There's not much more going on with a physical layer jammer. That's all this jammer does. It jams the GPS carrier band so that a receiver can't "hear" the satel

There's not much more going on with a physical layer jammer. That's all this jammer does. It jams the GPS carrier band so that a receiver can't "hear" the satellites. You can put together such a jammer from a lab signal generator and a microwave power amplifier that can cover in the GPS band. You may have to tweak the signal generator to get a suitable wide signal. GPS is not a narrow, but a wide-band signal. This helps receivers to reject narrow interference.