The race to find GPS alternatives

I really don't understand the founding motivation for this company. For one, autonomous vehicles (e.g. Waymo) don't use GNSS as the primary means of localization. You can also achieve centimeter (and higher) precision with RTK. The main source of errors is usually reflections, which are still a problem here. A higher SNR helps, but I'm not sure it helps enough to justify the endeavor.

The problem I see with investing in such technologies:

  1. Satellites are too far to fight anything on ground (Power per unit area (i.e., intensity) decreases as the square of the distance)
  2. If the Satellites are relaying to things on the ground, they are also relaying their location (easy adversarial targets)
  3. In a war (they mention Ukraine in the article), first thing that is toast is these satellites.

I don't think this is the right replacement for GPS. Perhaps someone here can correct me if I am wrong?

How good are accelerometers these days? With a known starting point, map data, a good clock, and accelerometers you should be able to compute your position using dead reckoning.

How did ships navigate 200 years ago? Not sure how accurate it was ?

How about using the stars? ... only at night ?

Use triangulation to known RF transmissions ( ie like direction finding of RF signals )

Geography recognition , rivers mountain's . towns etc ( Lidar ? )

Broadcast this info on some other secret frequency - drones only need to listen to the info

Use radar to track drone and broadcast its position to the item ...

Question please, it says that jamming these is more difficult. But doesn't that mean it's not impossible, so at some point in the future it could happen?