Distance estimation using bidirectional communications without synchronous clocking

A fundamental problem when locating sensors in a network is to estimate the distance between pairs of sensors. This paper considers a variety of time-of-arrival and phase-shift approaches that use bidirectional signaling to bypass the need for accurate synchronous clocking. The measurement techniques are simulated and analyzed to assess the accuracy of the distance estimation. The analysis demonstrates tradeoffs between the accuracy of the oscillators, the accuracy of the subsequent distance estimation, and the complexity of the methods.