5 ms·

Same reason they share GPS?

Retra 9y ago
They don't share GPS. They share a low-resolution subset of GPS. And they control the satellites and thus have the power to selectively disable it should their enemies decide to rely upon it.
- FigBug 9y ago
  Selective Availability was turned off in 2000, everybody gets the same GPS signal now. GPS III won't support it, so it won't be able to be turned back on.
  - nine_k 9y ago
    GPS can stop working for everyone but the US military at a flip of a switch. Seafloor features will likely last millennia.
    - noir_lord 9y ago
      It can which is why the Russians, the Chinese and the Europeans are all rushing to finish their constellations. Iirc the Chinese are a partner in Galileo (the European program). This is a good thing, hardware will rapidly appear that supports 2 or more of them meaning that either all the partners would simultaneously have to agree to disable theirs or (more unlikely) someone was shooting down the satellites which since that would realistically only happen during a global conflict means I'd have bigger things to worry about at the time.
      - bboreham 9y ago
        > hardware will rapidly appear that supports 2 or more of them Has been out for years. E.g. iPhone 4S supported GPS and GLONASS.
      - kuschku 9y ago
        Sadly, the EU system has a method for the US to shoot it down, as the US said they’d pre-emptively shoot down all satellites we put up unless we build such a backdoor (especially due to the chinese partnership in Galileo). Now we have a system where the chinese stopped being a partner, and the US forced us to add a backdoor and reduce the quality. I’m not sure I can see anything good in this.
        BrandoElFollito 9y ago
        Would you have any sources for this?
        kuschku 9y ago
        Of course, as it was in all the news, it’s even well-documented on Wikipedia. https://en.wikipedia.org/wiki/Galileo_(satellite_navigation)#Tension_with_the_United_States https://en.wikipedia.org/wiki/Galileo_(satellite_navigation)...
        BrandoElFollito 9y ago
        Thanks but I do not see any mention of a backdoor. A different frequency is not one, it allows for local jamming (which is also possible with GPS) and that's all.
        kuschku 9y ago
        The whole point was to put GALILEO on frequencies that overlap with military BeiDou and military GPS, so that no government could jam civilian GALILEO without jamming their own military tech.
        BrandoElFollito 9y ago
        The whole point of galileo is to have a system which is not dependent on the US and their GPS switch. Jamming is a local action, the US will be able to jzm Gallileo like we are able to jam GPS - again locally. Frequencies can be switched, if we only relied on the fact that they are the same then the US could switch theirs (and have equipment which is compatible if course) and there goes our security. I work in security and have worked for 12 years for a huge provider of telecom systems and hinestly do not see any real advantages to match the frequencies. Also, if we had the same frequency, WE could not jam GPS if we wanted to.
- jonknee 9y ago
  They share GPS, it used to be low-res but is now the real deal: https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_Positioning_System#Selective_availability https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_...
  - zb 9y ago
    The part they share is literally called "Coarse/Acquisition" and the part they don't share is called "Precise". (This has nothing to do with Selective Availability; they're broadcast in two completely different bands.) The GP's characterisation is broadly accurate.
deleted 9y ago
[deleted]
wongarsu 9y ago
To avoid navigational errors and save civilian lives, and presumably to make everyone depended on US-operated satellites (at least the last one is probably the reason why Russia and the EU both now operate their own system)? Honestly, I struggle to find any reasoning on why GPS is shared with the world beyond "Korean Air Lines 007 crashed, so Pres. Reagan made GPS free to (save the world|gain political capital). Later we removed the civilian precision restriction because that's cheaper than maintaining it", which I find a bit weak. Maybe somebody can enlighten me
- deleted 9y ago
  [deleted]
- lithos 9y ago
  How much value has Google and similar created with GPS. It slowed the need for other countries to put their own up. The satellites were not a secret Their encryption scheme was probably already cracked, so might as well open it anyways.
  - _delirium 9y ago
    It wasn't so much Google. The big players lobbying for the civilian degradation to be turned off in the late 1990s were the airline industry. Within the government, the FAA was also a big advocate, hoping it would be able to retire various other expensive systems if it could count on a reliable GPS.
- mikeash 9y ago
  KAL 007 showed the US government that there were important civilian uses for GPS, and they realized that they could do a lot of good by opening it up. The idea of government is that it lets us do things for the collective good what we would not do for ourselves individually. The US government, for all its faults, does sometimes follow that idea. It's not much different from maintaining the highway system. True, it covers the world, not just the US, but the nature of satellite navigation means that it wouldn't be any cheaper or easier to restrict the system to only work in the US, so why bother?
- 9y ago
samstave 9y ago
How many civilians/commercial vessels threatened by lack of accurate maps of the sea-floor? Zero, that the militaries care about. Subs and other military craft have been mapping, they won't share. How many secret villain lairs in the deep?

They don't share GPS. They share a low-resolution subset of GPS. And they control the satellites and thus have the power to selectively disable it should their enemies decide to rely upon it.

FigBug 9y ago
Selective Availability was turned off in 2000, everybody gets the same GPS signal now. GPS III won't support it, so it won't be able to be turned back on.
- nine_k 9y ago
  GPS can stop working for everyone but the US military at a flip of a switch. Seafloor features will likely last millennia.
  - noir_lord 9y ago
    It can which is why the Russians, the Chinese and the Europeans are all rushing to finish their constellations. Iirc the Chinese are a partner in Galileo (the European program). This is a good thing, hardware will rapidly appear that supports 2 or more of them meaning that either all the partners would simultaneously have to agree to disable theirs or (more unlikely) someone was shooting down the satellites which since that would realistically only happen during a global conflict means I'd have bigger things to worry about at the time.
    - bboreham 9y ago
      > hardware will rapidly appear that supports 2 or more of them Has been out for years. E.g. iPhone 4S supported GPS and GLONASS.
    - kuschku 9y ago
      Sadly, the EU system has a method for the US to shoot it down, as the US said they’d pre-emptively shoot down all satellites we put up unless we build such a backdoor (especially due to the chinese partnership in Galileo). Now we have a system where the chinese stopped being a partner, and the US forced us to add a backdoor and reduce the quality. I’m not sure I can see anything good in this.
      - BrandoElFollito 9y ago
        Would you have any sources for this?
        kuschku 9y ago
        Of course, as it was in all the news, it’s even well-documented on Wikipedia. https://en.wikipedia.org/wiki/Galileo_(satellite_navigation)#Tension_with_the_United_States https://en.wikipedia.org/wiki/Galileo_(satellite_navigation)...
        BrandoElFollito 9y ago
        Thanks but I do not see any mention of a backdoor. A different frequency is not one, it allows for local jamming (which is also possible with GPS) and that's all.
        kuschku 9y ago
        The whole point was to put GALILEO on frequencies that overlap with military BeiDou and military GPS, so that no government could jam civilian GALILEO without jamming their own military tech.
        BrandoElFollito 9y ago
        The whole point of galileo is to have a system which is not dependent on the US and their GPS switch. Jamming is a local action, the US will be able to jzm Gallileo like we are able to jam GPS - again locally. Frequencies can be switched, if we only relied on the fact that they are the same then the US could switch theirs (and have equipment which is compatible if course) and there goes our security. I work in security and have worked for 12 years for a huge provider of telecom systems and hinestly do not see any real advantages to match the frequencies. Also, if we had the same frequency, WE could not jam GPS if we wanted to.
jonknee 9y ago
They share GPS, it used to be low-res but is now the real deal: https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_Positioning_System#Selective_availability https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_...
- zb 9y ago
  The part they share is literally called "Coarse/Acquisition" and the part they don't share is called "Precise". (This has nothing to do with Selective Availability; they're broadcast in two completely different bands.) The GP's characterisation is broadly accurate.

deleted 9y ago

[deleted]

wongarsu 9y ago

To avoid navigational errors and save civilian lives, and presumably to make everyone depended on US-operated satellites (at least the last one is probably the reason why Russia and the EU both now operate their own system)? Honestly, I struggle to find any reasoning on why GPS is shared with the world beyond "Korean Air Lines 007 crashed, so Pres. Reagan made GPS free to (save the world|gain political capital). Later we removed the civilian precision restriction because that's cheaper than maintaining it", which I find a bit weak. Maybe somebody can enlighten me

deleted 9y ago
[deleted]
lithos 9y ago
How much value has Google and similar created with GPS. It slowed the need for other countries to put their own up. The satellites were not a secret Their encryption scheme was probably already cracked, so might as well open it anyways.
- _delirium 9y ago
  It wasn't so much Google. The big players lobbying for the civilian degradation to be turned off in the late 1990s were the airline industry. Within the government, the FAA was also a big advocate, hoping it would be able to retire various other expensive systems if it could count on a reliable GPS.
mikeash 9y ago
KAL 007 showed the US government that there were important civilian uses for GPS, and they realized that they could do a lot of good by opening it up. The idea of government is that it lets us do things for the collective good what we would not do for ourselves individually. The US government, for all its faults, does sometimes follow that idea. It's not much different from maintaining the highway system. True, it covers the world, not just the US, but the nature of satellite navigation means that it wouldn't be any cheaper or easier to restrict the system to only work in the US, so why bother?
9y ago

samstave 9y ago

How many civilians/commercial vessels threatened by lack of accurate maps of the sea-floor? Zero, that the militaries care about. Subs and other military craft have been mapping, they won't share. How many secret villain lairs in the deep?