All-Digital Carrier Frequency Synchronization for Distributed Radar Sensor Networks

Distributed radar applications have received significant attention in recent years owing to their potential to substantially improve radar performance compared to existing monostatic radar systems. However, in order for these distributed systems to work reliably, individual radar nodes in the network must be accurately synchronized in time, phase, and frequency. Synchronization procedures have been recently proposed which enable the compensation of time, phase, and frequency errors entirely in software with no external references or hardware. While previous efforts have demonstrated the time and phase synchronization in hardware, the software-defined frequency synchronization technique has only been demonstrated in theory and simulation. Thus, this paper provides a first-time hardware demonstration of the software-defined frequency synchronization technique using digital radar transceivers. The resulting compensation is demonstrated to achieve better than 10 ppb error on average and is shown to enable coherent summation of signals transmitted by different radar platforms.