Decentralized Digital Clock Drift Compensation in Distributed Radar Sensor Networks Through Single-Tone Frequency Broadcasts

This paper presents a decentralized broadcast technique for estimating the clock drift of platforms cooperating in a distributed radar sensor network for the purpose of achieving frequency, phase, and time synchronization. The proposed method is advantageous for existing digital radar systems as it can be implemented entirely in software without the use of additional RF hardware required by other frequency synchronization techniques. The signal model for signals transmitted and received in various clock domains is presented to highlight the impact of clock drift on signal transfers and an estimation model is subsequently derived for estimating and correcting the clock drifts on each platform. A modified version of a previously developed phase and clock bias correction procedure is outlined for correcting time and phase after the frequency synchronization is completed. The technique is validated in simulation and results are demonstrated showing the clock drift estimation accuracy as a function of signal-to-noise ratio (SNR), carrier frequency, and network size, as well as a comparison in bias estimation to the drift-free case assumed by other techniques.