An Asymmetric Double Sided Two-Way Ranging for Crystal Offset

Abstract

By measuring the time-of-flight (TOF) of ultra-wide bandwidth (UWB) signals, the distance between two transceivers can be obtained. A two-way ranging method has been considered because one-way ranging is susceptible to the network synchronization. However offsets between the crystal oscillators in different transceivers can generate frequency errors, which will influence the estimated round trip time of the signals. Temporal errors on the order of nanoseconds will eventually reduce distance errors on the order of decimeters. This paper presents a novel asymmetric double sided two-way ranging method, which enhances the tolerance for crystal offsets compared with the conventional two-way ranging method It also reduces the detection time of the symmetric double sided two-way ranging method by half.