RPR FOM – Real-time Platform-level Reference Federation Object Model
While the HLA Standards dictate how federates exchange data, it is a FOM (Federation Object Model) that dictates what data is being exchanged in a particular federation. HLA does not mandate the use of any particular FOM, however, several "reference FOMs" have been developed to promote a-priori interoperability. That is, in order to communicate, a set of federates must agree on a common FOM (among other things), and reference FOMs provide ready-made FOMs that are supported by a wide variety of tools and federates. Reference FOMs can be used as-is, or can be extended to add new simulation concepts that are specific to a particular federation or simulation domain.
The RPR FOM (Real-time Platform-level Reference FOM) is a reference FOM that defines HLA classes, attributes and parameters that are appropriate for real-time, platform-level simulations. Applications that have previously used DIS (or would have considered using DIS), often use the RPR FOM (or a derivative of it) when they play in an HLA world. The RPR FOM was developed by a Simulation Interoperability Standards Organization (SISO) Product Development Group (PDG). Its goal was not to just implement the DIS PDU structures within HLA object and interaction classes, but rather to provide an intelligent translation of the concepts used in DIS to an HLA environment.
RPR FOM 1.0 became a SISO Standard in 1999, under the name SISO-STD-001.1-1999. A companion document, known as the GRIM (Guidance, Rationale, and Interoperability Mappings) provides documentation for the RPR FOM. This document is known as SISO-STD-001-1999.
RPR FOM 1.0 is based on the IEEE 1278.1-1995 version of the DIS Standard. RPR FOM 2.0, based on the IEEE 1278.1a-1998 addendum is nearing approval as a SISO Standard.