A baseline is a complete description of the
configuration of a system at a particular point in its
development. Baselines are therefore form the basis for configuration management.
While the baseline description will vary in each
stage of the system lifecycle, all baselines serve the same
principal purpose in guiding the design and development process. Baselines
in systems design are like way points in navigation. In
navigation we do not take a bearing to our final
destination and simply head off in that direction because, for
the same angular error in our bearing, the error in
our arrival point increases with distance away from our start
point. Consequently, we take a short bearing to a known
feature, travel to that feature, convince ourselves that we are
at the correct point and then take another short bearing
to another way point, and so on. In systems engineering,
therefore, baselines serve as way points that guide our design
so that, at any point in our design, we are
not looking all the way back to the start point
(most probably the user need statement), but are rather only
looking back to the last confirmed baseline.
Baselines also
allow us to recover more easily from any errors we
make along the way, because we can simply return to
the last confirmed baseline and trace our design
from there, rather than trace all the way back to
the start point. Baselines are also very useful in systems
engineering when we change design teams. At a lower level,
the current design team needs only to refer back to
the last baseline.
In systems engineering, there are normally
considered to be three major baselines in a system lifecycle:
the Functional Baseline at the end of Conceptual
Design, the Allocated Baseline at the end of
Preliminary Design, and the Product Baseline at the
end of Detailed Design & Development. These three baselines are
the way points in our configuration management system.
Other topics in our resources on Systems Engineering related to Baseline include: