Best Practices for Improved Robustness of Time and Frequency Sources in Fixed Locations

This paper is intended as a best practices guide used by those responsible for installing and maintaining time and frequency sources (TFS) in fixed infrastructure locations for time and frequency (T&F) operations. Systems that must maintain time and frequency within strict accuracy limits often use Global Positioning System (GPS) receivers as sources of time and time interval. Although GPS has many attributes, there may be times where the radio frequency environment causes degraded or lost GPS signal reception. There are ways to install and operate GPS receivers, along with other timing sources, that enhance the assurance of T&F operations. This paper provides an initial discussion of these best practices. Some best practices associated with other sources of time and frequency are also listed.