Object oriented and formal methods for AUV development

The development of a real time embedded system such as an AUV is a highly complex process. These critical systems require a high level of maintainability and reliability. In this scope, the advantage of object-oriented analysis and design methods is that the object-based concepts is consistently applied during the whole software life cycle. This paradigm is well suited to implement subsystem frameworks which we would like to specify and to reuse them for the development of similar subsystems. UML (Unified Modeling Language) has got much attention when it comes to modeling of requirements. It provides an excellent framework for requirement capture and analysis. Unfortunately, the current UML semantics doesn´t give enough support for the development of distributed real-time systems which require the possibility to express unambiguous interfaces and to simulate designs before implementation. So we investigate a UML/SDL combination approach to take advantage of the best features of object modeling techniques and a formal language SDL (Specification and Description Language) for a more rigorous description of the dynamic behavior of subsystems. As an application of this approach, this paper describes the software architecture of the navigation system which merges many sensors data to provide the position, the speed and the attitude of the vehicle