Two-Way Time Transfer to Airborne Platforms Using Commercial Satellite Modems

Time-based communications (TBC) involves the use of an active data channel for time transfer. TBC was demonstrated in 2000 using commercial SATCOM modems for two-way satellite time transfer between static locations. In 2002, testing was conducted with the Air Force Research Lab (AFRL) at Wright Patterson Air Force Base to demonstrate a TBC implementation from the ground to an airborne platform using standard communications channels and equipment. Algorithms to perform Dynamic Two-Way Time Transfer (DTWTT) have been developed to correct raw time transfer data for platform motion and measurement effects. Flight tests were conducted in November 2002 to demonstrate the algorithms and determine the level of performance that can be expected from dynamic two-way time transfer. This paper begins with a review of time-based communications followed by the introduction of dynamic two-way time transfer. The flight experiment is presented with a description of the data collection hardware as well as a detailed presentation of the flight data. Conclusions on the use of DTWTT are drawn based on the results of the flight tests.
See also ADM001507. Presented at the Annual Precise Time and Time Interval (PTTI) Planning Meeting (34th) held in Reston, VA on 3-5 December 2002. Published in the Proceedings of the Annual Precise Time and Time Interval (PTTI) Planning Meeting (34th), p353-366, 2002. The original document contains color images.