Dual-Radio Tomographic Imaging With Shadowing-Measurement Awareness

Radio tomographic imaging (RTI) is a technology to locate the target by using an attenuation image. The attenuation image can be reconstructed from the shadowing received signal strength (RSS) measurements in a wireless network. However, due to multi-path interference and the limited measuring capability in hardware, not all the RSS measurements in a wireless network are informative shadowing measurements. Some measurements may increase or remain unchanged when the target shadows some links in the wireless network, which means that this part of RSS measurements is polluted. If the polluted RSS measurements are used to reconstruct the attenuation image, the image quality and the localization accuracy will deteriorate. To alleviate the effect of polluted RSS measurements, a dual-RTI approach with shadowing-measurement awareness is developed in this article. The proposed dual-RTI consists of two steps: 1) signal reconstruction step in dual space and 2) a backprojection step to obtain the attenuation image. The reconstruction in dual space can select the informative shadowing measurements automatically and allocate superior weights to them. Then, the backprojection step just utilizes the measurement vectors from the shadowing links to obtain the attenuation image. These two steps allow the dual-RTI to achieve better image quality and localization accuracy. Furthermore, the dual-RTI reduces the time consumption of the localization system, which facilitates the practical engineering applications. Finally, experiments from three different scenarios are conducted to validate the advantages of the dual-RTI approach.