Real-time Distributed Simulation Research Articles

An Open Architecture Framework for Electronic Warfare Based Approach to HLA Federate Development

A variety of electronic warfare models are developed in the Electronic Warfare Research Center. An Open Architecture Framework for Electronic Warfare (OAFEw) has been developed for reusability of various object models participating in the electronic warfare simulation and for extensibility of the electronic warfare simulator. OAFEw is a kind of component-based software (SW) lifecycle management support framework. This OAFEw is defined by six components and ten rules. The purpose of this study is to construct a Distributed Simulation Interface Model, according to the rules of OAFEw, and create Use Case Model of OAFEw Reference Conceptual Model version 1.0. This is embodied in the OAFEw-FOM (Federate Object Model) for High-Level Architecture (HLA) based distributed simulation. Therefore, we design and implement EW real-time distributed simulation that can work with a model in C++ and MATLAB API (Application Programming Interface). In addition, OAFEw-FOM, electronic component model, and scenario of the electronic warfare domain were designed through simple scenarios for verification, and real-time distributed simulation between C++ and MATLAB was performed through OAFEw-Distributed Simulation Interface.

Quantifying radar measurement errors in a Live–Virtual–Constructive environment to determine system viability: a case study

We present a case study that attempts to replicate the realism of a test range using a Live, Virtual and Constructive (LVC) simulation. Because resources are limited on a real test range, the Air Force Simulation and Analysis Facility at Wright-Patterson Air Force Base, Ohio, was tasked to build a simulation that emulated, to a high degree of fidelity, test range assets – the goal was to understand the impact of jamming on an enemy’s integrated air defense system. Before testing began, the simulated effects generated by the LVC simulation have to be viable, robust and realistic in order to provide credible data during later phases of experimentation. We present our approach to evaluating the correctness of the LVC simulation that considers sources of error associated with real-world radar measurements, errors caused by model abstraction and errors introduced due to real-time distributed simulation architectures, including shared state-space inconsistencies, coordinate conversion issues and a common time reference.

Fault Tree Analysis for Safety/Security Verification in Aviation Software

The Next Generation Air Traffic Management system (NextGen) is a blueprint of the future National Airspace System. Supporting NextGen is a nation-wide Aviation Simulation Network (ASN), which allows integration of a variety of real-time simulations to facilitate development and validation of the NextGen software by simulating a wide range of operational scenarios. The ASN system is an environment, including both simulated and human-in-the-loop real-life components (pilots and air traffic controllers). Real Time Distributed Simulation (RTDS) developed at Embry Riddle Aeronautical University, a suite of applications providing low and medium fidelity en-route simulation capabilities, is one of the simulations contributing to the ASN. To support the interconnectivity with the ASN, we designed and implemented a dedicated gateway acting as an intermediary, providing logic for two-way communication and transfer messages between RTDS and ASN and storage for the exchanged data. It has been necessary to develop and analyze safety/security requirements for the gateway software based on analysis of system assets, hazards, threats and attacks related to ultimate real-life future implementation. Due to the nature of the system, the focus was placed on communication security and the related safety of the impacted aircraft in the simulation scenario. To support development of safety/security requirements, a well-established fault tree analysis technique was used. This fault tree model-based analysis, supported by a commercial tool, was a foundation to propose mitigations assuring the gateway system safety and security.

COTS and Design Pattern Based High Fidelity Flight Simulator Prototype System

Flight simulator is among the most sophisticated software systems in existence. It is highly distributed, has rigorous timing requirements, and must be amenable to frequent updates to maintain high fidelity with the ever- changing vehicle and environment it is simulating. Current flight simulation framework and software developing pattern are complicated to use and time consuming. We have accomplished a flight simulator prototype system based on a new distributed real-time simulation framework and non-flight-certified Commercial-off-the-shelf (COTS) solutions and have proved its fidelity and coordination characters as a flight training device. The distributed real- time simulation framework uses mediator design pattern as an information broker among flight simulation models of a sub-system which minimizes model interdependencies, improves the extendibility for the simulator and makes the maintenance easier. Meanwhile, the simulation models and executable code in the simulator were generated through COTS software and run on a PC cluster by which the difficulties of programming tasks are descend. The simulation modeling process and virtual prototype of the motion system are also expatiated. The validation methods and contrasting simulation results are presented finally to show the feasible design to carry out flight simulation with high quality.

DEVS Approach to Real-time RTI Design for Large-scale Distributed Simulation Systems

HLA/RTI is one of the dominant middleware for large-scale distributed simulation. However, traditional RTI design and resulting implementations have been facing several difficulties, especially in satisfying the requirements for real-time distributed simulations. Many improved or novel RTI designs have been proposed in recent years, which aim to improve the real-time capabilities of RTI systems. Such designs are in general non-formalized, and the realizations of the designs are highly time-consuming and error-prone practices. In this paper, we propose a formal real-time RTI (RT-RTI) design approach using Discrete Event System Specification (DEVS). We discuss the feasibility of using DEVS and, as an additional step, we consider the case study of two recently proposed RT-RTI designs through a formalized DEVS model system. Our focus is how a DEVS component-based formalized design approach can predict some of the key design factors before the design is realized, or can further validate and consolidate realized RT-RTI designs.

A Fault-Tolerant Scheduling Algorithm for Heterogeneous Distributed Real-Time Simulation Systems

Heterogeneous distributed real-time simulation system is a special kind of real-time system. This paper solves its fault-tolerant problem based on the CSP (checkpoint-based spare processor) model, which is an improvement of the traditional SP (spare processor) model with checkpoint mechanism. Firstly, two propositions are put forward based on the characters of simulation system. Secondly, the Worst Case Response Time of the simulation tasks are analyzed based on Markov chains and the schedulability analysis rules for simulation task are presented. In the end of the paper, a fault-tolerant scheduling algorithm CSP-RTFT is proposed and simulated. The results show that the algorithm can achieve better stability, higher task accept ratio than SP-RTFT which is based on SP model, whereas the resource utilization ratio is lower than those based on PB model.

HLA 기반 대공유도무기 시뮬레이션 프레임워크 설계 및 사례적용

예측 불가능한 미래 전략 환경에 부합하고, 보다 경제적이며 과학적인 수단으로 무기체계개발을 수행하기 위해 모델링 및 시뮬레이션 기술의 적용이 확대되고 있다. 본 연구는 모델링 및 시뮬레이션 표준연동구조인 HLA(High Level Architecture)및 TCP/IP를 지원하고, 실시간 분산 시뮬레이션을 지원하는 소프트웨어 프레임워크인 ADSF(Air Defense Simulation Framework)를 개발한 경험을 기술하고 있다. 개발된 ADSF는 대공유도무기 M-SAM(Medium Range Surface to Air Missile) 체계시뮬레이터에 적용하였으며, 위성항법장치(GPS : Global Positioning System) 시계를 사용하여 요구조건에 만족하는 시험결과를 산출하였다. 그 결과 ADSF는 HLA를 지원하고 실무기 체계의 통신 프로토콜인 TCP/IP를 지원하는 통신미들웨어가 만들어지고, 실시간 분산 시뮬레이션의 핵심 기술인 정밀모사를 지원하는 시뮬레이션 엔진도 갖추게 되었다. 대공유도무기 체계시뮬레이터는 다수의 구성요소로 이루어진 실시간 분산 시뮬레이션 시스템이므로 실시간 분산 시뮬레이션을 지원해 주는 시뮬레이션 엔진 개발이 요구되었다. To correspond with the unpredictable future tactical environment, Ive expanded the application of M&S(Modeling & Simulation) that is more scientific and more economic in a field of weapon system development process. This paper describes experience in development of ADSF(Air Defense Simulation Framework) that supports not only HLA(High Level Architecture) which is an international standard in M&S but also TCP/IP as well as real-time distributed simulation. ADSF has been applied to the M-SAM(Medium Range Surface to Air Missile) System Simulator, and satisfying test results through GPS(Global Positioning System) timer has been acquired. As a result, an ADSF which is able to support HLA and TCP/IP as veil as precise real-time simulation has been successfully made. we were in need or a real-time simulation engine to support Air Defense System Simulators that were consisted of several subsystems.

Middleware for real-time distributed simulations

Distributed simulation applications often rely on middleware to provide services to support their execution over distributed computing environments. Such middleware spans many levels, ranging from ...

Terrain database interoperability issues in training with distributed interactive simulation

In Distributed Interactive Simulation (DIS), each participating node is responsible for maintaining its own model of the synthetic environment. Problems may arise if significant inconsistencies are allowed to exist between these separate world views, resulting in unrealistic simulation results or negative training, and a corresponding degradation of interoperability in a DIS simulation exercise. In the DIS community, this is known as the simulator terrain database (TDB) correlation problem. This is part of the larger synthetic environment correlation problem in DIS, which includes atmosphere, ocean, space, and a wide variety of dynamic effects, behaviors and models. In this article, we investigate the terrain database correlation problem and the resultant effects on interoperability in DIS systems. The fundamental elements of terrain databases designed for real-time distributed simulation are introduced. A generic data pipeline for terrain database generation systems is developed for the purpose of illustrating causes of the correlation problem and issues of terrain database fidelity. Implications of the problem are discussed, and testing methodologies are recommended for its mitigation. Several statistical methods have been developed to analyze consistency between various elements of the synthetic environment across DIS platforms. Correlation metrics have been formulated for terrain elevations and features. Comparisons and consistency of final rendered images have been addressed. Finally, a suite of software tools that has been developed for interoperability investigations and visual comparison of terrain databases is presented.

Effect of frame rate and force feedback on virtual object manipulation

Research on virtual environments VE produced significant advances in computer hardware graphics boards and i/o tools and software real-time distributed simulations. However, fundamental questions r...