Company the following year. His career has always progressed along two parallel paths, working in both industry and the academic sector. From 1979-1985, he taught Radar Techniques at the University of Naples and is now ‘Visiting Professor’ at internationally renowned centres such as the Department of Electronic and Electrical Engineering at University College London, and the Centre for Electronic Warfare Information and Cyber at Cranfield University. He is also a Distinguished Lecturer at the Institute of Electrical and Electronics Engineers (IEEE), the largest technical professional organisation in the world.

Alfonso has published more than 800 scientific articles, books and papers. This includes two books, released in 1985 and 1986, about Radar Data Processing: revolutionary publications of such a global impact that, following their publication in the United Kingdom and the United States, they were subsequently translated into Russian and Chinese. He has also won numerous international awards, being the first Italian to receive the prestigious Fred Nathanson Memorial Radar Award in 1987, the first to receive the Finmeccanica Technology Innovation Award in 2004, the IEEE Dennis J. Picard Medal for Radar Technologies and Applications in 2010, the IEEE Signal Processing Society Industrial Leader Award in 2017, the Christian Hülsmeyer Award in 2019, and the IEEE AESS Pioneer Award in 2020.

A pioneer in radar imaging, Alfonso has played a leading role in a number of major innovations. This includes his work on Synthetic Aperture Radar (SAR) in 1985; his ground-breaking work on algorithms for putting air traffic control radars online in Italy; and his radar development work for the ARGOS 10 programme that laid the foundations for modern electronic counter-countermeasure techniques used by the Italian Navy’s sensors.

We start our chat with Alfonso Farina with a discussion on the most promising upcoming developments in this field: the impact of digitalisation, the latest-generation multifunctional antennas, radar applications to support sustainable development and, in the longer term, quantum radars.

Thanks to digitalisation, it is now possible to design systems that are more flexible, more resilient, higher-performance and – in general – game-changing. Thanks to its digital approach, the Leonardo radar TMMR (Tactical Multi Mission Radar), enables the performance of multiple missions such as defence against drone attack and border surveillance using a single system architecture. The evolution of the entire national air defence network, based on 3D long-range radars, is also being researched with the introduction of modern digital radar signal reception devices.

“Modern radar has many applications that impact our daily lives in ways that are not always obvious. The antennas that will bring us 5G and 6G Internet are electronically scanned. The weather forecasts that we rely on could not exist without specific ground and space-based radars. Applications are also being found for radar in the medicine and emergency management fields, and are an integral part of the cars we drive.”

Farina also highlights the role that radars will have to play in creating a greener, more sustainable and fairer economy. “Now that radar technology, more than ever, is interacting with many other rapidly developing areas of technology, those of us involved in developing and producing it must combine innovation with responsibility.”

From this perspective, an interesting technology that may find new and more numerous applications is passive radar, which has the advantage of not needing to generate and transmit its own radiofrequency signals. Passive Coherent Location (PCL) is based on locating objects with electro-magnetic (e.m.) transmissions already existing in the environment. Farina is an innovator in this field, and promoted a development project for a PCL radar at a time when few believed in its potential. “The AULOS radar that we developed is a so-called ‘green’ radar that does not emit a radio frequency,” says Farina. “It comprises two circular array antennas mounted on a telescopic mast: the first is used to detect flying objects via the reception of FM radio frequencies, while the other one uses DVB-T (or digital video broadcasting) signals. The project began in 2004-2005, and since then, AULOS has demonstrated the ability to monitor air traffic up to 200km away, proving that it can also be used to track maritime traffic or even drones in flight.”

Aulos


The convergence between radar and telecommunications – one example being the use of electronically scanned antennas for 5G and 6G transmissions – points to another area of technological development with significant civilian and defence implications: multi-mission antennas. With the right waveforms and suitable hardware and software, the same antenna can be used for radar, as a communication system, as a receiver for different signals, and as a transmitter for jamming and electronic warfare. As widely known, Leonardo is working on the new AESA radar for the Eurofighter Typhoon, which is also expected to have an electronic countermeasure capability to actively oppose enemy sensors, while multi-role antenna technology is attracting close attention in several development programmes worldwide.

In space, the detection and tracking of space debris is now a major challenge. Since the first satellite was launched into orbit, the ever-growing number of activities being carried out in space has compounded the problem of orbiting debris. “It is estimated that over 100 tons of debris, comprising many thousands of objects, are orbiting at between 300 and 1,000km from the Earth. These objects represent a danger to satellites and all new space missions, so they need to be tracked and monitored until it is possible, ideally, to remove them. Radar plays a key role in this mission as part of networks that integrate a series of inter-connected sensors. Leonardo’s Long Range 3D radars have shown a good ability to detect and track orbiting satellites/debris.”

We have recently witnessed the successes in space of Virgin Orbit and Blue Origin, and we expect, in the near future, considerable growth in sub-orbital traffic as space tourism becomes more widespread. “In Italy too we’re planning a spaceport, at Grottaglie, and if space flights become more common, the control of air traffic will also have to expand its reach towards space,” explains Farina

Then there is the great challenge of quantum technologies, which are attracting attention all over the world. “In 2008, Professor Seth Lloyd at the MIT wrote an article on the use of the so-called phenomenon of ‘entanglement’ between photons for low-light quantum target identification applications using an ‘entangled’ pair of photons,” says Farina.

“In theory, the very close correlation created in this case between a pair of photons, which is a purely quantum effect, can be exploited to obtain advantages to identify a target. One photon is transmitted towards the target, while the other is held back in order to measure the correlation at the moment when the transmitted photon returns. A gain in the order of six decibels in the signal-to-noise ratio has been estimated, which is far from trivial. The quantum regime also gives protection from any interference precisely due to the close correlation between the photon sent and the one held back.

“Huge difficulties nonetheless need to be to overcome: the first demonstrator was built with an operative range of fractions of a metre and is not yet capable of measuring distance, speed and angular position. For the system to work, the correlated photons must be generated at temperatures close to absolute zero.

“The potential of quantum technology seems easier to exploit in terms of secure and encrypted communications, since any attempt at intrusion is immediately apparent: the mere observation of the quantum state irreversibly alters it, highlighting any attempt by an attacking party to detect the information being exchanged.”

Alfonso Farina concludes with the following reflections: “The blossoming of many ‘heroic’ stories of people, technologies, innovations and industrial enterprise – expressed in a range of contexts – has led to a national pooling of radar technologies and systems that demonstrate Italy’s expertise in innovating, designing, building and maintaining complex high-technology systems that satisfy the country's needs and create revenue by successfully competing in international markets.

 “Seventy years of expertise and excellence, imprinted in the Company's people and the broad spectrum of its multiple facets, is an undisputable wealth of knowledge that continues along the path to progress in line with Leonardo's purpose, mission and Charter of Values.”

 

A glance back at our history

In 1980 we had 2D radars with reflector antennas and Traveling Wave Tube transmitters. 3D radars followed in 1990, made possible by the use of multi-beams at different frequencies emitted from the same planar antenna,” recalls Alfonso Farina (his words replaying a piece of Italian radar history).

He adds that “From 1991-1995, there were key developments in Phased Array technology which led to the C-band, electronically scanned EMPAR radar (European Multifunction Phased Array Radar), and here I allow myself to claim a major contribution in developing the computer that acts as the radar's ‘brain’ and makes it possible to see through enemy electronic countermeasures. Between 1995 and 2005, our work was focused on developing the first active electronically scanned array (AESA) in L-band, with anti-ballistic missile defence capabilities”.

Then the modern family of KRONOS arrived. “Following this, from 2006-2015, modern, scalable AESA arrays in C-band were developed, with gallium arsenide (GaAs) semiconductors.

KRONOS GRAND NAVAL


The KRONOS radar family is now a flagship product for Leonardo, and a great commercial success”. We then come to more recent times, with the Dual Band Radar and many more along the way.

“Since 2015 – thanks to the Legge Navale (Naval Law) programme supported by the Italian Navy – the main focus has been on the development of the KRONOS DUAL BAND which integrates the four-fixed-face AESA KRONOS QUAD, in C-band with gallium nitride (GaN) technology, with the AESA KRONOS STARFIRE in X-band.

“Using two bands that are so different (C, X) optimises the long-range search and threat tracking functions. This integrated combination is a technology that few countries yet possess, and is intended for the full configuration for the Italian Navy’s Pattugliatore Polivalente d'Altura (PPA) ship. The latest arrival in the KRONOS family is the L-band POWER SHIELD, the first of the Digital Array Radars that constitute the pinnacle of current radar technology and systems.

“Another outstanding development is a new secondary radar for the Identify Friend or Foe (IFF) function, used on the Italian FREMM class ships, as well as on the new PPA. This is a Phased Array with a conformal truncated cylinder antenna, able to handle multiple beams through 360° of azimuthal coverage. It is a highly advanced development, the successor to the IFFs, with antennas made up of multiple planar ‘faces.’

“Finally, let’s remember two other outstanding successes of the Italian radar industry, which are radars for Air Traffic Control (ATC) and weather radars. Leonardo's ATC radars are used by more than 150 countries across the world, while Leonardo GmbH-made weather radars constitute 20% of all operational weather radars on the planet.”

ffThe success of Leonardo radars is also the result of a genuine tradition in this area that has been cultivated since the Selenia era, as Farina explains. “Starting in 1972, we had the Rivista Tecnica Selenia (Selenia Technical Review), which published such highly-valued articles to be regularly cited by the IEEE. A descendent of that first journal is the Polaris Innovation Journal, which has already printed contributions from 674 high-level authors and published 17 different dissertations on the subject of radar. Then there was a Radar School – dedicated to my esteemed friend and colleague Flavio A. Studer – which, in its various evolutions from the 1970s (in 2010 renamed the SELEX Academy) until today, has provided thousands of hours of courses and infinite opportunities for collaboration with universities by means of dedicated days

“Recently, the Leonardo Radar & Sensors Academy has been founded in the BU Electronics Italia, offering Basic, Intermediate and Advanced Courses. I have the honour of being its director, and we have the ambitious objective of issuing 2,200 hours of coursework to over 120 users for the last quarter of 2021 and the first quarter of 2022! Hopefully, the courses will continue during all the 2022”.

Finally, Leonardo is keeping alive the memory of everything that has been achieved in the field of radar through two important company museums: the Museo del Radar (Museum of Radar) at the Fusaro plant and the Museo delle ex Officine Galileo (Museum of the former Galileo Workshops) at Campi Bisenzio (Florence).

 

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