Improved Operations at the APL Time and Frequency Laboratory

During the past year, the APL Time and Frequency Laboratory has improved its operations while continuing to support critical APL projects. The acquisition of new hardware and the development of new computer algorithms have increased the timing capability of the lab to a quality of service that permits the lab to be a contributor to the computation of International Atomic Time. In July, the lab took delivery of a second Sigma Tau hydrogen maser, bringing the facility's complement of masers to three. The position of the lab's GPS antenna was accurately surveyed, greatly improving common-view time transfer accuracy, and the installation of redundant phase microsteppers has made possible the steering of UTC (APL). The implementation of a time scale algorithm has combined the labs three masers and three cesiums into a stable Mean time reference, and a UTC - UTC (APL) prediction algorithm based on the Mean has improved our capability to steer to the BIPM. While improving its timing capability, the lab has continued to support development of three NASA spacecraft (Messenger, Stereo, and New Horizons) in addition to that of flight oscillator projects. See also ADM001784. Presented at the Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (36th) held in Washington, DC on 7-9 Dec 2004. Published in the Proceedings of the Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (36th), p229-236, 2004. The original document contains color images.