Courtney Kraft, Andrew Hansen, Stephen Mackey, USDOT Volpe Center; Karen Van Dyke, USDOT/OST-R

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Abstract:

Resilient Positioning, Navigation, and Timing (PNT) is not only important to support critical infrastructure in the transportation sector but is also essential for national and economic security. The primary and most recognizable PNT service supporting critical infrastructure is Global Positioning System (GPS). However, because GPS relies on signals broadcast from satellites in Medium Earth Orbit (MEO), signal strength at the receiver is low and thus vulnerable to intentional and unintentional disruptions. This builds on the U.S. Department of Transportation Volpe National Transportation Systems Center (Volpe Center) Complementary PNT Technology Demonstration presented in prior work. Specifically, we focus on the Measures of Effectiveness, the rubrics developed to capture information from the demonstration, and the framework for organizing that information to support policy and decision making. The content driving the information framework is extracted from the 11 PNT vendor technologies, five that were demonstrated at the Volpe Center Aviation Weather Research Facility (AWRF) on Joint Base Cape Cod (JBCC) and six that were demonstrated at the NASA Langley Research Center (LaRC). The demonstration involved the design and implementation of nine positioning and timing scenarios (five timing and four positioning) representing critical infrastructure use cases. These scenarios included indoor and outdoor static and dynamic conditions and exemplified PNT functions in the absence of GNSS service under various operating conditions. We provide an overview of the scenarios, reference system, and analysis with detail on the information framework used to analyze the performance results. The Government’s reference PNT system was based on GPS Real-Time Kinematic (RTK) positioning and an atomic frequency standard to establish “system” time. Those results were evaluated under fourteen Measures of Effectiveness (MoEs), structured as rubrics. “Rubric” used in the context of this paper means a scoring guide that sets defined levels for use in assessment and scoring. The results of the MoE assessment were then collated into an information framework to convey the information in a convenient format that also provides stakeholder weighted scoring functions for needs and/or requirements application. This work provides instructive evaluations using the framework drawing on stakeholder input from the maritime and rail transportation modes. Further, we develop guidelines for extending the framework in a hierarchical fashion and incorporating information from more recent technology developments or other demonstrations. Such analysis supports development of requirements to be met by current capabilities or, as necessary, future commercial innovation.