Without GPS Satellites Jets cannot navigate usefully, missiles and drones cannot navigate usefully, Cell phones cannot work

 

• Global Positioning Satellites: (GPS) from Wikipedia

It is important to know that all the things said in the title are true. 

If Putin has his way and sets off a nuclear device large enough he likely could disable permanently any GPS satellites belonging the the U.S. in any one area on earth. Because GPS satellites are in Stationary orbits they turn with the earth exactly above the same location on earth in what is called a Geosynchronous orbit where they stay the same place exactly above the same spot on earth all the time.

GPS is accomplished through triangulation between any three GPS Satellites. You need three GPS satellites to establish where anything is on earth. But, they have to be above the location you want the coordinates for. 

GPS satellites were created simply because magnetic north was moving too fast to keep using magnetic north anymore especially for planes and jets. Trying to use magnetic north for navigation because it was moving was causing planes to either crash into each other or the ground or into mountains and the like.

So in the 1970s the U.S. invented GPS satellites to solve this navigational problem.

However, if Putin knocks them out with a large enough nuclear blast in space which causes a gigantic EMP (Electro magnetic Pulse) this destroys all GPS satellites in space in an area the size of the Continental United States.

So, at least in that one corridor the size of the continental United States the U.S. might be vulnerable to attack if other technology isn't also available based somewhere else in space to fix this problem (like on the moon or places like that). 

Note: an EMP does not blow up the Satellites so the satellites still exist. However, what it does do is to basically MELT everything electrical in those satellites so anything electrical will never work again (unless some space man or space woman replaces all the technology or a robot can be trained to do this to repair with entirely new electronic equipment installed in these satellites.

So, I'm thinking if Putin did this all new satellites that are GPS will likely be the easiest way to get GPS to work at least in that area of Space in relation to the ground in an area the size of the Continental U.S. wherever this happened.