Radar tracking of the shuttle, like the final accurate ground-based navigation, had not yet begun.

对航天飞机的雷达追踪，如最后精确的陆基导航，还没有开始。

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The Launch and Test Range System includes ground-based surveillance, navigation, flight operations and analysis, command and control, communications and weather assets for space missions.

发射和测试系统包括空间飞行的地面系统任务的监视，导航，飞行操作和分析，指挥和控制，通信和气象资产。

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An optical signature simulator was proposed and developed for simulations and ground experiments of optical-based autonomous navigation sensors for deep space exploration.

提出并实现了一种应用于深空探测自主光学导航地面仿真实验的光学信号模拟器。

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Each probe can pick up GPS signals and signals from eLoran, an enhanced version of Loran, the ground-based terrestrial radio-navigation system first used by the American and British navies during the second world war.

ECONOMIST: GPS jamming