Compact millimeter wave FMCW InSAR for UAS indoor navigation

Abstract

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

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

“…It is worth noting that this block has been developed to read and process not only simulated but also real raw data, thus achieving focused SAR images and data for real scenery. Finally, white rounded boxes are the outputs of simulator, that is, raw data matrix, focused data matrix, and information about ambiguities in the scene [16].…”

“…Millimeter wave FMCW SAR has been selected in this work. This is because FMCW radars show interesting features for indoor operations [1,[16][17][18][19][20]. Continuous signal means less transmitted peak power because the duty cycle is one.…”

“…In addition, Journal of Sensors 3 millimeter wave components typically show reduced dimensions with respect to other microwave elements. Finally, the signal experiences little attenuation through atmosphere and could pass through common obscurants like smoke and flames [16] in close-range operations. Therefore, this choice represents an ideal solution for fulfilling mission requirements set by dirty, dull, and dangerous indoor autonomous operations.…”

“…The second output is represented by information on ambiguous areas that could be observed during flight trajectories. The gradient method [26] is used to individuate ambiguous areas, that is, all the areas of the control volume which cannot be observed with the desired resolution at certain time and platform location or during a complex trajectory [1,16]. This output is necessary because, as noted above, envisaged missions, differently from most of conventional remote sensing applications, require the system to observe scene along directions that could be not perpendicular to the motion of platform, that is, regions in which image resolution can be degraded notably.…”

Network Optimisation and Performance Analysis of a Multistatic Acoustic Navigation Sensor

“…Motion capture systems [ 3 ], GNSS repeaters [ 4 ], and pseudolites [ 5 ] provide accurate positioning indoors, albeit at a higher cost. Various other indoor navigation techniques have been proposed in the literature, including millimetre wave radar [ 6 ], using magnetic field data to improve accuracy of inertial measurement units (IMUs) [ 7 ], a combination of laser, camera and IMU [ 8 ], and radio frequency identification (RFID) [ 9 ]. One of the pioneer works conducted in passive acoustic beacons is the “Cricket” indoor location system.…”