[Nokinside]

You can make spoofing harder. Most of these spoofing attacks target off-the-self drone GSP, and don't work against adversary who plan against them.

If you want to spoof more expensive gear, like those used in commercial shipping, you do it gradually. You start by transmitting the correct coordinates and then gradually start to increase the difference between correct and false coordinates. When done gradually, IMU can't detect GPS spoofing.

Unfortunately many otherwise good navigation systems are not doing even the bare minimum to detect spoofing. It's not the cost. Spoofing protection has not been priority.

[i_am_proteus]

This has been demonstrated on commercial shipping using the exact technique you described:

https://news.utexas.edu/2013/07/29/ut-austin-researchers-suc...