Research On Synthetic Natural Environment Modeling And Simulation

Synthetic Natural Environment (SNE) Modeling and Simulation (M&S) is not only the necessary requirement of modern defense and military M&S, but also the key of acquiring and improving interoperability, reusability and creditability of M&S, which becomes one of the common infrastructural and critical technologies in M&S. With the SNE M&S as its topic, the interoperability, reusability and creditability as its leitmotiv and the data, model and simulation as its main thread, this dissertation studies the interoperability, consistency, dynamicity, distribution, creditability and reusability in SNE M&S with emphasis.First of all, the dissertation establishes the Conceptual Reference Model (CRM) and the Technical Reference Framework (TRF) of SNE from the aspects of epistemology and methodology respectively, which provide high level view and technical reference reliance for SNE M&S principles and methods. The impacts of the consistency of data and model on the interoperability are also analyzed through the formalized description of the SNE CRM, leading to the proposition that the key of improving interoperability is to maintain the consistency of data, model and simulation simultaneously.Environment Data Model (EDM) is the definition and description of the concrete contents of SNE data as well as the logical relationships and the constraint conditions, while the Common Data Model Framework (CDMF) is the important foundation and primary approach for standard EDM definitions and rigorous EDM analysis. The dissertation designs and implements the CDMF with standard logical data model and common data semantic basis using JAVA, and also through interoperability analysis between different EDMs concludes that improving the interoperability between EDMs is a prerequeste to the problem of interoperability in SNE M&S. To meet the requirements of Computer Generated Forces (CGF) for high performance terrain data base, the mslCTDB format is designed and implemented using C/C++ which proves to have effective storage performace and fast computing speed through test results and is sufficient and appropriate for high performance CGF simulations.The consistency of SNE data is the key of the interoperability in M&S. The method for analyzing, evaluating and repairing the syntactic and the semantic consistency of SNE data automatically are proposed and deduced based on formal deduction and predicative assertion expressions to guarantee rigorous syntactic correctness and semantic consistency of SNE data. The time complexity of syntactic consistency analyse proves to be O(n) while the semantic consistency analyse can check and evaluate most typical semantic errors.The standard formal specification of model is beneficial to the interoperability and the reusability in M&S. The dissertation proposes a stantdard and universal formal specificationfor system models. The computability of the atomic and the coupled model is proved and some representative SNE models are introduced utilizing such specification. As for multi-resolution data and model, the dissertation presents the multi-resolution terrain based on spatial partitions and wavelets and through analysis concludes that there is no intrinsic relation between resolution and consistency or creditability. At the same time, a multi-resolution terrain feature model is brought forward based on feature classification, abstract representation and hierarchical aggregation. Also, a multi-resolution Gaussian puff smoke model is presented as well as a consistency measurement is proposed.Dynamicity is one of the most essential and prominent characteristics of SNE while the key techonlogies of dynamic natural environment simulation based on environment fedeartion include the distribution strategy and data communication protocol, state consistency and temporal correctness, dynamicity and time advancement, data distribution technique and etc. The dissertation designs brand new dynamic natural enrionment protocols, analyzes conservative and optimistic time advance strategies and proposes four different kinds of data distribution manners. The run of simulation proves that the environment federation designed and implemented based on dynamic natural envrionment protocol, optimistic time advance and HLA/DDM fulfils the functional requirements of dynamic natural environment simulation and guarantees the temporal state consistency and logical correctness as well as high run time performance simultaneously.