Can you explain what you mean by that? The only thing I can think of is that GPS has 2 modes : one civilian and other military use. But military use-case uses encryption so civilians can't use that mode anyway.
GPS was built primarily for the military and the signals available for civilian use were crippled to reduce accuracy. GPS receivers that provided high accuracy fell under the ITAR rules (ie you needed proper licensing to trade them)
Over time such restrictions have largely been lifted, but there are still US export controls on GPS receivers with particular features, such as those designed for use in high speed aircraft, those able to decode the still-military-only encrypted signals that piggyback GPS and provide greater positioning precision, or those designed for use in rockets/UAVs.
So, it's reasonable to assume that if you were to build your own, and do too good of a job, you would accidentally become subject to arms trade regulations, and that's probably not a place you want to unintentionally find yourself, particularly if you're publishing it as open source on the Internet :)
> those able to decode the still-military-only encrypted signals
How? I was under the impression that military-only signal was encrypted. And if someone breaks that encrpytion, blame should go to the poor handling of encryption rather than the person breaking it? Analogy : if you leave a classified document on the train and a passenger reads it, whose fault is it?
I never really thought of that. That's a pretty interesting restriction. Although any party with access to warheads that can fly 1000+ mph probably can bypass the GPS restriction, no?
I launched a high altitude balloon as part of a summer school program over a decade ago and we checked on edge cases. Off the shelf GPS are supposed to not work beyond a certain height 18,000 m and/or speed 515 m/s to be a barrier for use as a weapon. Some hardware treat that as AND; some treat that condition as OR. The term to look up is “CoCom Limits”.
cmsj|1 year ago
Over time such restrictions have largely been lifted, but there are still US export controls on GPS receivers with particular features, such as those designed for use in high speed aircraft, those able to decode the still-military-only encrypted signals that piggyback GPS and provide greater positioning precision, or those designed for use in rockets/UAVs.
So, it's reasonable to assume that if you were to build your own, and do too good of a job, you would accidentally become subject to arms trade regulations, and that's probably not a place you want to unintentionally find yourself, particularly if you're publishing it as open source on the Internet :)
AlexanderTheGr8|1 year ago
How? I was under the impression that military-only signal was encrypted. And if someone breaks that encrpytion, blame should go to the poor handling of encryption rather than the person breaking it? Analogy : if you leave a classified document on the train and a passenger reads it, whose fault is it?
nobodyknowin|1 year ago
So they won't work on warheads as part of a guidance system.
AlexanderTheGr8|1 year ago
rich90usa|1 year ago