搜了下还挺有意思的：
In GPS technology, the term "CoCom Limits" also refers to a limit placed on GPS receivers that limits functionality when the device calculates that it is moving faster than 1,000 knots (1,900 km/h; 1,200 mph) and/or at an altitude higher than 18,000 m (59,000 ft).[4] This was intended to prevent the use of GPS in intercontinental ballistic missile-like applications.

Some manufacturers apply this limit only when both speed and altitude limits are reached, while other manufacturers disable tracking when either limit is reached. In the latter case, this causes some devices to refuse to operate in very-high-altitude balloons.

【 在 bigold2 的大作中提到: 】
: 或者说gnss系统对高度和速度有什么限制？
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