Airbus Defence and Space Simulates Jupiter Icy Moons Explorer Mission Data Flows

计划用于果汁任务的每种仪器最多可产生四个数据流，并且数据速率随时间而变化。每个流都链接到一个SSMM目录，该目录包含将通过X或KA频带传输到地球的文件。如果在下行链路期间损坏了文件，则地面站将要求重新启动。仅在确认成功传输后才删除文件。

System variables, including the number of directories allocated to each instrument and the downlink priority of each directory, add to the complexity of the system. This complexity makes it difficult for operations architects to anticipate how various parameter configurations and interactions between subsystems could affect system performance.

空中客车防御和空间希望创建一个模型，该模型使建筑师能够运行模拟以验证其操作概念和调整参数，以根据分配的优先级满足文件潜伏期的任务要求（在车载收购和当地的全面接收之间的时间）。在果汁初步设计审查之前，该模型需要准备好。一个关键要求是模拟时间：模拟器必须能够在不到10分钟的时间内执行15天的任务，以允许建筑师运行大量代表性模拟。

Airbus Defence and Space engineers developed an event-driven model for simulating JUICE science data flows using SimEvents.

They created three discrete-event component blocks: an Equipment block that models instrument behavior, an SSMM Directories Manager block that models directory management logic, and a Downlink Band Management block that models transmission control logic.

These blocks have parameters that operations architects can adjust to explore various configurations and simulation scenarios. Parameters include the number of instruments, the number of streams for each instrument, the number of directories, directory sizes and priorities, and downlink transmission rates and error rates.

团队组建了一个参考系统模型从the individual component blocks that included 10 Equipment blocks, an SSMM Directories Manager block, and two Downlink Band Management blocks, one for Ka-band and one for X-band transmission.

实施团队使用simevents des块开发了模拟器。他们使用Matlab应用程序设计器构建了图形接口，以使操作架构师和其他用户易于配置和运行仿真并分析结果。

Operation architects used this discrete-event model to simulate representative mission scenarios and conduct what-if analyses of various system configurations.

由于他们在果汁项目上对事件驱动的模型进行积极经验，空中客车防御和太空工程师为内部项目开发了类似的模型，以验证新的操作概念。

• 模拟速度要求超出。“Our requirements stated that operations architects had to be able to simulate 15 mission days in less than 10 minutes,” says Cortier. “由于我们与Simevents的合作，我们开发的果汁模型的模拟时间少于5分钟。”
  
• 启用了开发时间30％。“我们在几周内开发了初始模型和用户界面，” Cortier说。“关于即将到来的项目，我们希望能够通过重新使用用户界面并直接从UML模型生成MATLAB代码来减少开发时间约30％。”
• 模拟关键任务方案。Cortier说：“使用我们的Simevents模型及其MATLAB界面的运营架构师告诉我们，他赞赏能够快速运行代表性模拟的特定问题的能力。”“该模型已经在多种方案上使用，并正在帮助有效载荷仪器经理更好地了解果汁数据存储和下行链路系统，并调整其负责的配置参数。”