The DIS Distributed Emission Regeneration (DER) protocol family, and specifically, the Electromagnetic Emission PDU, provides ample latitude and support to perform emitter, medium, and sensor interaction modeling in a symbolic frequency and time domains. However, the Emission PDU's complexity and format bias developers toward a platform-centric as compared to medium-centric approach. When new emissions, sensors, and media effects need to be added to an existing simulation, often this platform-centric approach forces modification of very tenured code.

This paper develops a coherent API (Application Programming Interface) using an object-oriented design that supports extensibility in emission modeling. Extensibility is achieved by coercing emission data into a medium-centric format. The design supports a client-server relationship between a given medium and its client sensors. Sensors are decoupled from direct association with an emission PDU; sensor modeling concentrates only on enumeration, detection, classification, and localization within beam patterns. Media, on the other hand, are directly associated with emission PDUs and carry the responsibility for target clustering and obscuration, line of sight and earth curvature, propagation loss, and emission jamming.

Extensibility of emission modeling is supported in three ways. First, modeling is extended via the typical class hierarchy - new sensors are derived from base sensors, new media are derived from existing media. Second, the attachment of new sensors to media is straight-forward via the client-server (CS) relationship - a natural extension of the CS paradigm. Third, and again using the CS relationship, processor load partitioning is spread across computer platforms without the modification of base code - extending the life and utility of the existing code.

Finally, the API unifies within the medium the treatment of emission and dead reckoning (DR) based sensors. Regardless of the source, emission or DR, treatment of the medium effect is the same.