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Comment by __dxtj__ | Hacker News Reader

It would suck, but guardrails on new technologies like this aren't unheard of. It's like when consumer GPS used to stop working at very high speeds because they didn't want people to use it for missile guidance systems.

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Consumer GPS is still disabled at high speeds. I would argue the analogy doesn't carry due to harm and error rate differences.

Yep a totally different use case and set of guardrails. There’s very little (not zero) consumer utility in GPS above say 15k feet AND 400 MPH or whatever the actual limit is. That’s basically tracking model rockets that are incidentally impacted and nothing else, from what I can think of.

It's also the sort of thing that has to have been thought up by someone with nothing better to do, given how ridiculous the premise is. You would have to assume the adversary is someone with the technology to build rockets, literally rocket science, but not the technology to build their own GPS receiver, which is simple 1970s radio technology?

Worse than that, it's 20th century radio technology in the 21st century when everyone has access to FPGAs and SDR.

The number of innocent people with model rockets or similar being negatively impacted by that rule is infinitely larger than the number of adversaries because the number of adversaries being impaired by it is zero.

Errr I at least thought it would be easier to build a small, bad rocket than a precision GPS receiver. But I am not an expert.

The only precision part about a GPS receiver is to assign precise timestamps when you receive a radio transmission from a satellite. The rest of it is just doing math.

Didn't early GPS have fudge factor on the most precise bits? As such you could only get to a few meters of accuracy. Not critical for sea navigation or even to general positioning when paper maps were still used.

The term of art here is "Selective Availability" and the added error margin was up to 100 meters.

> used to

When’d that change?

He’s probably thinking of the accuracy limit to civilians it launched with.

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