Antonio Fulvio Scannapieco

Preliminary Study of a Millimeter Wave FMCW InSAR for UAS Indoor Navigation

Small autonomous unmanned aerial systems (UAS) could be used for indoor inspection in emergency missions, such as damage assessment or the search for survivors in dangerous environments, e.g., power plants, underground railways, mines and industrial warehouses. Two basic functions are required to carry out these tasks, that is autonomous GPS-denied navigation with obstacle detection and high-resolution 3D mapping with moving target detection. State-of-the-art sensors for UAS are very sensitive to environmental conditions and often fail in the case of poor visibility caused by dust, fog, smoke, flames or other factors that are met as nominal mission scenarios when operating indoors. This paper is a preliminary study concerning an innovative radar sensor based on the interferometric Synthetic Aperture Radar (SAR) principle, which has the potential to satisfy stringent requirements set by indoor autonomous operation. An architectural solution based on a frequency-modulated continuous wave (FMCW) scheme is proposed after a detailed analysis of existing compact and lightweight SAR. A preliminary system design is obtained, and the main imaging peculiarities of the novel sensor are discussed, demonstrating that high-resolution, high-quality observation of an assigned control volume can be achieved.

Ultralight radar sensor for autonomous operations by micro-UAS

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 results of acquired data for navigation, SAA, and imaging applications are discussed. Main challenges related with data collection requirements are highlighted, too. The results suggest that valuable data for each envisaged application can be obtained.

Investigation on radar-based applications for mini-UAS and MAVs

This paper investigates the capability of a miniaturized radar sensor developed for mini Unmanned Aerial Systems (UAS) and Micro Aerial Vehicles (MAVs) to provide the flying platform with radar-based navigation and sense-and-avoid (SAA) functions. A radar sensor based on Frequency Modulated Continuous Wave (FMCW) technology developed by IMST GmbH is therefore exploited both for tracking, SAA, and Synthetic Aperture Radar (SAR) oriented acquisitions. Main challenges related with data interpretation are analyzed and the results suggest that valuable data for each envisaged application can be obtained.

Performance analysis of millimeter wave FMCW InSAR for UAS indoor operations

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 navigation. A solution based on a Frequency Modulated Continuous Wave (FMCW) technology is proposed. The outlined nominal configuration serves as a basis to analyze the performance of the sensor in possible operational scenarios by means of a software simulator. Four different focusing algorithms are implemented and tested and capabilities of the novel sensor are finally discussed, demonstrating that high-resolution, high-quality observation of an assigned control volume can be achieved.

Experimental Analysis of Radar Odometry by Commercial Ultralight Radar Sensor for Miniaturized UAS

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-Target Tracking strategy compliant with desired sensor and platform, which exploits both range and bearing measurements provided by the radar. A two-dimensional odometry approach is then implemented. Main results show real-time capabilities and standard deviation of errors in Forward and Cross-range directions smaller than 1.50 m and 3.00 m, respectively. Field test data are also used to discuss the potential of this technique, challenging issues, and future improvements.

Ultralight Radar Sensor for Autonomous Operations by Mini- and Micro-UAS

In recent years the boost in operations by mini- and micro-UAS (Unmanned Aircraft Systems, also known as Remotely Piloted Aircraft Systems - RPAS - or simply drones) and the successful miniaturization of electronic components were experienced. Radar sensors demonstrated to have favorable features for these operations. However, despite their ability to provide meaningful information for navigation, sense-and-avoid, and imaging tasks, currently very few radar sensors are exploited onboard or developed for autonomous operations with mini- and micro-UAS. Exploration of indoor complex, dangerous, and not easily accessible environments represents a possible application for mini-UAS based on radar technology. In this scenario, the objective of the thesis is to develop design strategies and processing approaches for a novel ultralight radar sensor able to provide the miniaturized platform with Simultaneous Localization and Mapping (SLAM) capabilities, mainly but not exclusively indoors. Millimeter-wave Interferometric Synthetic Aperture Radar (mmw InSAR) technology has been identified as a key asset. At the same time, testing of commercial lightweight radar is carried out to assess potentialities towards autonomous navigation, sense-and-avoid, and imaging. The two main research lines can be outlined as follows: - Long-term scenario: Development of very compact and ultralight Synthetic Aperture Radar able to provide mini- or micro-UAS with very accurate 3D awareness in indoor or GPS-denied complex and harsh environments. - Short-term scenario: Assessment of true potentialities of current commercial radar sensors in a UAS-oriented scenario. Within the framework of long-term scenario, after a review of state-of-art SAR sensors, Frequency-Modulated Continuous Wave (FMCW) SAR technology has been selected as preferred candidate. Design procedure tailored to this technology and software simulator for operations have been developed in MATLAB environment. Software simulator accounts for the analysis of ambiguous areas in a three-dimensional environment, different SAR focusing algorithms, and a Ray-Tracing algorithm specifically designed for indoor operations. The simulations provided relevant information on actual feasibility of the sensor, as well as mission design characteristics. Additionally, field tests have been carried out at Fraunhofer Institute FHR with a mmw SAR. Processing approaches developed from simulations proved to be effective when dealing with field tests. A very lightweight FMCW radar sensor manifactured by IMST GmbH has been tested for short-term scenario operations. The codes for data acquisition were developed in Python language both for Windows-based and GNU/Linux-based operative systems. The radar provided information on range and angle of targets in the scene, thus being interesting for radar-aided UAS navigation. Multiple-target tracking and radar odometry algorithms have been developed and tested on actual field data. Radar-only odometry provided to be effective under specific circumstances.

Multi-purposes radar for remote sensing and navigation by mini and micro unmanned aerial vehicles

This paper investigates the capability of a miniaturized radar sensor developed for Micro Aerial Vehicles (MAVs) to cope with complex mission scenarios that involve integrating and satisfying either Synthetic Aperture Radar (SAR) or Interferometric SAR and navigation and Sense-and-Avoid (SAA) requirements. A radar sensor based on Frequency Modulated Continuous Wave (FMCW) technology developed by IMST GmbH is exploited both for SAR and SAA acquisitions. The set of tests helps with understanding main issues and problems related with integration of different requirements and demonstrate that valuable data for each envisaged application can be saved with a single acquisition, thus paving the road for further and more detailed investigations.

Indoor Operations by FMCW Millimeter Wave SAR Onboard Small UAS: A Simulation Approach

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 parameters for Synthetic Aperture Radar (SAR), which should be able to cope with the stringent requirements set by indoor operations, and information about platform navigation and observed scene. The scene generation task is described in detail. This is based on models for point target response on either a completely absorbing background or fluctuating background and ray tracing (RT) techniques. Results obtained from scene processing are finally discussed, giving further insights on expected results from high-resolution observation of an assigned control volume by this novel SAR sensor.