By putting artificial constraints on off-the-shelf GPS technology, it forced bad actors away from off-the-shelf technology and instead forced them to roll their own. This often meant an inferior product with potential compatibility issues and significant development time and costs.

The same thing is done with export controls. It seems silly today but in 2000 they were limiting where a Playstation 2 could be exported because at the time a beowulf cluster of PS2s would have been a powerful super computer for a country like Iran.

\* Missing words...

\\ The next generation of GPS doesn't have Selective Availability, presumably because today there's 3 alternatives to GPS out side of US control.

I believe the US used to make their GPS slightly inaccurate, but this was done on the satellite side.

Please note: my apologies in advance for a comment that may be perceived as pedantic, but I just wanted to further illuminate this statement.

The U.S. regulation, which technically falls under the Export Administration Regulations (Navigation and Avionics), does not exclusively regulate GPS navigation in munitions applications; rather, it serves to regulate any airborne application where the GPS receiver is capable of resolving navigation telemetry at speeds in excess of 600 m/s. This equates to approximately 1,968.5 ft/s, or 1,342.16 MPH.

Given the speed limitation parameter of the aforementioned regulation, this regulation would not only apply to GPS receivers in munitions applications, but it would also apply to GPS receivers that are utilized in fighter aircraft, space vehicles, etc.

ICBMs on the other hand, reportedly go ten times the speed of an F22.

I fail to see what is so hard to believe that an actor _could_ use civilian parts to get military capabilities. Yes, sure the are points about performance and reliability and what not but I can't shake the feeling that at least some of those points are exaggerated or marketing speak and the re is obviously a point where these components are good enough to be dangerous.

GPS is still slightly inaccurate in its publicly available form: there's a second frequency broadcasting an encrypted signal, and with both frequencies you can better account for variations in the ionosphere.

Galileo I believe will shortly be the only system with worldwide coverage and publicly available multiple-frequency broadcast.

Although selective availability has been disabled for a very long time, even before SA was turned off it was easily possible to get a precision measurement by integrating over time as the SA error was pseudo-random. It is also possible to use things like the phase information from the non-civilian 'encrypted' signals to increase accuracy even though the data cannot be decoded. Some survey-grade receivers were doing this even before SA was disabled, and it's pretty standard now in the precision GPS world.

Your understanding of GPS is quite out of date. GPS began adding a second L2C frequency for consumer use 15 years ago, and started ramping it in 2014. They are in fact in the process of adding a third civilian signal called L5. You can get accuracy from the consumer signals <10cm while in motion today with the right receivers and antennas. L5 will make it more robust indoors and give higher accuracy with cheaper antennas.

Galileo is great, but I wouldn't be holding it up as a crown jewel of GNSS. They have had some major missteps and operational issues in the recent past.

For consumer applications, multi-GNSS receivers are really where it's at. Combining GPS + GLONASS + Galileo + BaiDou is not simply an excercise of comparing the resultant positions given by each networ, but actually being able to combine the information to produce a single faster or more reliable measurement. For instance, getting a 3d position from 2 GPS satellites + 2 Galileo satellites when ordinarily you would not even be able to get a 2d position from either network in that situation.

As far as I know, GPS and Galileo have a different timebase. If you don't know the time difference, you can be way off.

Should be pretty exciting when it becomes available. To the extent one can be excited about something that takes 20 years to be delivered.

[1] https://www.gps.gov/systems/gps/modernization/civilsignals/

You also missed discussing L1C, the 4th civilian signal being introduced with GPS III. This will work primarily with L5 to enhance indoor accuracy.

Apparently (that is, according to Wikipedia https://en.wikipedia.org/wiki/Global_Positioning_System#Rest... ) some systems implement the restriction as an "or" but the regs (https://web.archive.org/web/20080916123933/http://www.armsco... item 11 category II) don't require that.

A good example is shock absorbers designed for vehicles heavier than 30 tons. It has all kinds of civilian uses in heavy machinery, but since that's a key tech for armored vehicles, they are also on the munitions list. The same applies for rocket and jet engines above certain parameters, all kinds of space imaging technology, etc, etc.

It’s a bit political than technical that in American English guided rocket weapons are always called “missiles“. Same reason as J in NASA JPL stands for _jet_ though they don’t normally do turbine jets.

So calling non-military rockets as munitions could be, I think, potentially more straightforward.

Bad example. РПГ is "ручной противотанковый гранатомёт", approximately "man-portable anti-tank grenade launcher". Its round, "ПГ-7" is "anti-tank grenade". Rocket-propelled grenade is a backronym.

After all, you don't really need to have an explosive payload: just dropping a heavy enough missile can be devastating.

Since kinetic energy increases with the square of velocity, if you can create a payload that can travel at hypersonic speeds (like a tungsten rod) without burning up then the amount of kinetic energy is in the tens of millions of joules. That's enough to destroy any single target, but doesn't have nearly the same destructive power as a nuke, which releases trillions of joules of energy.

[0] https://en.wikipedia.org/wiki/Kinetic_bombardment

By the way, checkout small kinetic projectiles bombardment https://en.wikipedia.org/wiki/Lazy_Dog_(bomb)

but that’s enough to destroy any single target! Like some bunkers.

I suppose if you made the tungsten rods heavy enough and made made them travel fast enough you could get kinetic energy on par with small nukes, but the problem is it's highly directional (i.e. most of the energy is released underground and absorbed by the earth), unlike a nuke which can release all of its energy at once in an airburst 100 feet above a city.

It would be useful as a PGM in the arsenal, but probably not enough for MAD in an arms race. I could be wrong, though.

There's still some verbiage around commercial products and embargoed countries, but realistically, North Korea and Iran have access to OpenSSL, so it hardly matters.

A CPU switches a hell of a lot faster than either of those, although with much less current.

Would adding a speed restriction in their VHDL that could be trivially bypassed by patching out one line of code satisfy ITAR requirements?

AOSP has this sort of code in it (search for ITAR_SPEED_LIMIT): https://android.googlesource.com/platform/frameworks/base/+/...

I mean there's plenty of prior art with open-source crypto implementations here.

Now, the GCJ-02 is so well reverse engineered it's practically useless, and just introduces bugs in mapping software when different coordinate systems are used.