In this episode, I met Hugo Fruehauf (https://qeprize.org/winners/hugo-fruehauf) , one of the inventors of GPS, the global positioning system underpinning an enormous number of the technologies we rely on today. We dig into how GPS works, and how much of our world depends on it -- from cellphone networks to financial markets and the electric grid....  and the multiple attacks against it by spoofers and jammers.