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Guest Editorial: Advancements and future trends in noise radar technology

2024; Institution of Engineering and Technology; Volume: 18; Issue: 7 Linguagem: Inglês

10.1049/rsn2.12611

1751-8792

Christoph Wasserzier, Kubilay Savci, Łukasz Masikowski, Gaspare Galati, Gabriele Pavan,

Advanced SAR Imaging Techniques

The persuasive idea behind noise radar technology (NRT) states that the usage of random and non-periodic radar signals, in principle, eliminates all kinds of ambiguities that for many other radars are a driving design factor. However, practical aspects of NRT need to carefully evaluate the actual degree of randomness in their transmission, and the computational load the radar signal processing requires. The performance of noise radars has evolved in accordance with the advance of signal processing hardware and algorithms. From the first implementations of noise radars which used analogue delay lines, for the observation of a limited range swath, towards modern and complex Field Programmable Gate Array-based real-time implementations, it took several decades of intense research. During the evolution of NRT, other advantageous characteristics of noise radars have been identified, particularly in the aspect of electronic warfare (EW). The latter, being seen as the counterpart of radar sensing, may have several goals such as the interception and location of radar emitters, the identification of the radar and or its platform, an estimation of the task of the radar, an assessment of the threat that is represented by the radar's task in a particular situation, and the engagement of counter-actions either by jamming, spoofing or a hard-kill. The modern and more general term EMSO (electromagnetic spectrum operations) draws an even wider picture around EW and includes cyber aspects as well. The latter, thus, introduces an interesting aspect for use-cases in which NRT is considered for joint communication and radar sensing applications. The dear reader may be glad to see that this special issue on the advancements and future trends in noise radar contains contributions on anti-intercept features, security aspects, modern signal processing technology, such as programmable digital circuits and artificial intelligence. The article 'Implementation of a Coherent Real-Time Noise Radar System' by Martin Ankel, Mats Tholén, Thomas Bryllert, Lars Ullander and Per Delsing focuses on the implementation aspects of a basic range-Doppler processing method. That algorithm is enhanced by a motion compensation approach that aims to overcome the cell migration in the range-Doppler plane caused by the high time-bandwith product of the selected parameters. This paper presents the implementation of a demonstrator system on a very detailed level. It not only reasons the authors' selection of particular Simulink® and Xilinx IP-cores but also discusses the requirements, limitations and effects that the selected RFSoC Hardware and its peripherals have on the implementation results. Finally, the paper reports the set up and results of field trials that illustrate the limitations of the demonstrator in accordance with what was expected from the theoretical assessment of the power budget, the waveform particularities and the hardware limitations. Interesting recommendations to overcome some major limitations complete this work. Jaakko Marin, Micael Bernhardt and Taneli Riihonen contribute to this special issue by their work entitled 'Full-duplex capable multifunction joint radar-communication-security transceiver with pseudonoise-Orthogonal Frequency-Division Multiplex (OFDM) mixture waveform'. The authors' work is driven by a use-case that includes two communicating parties and a third party, the eavesdropper, who tries to steal the information exchanged by the two first mentioned parties. A combined waveform of an OFDM communications signal and an in-band pseudo-random bandlimited noise sequence is selected to ensure successful information exchange, prevent the eavesdropper's attempt to de-code the OFDM sequence by the jamming effect the pseudo-noise signal has, and additionally, to successfully perform radar sensing. Influences such as self interference and mutual interference are considered as well. The simulation results presented in this work not only demonstrate the achievement of the tasks introduced by the use-case but also present performance assessments under some idealised conditions clearly stated in the discussion part of this work. While eliminating range and Doppler ambiguities, the ability of NRT to withstand EW/Electronic Defence attacks is one of its main advantages. The article, 'On the Anti-Intercept features of Noise Radars' by Gaspare Galati and Gabriele Pavan presents a comparative analysis of the associated Low Probability of Detection (LPD), Low Probability of Interception (LPI) and of Exploitation (LPE) features for Continuous Emission Noise Radar (CE-NR) waveforms with varying 'degrees of randomness' and varied operational parameters, or 'tailored' waveforms. Time-frequency analysis is used to analyse three distinct noise radar waveforms, that is, a phase noise (advanced pulse compression noise) and two 'tailored' noise waveforms (FMeth and COSPAR). The article also discusses the detection of a radar signal by ESM or ELINT systems and includes simulation results regarding energy detector and multiple antennas receiver/correlator. Authors report that the LPD characteristics of a CE-NR are not substantially different from those of any CE radar transmitting deterministic waveforms when signal bandwith and duration is known a priori. Finally, the influence of tailoring, that is, sidelobe suppression is examined along with prospects for future work. It is envisaged that radar sensors enhanced with Artificial Intelligence hold great potential for modern radar systems. The article 'Artificial Intelligence Applications in Noise Radar Technology' by Afonso Lobo Sénica, Paulo Alexandre Carapinha Marques and Mário Alexandre Teles de Figueiredo aims to present a broad overview of the research conducted on artificial intelligence (AI)-powered radar systems in last recent years and make recommendations on AI's potential applications in NRT. The study comprehensively surveys AI-based applications from the antenna design (beamforming, MIMO, leakage suppression), waveform optimization, signal interception, target interception/recognition/classification and interference suppression aspects with prospects for noise radar usage. Authors also provided the fundamental tools needed to comprehend how new AI-based techniques may be applied to radar technology, demonstrated how well it works for NRT, and most importantly provided benchmarks and guidance for further research on the subject. This special issue covers many current topics, such as Artificial Intelligence, data security and integrity, the struggle with congested and contested spectral resources for different tasks, EW that seeks to dominate the electromagnetic spectrum, and an assessment of real-time implementation of noise radar sensing using state-of-the art signal processing hardware. We hope that this special issue provides you with valuable insights into the advancements and future trends of noise radar technology and that you enjoy reading it. Christoph Wasserzier: Conceptualization; writing—original draft; writing—review and editing. Kubilay Savci: Conceptualization; writing—original draft; writing—review and editing. Łukasz Masikowski: Conceptualization. Gaspare Galati: Conceptualization. Gabriele Pavan: Conceptualization. Data sharing not applicable. Christoph Wasserzier has received his Master's equivalent diploma degree in Electrical Engineering from RWTH Aachen University, Germany, in 2009. From 2009 until 2023, he worked as a researcher at the Fraunhofer institute for high-frequency physics and radar techniques FHR in Wachtberg, Germany. His research topics were focused on Electronic Warfare and LPI/LPE radars. During that period he also achieved his PhD in electrical engineering for his research on 'Noise Radar on Moving Plaforms' from Tor Vergata University Rome, Italy, supervised by Prof. Gaspare Galati. Dr. Christoph Wasserzier was a member of several NATO research task groups from 2011 to 2023 in the fields of Electronic Warfare and also on Noise Radar. From the SET NATO Panel he was awarded the 'early carreer award', from the IEEE he was elevated to senior member and he is a life-time member of the AOC. Since 2023, he is with ELT Group Germany, Meckenheim. Kubilay Savci received the B.S. degree from the Department of Electrical and Electronics Engineering, Turkish Naval Academy, Istanbul, Turkiye and the M.S. degree from the Ming Hsieh Department of Electrical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA, in 2008 and 2013, respectively. He received the special fellowship granted from the Turkish Naval Forces Command for the M.S. study at the University of Southern California. He holds a Ph.D. degree in electrical engineering from Koç university, Istanbul, Turkiye since 2022. He is currently serving as the Electronics Research and Technology Chief Engineer at the Electronics Development Group Division, Turkish Naval Research Center Command, with the rank of Navy Lieutenant Commander. Dr. Kubilay Savci has led various military electronic system projects including radar and involved with several aspects of radar developments. His research interests include radar systems, emerging radar technologies (cognitive radar and noise radar), radar waveform design techniques, and radar signal processing. Łukasz Masikowski received the M.Sc. in electrical and computer engineering (2011) and Ph.D. in telecommunications (2018) from the Warsaw University of Technology (WUT), Warsaw, Poland. He has been working at WUT since the start of his career and now he is an assistant professor there. Dr Maślikowski is the Co-Chairman of the NATO STO Research Task Group SET-287 'Capabilities of Noise Radar'. He was also a TPC member of the SPSympo 2023 Conference. His main research interests include radar signal processing, especially in noise, MIMO and passive radar as well as RF measurements and radar system design and validation. He took part in numerous R&D projects, mainly in the area of defence applications, including function of the Project Manager. He is a co-author of 46 papers indexed in Scopus. Gaspare Galati received the Dr. Ing. Degree (Laurea) in Nuclear Engineering in 1970. From 1970 until 1986, he was with the company Selenia S.p.A. where he was involved in radar systems analysis and design and, from 1984 to 1986, headed the System Analysis Group. From March 1986, he was the associate professor at the Tor Vergata University of Rome; from November 1996 to 2017, he was full professor of Radar Theory and Techniques at the Tor Vergata University. In 2017 he was designated Honorary Professor by the Ministry of Education. His main interests are in radar theory and techniques, detection and estimation, noise radar, navigation and air traffic management. He is author/co-author of about 300 papers, 20 patents and 10 books on those topics. Gabriele Pavan received the Electronics Engineering Degree (Laurea, 1993) and the Ph.D. in Environmental Engineering (2001) from the Tor Vergata University of Rome. After PhD he continued research on radarmeteorology. From 2007, he has been a researcher at the Tor Vergata University, where he currently teaches probability theory and signal processing. His focus of research is on radar systems.