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"Clinton" didn't disable or even decide anything about this. Learn it's from its.

This is so easy to check, you have to be an idiot to post a comment like that.

The accuracy commitments do not apply to GPS devices, but rather to the signals transmitted in space. For example, the government commits to broadcasting the GPS signal in space with a global average user range error (URE) of 7.8 m (25.6 ft.), with 95% probability. Actual performance exceeds the specification. On May 11, 2016, the global average URE was 0.715 m (2.3 ft.), 95% of the time. GPS Accuracy

User accuracy depends on many factors in addition to range accuracy, so the result is GPS Accuracy Levels it is possible now to get very accurate positions now, with differential GPS.

The really big change is that less expensive hardware is now able to handle the more complex math, and it is getting to market. Global Positioning System: The Mathematics of GPS Receivers

No. During the 1990s, GPS employed a feature called Selective Availability that intentionally degraded civilian accuracy on a global basis.

In May 2000, at the direction of President Bill Clinton, the U.S. government ended its use of Selective Availability in order to make GPS more responsive to civil and commercial users worldwide.

The United States has no intent to ever use Selective Availability again.

The same page also describes military GPS receivers that use two frequencies vs. civilian GPS receivers using only one.

Source: http://www.gps.gov/systems/gps...

I had always heard the lower accuracy from gps was a government imposed restriction or limitations of the protocols not a technical one. is that simply an old myth?

It used to be true. It wasn't a secret, and discontinued in 2000.

FCC? I'd be more worried about the U.S. Air Force, you know, the people that maintain the GPS network.
Those people have some very serious drones, and no one wants a delivery from one of them...
And, seeing they are part of Cyber Command, they most likely have a pretty good bead on, well, everything.

I have no idea how to get the GPS map data changed.

Put up a simple, self-closing, self-opening gate. Drivers will see it and realize that CAN'T possibly be a public road, but everyone can still drive right through it without getting out of their vehicle.
e.g. https://youtu.be/-C-TJkZYEXw

That's the best solution, because you'll NEVER get ALL the navigation apps to update their maps, and even if they did, some folks will continue using an old set of offline/downloaded data indefinitely.

However, if you are willing to invest some time, you can fix MOST navigation apps, by contacting the few biggest data providers. Expect it to take a year before the changes start to slowly trickling out to navigation apps users:

* http://www.gps.gov/support/use...

Any GPS discussion is bound to have loads of stupid since not many people realize just how inaccurate GPS really is.

Look at the organization website GPS.gov. You'll see worst-case is roughly 11m accuracy... best case (FAA) is 3.5 m. Basically, I consider any test that's under 11m to be noise. Hell, even the Air Force accuracy document says GPS errors are on the order of 0.8m best case. That's right, these guys are reporting 1m +/- 0.8m.

For them to do a test in a 10m square increments of 1 m and expect anything believable is a bit absurd.

As to the link, I think I cited the wrong link...
https://en.wikipedia.org/wiki/...

As to zeta joules, I can't process that information. The issue is that we're trying to audit each other's information and you're citing something that can't be audited because the units are odd and there is nothing I can compare this against. That means I can't audit it. And I don't like evidence that can't be audited.

As to the corrections on my math, thank you. I think this back of the napkin calculation actually does a better job of finding consensus than a lot of the other things we could do.

I'd throw this out then:
200 cubic kilometers of water
x 20 years

4000 cubic kilometers of water

So this is the amount of water that they say was added.

Lets compare that against sea level rise

The surface of the world's oceans is
~ 361,740,000 square kilometers

2.6mm x 20 years = 52mm

52mm = 0.000052km

0.000052km x ~ 361,740,000 square kilometers

18810.48 cubic km of water

Did I make another error here? Because these numbers are still no where near what they're talking about. That shows nearly five times the melting of that estimate. That's not even close.

Can they account for 18810 cubic kilometers of water in ice loss? If not... then where the hell did the water come from?

If we understand what is going on, then these numbers should be close. I could accept figures that were ~20% give or take. But these are off now by about 4.7 times.

As to your citation, it appears to start either in the 90s or around 1965. To blame this on the industrial revolution and our burning of fossil fuels, you're going to have to show a graph that predates the heavy emission of fossil fuels.

If the graph when you expand beyond that shows a similar trend line before fossil fuel burning then associating the trend line with fossil fuel burning is likely specious. If instead there is a change in the trend line roughly around where we start burning a lot of fossil fuels that will support your position.

Any trend that starts in the 90s or 60s will not be useful if we're talking about AGW.

As to shepard, apparently there was a problem with the system used to measure the ice:
http://www.gps.gov/governance/...

JPL admits the issue there and suggests a better satellite.

As to church,
http://sealevel.colorado.edu/c...

That shows a much lower rate of rise... I think they're saying inches per century.

A human in the cockpit is going to assess those situations much faster than an automated system can in many of these situations.

Depends on the human and depends on the automation and depends on the circumstances. Your assertion is far to broad to be correct as a general proposition.

You want to stop trains from speeding? screw the cameras, Put GPS in the engine

Already being worked on but controlling train speed isn't quite that simple. GPS has trouble in some locations on the ground so a reliable speed limiting system would necessitate something a bit more complicated. However I agree that there really isn't any good reason not to have it be a part of the technology package on trains.

I'd like to know how this can be determined when GPS accuracy appears to be good only to about 3 meters.
http://www.gps.gov/systems/gps...

They are talking about the GPS ground stations that monitors the GPS signals (and is programed with its exact position and altitude) and determine what corrections, if any, need to be made to the GPS signals (so that what it knows to be its correct position is the same as what its GPS receiver is telling it)

Actually, there are no such receiver stations for US GPS systems anywhere within the Russian Federation. I believe the GPS stations they are talking about are differential GPS stations, which are used to increase the accuracy of GPS positioning from satellites from about a couple meters to a few centimeters. A list of DGPS stations is here. Of the stations listed as associated with Russia, most show as either planned or currently on trial, which could explain where there are discrepancies in reporting about how many there are. Its possible that the reporting talks about eleven because of the nineteen stations showing as "on trial" eleven are actually on-line and delivering commercial signals.

the news should be read with few facts in mind. first of all, it was Musk who sought the ban of russian engines ( earlier slashdot story http://science.slashdot.org/st... ), so it hurts some companies, but not US, SpaceX will benefit from this 'ban', Musk is happy. then look at gps facilities http://www.gps.gov/multimedia/... - there is no one GPS facility in Russia. So this are not about GPS, but about those businesses, which provided more correct positioning information for Russian customers. If Rogozin wants to harm russian customers, let it be, but it hardly will have any effect anywhere else. And take Japan with a project http://www.qzs.jp/en/ - currently much of what provide ground stations could be transferred to satellites. So, it is quite possible, that even won't harm russian customers, they will be offered to use more satellites. as for threats to block International Space station beyond 2020, this might bite, but still not much. Though there are reports, that currently there are a lot of customers for international space station services, still unmanned satellites could perform almost all of these services, and more cheap and that was true for almost all time when astronautics existed - piloted stations added quite few actual results except for public attention to space research. So combined: if russian go the way of sanctions the biggest harm will be for russian space program and russian customers of space services. For US any announced threats are of very minor importance. So let this Rogozin hit russian interests with his own hands.

They are talking about the GPS ground stations that monitors the GPS signals (and is programed with its exact position and altitude) and determine what corrections, if any, need to be made to the GPS signals (so that what it knows to be its correct position is the same as what its GPS receiver is telling it)
Russia wants similar ground stations set up in the US for their GLONASS system, which I think is fair (and good for users of navigation systems, if not for the US military which would like to be able to turn off Russia's navigation systems).

All car navigation systems pretty much required this when the GPS system was still hobbled by the ~100m uncertainty caused by Selective Availability. (Ended by Clinton in May 2000).

The implementation is actually quite trivial: One sensor on each front wheel gives you two revolution counters (odometers).

Distance traveled is proportional to the sum of the two counters, while the difference in counts is proportional to how much you have turned.

As long as you have GPS reception you can use that to calibrate the odometers, so that differences in tire type & pressure is automatically compensated for.

Using a barometer you can do the same for altitude, automatically compensating for changes in local air pressure.

Terje

Or any of the former satellites of the CCCP for that matter. The authoritative list is here.

On that list was a station out in the middle of the Indian Ocean that caught my eye - Diego Garcia, and how it was depopulated by the British to enable the US to set up shop for military purposes. The following cable and corresponding wikipedia article was quite an interesting read on yet another hegemonic adventure undertaken by the US govt. I wonder how long before the European Court of Human Rights will take to decide the case. Odds anyone for the outcome?

Selective Availability was disabled in 2000 and will never be used again. The current generations of GPS satellites doesn't even have SA capability.

Here's the US ground station map. http://www.gps.gov/systems/gps/control/ Nothing in Russia.

Can't the Russians just put theirs in Cuba?

Or any of the former satellites of the CCCP for that matter. The authoritative list is here.

Nature doesn't care about time? Tell that to the laws of thermodynamics. Entropy only goes one way.

Time doesn't go either way. It's merely a comparison of two states: now and now. In between the instances when you read those two 'now's, the entire Universe completely changed states many billions of times over. It's decay and growth over the course of the entire Universe and the nothingness beyond everything. You might argue that reversing all of the decay and growth in the entire Universe would be reversing time, but no, it wouldn't. The Universe already changed, and the new changes to reverse the old changes didn't prevent the original changes from happening.

If you watch a video of a ball rolling on a desk, you can't tell just by the video whether time has been reversed. The physics governing that motion don't care about time. If you watch a video of an egg being shattered, you'll know when the video is reversed. You know all the contents of the egg can't spontaneously get back together as time moves forward. That would be going to a much more well-ordered state.

You don't need to know that the video has been reversed because that is, once again, a concept of something that doesn't physically exist. What happens in reality is that the video plays frame by frame, always changing frame. A frame in reverse is still a frame that is shown. Changing the order of the frames or randomizing them doesn't change the fact that a frame was shown, and playing any other frame even from the opposite end of the list of frames will never stop that previous frame from having been shown.

Also, the GPS device you use to triangulate your position and navigate to your destination? Well, consider that relativity tells us that the satellites zooming up above us have slower ticking clocks. They're actually moving through time slower than you are, and our current GPS accuracy wouldn't be achievable if we didn't take that into account.

No. In the first place, relativity only accounts for about 30 cm (12 inches) of accuracy, which is only what a satellite would be out by if it couldn't communicate to the ground stations regularly over the course of the day as they normally do. In the second place, accuracy of GPS is in the meter range. Not nano-, not micro-, not even milli-. "Real-world data collected by the FAA show that some high-quality GPS SPS receivers currently provide better than 3 meter horizontal accuracy." It gets down to about 0.9 meters of accuracy. That's 3-10 feet of accuracy without augmentations (that is, connecting to a ground station and checking its position against other satellites to confirm the "correct" time), or 3-33 times the relativistic effect. The rest of the accuracy gains are from the aforementioned augmentations which bring it down to 5 cm. Relativity makes things "better", not "perfect", and the augmentations make relativity worthless.

The reason why clocks appear to slow down at high speeds is that the atoms in the clocks used for the experiments are simply decaying less (because they expend less energy at higher altitudes and higher speeds) than ones that didn't get to move so fast. Because the timing of a second is measured in the half-life decay, any changes to that decay rate will also throw off the clock itself. Mechanical clocks have numerous moving parts that get thrown off by the change in speed, and even electrical clocks still have to deal with changes in the oscillator speed and material resonance.

The Mossbauer effect is for gamma rays, x-rays, and "nuclear events". It doesn't preclude classical physics from use in GPS satellites at all. The frequency change from the Doppler shift is the only real difference to be calculated between relativistic and classical; hardly a game-breaking calculation.

Here's a paper from 1996 pointing out that:

The pseudorange measurement can be regarded from two points of view. On the one hand,
pseudorange is simply range, once the clock offsets are removed. As described in the previous
section, the ranges measured by a moving observer are foreshortened by the (gamma) factor. For an
SV speed of 3.87 km/sec, (gamma)-1 is 8.33x10^-11". The range is typically about 30,000 km. The error
incurred neglecting the (gamma) factor is 30,000 km multiplied by 8.33x10^-11" - that is, 2.5 millimeters.
Close enough for government work.

Lest you think that 2.5mm is a big deal, the US Government GPS site says:

Higher accuracy is available today by using GPS in combination with augmentation systems. These enable real-time positioning to within a few centimeters, and post-mission measurements at the millimeter level.

Clearly other people posting about nanometer accuracy in GPS would be flabbergasted to find out that GPS is not the shining beacon of accuracy they were led to believe.

The US also has the ability to disable GPS for certain areas and has in the past degraded the quality of data for national security reasons ( http://www.gps.gov/systems/gps/modernization/sa/ ). Though this has been changing (new satelites don't have it, though really it's just a software update), it puts pressure on other places to put up their own systems that are either compatible or at least non-interferring so that should the US ever do anything like that again, they cannot be impacted by it. It's a bit like MAD but instead of destruction, nobody can ever get degraded service (assuming enough players). This also raises the question of who should pay for it all, since with three systems now going that all work, it could let each place share only a part of the costs (eventually).

You (or somebody) keeps saying that.

Heh, well, I was not the other poster(s?)

Why can't Lightsquared build towers that operate at power levels comparable to GPS signals? GPS receivers demonstrate that it's possible for a handheld device to receive GPS reasonably well, below the noise floor or not (and nearly every smartphone does, already), so why must these hypothetical towers operate at such radically higher power levels?

Okay, I will admit that I am speaking in conjecture in this response. However, it stands to reason that all of this is about coverage. LS' original plan was to use their satellite *only* (which would have been fine), but then they decided they needed all these terrestrial base stations to make their plans viable. Apparently, LS planned for up to 15 KW base stations (approx. 72 dBm), right in your locale. GPS satellites transmit 30 Watts and are 20,200 km away.

I imagine that it would require, in technical terms, a *metric fuckton* of terrestrial stations to get any sort of decent coverage if their transmission power were dialed back enough to avoid competing with GPS (GPS signal at receivers is typically around -130 dBm).

http://www.spacedaily.com/news/gps-00d.html

I'm not sure why people keep repeating this. Its not true, the civilian GPS is the same accuracy as the military since the Clinton administration.

They keep repeating it because it is true. Military GPS uses different signals which still result in better accuracy, even with the removal of selective availability.

From the US government's GPS page (emphasis added):

Is Military GPS More Accurate Than Civilian GPS?

The accuracy of the GPS signal in space is actually the same for both the civilian GPS service (SPS) and the military GPS service (PPS). However, SPS broadcasts on only one frequency, while PPS uses two. This means military users can perform ionospheric correction, a technique that reduces radio degradation caused by the Earth's atmosphere. With less degradation, PPS provides better accuracy than the basic SPS.

The DOD has much different requirements than the civilian GPS industry. In fact, as you probably know, the DOD has an entirely different service that provides a much more accurate level of detail called the Precise Positioning Service, whereas civilians have access to the explicitly degraded Standard Positioning Service (SPS). It's hard to say explicitly what LightSquared is talking about because they made no attempt to reference it beyond naming a standard that does not make any such explicit statements that they claim. If there was such a reference, then they would have produced it and silenced the entire industry. Instead, they are pointing at a technical document and hoping to confuse people.

I am no GPS signal expert, but I did track down the referenced DOD, GPS standard here, published in 2008. It's hard to say what they are referencing with regards to the guard band, considering they conveniently did not provide any references beyond the long, technical document, but it's obvious that they wanted the obfuscation. Have a look at the document, and you'll see why they don't reference anything specifically.

In reality, the FCC screwed the pooch here, and LightSquared is backtracking looking for a way to have their cake and eat it too. There is no legitimate way that someone can look at this entire process and say that is has been clean, or even reasonable. The public was given the opportunity to comment over the week of Thanksgiving. Really?

Acting like this is all because people failed to follow a relatively new standard (2008) is a bigger joke. Whether or not the GPS industry should be doing a better job at filtering the signal is not really my concern at this point. Pointing the finger at everyone else, when the most corrupt person in the room is you, is both scary and pathetic. I hope each one of these corrupt cockroaches is thrown in prison where they belong, and that includes people within the FCC.

Seems many of them built factories only to find them understaffed after a few months. The available labor (at that price) was quickly swallowed up by the first few factories, and those that built later found themselves stuck with colossal factories and a snooty labor force that demanded higher wages before they'd consider it. Natural market forces are a bitch when you're a wealthy scion expecting a guaranteed profit.

I've never seen this story (about labor "drying up" quickly) even in the most left-slanted historical accounts. I strongly suspect you're just making it up. Again, considering that completely unskilled children could do most of the work, it's extremely unlikely that (highly risky) political lobbying is the path of least resistance.