A disclosed example apparatus receives a tag transmission signal from a tag at a receiver, wherein the tag transmission signal comprises a series of pulses; determines a coarse estimate of a time-of-arrival (TOA) of the tag transmission signal based on a detection of a pulse of the series of pulses in an adjustable coarse timing window, wherein the coarse estimate is based on a plurality of coarse timing windows; determines a fine estimate of the TOA based on a detection of the pulse in at least one of a parallel set of fine timing windows; and determines a sub-window resolution of the TOA based on at least one detection transition between consecutive fine receiver windows of at least one of a plurality of pulses and a weighted average of the TOA for each pulse of the series of pulses.