GPS ground antenna and monitor station upgrades: system analysisand design

摘要

This paper discusses the system analysis and design aspects of thenGlobal Positioning System Operational Control System (OCS) remote sitenmodernization study. Requirements analysis for a mission-critical legacynsystem poses a unique set of challenges such as undocumentednrequirements, a continually evolving system, variances betweenndocumented requirements and the system as implemented, an unrecordednrepository of knowledge in designers and operators of the system, and sonon. The paper discusses how these challenges were recognized andnovercome. The system architecture designed to meet these requirementsnalso had to meet the broader goals of OCS modernization including annopen system architecture, increased dependability, expandability andnflexibility. The paper describes key features as well as the designnrationale of the architecture selected to meet these requirements