Solution for wireless time synchronization using sub-Nyquist sampling rates

This article presents an accurate low-cost solution for wireless time synchronization between different systems. The results are obtained using commercial-off-the-shelf 2.4 GHz transceiver components and a novel approach to the sampling of pseudo-random number code modulated signals that enables highly accurate estimation of signal arrival times using simple hardware. The method consists of sampling incoming signals at a sub-bit-rate frequency and subsequent data processing that estimates the shape of the pulse-form of each individual data bit. Based on this, the arrival time of the signal can be determined, with estimates achieving higher accuracy with increasing code lengths regardless of bit-rate. This means that accurate measurements can be achieved with modest hardware running at sample rates in the low megahertz range. The developed solution is thereby able to achieve sub-nanosecond resolution using a 32767-bit Gold code modulated signal with a chirp-rate of 3.2767 MHz.