Device-Free Multitarget Localization With Weighted Intersection Multidimensional Feature for Passive UHF RFID

The device-free localization (DFL) can locate the target without requiring the target to carry any radio equipment, which has a broad application prospect in the field of indoor positioning. Radio frequency identification (RFID), as a key technology for IoT implementation, has been widely used in objects identification and tracking. RFID-based radio tomographic imaging (RTI) method has received extensive attention due to its low cost, excellent real-time performance and easy to deployment. However, the indoor multipath effect, which leads to unpredictable variations of the received signal strength (RSS), especially in multi-target positioning. It is still a challenging problem to recognize the locations of multiple targets effectively in the complex indoor environment. In this paper, a novel method of intersection multidimensional feature analysis is proposed to solve this problem. The target impact region is introduced to extract the effective intersections, and then the multidimensional feature information is analyzed to determine the region where the real target may exist. The location estimation of the target is obtained by assigning appropriate weights to each intersection in the region. Extensive experiments are conducted with results are demonstrating that the method achieves high localization accuracy and localization stability in different indoor scenarios, while maintaining low computational complexity.