Jamming doesn't block the signal, it shouts over the signal. So, if your receiver can't hear the jammer, it will be unaffected, even if receivers between you and the satellite can hear the jammer.
IIRC, there exist things for GPS called "null steering antennas" that allow a receiver point a "null" at a jamming source to block it. I believe they're considered controlled munitions by the US government.