GPS is really hard to jam or spoof for any extended period or for any large area. Loran is just another radio navigation system and would be just as vulnerable to spoofing and jamming. Loran is not the solution to this problem. The military already have a backup for GPS so this is not for them. This is for commercial shipping in the case of pranksters and malicious actors so that ships will not be put at risk of getting lost. Today people can get a device that can do celestial navigation (with perhaps questionable accuracy) for less than a kilobuck. It also is water proof, contains it's own 12 hour (or better) battery, and fits in a back pocket. Not that long ago this would have been prohibitively expensive. This is a much better solution than Loran unless they have a trick up their sleeve they have not revealed yet. Much of the same can be said for inertial navigation. I remember reading about a proposed device for firefighters and such for navigating inside buildings. They'd get a reference point from GPS or something at the entrance but once inside this thing is supposed to give enough accuracy of location to find doors and hallways in a smoke filled building. This is supposed to handle being bounced down stairs and carried by someone tripping over fallen debris, not bolted to the floor of a ship. On a ship they have effectively unlimited space and power for such a system. That article I read about inertial navigation system for firefighters had to be years ago now, certainly they have improved it since. The assumption with Loran as a backup is that it is of sufficient power to make jamming and spoofing difficult. This can be proven false in the case of state actors and determined pranksters. With a celestial navigation system using a broadcast time signal it may be possible to mess with it using a false time signal. This should be easily dealt with by using multiple time sources (including GPS and internal clock) and ignoring obviously false transmissions. Large deviations in a time signal can be obvious, small deviations perhaps less obvious but also not likely to send a ship wildly off course either. I remember hearing of a demonstration of a common vulnerability in many GPS receivers. What is was is someone transmitted a false GPS satellite signal that indicated a stationary satellite located at the center of the earth, this caused a divide by zero error and crashed some systems. Unless this new Loran is tested sufficiently then how do we know it won't be equally vulnerable? Instead of having these ships buy a new Loran receiver tell them to load a celestial navigation app on their phone and bring it out if GPS fails. No one is going to blow up the sun and moon to put ships off course.