Experimental Imaging Results of a UAV-mounted Downward-Looking mm-wave Radar
Optical and thermal sensors mounted on Unmanned Aerial Vehicles (UAVs) have been successfully use... more Optical and thermal sensors mounted on Unmanned Aerial Vehicles (UAVs) have been successfully used to image difficult-to-access regions. Nevertheless, none of these sensors provide range information about the scene; and, therefore, their fusion with high-resolution mm-wave radars has the potential to improve the performance of the imaging system. This paper presents our preliminary experimental results of a downward-looking UAV system equipped with a passive optical video camera and an active Multiple-Input-Multiple-Output (MIMO) mm-wave radar sensor. The 3D imaging of the mm-wave radar is enabled by collecting data through the line of motion, thus producing a synthetic aperture, and by using a co-linear MIMO array perpendicular to the motion trajectory. Our preliminary results shows that the fused optical and mm-wave image provides shape and range information, that ultimately results in an enhanced imaging capability of the UAV system.
IEEE Transactions on Microwave Theory and Techniques, 2021
Conventional security screening systems cannot operate in real time and often suffer from false a... more Conventional security screening systems cannot operate in real time and often suffer from false alarms due to the profile-only imaging without further analysis on the object material properties. Reflectarrays were recently proposed as devices capable of performing real-time security screening using a single-frequency radar signal. This article presents first a physical optics (PO)-based simulation method to facilitate the design of a multireflectarray system. Then, an object material characterization method using geometrical optics (GO) is derived for such a system. The characterization process not only retrieves the complex relative permittivity of the object but also improves its profile reconstruction in terms of a more accurate thickness. Both simulations and experiments are carried out to verify the effectiveness and efficiency of the proposed methods. Primary results show great potentials for security screening, especially in scenarios where the inspection of human bodies for ...
This letter presents the first experimental results of our three-dimensional (3D) millimeter-wave... more This letter presents the first experimental results of our three-dimensional (3D) millimeter-wave (mm-wave) Compressive-Reflector-Antenna (CRA) imaging system. In this prototype, the CRA is 3D-printed and coated with a metallic spray to easily introduce pseudo-random scatterers on the surface of a traditional reflector antenna (TRA). The CRA performs a pseudo-random coding of the incident wavefront, thus adding spatial diversity in the imaging region and enabling the effective use of compressive sensing (CS) and imaging techniques. The CRA is fed with a multiple-input-multiple-output (MIMO) radar, which consists of four transmitting and four receiving ports. Consequently, the mechanical scanning parts and phase shifters, which are necessary in conventional physical or synthetic aperture arrays, are not needed in this system. Experimental results show the effectiveness of the prototype to perform a successful 3D reconstruction of a T-shaped metallic target.
This work presents and experimentally test the framework used by our context-aware, distributed t... more This work presents and experimentally test the framework used by our context-aware, distributed team of small Unmanned Aerial Systems (SUAS) capable of operating in real-time, in an autonomous fashion, and under constrained communications. Our framework relies on three layered approach: (1) Operational layer, where fast temporal and narrow spatial decisions are made; (2) Tactical Layer, where temporal and spatial decisions are made for a team of agents; and (3) Strategical Layer, where slow temporal and wide spatial decisions are made for the team of agents. These three layers are coordinated by an ad-hoc, softwaredefined communications network, which ensures sparse, but timely delivery of messages amongst groups and teams of agents at each layer even under constrained communications. Experimental results are presented for a team of 10 small unmanned aerial systems tasked with searching and monitoring a person in an open area. At the operational layer, our use case presents an agent...
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