Ligado and GPS future

[AlleyCat67]

I haven't really followed the issue, but I just came across this article on Ligado's plans for a 5G network that could interfere with GPS:
https://spacenews.com/gps-committee-calls-fcc-ligado-order-a-grave-error/

I know there are lots of engineer types on here who are smarter than I am. Without getting into the politics... how would competing L-band signals likely affect GPS applications for aviation? Is this a significant threat or just a minor nuisance?

 

[Arrow76R]

GPS signals are extremely weak and any strong terrestrial signal in adjacent frequencies can cause GPS loss. That is why the DoD, DHS, and many, many commercial GPS manufacturers and user groups are upset at the FCC allowing Ligado (ne Light Squared) to put up high powered terrestrial cell sites in urban (mostly) areas where there are also many airports that have GPS approaches. The FCC ignored multiple years worth of testing data that showed the impact on GPS and went after the $$ they reaped by "selling" the frequency space. The potential for severe impact is loss of RAIM (receiver autonomous integrity monitoring) for LPV approaches in IMC approaches or just plain terminal use of GPS for situational awareness. Bureaucrats run rampant again...

 

[AlleyCat67]

GPS signals are extremely weak and any strong terrestrial signal in adjacent frequencies can cause GPS loss. That is why the DoD, DHS, and many, many commercial GPS manufacturers and user groups are upset at the FCC allowing Ligado (ne Light Squared) to put up high powered terrestrial cell sites in urban (mostly) areas where there are also many airports that have GPS approaches. The FCC ignored multiple years worth of testing data that showed the impact on GPS and went after the $$ they reaped by "selling" the frequency space. The potential for severe impact is loss of RAIM (receiver autonomous integrity monitoring) for LPV approaches in IMC approaches or just plain terminal use of GPS for situational awareness. Bureaucrats run rampant again...

Interesting. Given that the FCC are political appointees, seems like it's the bureaucrats in the DoD and DHS that are actually fighting to preserve the capability.

 

[N1120A]

This is a situation where bureaucrats may well save us.

 

[Ghery]

I'm sure that the people over on the technical side of the FCC were not in favor of this, but the politicians won. At least for now.

I'd ask someone I know on the technical side, but he undoubtedly would not be able to say anything.

 

[Arrow76R]

Congress is getting into the act now too. They are pushing a bill to make Ligado liable for any retrofit/modifications necessary to existing equipment to mitigate effects of their cell-phone signals. Hopefully this will transcend the incessant squabbling that is the only thing Congress seems to know how to do.