Systems, devices, and methods for locating an item within an enclosure is described. The method includes affixing a first-tier label to a fixture within the enclosure, identifying a first location of the first-tier label based on at least three distance measurements between the first-tier label and a respective plane of the three orthogonal planar surfaces, identifying a second-tier label in proximity to the first-tier label, wherein the second-tier label is associated with an item, determining a first relative position of the second-tier label with respect to the first location of the first-tier label, and determining a second location of the second-tier label based on the first relative position with respect to the first location and the first location.