The Allied Modelling and Simulation Publication AMSP-03 NATO REFERENCE ARCHITECTURE FOR DISTRIBUTED SYNTHETIC TRAINING provides a common architectural approach for designing, developing and implementing Distributed Synthetic Training (DST) environments. Architecture principles and building blocks are the core of this Reference Architecture (RA). AMSP-03 uses AMSP-01 NATO M&S STANDARDS PROFILE (STANREC 4815) as the source of NATO mandated and recommended M&S standards.