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China Begins Using New Global Positioning Satellites

timothy posted more than 2 years ago | from the seasonal-ferry-across-the-river-crab dept.

China 168

cswilly writes with the news that China's satellite navigation system, called Beidou, has been successfully activated. "With ten satellites now, 16 in 2012, and 35 in 2020, China is making damn sure they are independent of the U.S. military's lock on GPS. According to the article, 'Beidou, or 'Big Dipper,' would cover most parts of the Asia Pacific by next year and then the world by 2020.'" The BBC also has slightly more detailed coverage.

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Frist Psot (-1)

Anonymous Coward | more than 2 years ago | (#38503308)

lolwut

Re:Frist Psot (-1)

Anonymous Coward | more than 2 years ago | (#38503352)

Second post! WOOOOHOOOOO

Interesting (0)

Anonymous Coward | more than 2 years ago | (#38503330)

Should read a bit more on this.

Not surprising (0)

Anonymous Coward | more than 2 years ago | (#38503332)

Have to have a legit purpose for the spy satellites somehow if they got discovered.

Re:Not surprising (5, Interesting)

InterestingFella (2537066) | more than 2 years ago | (#38503378)

China has a huge amount of their own infrastructure, so this isn't really surprising. Unlike U.S., China likes to do everything themselves. This also means you're not dependent on other countries like the U.S. is. What you don't understand is that China thinks long term, and everything they've done will grant them the leading country status some day, probably even within 10-15 years, especially when considering how much U.S. and EU are struggling now after thinking only short term financial gains.

Re:Not surprising (0, Insightful)

Anonymous Coward | more than 2 years ago | (#38503420)

yup. and in the 80's Japan because of their superior thinking and forward looking abilities and all around betterness than anything and everything done by the US was going to take over the US, and the evil Americans and their god the dollar would be goffed down and forgotten. But that didnt happen either :)

Re:Not surprising (5, Insightful)

Anonymous Coward | more than 2 years ago | (#38503558)

Umm... you are aware of the differences between China and Japan, right?

Such as, say, a massive difference in population? A massive difference in natural resources? The fact that China is now locking up energy and mineral resources around the world which will deny their use to the USA in 50 years?

China and Japan are in no way comparable in this sense. You WILL be second fiddle to China. You can like this or not, but that's the simple reality. You almost are already. You will be passed within a few years, and continue your downward slide as the world aligns more and more to the number one world power of the future: China.

Re:Not surprising (-1)

Anonymous Coward | more than 2 years ago | (#38503732)

> Umm... you are aware of the differences between China and Japan, right?

China = 1.3 billion people
Japan = 130 million

For the Americans reading who aren't up on maths, that means China has about 10 times the population of Japan. It also has about 26 times the land area.

Re:Not surprising (0, Troll)

Anonymous Coward | more than 2 years ago | (#38503936)

you guys are too young to see my point I guess. It is not about numbers. There will always be a doomsday scenario about why Russia is better than the US or will nuke the US, Japan is better, South America, China, whoever. It's always the same crap. Don't quote numbers and population and land area to me. You embarass yourselves when you do it, and you don't even realize it. I am trying to save you the embarassment.

Re:Not surprising (1)

Anonymous Coward | more than 2 years ago | (#38504432)

I'm old enough to have seen all the reports of Japan and Latin America rising to topple the United States as dominant power. I agree with you that China will likely fail (most of their books are cooked, the next generation is all but completely sterile due to God knows what pollution).

But that just leads to another question: WHEN will the United States implode? I can think of at least a dozen opportunities for it to simply fail and fail hard. Many other nations have failed due to less.

We understand full well why Japan, Latin America have failed. We have a good understanding on China's inevitable failure. What we don't understand is why the United States doesn't fail.

Re:Not surprising (3, Insightful)

Anonymous Coward | more than 2 years ago | (#38504748)

I'd say it's already started, but the decline is a slow process. Empires don't so much fall as decay. It took longer for the Roman Empire to completely fall than the United States has even existed. If you want to put a timeline on it, I'd say the decline started post-WW2. We had a good run shortly after as the sole manufacturing powerhouse of the world, but that wasn't going to last forever.

Bear in mind we are *still* one of the biggest centers of industry in the entire world though. We're just having to adjust to not being #1 by giant margins in every sector imaginable.

Re:Not surprising (1)

Gideon Wells (1412675) | more than 2 years ago | (#38505078)

I think part of the problem is that the world is recovering.

Post-WW2? China was a piddling country recovering from being ravaged by Japan and colonial powers. Total war had left Europe in pieces. And so forth. The U.S. and Russia were the big players as the U.S. was untouched by war on its lands and Russia had been (mostly) shielded by its Winter. The rest of the world has either recovered or has begun rising to the standards of everyone else, thus exaggerating the "fall" of the U.S.

However, I am not so nationalistic to deny that there isn't a fall. Heck, when you have two men stealing an entire bridge to sell as scrap the stories you used to think of a third world only become worrying.

Re:Not surprising (1)

Anonymous Coward | more than 2 years ago | (#38504888)

Freedom. Individual Americans have the freedom to discuss and try things, even unpopular or politically- or economically-incorrect alternatives to the current paradigm. Flexibility. When that which is popular or politically ascendant or otherwise "approved" turns out to be wrong, the alternatives are eventually tried. Unfree societies stamp out "error" and inflexible ones don't accept change.

Re:Not surprising (1)

Anonymous Coward | more than 2 years ago | (#38504548)

The Americans reading are definitely not up on maths. They're up on math.

Re:Not surprising (5, Insightful)

Anonymous Coward | more than 2 years ago | (#38503906)

Not this shit again. It looks like the shills from China are getting to the point where they even infect Slashdot.

Want to know one thing China lacks? The ability to grow food for its people. As of now, they are an exporter. Give it 10 years, and that isn't going to be the case. If the US gives a middle finger to the world, the country can keep its population fed. May not have the variety, but people would survive. Other countries would have mass starvations if it wasn't for their imports.

We have heard the second fiddle to China thing before. We were going to forever be second fiddle to Japan. We were going to be swallowed up by Communist countries because the USSR had so much land, puppet governments, and did not hesitate to use brutal force when called on. We were going to be swallowed up by every nation in the world going under Sharia law.

Not to say China isn't doing their part. The one thing China is good at is sabotage. They are going ape-shit dumping solar panels for way below the cost of materials + labor in the US market in effort to kill that industry and take it over for themselves. Instead of innovation, this is how they go about doing things. Hopefully in the fall of next year, we get a Congress elected that actually abide their oath of office and actively stop this crap.

The US has its faults. In fact, sometimes you wonder what the country does right, but like a NoSQL database where you wonder where the hell the consistency comes from but keeps its integrity over a period of time, the US keeps going.

Re:Not surprising (0)

Anonymous Coward | more than 2 years ago | (#38504332)

Most of your points are valid. However, do note that the US food production is heavily dependent on fossil fuel technology. The US, as one of the top food producers, won't likely remain in its position as fossil fuels start running out.

Re:Not surprising (1)

Maxo-Texas (864189) | more than 2 years ago | (#38504656)

And neither is the rest of the world...

That's one of the human race's doomsday scenarios and it's 50 to 150 years out. We'll probably solve it somehow tho.

Overpopulation is the one that won't be solved.

Canada has all the fossil fuels the Us requires (1)

arcite (661011) | more than 2 years ago | (#38504992)

And Alaska and Gulf of Mexico.

Re:Not surprising (1)

Anonymous Coward | more than 2 years ago | (#38504072)


You WILL be second fiddle to China

Ahhhh, I've heard this. You need to check with your minister of demographics.

How many people in China will be over 65 in the year 2025? How many people, as a percentage, will that be?

The great Chinese economic expansion will be quickly followed by the great Chinese population implosion due to not enough young Chinese. In fact, you'll be able to watch as Russia goes through this implosion right before China so you have a taste of what's to come.

Those mineral rights will be made irrelevant by what China fears most: A war that will annihilate the young Chinese. To use your phrase: You can like this or not, but that's the simple reality.

The decade of 2020 will not be pretty.

Re:Not surprising (2)

Rockoon (1252108) | more than 2 years ago | (#38504650)

Umm... you are aware of the differences between China and Japan, right?

Population really isnt the determining factor that people are making it out to be. Economic freedom is what its all about and countries with lots of it end up with similar purchasing powers and standards of living. E.U. with its $30K/person, South Korea and Israel with their $31K/person, Japan and Taiwan with their $34K/person, Canada with its $40K/person, U.S.A with its $48K/person.

China is at $8K/person and there is nothing that they can do about it without becoming just like the rest of us. Does it matter that China will end up with the highest GDP if that doesnt translate into a higher standard of living for its people? Seems to me like the western economies are doing very well vs China. Did you think that the Japanese cares that their GDP is only a fraction of the E.U. or U.S? People want a better life.. thats all.

Re:Not surprising (0)

equex (747231) | more than 2 years ago | (#38503616)

I'd say the dollar has taken a plunge halfway to death (dollar has fallen to half, sometimes a third of it's value in the 80's and 90's), and that governments around the world are re-structuring to be free from US-assets like bonds and other government-backed economic tools. And the Japanese are doing good. Has the most expensive properties in the world too.

Re:Not surprising (-1)

Anonymous Coward | more than 2 years ago | (#38504052)

Could you maybe make that extra apostrophe take a plunge to death? It's means IT IS.

Re:Not surprising (2)

nomadic (141991) | more than 2 years ago | (#38504366)

"I'd say the dollar has taken a plunge halfway to death (dollar has fallen to half, sometimes a third of it's value in the 80's and 90's)"

Helping American exports. Having a weak national currency is not necessarily a bad thing; if it were, why would the Chinese intentionally keep theirs devalued?

"that governments around the world are re-structuring to be free from US-assets like bonds and other government-backed economic tools"

Wrong. There has been a lot of demand for US treasury bonds because of the global economic downturn; they're considered "safe" investments.

And the Japanese are doing good

Absolutely wrong. Japan's economy is in terrible shape and it's only gotten worse in recent years.

Re:Not surprising (5, Interesting)

Maxo-Texas (864189) | more than 2 years ago | (#38504730)

China owns a trillion dollars worth of US debt.

With the dollar dropping by half in value, they've lost 500 billion dollars in purchasing power.

They do this to keep products cheap enough to sell to the US so they population has work and won't get antsy. They build empty cities for similar reasons (well actually I can't comprehend exactly why they build empty cities and empty buildings- it seems goofy).

China being a huge country is not an asset, it's a liability.

They do have a good legal lock on assets- but many of those assets are only rare at the current prices. As soon as rare earth prices go up 50%, millions of tons of rare earth can come on line- including a huge mine in the US.

About the time they stop building empty cities, the demand for copper and other building materials is going to drop through the floor.

--

The US leadership class appears to have lost it and descended into greed.

--
The true threat to the work is not china or the US but the corporations and the top 1%. And it's almost certainly two decades too late to do anything about it.

Re:Not surprising (4, Insightful)

j-pimp (177072) | more than 2 years ago | (#38503430)

China does everything themselves because that makes sense to them at the moment. In fifty years they will probably be outsourcing and not maintaining their infrastructure.

Re:Not surprising (2)

jellomizer (103300) | more than 2 years ago | (#38503760)

It is also part of China's culture. The Chinese tend to prefer isolationism and doing things themselves. Where in the short term (The next 20-50 years) does have advantages however in the long term if it ends up cutting themselves from the rest of the world may bring them back to their third world status again.

The United States has some of this in our culture, however the US culture tends to have a Duality in its culture which is often confused with being a nation of Hippocrates. So while we will openly work with others, we take great pride on what we can do ourselves.

But China really doesn't have that Duality in its culture. I would expect those are just as they say GPS system made by and controlled by China. Not so much because they have a problem with the US GPS but because it isn't theirs and their culture of We are China, we are the worlds largest country by population, and 3 or 4 by (Roughly the same as the United States, where if you add or remove disputed land) land mass. They feel that they really should have the rights to have their own. Without having to deal with the US and trust us. It is matter or pride for them.

Re:Not surprising (1)

Phil06 (877749) | more than 2 years ago | (#38503980)

The Chinese do not prefer isolationism, their totalitarian government demands it

Not at all (1)

a_claudiu (814111) | more than 2 years ago | (#38504324)

You are forgetting the main driver in China. It's not money but the big centralized party. Let's look into the future to see if the rich people will succeed in taking over the power (like in the west) or it will be the government keeping the power over oligarchs (Russia).

The Grand Canal (2)

Zephyr14z (907494) | more than 2 years ago | (#38504632)

That would be extremely uncharacteristic of China. We're talking about a civilization that built an 1100 mile long canal over a period of 1000 years or so. China has been doing long term planning, especially infrastructure planning, for an incredibly long time. That canal project started in the 5th century BC. http://en.wikipedia.org/wiki/Grand_Canal_(China) [wikipedia.org]

Re:Not surprising (0)

Anonymous Coward | more than 2 years ago | (#38503474)

It's true. Sad thing is that the EU, US and the rest of the West and Asia don't want to bury the hatchet and work with China. They are basically here to stay, but the USA and EU don't want to let them into the club.

Re:Not surprising (2)

joggle (594025) | more than 2 years ago | (#38504158)

Who does the US rely on for GPS? Only themselves of course, so this isn't exactly a good example.

Within 10-15 years, China will be deeply effected by their housing bubble as Japan was in the 90s. Unlike Japan, the primary thing maintaining social stability in China is continued economic growth. Without this, China will be facing very serious internal problems.

I recently read a Chinese article about how many celebrities in China have dual citizenship so that they can leave the country quickly. Many politically connected families send their girls overseas for college and the rich send both their boys and girls overseas. While this gives them an advantage for jobs within China, it also makes it easier for them to leave China in an emergency. They are very worried about social unrest, and I don't blame them.

Re:Not surprising (2)

Calibax (151875) | more than 2 years ago | (#38505120)

Just as important, 8 of the 9 members of the PolitBuro Standing Committee (the highest and most powerful decision-making body in China) are engineers by profession. The most popular profession in the US Congress is lawyer.

I know which I would expect to get things right over the long haul.

Re:Not surprising (0)

Anonymous Coward | more than 2 years ago | (#38505286)

>> China likes to do everything themselves

With the exception of China actually coming up with an original idea, this statement is true.

Re:Not surprising (0)

Anonymous Coward | more than 2 years ago | (#38505502)

What they want is obvious:A GPS system independent of the U.S. system, so they can jam ours (and perhaps surreptitiously shoot down ours) and still have theirs available for their military to use, and (as pointed out in a previous comment) a platform for them to have more spy satellites, except these are out in the open and we don't have much we can say about them. No matter, I'm sure we've already got the ability to jam their GPS system (which I'm sure doesn't work as well anyway).

Unlimited government (0)

Anonymous Coward | more than 2 years ago | (#38503394)

Unlimited government, whether a Chinese flavor of communism, or an American flavor of corporatism, is guaranteed to result in oppression. Only through STRICT limits on government power will freedom and justice ever prevail, and unfortunately, the entire world is going in the opposite direction (unlimited power, unlimited revenue for the elite at the top).

Re:Not surprising (2, Insightful)

jimbolauski (882977) | more than 2 years ago | (#38503662)

Satellites in geosynchronous orbit make poor spy satellites, for one they are stationary in relation to the ground so you have to look at an angle to see anything increasing the atmospheric distortion, they are also up much higher which also increases the distortion, and thirdly because they are stationary they are much easier targets for satellite weapons as height is their only protection. While permanently positioning a satellite over a test bed would seem like a great idea, either the test site is compromised or closed, the truth is that a high enough resolution can not be obtained with all the atmosphere to account for.

Re:Not surprising (-1)

Anonymous Coward | more than 2 years ago | (#38503824)

Satellites in geosynchronous orbit make poor spy satellites

No shit Sherlock. Which is why you don't put spy satellites there.

Know what else? You don't put navigation satellites either, nor do you put combined navigation/spy satellites in that orbit.

Holy fuck. You are seriously dense Mr. Jim Bolauski.

Re:Not surprising (0)

Anonymous Coward | more than 2 years ago | (#38504028)

If you think GPS satellites are in geo orbit, you're mistaken.

Re:Not surprising (2)

dgatwood (11270) | more than 2 years ago | (#38504048)

First, the word you're looking for is geostationary. Not all geosynchronous orbits are geostationary.

Second GPS cannot be done with geostationary orbits. You have to have a minimum of three non-collinear points to triangulate a location on the surface of the Earth, and geostationary orbits are effectively collinear for all practical purposes. As such, geostationary orbits would only get you longitude (position along that orbital line), not latitude.

Re:Not surprising (1)

nedlohs (1335013) | more than 2 years ago | (#38504134)

So what? GPS satellites aren't in geosynchronous orbit anyway making that a completely irrelevant point.

GPS orbits are completely unsuitable for spy satellites sure, but not for that reason.

Re:Not surprising (1)

LWATCDR (28044) | more than 2 years ago | (#38504478)

Okay where to start.
1. Navigation satellites are not in geosynchronous orbit to start with so what does that have to do with anything?
2. There are more than one type of "spy" satellite. Imaging is only type. Elint and Sigint satellites are often in geosynchronous orbit. They site over a country hovering up all the radio transmissions that it can including things like radar.

So would these make good spy satellites? That depends on what you mean by spying? For some missions they may have a use. Even a relatively small camera could spot a large warship or tanker at sea. A pretty simple receiver could pick up strong radar transmissions as well. The US puts radiation sensors on the GPS satellites to monitor the nuclear test band treaty.

I wonder if the Iridium constellation is being used for Sigint. You have a world wide coverage with satellites with really big antennas. Using doppler shift and the different spots they should have little trouble picking up many types of radars.

good (4, Funny)

roman_mir (125474) | more than 2 years ago | (#38503360)

the more the merrier.

Re:good (1)

TubeSteak (669689) | more than 2 years ago | (#38503748)

Accurate to within 10 meters is good?
Is there any way I can filter that signal out!?

Re:good (0)

Anonymous Coward | more than 2 years ago | (#38504130)

USA GPS is only accurate to 20m

Are they GPS satellites? (2)

Ded Bob (67043) | more than 2 years ago | (#38503382)

Or are they GPS satellites "equipped with nuclear missiles and a laser cannon"?

Re:Are they GPS satellites? (3, Funny)

msauve (701917) | more than 2 years ago | (#38503404)

You're thinking of sharks.

Re:Are they GPS satellites? (0)

Anonymous Coward | more than 2 years ago | (#38503444)

Nah, japan already ate them

Re:Are they GPS satellites? (0)

Anonymous Coward | more than 2 years ago | (#38503676)

You're thinking of whales.

Re:Are they GPS satellites? (1)

joebagodonuts (561066) | more than 2 years ago | (#38504096)

Japan ate them, too

Re:Are they GPS satellites? (1)

jd2112 (1535857) | more than 2 years ago | (#38504170)

Japan ate them, too

Just the fins.

Re:Are they GPS satellites? (0)

Anonymous Coward | more than 2 years ago | (#38503524)

Why just one laser cannon ? Are saying the chinese aren't that evil ?

Re:Are they GPS satellites? (0)

Anonymous Coward | more than 2 years ago | (#38503628)

You can't shoot sharks into orbit.

Re:Are they GPS satellites? (0)

Anonymous Coward | more than 2 years ago | (#38503710)

Why wouldn't you?

Re:Are they GPS satellites? (2)

Sponge Bath (413667) | more than 2 years ago | (#38503660)

No, but Beidou will help guide their missiles.

Re:Are they GPS satellites? (1)

jd2112 (1535857) | more than 2 years ago | (#38504204)

No, but Beidou will help guide their missiles.

And recon drones! If they end up in Iran we'll know where they got their UAV tech from.

Re:Are they GPS satellites? (1)

Maxo-Texas (864189) | more than 2 years ago | (#38504576)

This was my first thought too now.

GPS can be spoofed now. It can't be long before wide spread spoofing and jamming takes place. Seems like they'll have to go back to navigating by landmarks. Perhaps they could use something like google earth that scans and recognizes the terrain where they are.

Re:Are they GPS satellites? (5, Funny)

Terrasque (796014) | more than 2 years ago | (#38503838)

Well, a chinese spokesperson was quoted "They are as peaceful as the american GPS satellites, and contain no more armaments than those do" - so no worries.

We do have some strange reports of a high-ranking american general running from the press conference with a panic-struck look on his face, but that's probably unrelated.

Mod Parent Up (0)

Anonymous Coward | more than 2 years ago | (#38504842)

I'm just not sure if you should be modded +1 Funny, or +1 Insightful...

Re:Are they GPS satellites? (2)

lgw (121541) | more than 2 years ago | (#38505206)

Not really a concern - the US can certainly shoot down all the satellites it wants to. Those in lower orbits like GPS and spy sats can be taken down by (relatively) cheap missiles launched from a jet at high altitude. They'd all be gone in the first few hours of a real war.

Re:Are they GPS satellites? (1)

Lumpy (12016) | more than 2 years ago | (#38504084)

Dont need that.

Put a small nuclear warhead in the bird and wait for it to be overhead the target. BOOM, a nice wide area EM pulse to take out all of your enemy's electronics.

Re:Are they GPS satellites? (2)

joggle (594025) | more than 2 years ago | (#38504282)

They are very similar to the European Galileo satellites. They are similar to GPS, but use different frequencies than GPS.

Originally, China was involved with the development of the Galileo constellation. They backed out because they didn't feel like they had a big enough voice in its development.

The Chinese constellation, Compass, is intended to be as accurate as GPS. They will almost certainly have their constellation fully deployed long before Europe gets their act together and finishes the Galileo system.

By the way, GPS doesn't only provide positioning service. Each satellite also has a detector for nuclear explosions and can quickly locate the position of any nuke going off on, or above, the surface.

Can I hack it using my ipad and a ping pong ball? (-1)

Anonymous Coward | more than 2 years ago | (#38503406)

Since China seems to let it's citizens hack away at foreign entities with little or no repercussions. I wonder if their satellites are fair game for us?

Re:Can I hack it using my ipad and a ping pong bal (1)

AngryDeuce (2205124) | more than 2 years ago | (#38503498)

Now that Congress has authorized the official use of Cyberwarfare [slashdot.org] I'm sure they will be.

Although I'm far too cynical to believe that they've restrained themselves before now. That's just making it official...

Old news? (5, Interesting)

Bananana (1749762) | more than 2 years ago | (#38503434)

we have car navigation systems that use Beidou for some time now (maybe less than a year).

Re:Old news? (2)

cyfer2000 (548592) | more than 2 years ago | (#38503484)

I will mod this post "informative" if I have points.

Re:Old news? (0)

Anonymous Coward | more than 2 years ago | (#38504018)

...no, you won't, unless you have a sockpuppet account to use.

Re:Old news? (1)

dotancohen (1015143) | more than 2 years ago | (#38503878)

we have car navigation systems that use Beidou for some time now (maybe less than a year).

Who is "we"? Are you Chinese?

Re:Old news? (1)

Lumpy (12016) | more than 2 years ago | (#38504100)

We are the borg.... you will be assimilated.

Re:Old news? (0)

SJHillman (1966756) | more than 2 years ago | (#38504552)

The Chinese Borg use lead-based nanoprobes and the eye lasers have a tendency to blow up.

Actually, the Chinese do have a lot of parallels with the Borg... steal technology rather than develop it themselves, a large supply of cheap labor, putting the collective ahead of the individual, funny colored skin...

Re:Old news? (2)

dotancohen (1015143) | more than 2 years ago | (#38504864)

We are the borg.... you will be assimilated.

Resistance is V/I.

Re:Old news? (0)

Anonymous Coward | more than 2 years ago | (#38505030)

Resistance is V/I.

http://en.wikipedia.org/wiki/Ohm's_law [wikipedia.org]

Old tech or new? (0)

Anonymous Coward | more than 2 years ago | (#38503478)

Did they do anything to improve on the old tech of GPS?

So not "Global" then? (1)

chiBrian (2089894) | more than 2 years ago | (#38503574)

So not "Global" then?

Active vs passive systems (5, Interesting)

tylernt (581794) | more than 2 years ago | (#38503706)

From what I can tell from the Wikipedia article, Beidou is an active system where the "client" sends data to the satellites in orbit. It makes perfect sense for the Chinese though, because now they can track where their users are -- something not possible with the passive US system since the receivers only receive and can't transmit any data back. In short, Big Brother Beidou always knows where you are.

Seems like an active system has a huge disadvantage, though. You can DOS the satellites by pointing an antenna at each satellite and jamming their uplink frequencies, knocking out the whole system for everyone, everywhere. In the US system, you can only jam local terrestrial reception and anybody over the next hill won't be affected.

Re:Active vs passive systems (1)

gzipped_tar (1151931) | more than 2 years ago | (#38503918)

Another implication is that the terminal will be more complex, cost more and consume more power compared with the GPS terminal.

Re:Active vs passive systems (1)

tuxicle (996538) | more than 2 years ago | (#38503950)

So what you're saying is in Soviet Russia, navigation satellite tracks you?

Re:Active vs passive systems (0)

Anonymous Coward | more than 2 years ago | (#38504212)

No, that happens in Capitalist China.

Re:Active vs passive systems (4, Insightful)

chill (34294) | more than 2 years ago | (#38503952)

That was the "test" system. And their description is completely ass-backwards. I'm not sure how useful that would be for mobile units or wide spread use.

The terminal sends a signal to the satellites (say, 3 seconds latency due to distance). The satellites send the timestamps to a ground station (again, 3 seconds). They do some maths, then send the answers back to the satellites (again, 3 second), which send it back down to the terminals (finally, another 3 seconds). That is like 12 seconds, plus calculations, etc. Good luck using that info reasonably at 100+ KPH

That still leaves the issue of if terminals become popular, potentially MILLIONS of signals being broadcast skyward for the satellites to receive, sort, stamp and relay.

The Wikipedia article reads like an instruction manual on how NOT to do GPS. What am I missing?

Re:Active vs passive systems (2)

cswilly (56124) | more than 2 years ago | (#38504284)

Somebody needs to attend his Physics Classes. 3 seconds to send a signal to a low Earth orbit satellite? Non-sense.

Re:Active vs passive systems (3, Insightful)

chill (34294) | more than 2 years ago | (#38504422)

We're both wrong. Me more so than you, however.

The Beidou-1 satellites are Geo Stationary not LEO. That being said, according to Wikipedia [wikipedia.org] latency is about 1/4 of a second for each leg.

Still, the idea of transmitting potentially millions of signals blindly in the sky to a constellation of GEO satellites, and letting them do the work of sorting, stamping, and relaying seems a bit ass-backwards.
Square Peg, meet Mssrs Round Hole and BFH.

Re:Active vs passive systems (2)

youn (1516637) | more than 2 years ago | (#38504448)

To be fair, there may be other constraints such as bandwidth, collisions, processing on both ends... but somehow 3 seconds seems too much for that kind of thing

Better coverage through multiple systems (5, Interesting)

caseih (160668) | more than 2 years ago | (#38503806)

Something I didn't realize until recently is that in the northern latitudes (Canada, northern US), GPS coverage has occasional small gaps in it. My John Deere dealer was saying that in some areas every few days about 6pm (happens to be that time in those areas) GPS coverage drops below 1 meter accuracy levels, and in those areas GPS guidance on farm machines becomes unusable for about an hour or so. As well sometimes a satellite goes offline for maintenance. As agriculture is becoming very reliant on GPS (hence John Deere lobbying in washington against LTE usage of adjacent frequencies), this is a problem. Because of this John Deere now uses GPS and GLONASS together to get better coverage. When Galileo provides coverage, it will use those signals too. The point is, more GPS systems simply improve reliability for everyone, if the Chinese allowed western use of their signals.

Re:Better coverage through multiple systems (3, Interesting)

BorelHendrake (1496471) | more than 2 years ago | (#38503966)

When we were traveling across the United States, there was about 45 minutes of our trip through Utah where we were not receiving GPS signals. I believe it happened in the early afternoon. Fortunately there were not turns involved during that portion of the trip.

Re:Better coverage through multiple systems (3, Funny)

Anonymous Coward | more than 2 years ago | (#38504268)

That was the Mormon Effect.

Re:Better coverage through multiple systems (0)

Anonymous Coward | more than 2 years ago | (#38504312)

I think that was because the signals were evaporating in the air there due to the low humidity.

Re:Better coverage through multiple systems (1)

Anonymous Coward | more than 2 years ago | (#38504504)

Before GPS we used to use things called 'maps' and something given the fancy-pants name of 'dead reckoning' (figuring out where you are based on direction, average speed, and duration of travel). I am astonished that someone is complaining that they had a 45 minute window (75 km gap at 100 km/hour) where GPS was not available and were worried about getting lost.

Re:Better coverage through multiple systems (1)

GodInHell (258915) | more than 2 years ago | (#38504876)

I am astonished that someone is complaining that they had a 45 minute window (75 km gap at 100 km/hour) where GPS was not available and were worried about getting lost.

Me too -- where did you read this because it's not in this thread.

-GiH

Re:Better coverage through multiple systems (4, Informative)

DerekLyons (302214) | more than 2 years ago | (#38504584)

Something I didn't realize until recently is that in the northern latitudes (Canada, northern US), GPS coverage has occasional small gaps in it.

It doesn't. The constellation's orbital pattern is uniform across the entire surface of the Earth.
 

My John Deere dealer was saying that in some areas every few days about 6pm (happens to be that time in those areas) GPS coverage drops below 1 meter accuracy levels, and in those areas GPS guidance on farm machines becomes unusable for about an hour or so.

Your John Deere dealer is a little shaky on how GPS operates. The birds are in 12 hour sidereal orbits, which means the pattern (as seen from an fixed location on Earth) repeats every 11 hours and 56 minutes.... Which means (if such an effect as he describes existed) it would steadily and regularly drift earlier through the day. Thus not only would the effect be seen 'about 6PM' every two weeks or so, but it would also be visible at varying times through the day for a week roughly every other week. (This also implies the gaps drift across the Earth's surface in a regular pattern, and would be visible in places other than the northern latitudes.) In addition, he may not realize that GPS accuracy *normally* varies somewhat over spans of a few hours as the geometry of the visible portion of the constellation varies. So what he's seeing is something else, amplified by observer bias.
 

As well sometimes a satellite goes offline for maintenance.

Yes, they do. But the system is designed and operated such that having a bird offline for maintenance degrades total system performance by only a very small amount.
 

As agriculture is becoming very reliant on GPS (hence John Deere lobbying in washington against LTE usage of adjacent frequencies), this is a problem.

The problem isn't the GPS system. The problem is John Deere is trying to use the system at an accuracy (100% availability at 1m) greater than the specified [civilian] performance levels (95% availability at 7m).

Re:Better coverage through multiple systems (1)

maeka (518272) | more than 2 years ago | (#38505270)

The problem isn't the GPS system. The problem is John Deere is trying to use the system at an accuracy (100% availability at 1m) greater than the specified [civilian] performance levels (95% availability at 7m).

While I can't speak as to the John Deere system in particular, most the Ag navigation systems are using WAAS on the low end and VRS RTK subscription systems on the high end.

Here in Ohio ODOT offers a reduced-fee reduced-accuracy VRS option for farmers, who don't need the sub-cm service.

Is it possible to combine systems in a receiver? (3, Interesting)

ChronoFish (948067) | more than 2 years ago | (#38503820)

Would be possible to get a more accurate position if a receiver combined the various GPS systems - as a kind of check/balance. For non-military use the GPS systems introduce inaccuracies. Is there an algorithm that would bring the resolution down from 10 meters to 1 meter or less?

-CF

Re:Is it possible to combine systems in a receiver (0)

Anonymous Coward | more than 2 years ago | (#38504350)

That is called "Sensor Fusion" and is very possible. Google sensor fusion and kalman filter for a good time.

Re:Is it possible to combine systems in a receiver (2)

DerekLyons (302214) | more than 2 years ago | (#38504756)

For non-military use the GPS systems introduce inaccuracies.

No, GPS does not deliberately introduce inaccuracy - that was part of selective availability, which was turned off in 1998. What GPS does do is not make available to civilians the correction mechanism that enable military grade accuracy.
 
The accuracy of civilian GPS units (within what's available from the system) is mostly dependent on factors outside of the government's control... The design of the antenna, how well it's matched to the receiver, the accuracy and stability of the clock circuits, etc... etc... all effect the accuracy of the GPSr.
 

Is there an algorithm that would bring the resolution down from 10 meters to 1 meter or less?

Using WAAS corrections, even a cheap-ass handheld unit can routinely obtain accuracies under 5m, and accuracies under 3m are not unheard of. Surveyor grade GPSr's can obtain sub-meter (down to centimeter) accuracy using GPS alone, but require that the receiver be stationary for extended periods (a couple of hours) and use high quality antennas and electronics. (Which is why they cost $10k+.)
 

Would be possible to get a more accurate position if a receiver combined the various GPS systems - as a kind of check/balance.

Yes, and such units are commercially available, but generally only in higher end units because you're essentially buying two systems in one box.

Re:Is it possible to combine systems in a receiver (5, Informative)

batistuta (1794636) | more than 2 years ago | (#38504786)

Yes. This has been done for many years in survey equipment. a typical combination of Navstar (U.S. GPS)/GLONASS increases the number of satellites in view and therefore the accuracy. The biggest problem with combinging Navstar and GLONASS is that Navstar is CDMA (code division multiple access) while GLONASS is FDMA (frequency division multiple access). The former technique makes each satellite use a different "language" sort to say, while the later one uses different frequencies. The result is that a dual receiver needs two independent receivers, making them more expensive. New GLONASS satellites will start using CDMA signals in addition to the FDMA, so that legacy receivers work, and some time in the future new CDMA receivers can use both Navstar and GLONASS with a single type of tuner. Galileo was from the ground up designed to use CDMA and as a result, it is much easier to design a Navstar/Galileo dual receiver. As a matter of fact, many survey devices designed for Navstar can be upgraded via a firmware update to use Galileo as well. You can't upgrade to use GLONASS with a simple firmware update, you also need another tuner.
Regarding accuracy, the thing is that you can't go much less than 5m by just adding more satellites. This is because this error is part of ionosphere delays, and more satellites can't correct this error. It is like trying to do a measurement by averaging 1000 readings, but all done with a bad ruler. At some point, you need to figure out how good your ruler is. And the problem is that this changes dynamically so standard Kalman filter techiques also stop being effective for better than 5m accuracy. There are two approaches for this: the first one is dual frequency, and this is in part how Galileo achieves better accuracy. The idea here is to exploit the dispersion property of the ionosphere. It works like this: different frequencies have different delays, so you send the same signal using different frequencies, measure the delay different, and solve for the ionosphere error. This is what survey-grade equipment do, but they do this by tracking the encrypted military P(Y) code, which is encrypted. The result is a dual frequency solution but full of hacks that make it unstable. This means, as soon as the signal is interrupted for a short time, you need to re-sync.
The other approach for sub meter accuracy come from differential GPS. This technique uses to close receivers, one with a fixed known location. By measuring the error on the known location, you can apply corrections to the moving rover. But for this you need a link between the two (radio, UMTS, GSM, etc) or some post-processing. In addition, you need receivers capable of recording RAW data and then doing some complex math.
The cream of the desert comes from using carrier-phase measurements. With this technique you can go up to cm accuracy. This requires tracking the actual carrier wave, and a very precise model of the earth or post-processing software. The accuracy comes at a price: very very unstable. You need clear blue sky and uninterrupted signals. Plus about 20 seconds to lock the signal, even after small interruptions.
So to answer your question: more satellites guarantee better consistency and readings, particularly in cities and urban landscape. But you can't go below 5m unless you enter differential GPS or dual frequency measurements.

Re:Is it possible to combine systems in a receiver (1)

maeka (518272) | more than 2 years ago | (#38505368)

Close.

Carrier tracking does not require a very precise model of the earth. Real Time Kinnematic GPS has been done for well over a decade with rather sane processing requirements. It also isn't unstable. So long as the L1 and L2 signal of five satellites are tracked one can initialize on the fly, and you only need to track four continuously to maintain said initialization.

Like differential (a code-base correction) kinnematic requires a base receiver and a rover receiver. They can either be in real time contact or the results can be post-processed. Differential and kinnematic both work by estimating the ionospheric delays, the difference is between tracking the long-period time code or tracking the short-period (19cm) carrier wave.

Re:Is it possible to combine systems in a receiver (0)

Anonymous Coward | more than 2 years ago | (#38505084)

Civilian GPS signals no longer intentionally introduce inaccuracies: http://www.gps.gov/systems/gps/modernization/sa/

Increased geometrc diversity (more satellites) leads to a lower dilution of precision: http://en.wikipedia.org/wiki/Dilution_of_precision_(GPS)

Could cause a problem for the USA.... (2, Funny)

Lumpy (12016) | more than 2 years ago | (#38504046)

If the China system does not have the same DOP setup then it will be easy for hackers to use two receivers to read a location from both and create a correctional signal or negate the DOP that the Us military puts on the US GPS system. Giving the TERRORISTS ultra precise coordinates to invoke their TERROR

Or at least that is how Fox news will spin it.

Re:Could cause a problem for the USA.... (0)

Anonymous Coward | more than 2 years ago | (#38504278)

If the China system does not have the same DOP setup then it will be easy for hackers to use two receivers to read a location from both and create a correctional signal or negate the DOP that the Us military puts on the US GPS system. Giving the TERRORISTS ultra precise coordinates to invoke their TERROR

I think you are referring to Selective Availability that was shut off toward the end of the Clinton Administration since it was useless with DGPS.

Good News (0)

Anonymous Coward | more than 2 years ago | (#38504196)

This is GREAT NEWS, i cant wait for the new multi constellation receiver.

cool (0)

Anonymous Coward | more than 2 years ago | (#38504202)

more satellites for them to shoot down or blow up when they malfunction or reach eol (leaving millions of destructive fragments behind)

What a (global) waste of money... (1)

mholve (1101) | more than 2 years ago | (#38504516)

The U.S. has theirs, China just went online, the Russians also have their own and the EU is also planning one. While I can certainly see why each country (or interest) would like to have their own to prevent being locked out - c'mon. What a huge waste of money and resources that could surely be spent in better ways. Then again, militaries have never really been known for their altruistic interests.

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