Timing Synchronization among UAVs Swarm via Quantum-Well Modulating Retroreflecting Optical Communication for Distributed Interferometric Antenna

The paper presents a timing synchronization algorithm and an associated mission concept to use a swarm of unmanned aerial vehicles (UAVs) to form a large distributed interferometric antenna in the frequency range of 0.1 to 1GHz. The algorithm is customized to passive optical communications between multiple ground laser interrogating terminals and the UAVs with quantum-well modulating retroreflecting devices. The mission concept allows a large number of UAVs to be used as distributed interferometric nodes and identified (via different local modulating frequencies) by a small number of ground terminals, eliminating the complexity of a large number of one-on-one optical links in this scenario. We will present the precision position and attitude determination methodology of the UAV by mounting several quantum-well devices on a single UAV with a series of optical aperture designs. We will present the analytic result of the receiving communication data rate using the distributed antenna. Our mission concept involves forming a low-cost, fast-implementation large communication antenna using UAVs and a few laser ground terminals. At the wavelength of 0.1 to 1GHz, it is challenging to directly use GNSS signal to provide real-time feedback and data processing of such interferometric antenna. Taking advantage of the fast advances of the quantum-well modulating retroreflecting with very low power consumption, such implementation is promising and may have wide applications, such as emergency communication in natural disasters that lack basic communication infrastructure. We present here a detailed study and time synchronization, including high-precision positioning and attitude measurements enabled by the modulating retroreflecting links