Line-of-sight signal identification for passive multi-target localization in multipath environments

ABSTRACT

Target localization is essential in a wide range of applications, including navigation, augmented reality, and industrial automation. Compared with active targets, which transmit distinctive signals that can be directly received by sensors, passive targets are RF-silent and rely on illumination from external transmitters. Consequently, passive localization is considerably more challenging, particularly in complex multipath environments. When illuminated by the same source, all passive targets reflect the same waveform. As a result, a non-line-of-sight (NLOS) echo from one target may be mistaken for a line-of-sight (LOS) echo from another, making passive localization generally more difficult than its active counterpart. In this seminar, we focus on delay-based localization and begin by examining the geometric characterization of LOS and NLOS propagation paths. We then present an efficient clustering algorithm for LOS identification in multipath environments containing multiple passive targets, assuming that the total number of targets is known. Finally, we discuss the extension of this approach into a hierarchical framework that operates under more challenging conditions, including partially obstructed environments, without requiring prior knowledge of the number of targets.

BIOGRAPHY

Yifan Liang received the B.S. degree in optoelectronic information science and engineering from the Harbin Institute of Technology, Harbin, China, in 2019, and the M.S. degree in electrical engineering in 2021 from the Stevens Institute of Technology, Hoboken, NJ, USA, where he is currently working toward the Ph.D. degree in electrical engineering. His research interests include source localization, signal processing, and integrated sensing and communication.