There is / was a working solution to this called LORAN-C that is being phased out. The accuracy isn't all that great (60 ft / 18 metres at best) but can be used

There is / was a working solution to this called LORAN-C that is being phased out. The accuracy isn't all that great (60 ft / 18 metres at best) but can be used to provide a 'disagree' alert to navigation systems. ( https://en.wikipedia.org/wiki/LORAN-C#The_future_of_LORAN https://en.wikipedia.org/wiki/LORAN-C#The_future_of_LORAN )