Developing Requirements from Models – Why and How

One of the benefits of having an integrated solution for requirements management and model-based systems engineering is you can easily develop requirements from models. This is becoming an increasingly used practice in the systems engineering community. Often times as requirements managers we are given the task of updating or developing an entirely new product or system. A a great place to start in this situation is to create two models a current model and a future (proposed) model. This way you can predict where the problems are in the current systems and develop requirements from there. Innoslate has an easy way to automatically generate requirements documents from models. Below we’ll take a well known example from the aerospace industry, The FireSAT model,  to show you how you can do this.

The diagram below shows the top level of the wildfire detection and alerting system. Fires are detected and then alerts are sent. Each of these steps are then decomposed in more detail. The decomposition can be continued until most aspects of the problem and mechanisms for detection and alerting have been identified. If timing and resources are added, this model can predict where the problems are in the current system. This model can show you that most fires are detected too late to be put out before consuming large areas of forests and surrounding populated areas.

One system proposed to solve this is a dedicated satellite constellation (FireSAT ) that would detect wildfires early and alert crews for putting them out. The same system could also aid in monitoring on-going wildfires and aid in the fire suppression and property damage analysis. Such a system could even provide this service worldwide. The proposed system for the design reference mission is shown below.

The “Perform Normal Ops” is the only one decomposed, as that was the primary area of interest for this mission, which would be a short-term demonstration of the capability. Let’s decompose this step further.

Now we have a decomposition of the fire model, warning system, and response.. The fire model and response were included to provide information about the effectiveness of such a capability. The other step provides the functionality required to perform the primary element of alerting. This element is essentially the communications subsystem of the satellite system (which includes requirements for ground systems as well as space systems).

Innoslate allows you to quickly obtain a requirements document for that subsystem. The document, in the Requirements View looks like the picture below.

This model is just for a quick example, but you can see that it contains several functional requirements. This document, once the model is complete, can then provide the basis for the Communications Subsystem Requirements.

 

If you’d like to see another example of how to do this, watch our Generating Requirements video for the autonomous vehicle example.