Wireless Synchronization for Distributed Coherent Phased Arrays
Daniel T. Goff, Robert B. Alwood, Alex Moody, Michael Picciolo, ENSCO, Inc.
Location: Shoreline (Floor 1)
Date/Time: Tuesday, Jul. 10, 5:05 p.m.
Round-trip time-of-flight radio frequency (RF) transactions combined with two-way time transfer (TWTT) measurements using band-limited communications enable relative measurements of time, frequency, distance, and distance rate, which can be used to actively synchronize frequency and phase across a network of untethered radio platforms. These measurements and synchronized reference signals can be used to virtually connect distributed RF systems or sensors, and provide the phase and frequency synchronization necessary for these systems to operate as a coherent phased array.
Virtual synchronization of array elements through real-time RF measurements enables the dynamic creation of sparse phased arrays and supports wide separation between array elements, arbitrary placement of elements, and mobile operation. Unconstrained by physical connection of array elements, this virtual phased array synchronization creates new possibilities for coherent operation of warfighting systems. Applications include cohering communications transmitters on the battlefield to provide critical power gain and emissions directionality, distributing the apertures of coherent sensor systems on autonomous vehicle swarms, protection from direction of angle estimation, among many others.
In this work, precise frequency and phase synchronization is demonstrated across a network of handheld Timing, Communications, and Ranging Devices (TCR-Ds), which are used to virtually cohere two software defined radios (SDRs), creating a sparse phased array with a long baseline between the two SDR array elements. The TCR-D provides measurements of relative time, distance, distance rate, frequency, and phase between the array elements. These measurements are used to provide active frequency and phase synchronization with precise and programmable phase alignment between the SDR apertures, enabling the ability to form narrow and steerable array beams with a virtual synchronization link.