Alfredo Renga

University of Naples Federico II | UNINA · Department of Industrial Engineering

Satellite-based onboard data processing is crucial for time-sensitive applications requiring timely and efficient rapid response. Advances in edge artificial intelligence are shifting computational power from ground-based centers to on-orbit platforms, transforming the "sensing-communication-decision-feedback" cycle and reducing latency from acquis...

The field of maritime surveillance is one of great strategical importance from the point of view of both civil and military applications. The growing availability of spaceborne imagery makes it a great tool for ship detection, especially when paired with information from the automatic identification system (AIS). However, small vessels can be chall...

Distributed Synthetic Aperture Radar (DSAR) systems represent an appealing solution to lower the overall costs and improve flexibility and efficiency of future Earth Observation missions. However, this type of systems requires receivers to fly very close to each other for enabling coherent beamforming techniques. Autonomous formation flying strateg...

Along with the monostatic radar imaging configuration, as a standard approach for Synthetic Aperture Radar imaging, new generation ideas of radar imaging geometry are emerging under the name of bistatic configurations. Due to the separation of the transmitter and receiver positions in bistatic SAR systems, different configurations can be imagined f...

The underwater environment poses numerous challenges and risks, making Unmanned Underwater Vehicles (UUVs) an indispensable alternative to human operators. Numerous Remotely Operated Vehicles (ROVs) and Autonomous Underwater Vehicles (AUVs) have been developed as a valuable resource in a broad spectrum of underwater operations. However, the deploym...

The capability to synthesize an image of improved performance combining both in amplitude and in phase a stack of low performance bistatic Synthetic Aperture Radar (SAR) images is qualifying to enable future missions based on clusters of nanosatellites or CubeSats. This is called multi-platform image synthesis and it is investigated in this paper w...

The LEO-PNT multi-tier approach needs enhanced Precise Orbit Determination (P2OD) capabilities. During nominal payload operations, the GNSS works as a system generating the broadcast ephemeris and clocks corrections for the target PNT application. However, such LEO infrastructures exploit the on-board navigation also to enable autonomous operations...

Global warming affects the whole Earth's climate, particularly on polar regions, where large ice volumes are continuously melting at unprecedented rate. These phenomena are also monitored by satellite-based Climate Change Monitoring (CCM) methodologies contributing to depicting the global climate evolution. However, although remote sensing satellit...

In the framework of maritime surveillance, vessel detection techniques based on spaceborne synthetic aperture radar (SAR) images have promoted extensive applications for the effective understanding of unlawful activities at sea. This paper deals with this topic, presenting a novel approach that exploits a cascade application of a pre-screening algo...

In the framework of maritime surveillance, vessel detection techniques based on spaceborne Synthetic Aperture Radar (SAR) images have promoted extensive applications for the effective understanding of unlawful activities at sea. The paper deal with this topic presenting a novel approach exploiting a cascade application of a pre-screening, and discr...

The wakes generated by moving vessels represent relevant patterns in remotely sensed images. They are a marker of ship presence and can be processed to infer route, speed, size, and type of ships. Automatic wake detection can be exploited by law enforcement agencies and local authorities for ensuring a wide range of applications, including maritime...

In the framework of autonomous spacecraft navigation, this manuscript proposes a novel vision-based terrain relative navigation (TRN) system called FederNet. The developed system exploits a pattern of observed craters to perform an absolute position measurement. The obtained measurements are thus integrated into a navigation filter to estimate the...

Space systems exploiting modularity, formation flying, payload distribution and fractionation concepts can be used for a variety of applications, including Earth observation and on-orbit servicing. Concerning Earth observation, in a Formation Flying SAR (FF-SAR) the Synthetic Aperture Radar (SAR) payload is distributed among several smaller platfor...

Distributed Synthetic Aperture Radar (DSAR) is one of the most promising approaches to enable the utilization of small satellite platforms for gathering radar images as well as reducing the time-to-market and costs. The paper aims at estimating the main imaging properties achievable by a DSAR under realistic satellite trajectories and working condi...

Spaceborne synthetic aperture radar (SAR) represents a powerful source of data for enhancing maritime domain awareness (MDA). Wakes generated by traveling vessels hold a crucial role in MDA since they can be exploited both for ship route and velocity estimation and as a marker of ship presence. Even if deep learning (DL) has led to an impressive pe...

Scientific community agrees that Long Period Comets (LPCs) keep a record of the physical and chemical processes that occurred during the early stages of the evolution of our Sun and Solar System. MELCHIOR is a mission aiming to characterize surface, shape, structure and chemical composition of an LPC. The mission starts before 2030 with a spacecraf...

The recognition of wakes generated by dark vessels is a tremendous and interesting challenge in the field of maritime surveillance by Synthetic Aperture Radar (SAR) images. The paper aims at assessing the detection performance in different scenarios by processing Sentinel-1 SAR images along with ground truth data. Results confirm that the Radon-bas...

This paper analyzes the process of image synthesis for a Formation Flying Synthetic Aperture Radar (FF-SAR), which is a multistatic Synthetic Aperture Radar (SAR) based on a cluster of receiving-only satellites flying in a close formation, in the framework of the array theory. Indeed, the imaging properties of different close receivers, when analyz...

The present manuscript faces the problem of performing high-resolution Unmanned Aerial Vehicle (UAV) radar imaging in sounder modality, i.e., into the vertical plane defined by the along-tack and the nadir directions. Data are collected by means of a light and compact UAV radar prototype; flight trajectory information is provided by two positioning...

The paper focuses on space system design aspects related to an end-to-end demonstration mission, aiming at showing the feasibility of a Formation Flying Synthetic Aperture Radar (FF-SAR) with microsatellite class platforms (∼100 kg). Trajectory design approaches that can fulfil payload requirements are addressed to enable selected FF-SAR applicatio...

This paper deals with a feasibility study assessing the reconstruction capabilities of a small Multicopter-Unmanned Aerial Vehicle (M-UAV) based radar system, whose flight positions are determined by using the Carrier-Phase Differential GPS (CDGPS) technique. The paper describes the overall radar imaging system in terms of both hardware devices and...

Formation-flying synthetic aperture radar (FF-SAR) enables new working modes and can achieve very high performance through a series of very compact, low-weight, satellite platforms thanks to passive operations of conveniently distributed formation-flying receivers. System timing is a crucial aspect of FF-SAR. The manuscript presents a novel approac...

The synergic utilization of data from different sources, either ground-based or spaceborne, can lead to effective monitoring of maritime activities. To this end, the integration of synthetic aperture radar (SAR) images with data reported by the automatic identification system (AIS) is of high interest. Accurate matching of ships detected in SAR ima...

Monocular Visual Odometry (VO) is widely used for small aerial platforms navigation. However, environment conditions can limit the use of cameras. Radar Odometry (RO) can be envisaged when illumination conditions hinder visual navigation. Indeed, radar can help estimation of platform speed and interframe platform displacement, thus solving also the...

Monocular Visual Odometry (VO) is widely used for small aerial platforms navigation. However, environment conditions can limit the use of cameras. Radar Odometry (RO) can be envisaged when illumination conditions hinder visual navigation. Indeed, radar can help estimation of platform speed and interframe platform displacement, thus solving also the...

This paper presents a cooperative navigation technique which exploits relative vision-based sensing and carrier-phase differential GPS (CDGPS) among antennas embarked on different flying platforms, to provide accurate UAV attitude estimates in real time or in post-processing phase. It is assumed that all UAVs are under nominal GPS coverage. The log...

Radar is a valuable sensor to support mini-UAS navigation in complex environments where GPS signal may be neither available nor reliable. Based on the increasing availability of compact radar sensors for mini-UAS, this work presents the results of an experimental campaign in which radar is tested as a standalone navigation sensor through radar odom...

Over the last decades spaceborne synthetic aperture radar (SAR) has proved its capability as a remote sensing technique of great power and value. A number of precise SAR instruments (e.g., [1]–[4]) have been developed by space and defense agencies around the world and are being used today for a wide range of applications in wide-area land (e.g., [5...

Distributed Synthetic Aperture Radar (DSAR) is defined as a SAR in which the signal emitted by the transmitter and scattered from the area of interest is not collected by a single receiver but by many, conveniently distributed, formation flying, receivers. The concept of distributed aperture can enable new SAR working modes, but more important, tha...

This paper presents a segmentation algorithm for marine synthetic aperture radar (SAR) images. The proposed approach is based on the analysis of image sublooks along azimuth direction and exploits a novel indicator, called incoherent entropy, to divide the input targets into three classes, namely, ship, sea, and ambiguity. A global threshold detect...

Autonomous navigation of miniaturized Unmanned Aircraft Systems (UAS) in complex environments, when Global Positioning System is unreliable or not available, is still an open issue. This paper contributes to that topic exploring the use of radar-only odometry by existing commercial ultralight radars. The focus is set on an end-to-end Multiple-Targe...

Micro-Unmanned Aerial Vehicles (UAVs) are flexible observation platforms suitable to cover inaccessible areas on demand. Accordingly, huge attention is deserved towards development of miniaturized sensing technologies compliant with UAV payload constrains and capable of providing high-resolution images of the region under test. As a contribution to...

Formations of small satellites are becoming more and more important to many space applications, since they offer the possibility of distributing the payload functionality among the different elements of the formation, so to improve scientific return, providing at the same time a number of advantages in terms of overall system reliability, flexibili...

Ionospheric delays compensation is a mandatory step for precise absolute and relative positioning of Low Earth Orbit Satellites (LEO) by GPS measurements. The most frequently used ionosphere model for real-time GPS-based navigation in LEO is an isotropic model proposed by Lear, which uses the Vertical Total Electron Content (VTEC) above the receive...

Human-assistive wearable technologies can monitor the position of a worker in a critical worksite and improve his safety by raising warnings when he is in a dangerous zone. In railway worksites, it is observed that GNSS localization is not applicable due to the relevant localization errors, which are only partially attributable to the specific char...

Spaceborne synthetic aperture radar (SAR) can be considered an operational asset for maritime monitoring applications. Well-assessed approaches exist for ship detection, validated in several maritime surveillance systems. However, measuring vessel velocity from detected single-channel SAR images of ships is in general difficult. This letter contrib...

This paper presents a radar approach to navigation of small and micro Unmanned Aerial Vehicles (UAV) in environments challenging for common sensors. A technique based on radar odometry is briefly explained and schemes for complete integration with other sensors are proposed. The focus of the paper is set on ultralight radars and interpretation of o...

In the framework of the novel navigation scenario offered by the next generation satellite low thrust autonomous LEO-to-MEO orbit transfer, this study proposes and tests a GNSS based navigation system aimed at providing on-board precise and robust orbit determination strategy to override rising criticalities. The analysis introduces the challenging...

This paper deals with the exploitation of Doppler centroid measurements for ship velocity estimation from focused single-look complex synthetic aperture radar (SAR) images. An algorithm is presented, which can be used as a discrimination tool to reduce the false alarm rate of standard adaptive threshold detectors and to complement the ship detectio...

This paper examines the capability of a miniaturized radar sensor developed for micro Unmanned Aerial Systems (UAS) to assist the flying platform with autonomous navigation, sense-and-avoid (SAA), and imaging functions. An ultralight radar sensor based on Frequency Modulated Continuous Wave (FMCW) technology and developed by IMST GmbH is tested and...

The study proposes and tests Multipurpose Earth Orbit Navigation System (MEONS) architecture aimed at providing a proper GNSS based orbit sequential estimation strategy to override rising scenario criticalities. The activity is focused on a complete feasibility and performance assessment of the developed filtering scheme by testing it on a high fid...

Submerged palaeolandscapes can contain pristine underwater heritage. Regular monitoring of these areas is essential to assess and mitigate threats from development including construction, mining, and commercial trawling. While bathymetry alone may be insufficient to detect submerged palaeolandscape features, it can nonetheless recognize previously...

A dedicated system simulator is presented in this paper for indoor operations onboard small Unmanned Aerial Systems (UAS) by a novel millimeter wave radar sensor. The sensor relies on the principle of Synthetic Aperture Radar (SAR) applied to a Frequency Modulated Continuous Wave (FMCW) radar system. Input to the simulator are both design parameter...

Abstarct : This work provide a possible design methodology devoted to future development of a generalized on board Earth orbit navigation system. An updated multipurpose dynamic model architecture is exploited in order to accomplish trade-off and sensitivity analysis for orbit propagation force model and structural parameters identification wrt a t...

This paper discusses the performance of a novel millimeter wave radar sensor for UAS autonomous indoor operations. A sensor based on the interferometric Synthetic Aperture Radar (SAR) principle should be able to satisfy the stringent requirements set by indoor operations in terms of high-resolution three-dimensional mapping and autonomous navigatio...