Does Japan have its own GPS system?

Question

is the American GPS the only civil gps system available?

Answer 1

The GPS system operates from satellites that cover the entire world.  All GPS systems use these same satellites.  It doesn't matter what country you're in, the system is the same.  Other countries may offer their own brand of receivers but they all use the same satellite system.  The only thing you have to worry about is getting the correct maps installed in your GPS if you're using them.  

Other countries have started to launch their own satellites or have a satellite system proposed  but the American system is the only active one.  See the wiki link below.

Answer 2

Japan does not have their own Global Positioning System.  There is the American NAVSTAR system, Russia's partially complete but rejuvenated (with the help of India) GLONASS system, and Europe's Galileo system, which is still launching test satellites.  I also recall something about China announcing their own global positioning system, though I don't know if anything ever happened with that.

Japan does have their own space-based augmentation system, which issues correction info for ionospheric conditions.  Their system is called MSAS; the US has WAAS and Europe has EGNOS.

Answer 3

American military GPS is the only GPS available, period.  The civilian GPS systems simply piggyback on signals that are already coming down from the military GPS satellites.

The Russians, back when they were the Soviet Union, started to launch satellites for their own version of GPS, but the program got cancelled partway through.  

The EU has started launching the satellites for their own, competitor to the American military GPS, but they're launching very slowly, mostly because the US government will allow them to use US rockets for launching.  And the high cost of the program has led to calls in Europe to cancel it, as well.