Millimeter Wave Indoor SAR Sensing Assisted With Chipless Tags-Based Self-Localization System: Experimental Evaluation

This article addresses indoor environment mapping by employing the synthetic aperture radar (SAR) technique at millimeter wave (mmWave) frequencies. The mmWave-based SAR can provide a high-resolution map, for example, of an emergency scenario like a burning room. The high-resolution map drives a new era of SAR applications such as object detection, classification, characterization, and precise localization. A major requirement at high frequencies is the precise knowledge of SAR trajectory, where radar sensors are mounted on a mobile platform such as a drone or unmanned aerial vehicle (UAV). State-of-the-art localization methods such as global positioning system (GPS)-aided inertial measurement units (IMUs) are not valid due to limited coverage and accuracy. One of the primary solutions could be the SAR assisted with an indoor localization system, which is exploited in the work. The presented indoor localization system comprises two types of passive chipless frequency-coded tags, based on dielectric resonators (DRs) and frequency-selective surfaces. In this work, first, the proposed method of integrating SAR and localization systems is evaluated in a single-tag environment. Further, a version of a room equipped with a multitag system is considered for real-time applications, and a successful demonstration of indoor environment mapping for the frequency spectrum of 75-110 GHz is presented.