Date Added: May 2012
Estimating a mobile terminal's position using radio signals that are subject to Non-Line-Of-Sight (NLOS) propagation has long been recognized as a challenging problem. Conventional radiolocation techniques, namely Angle-Of-Arrival (AOA), Received Signal Strength (RSS), and Time-[Difference]-Of-Arrival (T[D]OA) are based on the assumption that signals propagate through Line-Of-Sight (LOS) paths. However, in cluttered urban environments, the transmitter's signal could only reach the receiver through reflection, diffraction, and scattering on various objects. Violation of such assumption introduces error in range measurements and leads to erroneous location estimate.