[gvb]

Well, the requirement for GPS was that they be able to filter out adjacent low power level signals (signals from space).

LightSquared is now arguing that changing the requirement to be able to filter out high power (terrestrial) signals is reasonable, and it is reasonable to retroactively apply that requirement against the millions of existing GPS receivers that were designed to meet a different requirement and thus will have to be discarded.

I would have a lot less heartache over the requirements change if LightSquared would be willing to bear the cost of their proposed change of requirements, rather than forcing me to bear the costs. This means they would need to replace my GPS receivers (a car navigation unit, a boat navigation unit, three cell phones, and an iPad). A quick mental summation is about $2,500, and that is pretty cheap compared to a lot of people out there.

[Czarnian]

You think that's expensive, think of all the military gps units that would need to be replaced. Do you have any idea how much one military-grade gps unit costs? Probably more than all the civilian gps units on your whole block combined. And just about every military vehicle in production has at least one. Aircraft have 2-3. Then there are the commercial gps units in airplanes, which also have redundancy requirements.

There is no chance that LightSquared will get their way. The cost to the military (taxpayers) would be stupendous.

[kronusaturn]

I would assume that part of the reason military units are so expensive is that they already have high quality RF filters for jamming resistance.

[CamperBob]

Such filters would be of no use against deliberate in-band interference.