\section{Conclusions}\vspace{1ex}%\noindent
The  reported research provides a comprehensive view on the
possible structure of an intelligent integrated CAD/NAST
environment that is essential for navigation aids concurrent
engineering. The structure discussed in this paper is the key
towards the development of an intelligent system which integrates
CAD technology and numerical analysis and computer simulation
tools and methods that are typical of modern navigation systems
design and performance evaluation.

The  computational framework adopted in this research promises of
being very efficient. However, it should be noted that the
efficiency of recommendations to build such a system considerably
depends on the fact to what extent the in-built knowledge-bases
and expert systems are identical to the real-world design
problem-solving scenarios and to what extent the ``truth''
mathematical models of the data sources are adequate to describe
the real-world inertial navigation system and the aiding external
measuring devices. This is the place where the main challenge is
seen.

Embodiment  of the described system needs a serious effort to be
mounted by   many engineering and mathematical experts, as well as
experienced programmers. We strongly believe that such efforts
will be rewarding as ``knowledge-based computational systems
(intelligent CAD) will revolutionize the entire task of automated
design procedure'' \cite{roy:1994}.


\section*{ACKNOWLEDGMENTS}\vspace{1ex}%\noindent
We  sincerely acknowledge the useful cooperation with Dr.~Vladimir
Polosenko, a known specialist from aeronautical equipment
engineering industry, whose experience and knowledge and genuine
interest to our project ASPID \cite {semoushin:2002} inspire
confidence into us that the above environment will reach its
successful completion.

We also  acknowledge the fruitful discussions we recently had 
with the group of aeronautical equipment designers headed by
Mr. Victor Kozhevnikov. These discussions show once again that 
the systems similar to the above considered are in demand and 
of great business benefit.\medskip
