On the Synchronization Algorithms for Distributed Satellite Cooperative Beamforming

A fundamental prerequisite for implementing distributed satellite cooperative beamforming (DSCBF) is achieving accurate time, phase, and frequency synchronization. However, existing synchronization techniques often fall short of the accuracy required for DSCBF applications. Moreover, many of these techniques rely on external references, such as GPS, to coordinate electrical states, thereby limiting their applicability in environments where external references are unavailable. Furthermore, many synchronization techniques fail to rigorously account for the impacts of platform motion, thereby constraining their applicability in distributed satellite systems (DSS). In this paper, we first analyze the impacts of timing offset, frequency offset, and phase shift on cooperative beamforming gain, thereby establishing the synchronization requirements for DSS. Subsequently, the waveform-based synchronization algorithm is proposed in this paper that enables high-precision frequency offset estimation without additional hardware or external references while effectively compensating for Doppler frequency shifts induced by relative motion. Simulation results demonstrate that the proposed algorithm significantly enhances the performance of beamforming in mobile DSS.