FLIGHT TEST WEEK 'OPEN CONFERENCE' - hosted by Society of Flight Test Engineers (SFTE)
Running in Auditorium 3 on the Exhibits floor) on 18, 19, 20 Nov 2008
System Wide Synchronization in Network-Based Data Acquisition Systems and its Effect on Sampling Simultaneity Thursday 20th November 2008 10.00 - 10.30 Auditorium 3
Simultaneous sampling is a key requirement of flight test applications, greatly simplifying accurate analysis of test events that span multiple sensor types distributed on a test surface. While simultaneous sampling is often cited as a requirement, and supported by instrumentation vendors, true simultaneous sampling is impossible due to errors in synchronization and sampling from several sources. This becomes an issue of concern as flight test instrumentation moves to the networked data acquisition units posited for twenty-first century systems. This paper discusses the sources of error in real-world simultaneous sampling hardware. We examine the user requirements and tolerances for sampling simultaneity, and we quantify contributions of individual system elements and synchronization methods to sampling errors. With regard to networked systems, it will be shown that errors associated with network synchronization using IEEE-1588 protocol have insignificant contribution towards overall sampling simultaneity when compared with synchronization using traditional methods
