Time-Tagging Issues Relating to Networked Data Acquisition Systems

Abstract

The CENTS Program is a Central Test and Evaluation Investment Program (CTEIP) effort conducted by the 46th Test Wing at Eglin Air Force Base, Florida. The project uses advanced internetworking technology to collect data unobtrusively from multiple sensors located throughout the aircraft without the time and expense of installing new wires. The sensors are used to unobtrusively extract data from several Line Replaceable Units (LRU’s). The harvested data is then transported to a master network controller using the existing aircraft power lines. A critical aspect of networked data acquisition is time-tagging the data so that the data timeline can be reconstructed to a specified resolution at the conclusion of the tests. This paper will discuss the time-tagging issues that arise when developing a networked data acquisition system, especially how they relate to the current effort to develop a power line based data acquisition network. In addition this paper will detail the scheme currently being tested to time tag data in the Common Event Network Test-Instrumentation System (CENTS) developed by the 46 TW/TSI Flight Test Division, Air Armament Center, Eglin AFB, FL.