Military Embedded Systems

Requirements tracing tools can manage legacy systems, too


July 14, 2010

Pete Decher

Mentor Graphics Corporation

The new requirements-driven process, more control of component-level legacy issues, and helping hand off system-level projects are advantages to using requirements tracing tools in managing legacy military systems

When it comes to managing legacy systems, one option, of course, is to stay with the status quo. But the status quo typically amounts to many man hours spent manually slogging through the system’s legacy artifacts and hoping nothing important gets overlooked. A more effective approach is to connect these legacy artifacts to an automated requirements tracing tool, however, which can help show how legacy devices and systems are interconnected. There are four reasons why this second option of utilizing automated requirements tracing tools might make sense.

The new normal: Requirements-driven process

First, using requirements tracing tools is consistent with a subtle but clear shift in the military and aerospace industry’s approach. Military contractors today are unlikely to obtain customer or regulatory sign-off on a project if the contractor has merely practiced a minimal, after-the-fact approach to compliance. The new goal is embracing standard requirements-driven processes that encourage more efficiency, reuse, and integration at all project stages.

One example of this shift is the DO-254 standard, formally implemented as policy by the FAA in 2005. DO-254 covers complex electronic hardware for avionics systems, mandating requirements capture and tracking throughout the design and verification process for devices such as FPGAs, PLDs, and ASICs.

The bottom line is that in the years ahead, military and aerospace customers will likely demand increasingly transparent and requirements-driven approaches to all technical projects. For now the focus is on new devices and systems, but it seems inevitable that soon enough, the same will be required of legacy technology. A requirements tracing tool can prepare the industry now for what is to come.

More control of component-level legacy issues

Second, requirements tracing tools can deliver results today, particularly when it comes to managing issues with legacy components. Consider the case of a company that builds electronic components for passenger aircraft. When a 15-year-old component containing a circuit board with a simple PLD controlling the deployment of the evacuation slide needed to be updated, the company had to scramble because the original PLD was no longer available. Its efforts to procure and configure a new PLD would have been easier and less risky if it could have had clear visibility of the relationships of all the legacy documentation, especially the test cases mapping to the specific device requirements. A properly configured requirements tracing tool would have made such visibility possible.

Help in handing off system-level projects

Third, such tools can manage legacy issues at the system level, as well. Consider another example, this one concerning an engineering team working on virtual prototypes for key performance aspects of a new missile system. The team has generated vast numbers of SysML or UML files, and then uses these files to build software-based simulation models to help understand if the missile will fly well in an expected set of conditions (air pressure, thrust, and so on).

These simulation models, virtual prototypes that can be shared with customers, can become legacy artifacts of their own. This is especially true for large, long-lived platform projects that typically involve developing multiple product variants over the life of the platform. Again, a requirements tracing tool is key in alleviating any future difficulties.

Data adds transparency: A relief to risk-averse cultures

At one firm, a technical manager on the maintenance side of a bifurcated engineering division mentioned that his group should not even accept projects from the new product development team unless all the relevant documentation, test files, and code are loaded in a requirements tracing tool.

How hard this technical manager pushes for requirements tracing tool adoption depends on the culture of his employer. In general, change is slow in the military and aerospace sectors, which are relatively top down and risk averse. So … the fourth and possibly most important benefit to utilizing requirements tracing tools is this: Properly connected to project data, such requirements tracing tools, including Mentor Graphics’ ReqTracer, for example, can be used as real-time project dashboards. These tools enable all project stakeholders to better understand dependencies among system artifacts – and the risks involved in making needed changes and upgrades.

Ultimately, manual processes mean more risk

In short, yes, it is always challenging to propose adopting a new tool. But the bigger potential time and resource sink is the effort and associated risk of trying to manually trace documentation and design artifacts written by long-retired colleagues.

Pete Decher is the program manager for requirements tools in the Design Creation and Synthesis Division at Mentor Graphics. He has more than 30 years of experience in EDA and electronic system design and test. Pete holds a B.S. in Electrical Engineering from Georgia Tech and an M.S.E.E. from Stanford University. He can be contacted at [email protected].


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