[ec429]

According to the article, the interference is 86dB above the GPS signal (400mn.×). Wikipedia gives figures of 60-80dB. The LightSquared band is from 50MHz to 16MHz below the GPS L1 band, which as a percentage of 1.5GHz is from 1% to 3%. This is not very far away, and 86dB is a lot. I don't think it's reasonable to expect any equipment to have that kind of selectivity; after all, high-Q filters are not only expensive, they are often also heavy and bulky.

Also there is an upper bound on filter sharpness given by the latency constraints (GPS needs accurate timing, and a brick wall filter has infinite latency) but that bound's probably not even being approached here; I don't have hard data on GPS signal latency requirements nor a simple formula relating rejection to latency.