There is a pressing need in the military for a system that interprets data from a suite of wearable physiological sensors to infer a soldier's current clinical state on the battlefield. The Warfighter Physiological Status Monitoring (WPSM) concept is envisioned by the US Army to address this need. Life sign detection is a key component. The future WPSM system will consist of a body-worn network of biosensors with a central processing control unit containing firmware for assessing the soldier's physiological status. In the present application, the system will diagnose a Dead, Alive, or Unknown (DAU) physiological state, and this information will be made available to field medics and others over separate communication channels. This paper describes the various modules in the DAU determination algorithms and how they interact with each other, as well as a simulator system built for parametric studies of the overall system.