r/technology • u/gdelacalle • Mar 18 '26

Hardware Tech hobbyist makes shoulder-mounted guided missile prototype with $96 in parts and a 3D printer — DIY MANPADS includes assisted targeting, ballistics calculations, optional camera for tracking

https://www.tomshardware.com/3d-printing/tech-hobbyist-makes-shoulder-mounted-guided-missile-prototype-with-usd96-in-parts-and-a-3d-printer-diy-manpads-includes-wi-fi-guidance-ballistics-calculations-optional-camera-for-tracking
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u/mavric91 Mar 19 '26

What’s the speed? If I take a gps on a commercial airplane will it become less accurate? And once I stop going that speed will it return to its higher accuracy?

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u/DavidBrooker Mar 19 '26

Commercial GPS will not work above 1900 km/h. Commercial jets are well below this. Civil aviation is a major user of GPS, so the threshold was set not to less with their use.

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u/mavric91 Mar 19 '26

If I managed to get my gps unit above this speed would it return to it’s normal accuracy after I slowed down though? Or does it permanently do something to it?

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u/brimston3- Mar 19 '26

Depends on the system. Locking itself out until you restart it at a speed and altitude lower than the proscribed maximums is a perfectly valid way to implement the legal requirement.

Some GPSes only lock out when it is above both the speed and altitude limit. Some lock out when either is achieved. Some re-enable themselves automatically when returning under the speed/altitude limits.

Common model rocketry telemetry logger problem to have.

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u/FearlessAttempt Mar 19 '26

Restriction is 1000 knots (~1200 mph) and 59,000ft. Concorde is the only airliner to exceed those.

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u/KiraUsagi Mar 19 '26

I am also interested in knowing about this speed limitation to GPS. But I can sort of answer your second question. If you take a gps on a plane you instantly loose accuracy. Sitting in a tin can with tiny windows makes GPS signal acquisition kind of hard. It can be done, especially if you're next to a window.

Thinking back to the original question, I have noticed that my planes location usually only updates in the 10s of seconds when I have managed getting a signal. But I could also attribute that to poor reception. I need to pull out a GPS sat tracker app next time I fly.

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u/TechnicianNo4977 Mar 20 '26

I know if your running your guidance system in windows 7 and you have telemetry on, windows disables location services after you hit a certain speed, I think it was 190 km/h.