3 ms·
> Some GPS modules are crippled to not work very high and very fast so they can't be used on ballistic missiles. You can do one or the other. Mach 1.5+ below
by jolan 16y ago
> Some GPS modules are crippled to not work very high and very fast so they can't be used on ballistic missiles.
You can do one or the other. Mach 1.5+ below 60,000 feet. Above 60,000 feet below Mach 1.5.
Not really sure how much protection that provides given that most commercial flights are below those speed and altitude thresholds.
- deleted 16y ago[deleted]
- russss 16y agoYes, the rules (http://en.wikipedia.org/wiki/CoCom http://en.wikipedia.org/wiki/CoCom) dictate that the GPS should cut out if the device exceeds a speed of 1000kts AND an altitude 60,000 feet. A lot of GPS units wrongly interpret these limits as being 1000kts OR 60,000 ft, and so aren't suitable for high-altitude ballooning. Of course, it's a silly restriction because if you've got enough money to build a ballistic missile, you've probably got enough to build your own GPS receiver (CU Spaceflight have built a software GPS receiver themselves).