Spare supply system for Globalstar, a worldwide telecommunication system

This work describes the Optimal Spare Allocator (OSA), a overdot software t ool for Globalstar, which is a worldwide satellite telecommunication system designed at QUALCOMM (San Diego, USA). The Globalstar spare supply system is hierarchical and has three levels: Central Spare Stock (CSS), Regional S pare Stocks (RSS) and On-Site Spare Stocks (OSS). OSS is destined to supply spares to a Globalstar base station (gateway). The tool allows us to solve direct and inverse problems of optimal redundancy: (1) minimize the total cost of spare units given stock reliability requirements, and (2) maximize the stock reliability for a given total cost of spare units. The optimizati on is based on the steepest descent algorithm. The OSA computer model has a user-friendly interface and a convenient reporting utility. We are also ab le to predict approximate solution trend analytically. (C) 1999 Elsevier Sc ience Ltd. All rights reserved.