There are a couple of very interesting articles on GPS spoofing. Not only is it doable [0] but there are some interesting cases that most people don't really think about. Consider that GPS is often used as a timing signal by various financial entities (including stock exchanges). If you override the legitimate GPS signal (not a lot of power required as you'll be much closer to the receiver) and introduce a small deviation into the timing signal you can create some very interesting (and profitable) effects in the stock market. [1]

Even introducing an error into the system can cause disastrous effects [2]

[0] https://arstechnica.com/information-technology/2018/07/a-225...

[1] https://radionavlab.ae.utexas.edu/images/stories/files/paper...

[2] https://blog.themistrading.com/2012/07/could-gps-spoofing-ca...