Ion mobility spectrometry (IMS) systems, devices, and associated methods of operation are disclosed herein. In one embodiment, an IMS system includes an ionization region configured to receive and ionize a sample into ionized molecules and a detector configured to detect ionized molecules. The IMS system also includes a drift region in between and directly coupled to both the ionization region and the detector. The drift tube includes a first ion gate proximate the ionization region and a second ion gate proximate the detector. The first and second ion gates are configured to alternately introduce a batch of ionized molecules toward the detector while the other is maintained open, thereby allowing accurate measurement of a drift time of the ionized molecules corresponding to a drift length that is a distance between the first and second ion gates.