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Comment by kalleboo | Hacker News Reader

I don't know why anyone would trust this system. China already requires maps to be "fuzzed" for location (if you use Google Maps on your phone in China, your location on the map will be up to 1km wrong), so there doesn't seem to be anything stopping them from doing the same here when they feel it's a sensitive time or area.

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This was my initial impression too, but I got the feeling from the article that the Chinese government probably really don't care if no one else uses it, it's for use by their own military and as a means of "protection" against thew US shutting off GPS services to them - highly critical if they want to build those drones which rely on GPS.

As an aside, how does the US government make money from the GPS? As a consumer, I pay no money, so I can only assume the GPS chip manufacturers pay some sort of royalty fee?

The government doesn’t charge anything for GPS: http://www.gps.gov/policy/funding/

yes that is true if you dont count the money you paid for the chain products of GPS.

I don't think the purpose was primarily military-related. The US's GPS system can be jammed as is, and I don't see any reason why this system would be any different. GPS satellites are very far up in the atmosphere and thus produce a very weak signal to near-earth. This isn't just a theoretical attack: a few years ago, a truck driver with a GPS jammer accidentally jammed the GPSs of planes above him landing at Newark [1].

I think it's more a matter of national pride issue: to show the world that China doesn't have to rely on the US for technology. Russia's GLONASS system (briefly referenced in the article) is more or less the same thing. The good news is that this system, like GLONASS, will likely improve positioning speed / reliability, since there will be more navigation satellites in the sky. Already, receivers can tie GLONASS and GPS together; it's only a matter of time before Beidou is integrated as well.

[1] http://www.economist.com/node/18304246

> As an aside, how does the US government make money from the GPS?

Do they? What would the royalties be for, licensed chip design?

IIRC Galileo has DRM on the signal so they can charge for it. Not that different from satellite TV I guess.

You have one open and freely available channel and one encrypted, much like how GPS operates with one open channel and one encrypted. Only difference is that the encrypted version on Galileo is intended for commercial use, probably shipping or something.

Or, rather, you will have. If the project ever finishes.

The US government does not make money from GPS. It was built by and for the military, with civilian use as an afterthought. Once civilian use took off, though, the government decided to basically give it as a gift to the rest of the world. http://www.wired.com/politics/law/news/2000/05/36021

The military retains control (which is why other nations are still working on their own systems), but this really was a remarkable act of generosity by the US government.

According to Wikipedia, civilian availability was prompted by the shooting down of a 747 that drifted into Soviet airspace due to an improperly calibrated inertial navigation system.

Thanks. It did make me wonder when the article said China were planning on launching 40 satellites there must be a pretty high cost associated with that.

If the cost of receivers comes down sharply, devices might try to use as many networks as possible to get an accurate fix as rapidly as possible. I can definitely see GPS-Beidou-Galileo together.

Definitely. Mid-range and high-end receivers (for things like ecology surveys and continental drift tracking) integrate GLONASS and GPS already.

I don’t have the RF/SP domain knowledge to back this up, but I speculate that multiple low-end receivers for 2–4 of these networks on a single chip might be more useful in practice than a single good receiver for any one network. In other words, a $20 Galileo chip + a $20 GPS chip might give me a faster time-to-fix than a $40 GPS chip. (In terms of units shipped, most GPS goes into phones, where time-to-fix is way more important than centimeter accuracy.)

Even phones, if they want to be sold in Russia, integrate GLONASS and GPS now.

There's no reason mobile phones with GPS-only chipsets can't be sold in Russia -- they just get hit with ~25% import duties that phones with GLONASS-supporting chipsets don't have.

I wouldn't be surprised at all if China does something similar with Beidou and mobile phones sold in China.

iOS and iPhone hardware since the 4s has supported both aGPRS and GLONASS. Qualcomm snapdragon parts also supported both (so the S2 maybe?)

Faster time to fix translates into longer battery life. Whether this matters in practice for much of the Continental US I don't know.

The beautiful thing is that with 4 more or less independent global navigation satellite systems in play (GPS, Galileo, Compass/Beidou, and GLONASS), there will be more than 70+ satellites in orbit providing ultra-reliable, ultra-accurate navigation and positioning and you won't necessarily have to trust any one of those networks individually.

Do you have a receiver that works with all four systems?

software defined radio would be a good bet for that.

I'm curious how soon mobile phones will have so many tuners that SDR is worth it. A typical phone now has what, 4 GSM bands, 3 UMTS bands, 3 LTE bands, WiFi, Bluetooth, GPS, GLONASS, FM Radio, 1seg, NFC...

They would probably have more if they were cheaper, all sorts of countries have random frequency bands being freed up for mobile. But I think power consumption still the limiting factor.

Such a thing doesn't exist.

For one, neither Beidou nor Galileo are operational GNSSes, so there is no economic incentive to create receivers that work with those services.

Also, the Chinese government only just today published Beidou's ICD, the document that specifies the open-access Beidou signals: http://www.insidegnss.com/node/3331

That was the unstated thesis of my comment.

Neither Beidou nor Galileo are usefully operational yet. There are receivers that can handle GPS+GLONASS, though.

And my point was that no one who isn't compelled to use only the Chinese system need trust the Chinese system - for most navigation consumers around the world Compass will be there to provide redundancy and to make the error bars smaller.

The Chinese military will trust it and Chinese consumers will be coerced into using it just like all the other homegrown standards.

Originally the american GPS system had a encrypted higher-precision signal for military use, and and an open lower-precision signal for civilian use, which could be independently shut off. One day they decided to open up the full precision to everyone. I don't know if the Chinese system is set up similarly, but it's a possibility that the military gets different data from civilians.

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