Joint Signal Processing-Based Frequency and Time Synchronization for Uncoupled Digital Radar Networks

Uncoupled digital radar networks offer many attractive features such as flexible sensor placement, freedom in the choice of modulation schemes and large virtual apertures. However, establishing coherency without the coupling of individual sensors, e.g. by distributing the local oscillator (LO) signal, poses a challenge. This lack of coherency leads to errors including sampling frequency offsets (SFO), carrier frequency offsets (CFO) and trigger offsets (TO). Consequently, new synchronization approaches are required. The herein presented signal processingbased approach exploits the symmetry of the aforementioned coupling-induced errors. Thus, no additional synchronization signals or coupling mechanisms are required. Furthermore, since all algorithms operate on standard radar images, they are easily adaptable for any digital modulation scheme. In this work, an exemplary orthogonal frequency-division multiplexing (OFDM) radar is utilized. Measurements of multi-target scenes are conducted and analysed, validating the robustness and accuracy of the proposed network synchronization approach.