Physics & Engineering Physics Colloquium

Guest speaker John Murray, FCRH ’16 and affiliate of the Harris Corporation, will present “The Global Positioning System: History, Technology, and Applications.” In addition, Luigi Greco, Ph.D., FCRH ’87 and an affiliate of the same company, will present “Overview of the Multipaction Phenomenon.”

Murray’s presentation will focus on GPS technology. Behind your favorite maps app is one of the most ambitious—and most successful—feats of engineering ever undertaken by humanity. Designed in the 1970s, GPS provides precise positioning and timing information to users all over the globe. The service has become taken for granted as a near utility in an ever-connected world, but the average user is often unaware of the underlying technology and physical phenomena behind global navigation satellite systems. A brief history of GPS will precede an overview of the system at large and the remarkably simple principles that make it possible.

Greco’s presentation will focus on multipaction. Multipaction is an electron resonance phenomenon encountered in many high-power radio frequency systems that operate in a vacuum environment. Sustained multipaction events in these systems can lead to degraded performance, significant physical damage to hardware, and in some cases mission failure. Topics covered include a description of multipaction, historical background, simulation/analysis/test methods, and mitigation guidelines.