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 improvement

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.

This paper presents a novel millimeter wave radar sensor for UAS applications, in particular autonomous navigation in indoor GPS-denied environment. The sensor is aimed at both navigation with obstacle detection and highresolution 3D mapping with moving target detection. Poor visibility due to dust, fog, smoke or flames often causes failure of state-of-the-art sensors for UAS, which are very sensitive to environmental conditions. On the contrary, a sensor based on the Interferometric Synthetic Aperture Radar (InSAR) principle has been identified as potential candidate to satisfy stringent requirements set by indoor autonomous operations. Main features of the architectural solution based on frequency-modulated continuous wave (FMCW) scheme and millimeter-wave technology are discussed. New procedures for system design are outlined and a set of nominal values for the system are provided. Finally, a software simulator, developed in order both to demonstrate that high-resolution, high-quality observation of an assigned control volume can be achieved and to assess mapping capabilities, is presented