Basically they are trying to exploit a loophole in the system: If you have a satellite transmission network, you are allowed to use terrestrial stations to fill-in the gaps. They are essentially trying to deploy a terrestrial network by defining it as an extension of a fairly minimal satellite network.

All of that is just regulatory issues though. What really matters is interference; I don't (and the FCC doesn't seem to) care if a transmission comes from the ground or a satellite, so long as it doesn't mess with anybody else's services.

The two points of view are:

1) LightSquared is operating within their spectrum requirements, so while there are GPS receivers that will go haywire when they deploy, those GPS receivers are faulty (as they don't properly deal with neighboring transmissions on frequencies outside their band).

2) GPS should be granted a special exception to the rules about accepting interference as GPS is very important and the GPS signals are very weak, so therefore a receiver with little filtering on the front end is far superior to one more tolerant of high power signals on neighboring frequencies.

Both arguments have their merit, so it should be interesting to see how things play out. The more you look into how GPS works, it's a wonder that it works at all which such low powers (and satellites in the middle of a radiation belt, no less!)

Valid points. If I recall correctly, the Obama administration is also pushing for a nationwide wireelss network (http://www.google.com/webhp?hl=en&tab=nw&q=obama%20w...) , and I believe Lightsquared made a pretty good pitch to them to be able to use the spectrum. I also knew a lawyer who was doing work for the FCC, that was examining the possibility of buying back some of the lesser used satellite bands, for both the lightsquared type of work, as well as for mobile carriers.