It's strategically foolish for the major economies like the EU, Russia & China to depend on the US's goodwill in maintaining a system that drives a huge part of their economy, GPS is used pervasively for everything, and that's only increasing.
Trump wants NATO countries to pay their fair share, how long until he gets the idea that all countries around the world should pay a GPS licensing fee least GPS regional denial be turned on?
Those are the sort of reasons for why it makes sense to develop a GPS alternative, even if you're only aiming for feature parity, or even less than that.
1. https://www.faa.gov/about/office_org/headquarters_offices/at...
Exactly. For this same reason, India recently deployed its own satellite navigation system NAVIC[1][2].
[1] https://en.wikipedia.org/wiki/Indian_Regional_Navigation_Sat...
http://timesofindia.indiatimes.com/home/science/How-Kargil-s...
Yet US sides with dictatorship which doesn't even control its own secret service which creates its own terrorist organizations (laskar-e-taeba).
Also, India did invade and annex Goa in '62.
... because Goa is an historically Indian territory, and Republic of India just got it back from foreign invaders!?
India "attacked" East Pakistan in the Bangladesh Liberation War [1]. Whether or not you or I feel it was justified is besides the point: it violated the sovereignty of another nation (similar to the U.S. in Iraq and Russia in Crimea).
[1] https://en.wikipedia.org/w/index.php?title=Bangladesh_Libera...
"India joined the war on 3 December 1971, after Pakistan launched preemptive air strikes on North India."
which doesn't sound out of the blue to me.
There is an enhanced footprint signal boost capability for the military but that's the opposite of what you describe.
The military has airborne and surface-based electronic warfare platforms that can be used to jam GPS. That's what is referenced on that page.
The FAA is not considered an authority for GPS, with the exception of certifying that WAAS is in-service for aircraft when it is meeting FAA specifications. For civilian information purposes the appropriate agency is the US Coast Guard NAVCEN.
The Air Force Space Command is the holds primary developmental, specification, and operational responsibility.
But I've searched around and can't find anything that indicates that this is a feature of the satellites themselves, rather it's just as you say, the US military has replaced SA with the general ability to jam local radio traffic, including GPS. E.g. [1] is another source for that.
So it does look like the US can't block GPS for entire countries anymore, I take that back.
I must say though, I think any public commentary about GPS capabilities should be taken with a huge grain of salt. It's a military system, they're very likely lying or not telling the full truth about what it's really capable of. E.g. I find the claim that the new generation can't do SA by design dubious, surely just fuzzing the signal by some offset is a rather trivial change.
1. https://web.archive.org/web/20050921115614/http://ngs.woc.no...
[1] http://www.dote.osd.mil/pub/reports/fy2011/pdf/af/2011gps.pd...
Each of those satellites in view would have to be implementing this scheme you suggest in order for it to be effective.
Since the satellites only have a single transmitter for each signal their entire receiving area would be affected by whatever modifications are made to implement SA. This means that to turn SA on for a single area more than half the globe would be getting a degraded signal from 1 or more satellites, which ones being undetectable.
I'm afraid SA is an all-or-nothing idea. Area denial (jamming) by surface and airborne transmitters is a much more workable approach. One could imagine jamming from space, but not using the GPS satellite vehicles.
So, to GPS. In the original GPS SA it is certainly true that many satellites would have to be using degraded mode to guarantee degradation for a specific point. However, the newer satellites have an additional directional antenna. While primarily for transmitting M-code to a specific region, it could equally be used for transmitting a self-jamming signal.
[1] https://en.wikipedia.org/wiki/Galileo_(satellite_navigation)...
Now now, do not insert political commentary into this discussions. I got yelled at for doing that. [1]
EDIT: to wit, the institution is the most powerful military force, active across the globe https://en.wikipedia.org/wiki/List_of_wars_involving_the_Uni...
It seems perfectly fair and reasonable reason to mention the power the president has in the situation given some of the president elect's statements.
Don't rely on GPS because it is controlled by a single country and that country can shut it down whenever it likes.
No country is your friend forever, you only have to look at the Trump administration. It takes 1 election and everything can swing in the wrong direction.
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".
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.
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...
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.
Even SEALs are issued the same Garmin Foretrex 401 you can get at Best Buy.
If this doesn't exist then those missiles don't work...
[1] https://en.wikipedia.org/wiki/Global_Positioning_System#Rest...
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...
...and that was removed quite a few years ago now.
https://en.wikipedia.org/wiki/BeiDou_Navigation_Satellite_Sy...
Not even remotely. GNSS is far too important to be left up to one or two militaristic providers whose interests (to put it mildly) may not always coincide with your own.
If anything we need more systems up there.
GPS has had sub-millimeter survey grade accuracy for quite some time. However, these require post-processing which takes maybe a day, read that as not realtime.
WAAS+GPS currently gives 2-3 meters.
Could you provide some links to read? I just can't imagine how it's possible.
(full disclosure: I work for Leica Geosystems.)
With real-time kinematic service, our GPS receivers give you 8mm horizontally and 15mm vertically. And you will get 3mm hz and 4mm vertical with post processing.
Very high (few centimeter) resolution can be done in real-time, in fact, under some limitations. Keyword: real-time kinematic.
One important component is using a reasonably short baseline: you have a receiver at a known location somewhat nearby (in many places there are networks of stations run by the relevant governments), and you compute difference between your solution and the station's solution. Most of the errors are common between the two and so they cancel.
Another important component is carrier phase tracking: The receiver processes the signal to recover the carrier phase. This boosts the resolution from the code timing to a level determined by the carrier frequency (and signal bandpass). Unfortunately, it leaves an integer ambiguity-- you know you are 'something' + 0.233 cycles from the sat, you need to solve for the 'something'; you can do this by collecting enough data as the sats move around or by starting at a known position and moving while holding a lock.
Another component is multiple frequency operation. There is a set of GPS signals on the L2 band some 350MHz lower in frequency. If you imagine the lattice of integer solutions in 3D space for two different frequencies you can observe the the integer solutions coincide very infrequently, leaving few options to choose between. Dual frequency operation also allows for correction of ionospheric effects.
Another component is semi-codeless tracking: The L1 and L2 GPS signals have a military P-code signal which is encrypted. The P code signal runs at 10x the speed and has a much longer repeat interval, this increases the accuracy of code tracking and improves multipath resistance. The L2 signal has historically only had the P-code stream. The encryption would be a barrier except it's kind of broken: The codestream is 10MHz but the stream cipher runs at only 500KHz and the same signal is sent on L1 and L2. Because of the first property you can still range against the P-code and because of the second you can find the phase offset between L1 and L2 quite precisely. (Trade name for this kind of codeless tracking is "Z-tracking"). --- this is hopefully becoming less necessary now with new civilian (unencrypted) signals on L2 and L5. The new signals also have better anti-multipath properties.
Any survey receiver worth the name implements these techniques and many more. For realtime (non-postprocessed) output using the above, accuracy is 2cm +/- 2ppm (of the distance to your reference station) or so.
What postprocessing does is lets you use very accurate orbital and ionospheric data which is available for download some hours later, built based on observations by many known-position ground stations. (I believe the Galileo sats even have retro-reflectors for laser based ranging, though I don't know if they're used yet.) ... plus using many hours of observations as the sats move through the sky.
So like any modern technology, the state of the art result isn't given by any one technique but by many combined.
I think I overstated but still it is possible. Millimeter survey grade is commercial.
https://www.scientificamerican.com/article/gps-and-the-world...
Yes, but it's not a commercial venture. Surely there is equivalent value in having a satellite system that European governments throw billions of euros at, no?
If you're excited and interested in Galileo it's really worth reading up on how GPS works and was built. The first satellite was launched almost forty years ago and it was operational in the 1980s. It's truly one of the coolest and most amazing things made by humans.