weapons operator to place usable bounds on this parameter, allowing bomb drops close to troops in contact with or near civilian targets, while avoiding fratricide or civilian casualties. Afghanistan continues the trend with weapons launched from long-distance, remotely piloted vehicles (RPVs). News photos have illustrated the awesome capabilities for precision strikes that have been enabled by precise timing capabilities.

Chapter 5 provides concrete examples of how PTTI affects the warfighter and what battlefield capabilities might be enabled by improvements in PTTI.


Navy responsibility in PTTI is currently designated in DOD Instruction 5000.2, Part 7, Section C, which calls for the Navy to

  • Maintain the DOD reference standard through the USNO, and

  • Serve as the DOD precise time and time interval (frequency) manager, with responsibilities for

    • Developing an annual DOD-wide summary of precise time and time interval requirements and

    • Coordinating the development of precise time and time interval techniques among DOD components.

SECNAV Instruction 4120.20 assigns responsibilities within the Department of the Navy for implementation of the Navy’s responsibilities in PTTI. It names the Assistant Secretary of the Navy (Research, Engineering and Systems) as the Department of the Navy PTTI Coordinator and the Superintendent of the USNO as the DOD PTTI Manager. It further states that the Chief of Naval Operations shall program funds necessary to maintain the DOD reference standard and the means for dissemination to the accuracies required by the components and user agencies.

In addition to maintaining the DOD Master Clock for the DOD, USNO has an active research effort in clock development, time-scale algorithms, and time transfer through both GPS carrier phase and TWSTT. NRL maintains the Navy expertise in space clock technology, providing services and advice to Navy and DOD programs related to the space-based clocks used in GPS and other systems. NRL uses both in-house programs and commercial vendors to develop and test space clock technology. ONR sponsors basic research and development intended to enable future advances in PTTI technologies.

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