Devices and methods for detecting the length of analytes, and/or sequencing analytes are provided in which two or more electrical signals are obtained as an analyte traverses a fluidic channel. Detection of the relative position of probes hybridized to a biopolymer and/or the length of the analyte (e.g., a biopolymer) does not rely on the absolute time between detection events of a given electrical signal to determine a distance associated with the biopolymer. Instead, multiple signals are obtained as functions of time) corresponding to a plurality of detector volumes at known locations along a fluidic channel through which the biopolymer passes, and the distances are determined from the multiple signals.