Experimental Verification: Enabling Obstacle Mapping Based on Radio Tomographic Imaging

Radio tomographic imaging (RTI) based on received signal strength (RSS) measurements has emerged to be one of promising and effective technologies to reveal the obstacle in the resulting attenuation image. Suffering from the coarse elliptical weighting model and the multipath interference, the traditional RTI is unable to accurately map the obstacle, especially in outline recognition. In this paper, we demonstrate an improved RTI method for obstacle mapping. Since the detail mapping requires radio propagation more concentrated, we apply the inverse area elliptical propagation model to describe the RSS attenuation occurred in the propagation path across the obstacle. Moreover, introducing the directional information into the spatial correlation matrix, we enhance the imaging accuracy by a modified Tikhonov regularizer with a non-negative constraint. Field mapping experiments using directional antennas are performed with obstacles built of different materials. Experimental results suggest that the obstacle mapping quality of the improved method is better than that of the traditional RTI method.