Mr. Todd Stock is a Principal Engineer and Research Project Pilot with the MITRE Corporation’s Center for Advanced Aviation Systems Development. Mr. Stock’s career in aviation operations, aviation-focused research and development, and systems engineering spans nearly 49 years, with both extensive operations experience (as a military aviator and civil Part 91/135 pilot) and a engineering focus which includes ADS-B development, alternative PNT technologies, UAS/AAM introduction and identification of both the risks and opportunities associated with new entrants to NAS. During his 26 years with MITRE, Mr. Stock has conducted a wide range of aviation operations, aircraft, avionics, and safety research, with a recent focus (5+ years) on GPS resiliency for airports and spaceports.