Ship system 2000, a stable architecture under continuous evolution

Abstract

SaabTech Systems AB S:t Olofsgatan 9 A SE-753 21 Uppsala Sweden rest@systems.saab.se 1. ABSTRACT Ship System 2000 was conceived in the middle of the 1980s. It was started as a development project for a general Command and Control and Weapon Control Systems for naval ships (C2 and WCS), intended for reuse. Its first use was for three different ship types. Following these orders, later deliveries with similar functionality were made. From the beginning the company chose to use the Ada language for future systems in this area and selected Rational as the first programming environment. A strategic decision was made to include all the Ada components developed in a family of reusable components. The number of components has grown and variants for different platforms and compilers have been included.In the early days the word was Reuse, and later the terms Dual Life Cycle and Product Line Management have been introduced for the same concept. Since then, the 1 st generation has been successfully reused for ships from many other navies and air forces. However, the architecture has evolved in two major steps, and several minor steps. Thus, it is still a modern architecture, but with a heritage. SYSTEM DESIGNThe system is a distributed system, where typically 20 nodes are connected using a double Local Area Network (LAN), for redundancy reasons. Each node is a single or multi-CPU node. In principle there is one node for each sensor, weapon and operator. From the start, we tried to use as much commercially available equipment and software as possible. The first generation used M68K series computers, and the Ethernet LAN was based on the ISO standard (i.e. not IP). At that time, (the end of 1980s,) the coming dominance of IP was not easy to foresee. The operating system was OS9, which is mostly used for industrial automation purposes. The networking system was mostly custom made by us.

Ada for the control of degradation of service

“…Networks monitor packet loss to maintain degradations within acceptable limits. Similarly, networks connecting sensors and weapons continuously modify parameters to control component behavior [8] and maintain input and output degradations within acceptable deviations.…”

“…Typically, deviations are monitored to identify those that threaten to exceed acceptable limits. Parameters are then adjusted to control suspected degradations [8,18].…”