Since we already have GPS why....

Question

Are the Russians building GLONASS, the Europeans building Galileo, the Chinese making Compass, and the Indians proposing IRNSS?

If they are all complimentary to each other, and if GPS is already extremely accurate, are these countries only making their own constellations so that they themselves can have the military benefits of GPS? I would imagine that the U.S hasn't allowed countries like Russia, India and China to use the highly accurate GPS and have instead limited them to the civilian accuracy?

But why the E.U?

Just seems stupid to have like 4 redundancies. I guess having the U.S holding the control to GPS is troublesome for them, but do they really all need to build them?

As I understand it, space is our orbit is limited, and it seems wasteful to fill it with what, 120-150 satellites dedicated to a task that 30 can handle?

Is it fear that if they were in a shooting war with the U.S or one of its allies and relied on GPS for military applications that the Yanks would just restrict them access to the system so that their weapons were ineffective?

Answer 1

Well, "somebody" lost a probe to Mars over an error to do with physical units (distance was it?), so may be there is an issue of TRUST.  

Answer 2

Two reasons really: GPS is a US *military* system that was designed to provide location signals to US military users. The US has had the capability to block the "civilian" signals while still being able to use the "military" signal. There also is the possibility to degrade the "civilian" signals by introducing errors to make them less accurate. Civilian signals allow an accuracy of about 10 meters.

Secondly, GPS was deployed in the 90s and Galileo uses more modern techniques supposedly more accurate and with longer satellite lifetimes.

GPS and Galileo are in low altitude orbits, where there is space enough (unlike the geostationary orbits).

Answer 3

  Each country want a system that they control themselves and are not at the mercy of someone who could shut it down.

Answer 4

People like autonomy.  It's not yet one big happy world.  I doubt the United States will get in a shooting war with Europe, but it's understandable that the European Union would want a navigation system over which they have complete control.  Otherwise it's a matter of negotiation and diplomacy.

The geostationary belt is hotly contested, but GPS satellites do not occupy it.  In fact there are a number of orbital configurations that enable satellite-based positioning, and they are not in danger of filling up anytime soon.