The Synchronized Player Models (SPM) project supports the U.S. Army Inter-Vehicle Embedded Simulation Technology (INVEST) Science & Technology Objective (STO) Program [1]. The overall goal of the SPM project is to reduce the network bandwidth required to maintain synchronization between a Live vehicle, a Modular Semi-Automated Forces (ModSAF) player model simulation and its associated clone models in separate simulation environments. The SPM project conducted a series of experiments in order to determine the feasibility of the SPM objective. The first experiment, reported in this paper, focused on the ability to have computer-generated forces operate identically in separate simulation environments without requiring network communication. To obtain this level of synchronization it is necessary to have a repeatable ModSAF that provides simulation events (e.g., vehicle location events, firing events, damage events) that occur at the same simulation time in each run of the same scenario.

This paper discusses the use of repeatability to support synchronized embedded simulation and focuses on the modifications required to produce a deterministic, repeatable ModSAF. Experiments were conducted to test and demonstrate the repeatable ModSAF and are illustrated in this paper. These ModSAF modifications, that were developed in support of SPM, were the basis for developing the repeatability mode currently supported in the ModSAF version 4.0 baseline.