Multi-Antenna GNSS-Over-Fiber Architecture for Extensive Remote Multi-Baseline Network

GNSS carrier-phase-based double-difference positioning has been widely used in various precision positioning systems. This paper proposes a cost-effective scheme for an extensive multi-antenna remote multi-baseline network using a single GNSS-over-fiber system. First, GNSS signals are acquired by multiple remote antennas and transmitted to the local station through long microwave photonic links. Second, the GNSS receivers are reused in time division multiplexing mode via fast multi-port optical switches, providing enhanced temporal resolution and low cost for supporting massive monitoring antennas. Finally, compared with a single baseline, the standard deviation of the three-dimensional coordinate in the multi-baseline network is significantly reduced from millimeter to sub-millimeter level (from 2.9 mm to 0.5 mm). It demonstrates that a smaller number of receivers can support more synchronous observation loops, as well as an asynchronous group of them by fast switching, in this proposed scheme. The main contributions are twofold. First, the GNSS-over-fiber architecture is exploited and extended from single to multiple baselines, extending the spatial coverage. Second, the GNSS receivers are reused via optical switches in a fast surveying campaign, providing enhanced temporal resolution cost-effectively. This work will find applications in the large-scale GNSS baseline network, such as civil engineering and natural environment measurement.