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Comment by 6t6t6t6 | Hacker News Reader

Completely agree.

GPS is so essential, that is becoming more and more a "single point of failure" for our civilization.

Without having any data, I have the intuition that the cost of deploying our own GPS system may be worth just as an "insurance".

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To all who are writing that the EU Galileo system is "insurance" against the US's regional denial capability, it appears you haven't thought through how they would do that.

It would not be by turning off or fuzzing the US GPS signal. It would be by deploying vessels with jammers.

Galileo was originally designed to be on an independent frequency, and the US has pushed to have it so close to the US GPS frequency that jamming will effectively kill both.

Not great insurance.

http://www.navipedia.net/index.php/GNSS_signal

> Galileo was originally designed to be on an independent frequency, and the US has pushed to have it so close to the US GPS frequency that jamming will effectively kill both.

This (as I wrote in another comment) is the exact opposite of what actually happened [1].

Edit: Added a reference.

[1] https://en.wikipedia.org/wiki/Global_Positioning_System#Rest...

Ok, you are correct.

Galileo was originally designed to use the same frequencies as GPS.

Now they use different enough frequencies that Galileo can be jammed without jamming GPS. Of course, jamming both is also possible.

I wonder if we've gotten to the point were attempting to turn it off would harm us (United States) directly as much as anyone else, even if we only do it in certain sections of the world.

Turing off GPS would not have to be binary. There is a seperate, encrypted, GPS frequency that the US government can continue using even in places that they shut down GPS for everyone else. Additionally, they can degrade the accuracy of civilian GPS (also in a targeted area if they wanted).

During the Iraq war everyone kept trying to find these magic encrypted GPS devices that used military only frequencies. I never saw one, or heard of anyone using one.

Even SEALs are issued the same Garmin Foretrex 401 you can get at Best Buy.

The GPS clearly only works at certain speeds and heights, there's another level...

If this doesn't exist then those missiles don't work...

A GPS receiver is not supposed to work at an altitude greater than 60000 feet or while travelling at over 1000 knots, but the system itself does not in any way enforce this restriction [1].

[1] https://en.wikipedia.org/wiki/Global_Positioning_System#Rest...

A friend in Houston was telling me in the early 2000s about working on a NASA JSC project to use an off the shelf GPS receiver on the space shuttle. It took a few iterations on the firmware to handle 18,000 mph, etc., but he said the vendor eventually converged on firmware that worked in orbit.

To be clear, it's not that a receiver couldn't work, but that it shouldn't.

A civilian receiver is meant to deactivate under certain conditions lest it be suitable for use in things that go very fast and fly very high, e.g. missiles.

So as you say, you may be able to change the firmware to disable these restrictions, just don't try and take them out of the US...

Or buy a receiver from outside the US that's ITAR-free.

I believe that they're considered classified material and are also big, clunky and expensive, which is why the military just ends up using standard civilian GPS equipment a lot of the time.

Government fab and production tech can't compete with the stuff on the open market. From GPS to crypto hardware, civilian stuff is almost always smaller and more usable. I suspect most hardware using the encrypted GPS channels is in munitions.

you're describing 'Selective Availability'.

...and that was removed quite a few years ago now.

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