Wireless Precision Time Synchronization Alternatives and Performance

Ganesh Basawapatna, Joshua White, Phillip Van Hooser

Abstract:	Precision Time Synchronization techniques and approaches have assumed increasing importance in multi-body dynamic systems in Global Positioning System (GPS) and Global Navigation Satellite System (GNSS) denied and degraded environments. In multi-body military systems based upon Alternative Position, Navigation and Timing (alt-PNT) and Assured Position, Navigation and Timing (APNT) scenarios many different approaches to time synchronization between bodies have been proposed and developed. Some of these have been extensions of CERN’s White Rabbit (WR) system while others have been developed on the basis of the IEEE 1588 Precision Time Protocol and the Network Time Protocol. There have also been demonstrations of Satellite based two-way time transfer and Optical or Laser based time transfer. In alt-PNT and APNT based military operations a mission might include a combination of Dismounted Soldiers, Land based vehicles, Drones, Fixed Wing and Rotary Wing aircraft, and Naval assets, all of which have different velocity and acceleration vectors associated with them at any instant. In such situations the requirements of a system that meets mission-based time precision between the various elements presents a higher order of complexity than two or multiple element static systems, twoway directional Over the Air (OTA) systems, and other GPS dependent systems. Often the time precision can be achieved by simple time transfer while at other times or in other parts of a mission phase coherence between many clocks in the system may be required. Since future military systems will be expected to adhere to the Modular Open Systems Approach (MOSA) and Sensor Open Systems Architecture (SOSA), the time synchronization considerations become significantly more complex because of added highly non-deterministic communication and signal transit times. One of the important considerations in the type of missions envisaged, apart from MOSA / SOSA compatibility, is Size, Weight, Power Consumption and Cost (SWaP-C). We compare the different techniques for achieving the performance necessary, effects on SWaP-C reduction, and show the kind of performance that is possible in the type of missions under consideration. This paper presents Riverside Research Institute’s analysis and findings relating to the methods to achieve precision time synchronization under the above conditions. The authors present and compare the various techniques that have been developed in terms of applications compatibility, resource requirements, expected accuracy and ability to be used in future dynamic military missions. We will present the sensitivities of elements associated with the various approaches. We will also share results based upon our research to date.
Published in:	Proceedings of the 54th Annual Precise Time and Time Interval Systems and Applications Meeting January 23 - 26, 2023 Hyatt Regency Long Beach Long Beach, California
Pages:	150 - 164
Cite this article:	Basawapatna, Ganesh, White, Joshua, Van Hooser, Phillip, "Wireless Precision Time Synchronization Alternatives and Performance," Proceedings of the 54th Annual Precise Time and Time Interval Systems and Applications Meeting, Long Beach, California, January 2023, pp. 150-164. https://doi.org/10.33012/2023.18689
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