That won't work. Global Positioning System is currently a promotion for Missile units, of all things (I'm not sure that promotions are worthwhile for one-shot units, but that's what we currently have). The problem is that GPS comes at Communication Networks, which is a late Modern Era tech, and that's the earliest I would put anything GPS-related at. Relativity and Quantum Physics are late Industrial Era. I really don't want to use content from a later era to back up a tech; it feels definitely inelegant and a little unfair (the tech is promising something good, but then the reveal is you have to wait another era to actually get all the necessary techs) and on top of that, tech redundancies will likely kick in as well and render the first technology unnecessary. I'm adding Fission to the prerequisites for Nuclear Power and Advanced Rocketry to cover for the loss of Modern Physics, so anything beyond Adv Rock (including Satellites, Communication Networks, and from there most of the late Modern and Transhuman Eras) won't benefit.