The Prime Power Unit (PPU) is an air- and highway-transportable, trailer-mounted 1.3MW (megawatt) Generator Set, a key component of the Terminal High Altitude Air Defense (THAAD) system.
The Global Positioning System enables properly equipped users to determine precise time and velocity and worldwide latitude, longitude and altitude to within a few meters.
GPS允许持有对应设备的用户来确定精确的时间、速度、经纬度以及海拔，而误差只有几米。
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13 p.m. - Messages report more problems: The system that monitors speed, altitude and direction failed.