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by nabla9 2016 days ago
Or GPS receivers not working at high altitude unless you buy some Asian brands with right chipsets.
1 comments

Note that the rules require GPS receivers not to work when above 60,000ft AND at a speed higher than 1000kt. Some manufacturers made that an OR, but that's not required.

You're very very unlikely to ever make it above 60,000ft at a speed faster than 1000kt unless you own a fighter jet.

If you build nanosatellites or cubesats or do rocketry those limits are exeeded. For example NovAtel OEM-719 GPS has no COCOM limits.

Fortunately COCOM limits for GPS are not enforced. It's empty clause.

Rockets that go above 60,000ft and at 1000kt are the case that this limit was designed for, they didn't want enemy ballistic missiles guided by GPS.

Of course that regulation is now useless because foreign receivers don't implement the limit and competing GNSS systems also don't have it. But at the time it was written this was a sensible restriction because it was a unique technology.

High powered model rocketry can and does exceed this.
Since it's so unlikely, I guess most manufacturers haven't even tested it.