JPALS Availability Modeling and Assessment in Nominal and Jamming Environments

J.R.A. Stevens, M.E. Lage, Y.S. Nam, B.R. Peterson

Abstract:	The Joint Precision Approach and Landing System (JPALS) is the next generation aircraft landing system for the U.S. military and its allies. The system will allow appropriately equipped aircraft to undertake precision approach operations at any suitable surface worldwide, including low ceiling and/or visibility conditions. JPALS is currently in the Technology Development phase whose focus is to identify and define the functional requirements for the system and to develop candidate physical architectures. This paper presents an overview of the current JPALS requirements for guidance quality (integrity, continuity and accuracy) and availability for the different system operating environments. A discussion of the relationship between the JPALS availability requirements, and the equivalent requirements defined for LAAS, is presented and the concept of a JPALS mission service availability is introduced. To support the systems engineering process within the JPALS Technology Development phase, a software modeling tool for availability assessment has been developed based upon an extension of the concepts employed for LAAS. The paper provides an overview of this availability model and, in order to illustrate how it is currently being employed to assist in functional and architectural trade studies, some results from a preliminary sensitivity analysis are presented showing the impact on land-based JPALS performance of different system configurations and external assumptions. In contrast to a civil system, JPALS must be capable of operating in the presence of various external threats including electronic interference (jamming and spoofing) targeted either at the system itself, or at the GPS signal-in-space. A vulnerability requirement has therefore been defined which specifies the resistance of the system to external GPS signal disruption threats. The paper outlines in a generic manner how the LAAS availability model concept is being extended to support the analysis of system vulnerability in a jamming environment. Quantitative information relating to the jamming threats and the associated availability results are not appropriate for inclusion in this paper.
Published in:	Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003) September 9 - 12, 2003 Oregon Convention Center Portland, OR
Pages:	2337 - 2348
Cite this article:	Stevens, J.R.A., Lage, M.E., Nam, Y.S., Peterson, B.R., "JPALS Availability Modeling and Assessment in Nominal and Jamming Environments," Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003), Portland, OR, September 2003, pp. 2337-2348.
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