Positioning and Synchronization of UAVs Swarm for Distributed Coherent Signal Reception

Unmanned aerial vehicle (UAV) equipped with a software defined radio (SDR) device could serve as a flexible and inexpensive receiver element, while the whole swarm forms a reconfigurable antenna array. However, it is a challenging task to perform coherent processing on signals collected by the distributed UAVs swarm due to the high mobility of the array structure as well as the inherent time, frequency and phase uncertainties between each individual SDR receivers. Here, a concise and cost-effective method for positioning and synchronization of UAVs swarm is proposed. This method is based on post processing of received white noise signals from asynchronous ground beacons. With this approach, the only payload onboard is an SDR device while there is no need for GNSS modules or distribution of local oscillator (LO) signals. The architecture of the receiving mode of the UAVs swarm is mathematically modeled. The received baseband signals are generated with swarm size of 6 and instantaneous bandwidth of 24MHz during simulation. Positioning, synchronization and coherent signal processing are performed. Furthermore, angle of arrival (AoA) estimation and target localization are investigated with the proposed distributed coherent signal reception scheme.