At the recent ERTS² 2010 conference held in Toulouse, Thomas Quinot presented a paper entitled “Object and Source Coverage for Critical Appl ications with the Couverture Open Analysis Framework“.
It presents the Couverture approach to object and structural coverage analysis for certified safety-critical applications, in particular in the context of DO-178.
In a recent announcement, IEEE has approved work to develop a standard for a language to capture software requirements.
Unfortunately, I have not found much information about it. They mention that the information will be presented in a tree-like structure, which should fit well with the hierarchical organization of requirements in typical safety-critical development.