洛克希德·马丁太空系统开发了虹膜卫星的GN＆C系统，其基于模型的设计

在过去的类似项目中，洛克希德·马丁工程师（Lockheed Martin Engineers）生产了广泛的算法设计文档，长达1000多页。程序员根据对这些文档的解释手动编写代码。整个过程都很慢，有时在手动编码期间引入缺陷。

With just 23 months scheduled for software design, integration, and testing, the team needed to accelerate the software delivery process significantly. To meet this goal, they sought to replace the detailed algorithm design document with a self-documenting design, reuse existing plant models for satellite hardware, replace hand coding with automatic code generation, and use a single environment for analysis and software development.

Lockheed Martin engineers accelerated the development of the IRIS GN&C flight software by using Model-Based Design.

Working in MATLAB and Simulink, the engineers developed a basic model of the control system to analyze pointing performance, or how accurately the spacecraft could be reoriented.

为了创建植物模型，团队重复了现有的simulink和stateflow金宝app^®models of satellite components developed by the Lockheed Martin Space Vehicle Integration Laboratory (SVIL). They combined models of reaction wheels, magnetic torque rods, a star tracker, sun sensors, and other components with a Simulink model of the environment.

该团队使用Simulink Report Gen金宝apperator™导出了他们的Simulink控制模型，以创建一个交互式Web视图，该视图在设计评论过程中进行了深入研究。

They verified the initial GN&C design by running closed-loop simulations with the plant model and performing model coverage analysis on the simulations using Simulink Coverage™.

他们与Mathworks Pilot Engineering Group合作，将其初始飞行软件GN＆C模型分为组件，包括姿态控制器，反应轮控制器和态度确定模块。每个组件对应于飞行代码中的软件单元。

They used Embedded Coder^®to generate C code for these components, adding a small amount of hand-generated “glue” code for a Moog Broad Reach Engineering radiation-hardened microprocessor and its executive software. Using a custom MATLAB user interface, the team exercised a variety of Simulink test cases for each GN&C flight software unit.

SVIL工程师在工厂模型中添加了一个集成层，并使用嵌入式编码器生成C代码，该代码已部署到实时计算机进行处理器进行测试。

After running real-time tests and optimizing the design in Simulink, the team generated approximately 20,000 lines of code for the production RAD750 processor. The GN&C system is in operation aboard IRIS, which is already delivering high-resolution images and spectral data.