Radio altimeters measure the distance of an aircraft above the ground rather than above sea level, they are used in automatic navigation and Blind-landing systems.

无线电高度表测量的是飞机离地面而不是离海平面的距离，用于自动导航及仪表着陆系统上。

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The opto chip's speed also stands to benefit businesses that transmit large amounts of data around the globe, and the military could use it to improve navigation systems for ships and aircraft.

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This hardware was used to build a simulated aircraft that ran many of the systems found on commercial aircraft and could swap data via radio with the air traffic and navigation systems used in the real world.

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But America's fears are economic as well as military: it suspects that the EU might try, for instance, requiring aircraft entering its air space to use Galileo-based navigation systems, to the detriment of American firms with products based on GPS. And European countries, China and the like might develop weapons that are compatible with Galileo rather than GPS, which would mean American defence firms losing a competitive advantage.

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