Development of a Performance Specification for Monitoring the GPS Civil Service

Tom Nagle, Brent A. Renfro and John W. Lavrakas

Abstract:	The GPS Standard Positioning Service (SPS) Performance Standard (PS) states, “The U.S. Government does not currently monitor and assess SPS performance in real time.” It also states, “The U.S. Government intends to assess ways for improving its GPS monitoring and measurement capabilities.” The lack of continuous SPS monitoring has been a concern of the civil community for some time. The GPS JPO is moving forward to implement civil monitoring. However, there are various ways to define monitoring. To some, monitoring means verifying the signal range error does not exceed a threshold value. To others, it means verifying the GPS service is managed to commitments made in the SPS PS. To others still, it means verifying the signal waveform meets expectations. For all cases, an expectation exists that if a signal is not conforming to government commitments, action will be taken in a timely fashion to correct the problem. The Civil Applications Office of the GPS JPO has taken steps to address such ambiguities by developing a GPS Civil Service Monitoring Performance Specification with the purpose of codifying in a single document civil user’s expectations for monitoring the GPS service. The document will be approved by the Civil Positioning and Navigation Executive Committee and will be provided to the GPS JPO as a concise statement of what is expected for civil monitoring. The development of this document has been undertaken as part of an Interagency GPS Executive Board (IGEB) stewardship project. The performance specification is currently undergoing further government review. This paper outlines the motivation for developing the performance specification, describes how the specification was developed, provides examples of the contents, and summarizes the current status of the effort.
Published in:	Proceedings of the 2005 National Technical Meeting of The Institute of Navigation January 24 - 26, 2005 The Catamaran Resort Hotel San Diego, CA
Pages:	365 - 370
Cite this article:	Nagle, Tom, Renfro, Brent A., Lavrakas, John W., "Development of a Performance Specification for Monitoring the GPS Civil Service," Proceedings of the 2005 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 2005, pp. 365-370.
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