[Goose]

Just to put jamming strength into perspective, I'm going to paraphrase what someone else said one time:  Receiving a GPS signal is like watching a light bulb that is 50% further away than the diameter of the earth.

That isn't actually an apt analogy, fortunately :-). The "light bulb" is a source of an incoherent signal spread out (granted unevenly) across the entire spectrum of visible light. The GPS signal operates on a very specific frequency and has a very specific coded structure. The specific frequency allows a narrow processing bandwidth of 2 MHz. The coded structure of the signal supplies 43 dB of "processing gain". That is a factor of 20,000. almost. Without that, GPS would indeed not be very practical.

The document https://www.ieee.li/pdf/viewgraphs/gnss_...entals.pdf even includes the relativistic effects. Like all technological miracles, it is "easy" when many other very smart people have already figured it out :-).

[Goose]

Just to put jamming strength into perspective, I'm going to paraphrase what someone else said one time:  Receiving a GPS signal is like watching a light bulb that is 50% further away than the diameter of the earth.

That isn't actually an apt analogy, fortunately :-). The "light bulb" is a source of an incoherent signal spread out (granted unevenly) across the entire spectrum of visible light. The GPS signal operates on a very specific frequency and has a very specific coded structure. The specific frequency allows a narrow processing bandwidth of 2 MHz. The coded structure of the signal supplies 43 dB of "processing gain". That is a factor of 20,000. almost. Without that, GPS would indeed not be very practical.

The document https://www.ieee.li/pdf/viewgraphs/gnss_...entals.pdf even includes the relativistic effects. Like all technological miracles, it is "easy" when many other very smart people have already figured it out :-).