Proceedings of the 45th Annual Precise Time and Time Interval Systems and Applications Meeting

Abstract

Accurate and precise frequency references and timekeeping systems are required for a wide range of applications, such as stock market trading, power generation and distribution, and telecommunications. Over the years, the Global Positioning System (GPS) has become the “go-to” solution for time transfer. This paper details the initial time transfer capabilities of Locata, a localized GPS-like technology. In order to investigate this capability, two time transfer experiments were conducted using two configurations of LocataNets. A LocataNet consists of a single master LocataLite transceiver and one or more slave LocataLites. The process by which the slaves are synchronized to the master (or other slaves) is known as TimeLoc. he first experiment, demonstrating external time transfer, consisted of a master and two slave LocataLites. Each LocataLite was located at an independent site. The master was synchronized to GPS Time (GPST) via the pulse per second (PPS) signal output by a co-located GPS receiver. The first slave was TimeLoc’d to the master with a site separation of 45km. The second slave was TimeLoc’d to the first slave with a site separation of 28km, providing a total time transfer distance of 73km. The time difference between the PPS signals output by the second slave and an independent, but co-located GPS receiver was measured. The mean and standard deviation of the time difference were both on the order of a few nanoseconds. The frequency difference, as derived from the time difference, had a standard deviation of approximately 1 part per billion (ppb). The second experiment, demonstrating internal time transfer, also consisted of a master and two slave LocataLites, albeit in a different configuration. The first slave was TimeLoc’d to the master with a site separation of 28 km and the second slave was adjacent to the master, though TimeLoc’d to the first slave 28 km away, providing a total time transfer distance of 56 km. The time difference between the PPS signals output by the master and the adjacent second slave was measured. The mean and standard deviation of the time difference were on the order of a few nanoseconds and a couple of hundred picoseconds, respectively. The frequency difference, as derived from the time difference, had a standard deviation of less than 0.1 ppb. The purpose of the external and internal synchronization experiments was to demonstrate the absolute and relative time transfer performance of Locata, respectively.Publications Article Search Browse Publications Journal Proceedings Newsletter Other Publications Download Subscriptions Buy Publication