- Serafino, F. Scotti, L. Lembo, B. Hussain, C. Porzi, A. Malacarne, S. Maresca, D. Onori, P. Ghelfi, A. Bogoni, “Towards a New Generation of Radar Systems Based on Microwave Photonic Technologies”, IEEE Journal of Lightwave Technology, vol. 37, is. 2, Jan. 15, 2019.
Abstract: This paper reviews on the latest advances in microwave photonics applied to radar systems, tracing the evolutions of functionalities in the photonic radar toward a new generation of enhanced-performance systems. Photonics is demonstrated to enable a new generation of miniaturized, heterogeneous, and distributed radars, i.e., future radars on chip with different features, working in different radio spectral regions, and organized in spatially distributed sensors for the enhanced detection of a wider range of target properties. In these systems, the use of photonics assures benefits in terms of frequency flexibility, accuracy, and computational load reduction. Innovative capabilities supported by the photonic approach are presented, such as the use of coherent sparse bands for the synthesis of ultrawide bands, the use of distributed sensors for multiple-input multiple-output detections, and the use of an ultrawide band photonics-based receiver for radio frequency spectrum scanning. The presented novel concepts will open the way to new research activities both in photonic technology and radar systems, contributing to the development of a new generation of remote sensing systems. This expanding cross fertilization will lead to exciting and challenging research activities in the years to come.
- Serafino, S. Maresca, C. Porzi, F. Scotti, P. Ghelfi, and A. Bogoni, “Microwave Photonics: from Basic Concepts to High-Level Functionalities”, invited tutorial paper, accepted for publication by IEEE Journal of Lightwave Technology, 2020. DOI: 10.1109/JLT.2020.2989618.
- Bogoni, G. Serafino, and P. Ghelfi, “Remote Sensing Systems Based on Photonics”, 23rd Opto-Electronic and Communications Conference (OECC), Jeju-do, Korea, July 2018 (invited paper).
Abstract: In the next future, remote microwave sensing will require innovative heterogeneous, distributed and miniaturized radars, for collecting complete information on the scene under observation, thus being able to precisely detect, recognize and classify the different targets. Heterogeneous radars, with different features and working in different radio spectral regions, will increase the system detection capability and reliability, along with its robustness to the environmental conditions. Coherent data fusion among heterogeneous detections permits to exploit all the acquired information, increasing the system precision. For this reason, coherence among bands will be largely sought. As a fact, conventional RF (radio frequency) electronics have an intrinsic narrow band; therefore, multiband radars can be obtained only using several independent single-band apparatuses. This paper reviews some recent evolutions of radars based on photonics. The potentials of two noteworthy applications like the coherent MIMO radar network and the wideband RF scanning receiver are reported and discussed.
- Lembo, P. Ghelfi, A. Bogoni, “Analysis of a Coherent Distributed MIMO Photonics-Based Radar Network”, the European Radar Conference (EuRAD), Madrid, Spain, Oct. 2018.
Abstract: Multistatic radars are of great interest to achieve an enhancement in the cross range resolution, observing stealth targets and instantaneously evaluating the velocity in all directions. Current multistatic radars operate independently and heavy synchronization algorithms are required to permit the fusion of the collected data. Recently, photonics has been demonstrated to enable the development of coherent multistatic radars. Here, for the first time, these systems are studied considering the effect of the main system parameters and noise sources. Their capability to provide super-resolution in cross range is confirmed.
- Lembo, G. Serafino, F. Scotti, P. Ghelfi, A. Bogoni, “Microwave Photonics in Radar”, 31st Annual Conference of the IEEE Photonics Society (IPC), Reston, VA, USA, Oct. 2018.A
Abstract: An overview on the trend and main issues of radars and the potential of introducing photonics will be presented. The advantages in terms of frequency-agility, multi-band operation and performance on a single radar apparatus and on multiple input-multiple output radar systems will be detailed.
- Maresca, A. Bogoni, P. Ghelfi, “CFAR Detection applied to MIMO Radar in a Simulated Maritime Surveillance Scenario”, EuRAD08-4, European Microwave Week 2019, Paris (France), 29 Sept – 4 Oct. 2019.
Abstract: In this paper, a multiple-input multiple-output (MIMO) radar with separated antennas is simulated in a maritime surveillance scenario to detect extended naval targets. The simulator first extracts the main scattering elements of the targets, then it generates the signals transmitted/received by each bistatic radar node and it evaluates the MIMO cross-ambiguity function in the Cartesian search space. Moreover, a modified version of the cell-averaging constant false alarm rate (CA- CFAR) detection algorithm is applied, in which the noise level is evaluated from the bistatic range cells around the cell-under-test. Preliminary results demonstrate the improvement granted by this training method with respect to the rectangular window in terms of reduced number of false alarms. Far from being exhaustive, this paper addresses some of the signal processing issues that rise from a real maritime surveillance scenario, in which a MIMO radar with widely separated antennas and based on photonic technology will be operated.
- Lembo, A. Malacarne, P. Ghelfi, A. Bogoni, “SAR-Like Multi-Input Multi-Output Radar for Naval Applications”, EuRAD06-12, European Microwave Week 2019, Paris (France), 29 Sept – 4 Oct. 2019.
Abstract: Coherent Multi-Input Multi-Output (MIMO) radars enable angular resolution in fixed-antennas radar systems. To reduce the angular ambiguity given by the sidelobes, it is necessary to increase the spatial information using several distributed antennas. However, this increases considerably the system complexity and cost. In this paper, we present a novel processing scheme that combines the principle of Synthetic Aperture Radar (SAR) to a MIMO system with widely separated antennas. Exploiting multiple consecutive observations, the spatial information increases and the sidelobes are considerably mitigated. The approach is particularly suitable for naval scenarios, where the low speed of the platform and the long pulse repetition interval make the MIMO processing more indicated than SAR. A simulative analysis considering realistic parameters for a maritime application reveal a sidelobe suppression enhancement as high as 14 dB. Moreover, specific tests show that an error of 10% in the estimation of the platform speed does not affect the overall detection performance. The proposed approach appears very promising since the SAR-like data fusion allows lowering the sidelobes while preserving the high cross-range resolution enabled by the coherent MIMO processing.
- Ghelfi, L. Lembo, F. Scotti, G. Serafino, S. Maresca, A. Bogoni, “Distributed Coherent Radars Enabled by Fiber Networks”, 21st International Conference on Transparent Optical Networks (ICTON), Angers, (France), July 2019.
Abstract: In the last few years, we have been proposing the use of photonics to bring new functionalities in radar systems, exploiting its precision and tunability to give radars improved performance and reconfigurability. This paper will present the most recent evolution of the original idea of photonics-based radars, which considers the exploitation of the increasingly available fiber connections to implement a network of widely distributed radars. The centralized photonic approach allows driving several separated radars simultaneously, enabling the novel class of distributed coherent radar systems. Through the implementation of specific multi-input multi-output (MIMO) processing, the photonics-enabled radar network is capable to push the radar detection resolution far beyond the limits usually set by the signal bandwidth alone.
- Lembo, P. Ghelfi, A. Bogoni, “Antenna Position Optimization in a MIMO Distributed Radar Network through Genetic Algorithms”, 21st International Radar Symposium (IRS), Ulm, (Germany), June 2019.
Abstract: Sidelobes are a major drawback in MIMO radars with widely distributed antennas, and signal bandwidth and antenna geometry have a deep impact on the shape of the detection ambiguity function. In this paper, moving from the main design requirements of a naval surveillance radar, a suitable antenna geometry is found. The effectiveness of a genetic algorithm applied to a MIMO scenario simulator for the computation of the fitness function is verified. By means of the proposed approach, a MIMO antenna geometry is identified that ensures excellent resolution capability and sidelobes suppression (>13 dB) with respect to a non-optimized geometry.
- Maresca, G. Serafino, F. Scotti, F. Amato, L. Lembo, A. Bogoni, P. Ghelfi, “Photonics for Coherent MIMO Radar: an Experimental Multi-Target Surveillance Scenario”, 21st International Radar Symposium (IRS), Ulm, (Germany), June 2019.
Abstract: This paper investigates the target detection and localization capabilities of a coherent multiple input multiple output (MIMO) radar network designed and implemented using photonic technology. The benefit offered by photonics is twofold: it guarantees long-time phase stability and frequency/phase coherence between the transmitted and received radio frequency signals; secondly, it allows remoting the antennas by exploiting optical fibers. The proposed radar network demonstrator, which is composed of two transmitting and two receiving antennas in the X-band with 100 MHz signal bandwidth, operates in a real down-scaled outdoor scenario for detecting two collaborative closely-spaced moving targets. The preliminary results demonstrate the effective impact of photonics applied to coherent centralized radar networks and provide some guidelines for the development of more complex and application-tailored radar networks.
- Maresca, G. Serafino, F. Scotti, L. Lembo, P. Ghelfi, A. Bogoni, “Photonics applied to Coherent Radar Networks for Border Security”, 1st Maritime Situational Awareness Workshop, (MSAW), Lerici (Italy), Oct. 2019.
Abstract: This paper investigates the target detection and localization capabilities of a centralized radar network with widely separated antennas in the framework of maritime border security. The proposed system takes advantage from photonic technology for signal generation/detection and signal distribution between the central and the remote radar nodes. Such a solution allows to achieve the necessary level of time and phase synchronization to benefit from the coherent multiple input multiple output (MIMO) paradigm for very high cross-range resolution. The proposed photonics-based radar network is developed within the NATO-funded "Multistatic and multi-band coherent radar fleet for border security (SOLE)" project. Currently, the radar network architecture consists of two transmit/receive radar front-ends, for a total of four coherent virtual channels, employing linear frequency modulated pulses in time diversity at 9.7 GHz with 100 MHz bandwidth. The system has been operated in a preliminary down-scaled outdoor scenario for detecting two collaborative closely-spaced moving targets. With respect to the nominal aperture of the antenna, the cross-range resolution has been improved by a factor of five. The preliminary results demonstrate the impact of photonics applied to coherent centralized MIMO radars and suggest the possibility to soon endow the radar network with high-performance radar imaging capabilities.
- Bogoni, “Photonics for microwave systems”, IEEE International Topical Meeting On Microwave Photonics (MWP), Plenary Session 1, Ottawa (Canada), Sept. 2019.
Abstract: The potential of photonics in the next generation RF systems for communications and sensing is summarized in this paper. Photonics will allow for an increasing interactions between networks of sensors and communications networks, both of them more and more heterogeneous, flexible and miniaturized.
- Lembo, S. Maresca, G. Serafino, F. Scotti, A. Malacarne, P. Ghelfi, A. Bogoni, “Microwave Photonics for a Radar Network”, OSA Advanced Photonics Conference (APC), Chengdu (China), Nov. 2019.
Abstract: The benefits of photonics-based fully coherent radar networks are analyzed. The first photonics-based coherent 2×2 MIMO radar network has been implemented and tested in real environments confirming the potential of photonics in overcoming RF issues.
- Lembo, S. Maresca, G. Serafino, F. Scotti, F. Amato, P. Ghelfi, A. Bogoni, “In-Field Demonstration of a Photonic Coherent MIMO Distributed Radar Network”, IEEE Radar Conference (RadarConf), Boston, (USA), 2019.
Abstract: This paper reports an in-field experiment of a photonics-based coherent MIMO radar network. The use of photonics guarantees the coherence of the transmitted and received RF signals, and allows remoting the antennas exploiting deployed optical fibers, thus a MIMO approach can be applied on a network of widely distributed coherent radars. In the in-field experiment, a photonics-based radar core connects two transmitters and two receivers, with 100-MHz bandwidth signals in X-band, observing a collaborative target. The results demonstrate an improvement in radar precision, and envisage real applications wherever fiber is available for deploying the radar network.
- Maresca, D.R. Sanchez Jacome, L. Lembo, F. Scotti, G. Serafino, A. Malacarne, C. Rockstuhl, P. Ghelfi, A. Bogoni, “Photonics-enabled 2Tx/2Rx coherent MIMO radar system experiments with enhanced cross resolution”, in Optical Fiber Communication Conference (OFC) 2020, OSA Technical Digest (Optical Society of America, 2020), paper Th2A.41.
Abstract: Photonics enables a multi-target experiment of coherent MIMO radar. It confirms that coherence introduces almost one order of magnitude improvement in the cross-range resolution. Simulations demonstrates the coherent bi-band operation benefits on the system performance.
- Scotti, S. Maresca, L. Lembo, G. Serafino, A. Bogoni, P. Ghelfi, “Dual-Band Radar System with Multiple Distributed Sensors for Coherent MIMO”, accepted at the International Radar Symposium 2020.
Abstract: A new architecture for a widely distributed dual-band coherent multiple-input multiple-output (MIMO) radar system is illustrated, and its implementation and testing are reported. The system consists in a central unit based on a single mode-locked laser, supporting multiple remote radar nodes linked by standard optical fiber pairs. Every remote node operates both in the S- and X-band, and it can be displaced over distances of several kilometers, allowing to monitor a scene under different angles of view. All the remote nodes share the same oscillator and digital signal processing unit, both located in the central node. This architecture allows to perform centralized data fusion on the signals acquired by the remote nodes, and, by virtue of the system coherence, to take advantage of the coherent MIMO processing strategy thus to offer a superior spatial resolution, which is even magnified by the dual-band approach.
Link: n/a yet.